WorldWideScience

Sample records for aboveground carbon gain

  1. Annual measurements of gain and loss in aboveground carbon density

    Science.gov (United States)

    Baccini, A.; Walker, W. S.; Carvalho, L.; Farina, M.; Sulla-menashe, D. J.; Houghton, R. A.

    2017-12-01

    Tropical forests hold large stores of carbon, but their net carbon balance is uncertain. Land use and land-cover change (LULCC) are believed to release between 0.81 and 1.14 PgC yr-1, while intact native forests are thought to be a net carbon sink of approximately the same magnitude. Reducing the uncertainty of these estimates is not only fundamental to the advancement of carbon cycle science but is also of increasing relevance to national and international policies designed to reduce emissions from deforestation and forest degradation (e.g., REDD+). Contemporary approaches to estimating the net carbon balance of tropical forests rely on changes in forest area between two periods, typically derived from satellite data, together with information on average biomass density. These approaches tend to capture losses in biomass due to deforestation (i.e., wholesale stand removals) but are limited in their sensitivity to forest degradation (e.g., selective logging or single-tree removals), which can account for additional biomass losses on the order of 47-75% of deforestation. Furthermore, while satellite-based estimates of forest area loss have been used successfully to estimate associated carbon losses, few such analyses have endeavored to determine the rate of carbon sequestration in growing forests. Here we use 12 years (2003-2014) of pantropical satellite data to quantify net annual changes in the aboveground carbon density of woody vegetation (MgC ha-1yr-1), providing direct, measurement-based evidence that the world's tropical forests are a net carbon source of 425.2 ± 92.0 Tg C yr-1. This net release of carbon consists of losses of 861.7 ± 80.2 Tg C yr-1 and gains of -436.5 ± 31.0 Tg C yr-1 . Gains result from forest growth; losses result from reductions in forest area due to deforestation and from reductions in biomass density within standing forests (degradation), with the latter accounting for 68.9% of overall losses. Our findings advance previous research

  2. Tropical forests are a net carbon source based on aboveground measurements of gain and loss

    Science.gov (United States)

    Baccini, A.; Walker, W.; Carvalho, L.; Farina, M.; Sulla-Menashe, D.; Houghton, R. A.

    2017-10-01

    The carbon balance of tropical ecosystems remains uncertain, with top-down atmospheric studies suggesting an overall sink and bottom-up ecological approaches indicating a modest net source. Here we use 12 years (2003 to 2014) of MODIS pantropical satellite data to quantify net annual changes in the aboveground carbon density of tropical woody live vegetation, providing direct, measurement-based evidence that the world’s tropical forests are a net carbon source of 425.2 ± 92.0 teragrams of carbon per year (Tg C year-1). This net release of carbon consists of losses of 861.7 ± 80.2 Tg C year-1 and gains of 436.5 ± 31.0 Tg C year-1. Gains result from forest growth; losses result from deforestation and from reductions in carbon density within standing forests (degradation or disturbance), with the latter accounting for 68.9% of overall losses.

  3. Tropical forests are a net carbon source based on aboveground measurements of gain and loss.

    Science.gov (United States)

    Baccini, A; Walker, W; Carvalho, L; Farina, M; Sulla-Menashe, D; Houghton, R A

    2017-10-13

    The carbon balance of tropical ecosystems remains uncertain, with top-down atmospheric studies suggesting an overall sink and bottom-up ecological approaches indicating a modest net source. Here we use 12 years (2003 to 2014) of MODIS pantropical satellite data to quantify net annual changes in the aboveground carbon density of tropical woody live vegetation, providing direct, measurement-based evidence that the world's tropical forests are a net carbon source of 425.2 ± 92.0 teragrams of carbon per year (Tg C year -1 ). This net release of carbon consists of losses of 861.7 ± 80.2 Tg C year -1 and gains of 436.5 ± 31.0 Tg C year -1 Gains result from forest growth; losses result from deforestation and from reductions in carbon density within standing forests (degradation or disturbance), with the latter accounting for 68.9% of overall losses. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  4. Above-ground tree outside forest (TOF) phytomass and carbon ...

    Indian Academy of Sciences (India)

    to classify TOF, to estimate above-ground TOF phytomass and the carbon content ... eral, trees outside forests (TOF) mean the trees ..... have been used to stratify the area, based on the ... The optimum plot size and num- .... population centres.

  5. Urban warming reduces aboveground carbon storage

    DEFF Research Database (Denmark)

    Meineke, Emily; Youngsteadt, Elsa; Dunn, Robert Roberdeau

    2016-01-01

    sequestration (carbon stored per year) of mature trees. Urban warming increased herbivorous arthropod abundance on trees, but these herbivores had negligible effects on tree carbon sequestration. Instead, urban warming was associated with an estimated 12% loss of carbon sequestration, in part because...... photosynthesis was reduced at hotter sites. Ecosystem service assessments that do not consider urban conditions may overestimate urban tree carbon storage. Because urban and global warming are becoming more intense, our results suggest that urban trees will sequester even less carbon in the future....

  6. Global patterns of aboveground carbon stock and sequestration in mangroves

    Directory of Open Access Journals (Sweden)

    GUSTAVO C.D. ESTRADA

    Full Text Available ABSTRACT In order to contribute to understand the factors that control the provisioning of the ecosystem service of carbon storage by mangroves, data on carbon stock and sequestration in the aboveground biomass (AGB from 73 articles were averaged and tested for the dependence on latitude, climatic parameters, physiographic types and age. Global means of carbon stock (78.0 ± 64.5 tC.ha-1 and sequestration (2.9 ± 2.2 tC.ha-1.yr-1 showed that mangroves are among the forest ecosystems with greater capacity of carbon storage in AGB per area. On the global scale, carbon stock increases toward the equator (R²=0.22 and is dependent on 13 climatic parameters, which can be integrated in the following predictive equation: Carbon Stock in AGB = -16.342 + (8.341 x Isothermality + (0.021 x Annual Precipitation [R²=0.34; p < 0.05]. It was shown that almost 70% of carbon stock variability is explained by age. Carbon stock and sequestration also vary according to physiographic types, indicating the importance of hydroperiod and edaphic parameters to the local variability of carbon stock. By demonstrating the contribution of local and regional-global factors to carbon stock, this study provides information to the forecast of the effects of future climate changes and local anthropogenic forcings on this ecosystem service.

  7. Carbon sequestration rate and aboveground biomass carbon potential of three young species in lower Gangetic plain.

    Science.gov (United States)

    Jana, Bipal K; Biswas, Soumyajit; Majumder, Mrinmoy; Roy, Pankaj K; Mazumdar, Asis

    2011-07-01

    Carbon is sequestered by the plant photosynthesis and stored as biomass in different parts of the tree. Carbon sequestration rate has been measured for young species (6 years age) of Shorea robusta at Chadra forest in Paschim Medinipur district, Albizzia lebbek in Indian Botanic Garden in Howrah district and Artocarpus integrifolia at Banobitan within Kolkata in the lower Gangetic plain of West Bengal in India by Automated Vaisala Made Instrument GMP343 and aboveground biomass carbon has been analyzed by CHN analyzer. The specific objective of this paper is to measure carbon sequestration rate and aboveground biomass carbon potential of three young species of Shorea robusta, Albizzia lebbek and Artocarpus integrifolia. The carbon sequestration rate (mean) from the ambient air during winter season as obtained by Shorea robusta, Albizzia lebbek and Artocarpus integrifolia were 11.13 g/h, 14.86 g/h and 4.22g/h, respectively. The annual carbon sequestration rate from ambient air were estimated at 8.97 t C ha(-1) by Shorea robusta, 11.97 t C ha(-1) by Albizzia lebbek and 3.33 t C ha(-1) by Artocarpus integrifolia. The percentage of carbon content (except root) in the aboveground biomass of Shorea robusta, Albizzia lebbek and Artocarpus integrifolia were 47.45, 47.12 and 43.33, respectively. The total aboveground biomass carbon stock per hectare as estimated for Shorea robusta, Albizzia lebbek and Artocarpus integrifolia were 5.22 t C ha(-1) , 6.26 t C ha(-1) and 7.28 t C ha(-1), respectively in these forest stands.

  8. Future forest aboveground carbon dynamics in the central United States: the importance of forest demographic processes

    Science.gov (United States)

    Wenchi Jin; Hong S. He; Frank R. Thompson; Wen J. Wang; Jacob S. Fraser; Stephen R. Shifley; Brice B. Hanberry; William D. Dijak

    2017-01-01

    The Central Hardwood Forest (CHF) in the United States is currently a major carbon sink, there are uncertainties in how long the current carbon sink will persist and if the CHF will eventually become a carbon source. We used a multi-model ensemble to investigate aboveground carbon density of the CHF from 2010 to 2300 under current climate. Simulations were done using...

  9. Ability of LANDSAT-8 Oli Derived Texture Metrics in Estimating Aboveground Carbon Stocks of Coppice Oak Forests

    Science.gov (United States)

    Safari, A.; Sohrabi, H.

    2016-06-01

    The role of forests as a reservoir for carbon has prompted the need for timely and reliable estimation of aboveground carbon stocks. Since measurement of aboveground carbon stocks of forests is a destructive, costly and time-consuming activity, aerial and satellite remote sensing techniques have gained many attentions in this field. Despite the fact that using aerial data for predicting aboveground carbon stocks has been proved as a highly accurate method, there are challenges related to high acquisition costs, small area coverage, and limited availability of these data. These challenges are more critical for non-commercial forests located in low-income countries. Landsat program provides repetitive acquisition of high-resolution multispectral data, which are freely available. The aim of this study was to assess the potential of multispectral Landsat 8 Operational Land Imager (OLI) derived texture metrics in quantifying aboveground carbon stocks of coppice Oak forests in Zagros Mountains, Iran. We used four different window sizes (3×3, 5×5, 7×7, and 9×9), and four different offsets ([0,1], [1,1], [1,0], and [1,-1]) to derive nine texture metrics (angular second moment, contrast, correlation, dissimilar, entropy, homogeneity, inverse difference, mean, and variance) from four bands (blue, green, red, and infrared). Totally, 124 sample plots in two different forests were measured and carbon was calculated using species-specific allometric models. Stepwise regression analysis was applied to estimate biomass from derived metrics. Results showed that, in general, larger size of window for deriving texture metrics resulted models with better fitting parameters. In addition, the correlation of the spectral bands for deriving texture metrics in regression models was ranked as b4>b3>b2>b5. The best offset was [1,-1]. Amongst the different metrics, mean and entropy were entered in most of the regression models. Overall, different models based on derived texture metrics

  10. Aboveground vs. Belowground Carbon Stocks in African Tropical Lowland Rainforest: Drivers and Implications.

    Directory of Open Access Journals (Sweden)

    Sebastian Doetterl

    Full Text Available African tropical rainforests are one of the most important hotspots to look for changes in the upcoming decades when it comes to C storage and release. The focus of studying C dynamics in these systems lies traditionally on living aboveground biomass. Belowground soil organic carbon stocks have received little attention and estimates of the size, controls and distribution of soil organic carbon stocks are highly uncertain. In our study on lowland rainforest in the central Congo basin, we combine both an assessment of the aboveground C stock with an assessment of the belowground C stock and analyze the latter in terms of functional pools and controlling factors.Our study shows that despite similar vegetation, soil and climatic conditions, soil organic carbon stocks in an area with greater tree height (= larger aboveground carbon stock were only half compared to an area with lower tree height (= smaller aboveground carbon stock. This suggests that substantial variability in the aboveground vs. belowground C allocation strategy and/or C turnover in two similar tropical forest systems can lead to significant differences in total soil organic C content and C fractions with important consequences for the assessment of the total C stock of the system.We suggest nutrient limitation, especially potassium, as the driver for aboveground versus belowground C allocation. However, other drivers such as C turnover, tree functional traits or demographic considerations cannot be excluded. We argue that large and unaccounted variability in C stocks is to be expected in African tropical rain-forests. Currently, these differences in aboveground and belowground C stocks are not adequately verified and implemented mechanistically into Earth System Models. This will, hence, introduce additional uncertainty to models and predictions of the response of C storage of the Congo basin forest to climate change and its contribution to the terrestrial C budget.

  11. Aboveground vs. Belowground Carbon Stocks in African Tropical Lowland Rainforest: Drivers and Implications.

    Science.gov (United States)

    Doetterl, Sebastian; Kearsley, Elizabeth; Bauters, Marijn; Hufkens, Koen; Lisingo, Janvier; Baert, Geert; Verbeeck, Hans; Boeckx, Pascal

    2015-01-01

    African tropical rainforests are one of the most important hotspots to look for changes in the upcoming decades when it comes to C storage and release. The focus of studying C dynamics in these systems lies traditionally on living aboveground biomass. Belowground soil organic carbon stocks have received little attention and estimates of the size, controls and distribution of soil organic carbon stocks are highly uncertain. In our study on lowland rainforest in the central Congo basin, we combine both an assessment of the aboveground C stock with an assessment of the belowground C stock and analyze the latter in terms of functional pools and controlling factors. Our study shows that despite similar vegetation, soil and climatic conditions, soil organic carbon stocks in an area with greater tree height (= larger aboveground carbon stock) were only half compared to an area with lower tree height (= smaller aboveground carbon stock). This suggests that substantial variability in the aboveground vs. belowground C allocation strategy and/or C turnover in two similar tropical forest systems can lead to significant differences in total soil organic C content and C fractions with important consequences for the assessment of the total C stock of the system. We suggest nutrient limitation, especially potassium, as the driver for aboveground versus belowground C allocation. However, other drivers such as C turnover, tree functional traits or demographic considerations cannot be excluded. We argue that large and unaccounted variability in C stocks is to be expected in African tropical rain-forests. Currently, these differences in aboveground and belowground C stocks are not adequately verified and implemented mechanistically into Earth System Models. This will, hence, introduce additional uncertainty to models and predictions of the response of C storage of the Congo basin forest to climate change and its contribution to the terrestrial C budget.

  12. Aboveground tree growth varies with belowground carbon allocation in a tropical rainforest environment

    Science.gov (United States)

    J.W. Raich; D.A. Clark; L. Schwendenmann; Tana Wood

    2014-01-01

    Young secondary forests and plantations in the moist tropics often have rapid rates of biomass accumulation and thus sequester large amounts of carbon. Here, we compare results from mature forest and nearby 15–20 year old tree plantations in lowland Costa Rica to evaluate differences in allocation of carbon to aboveground production and root systems. We found that the...

  13. Quantifying aboveground forest carbon pools and fluxes from repeat LiDAR surveys

    Science.gov (United States)

    Andrew T. Hudak; Eva K. Strand; Lee A. Vierling; John C. Byrne; Jan U. H. Eitel; Sebastian Martinuzzi; Michael J. Falkowski

    2012-01-01

    Sound forest policy and management decisions to mitigate rising atmospheric CO2 depend upon accurate methodologies to quantify forest carbon pools and fluxes over large tracts of land. LiDAR remote sensing is a rapidly evolving technology for quantifying aboveground biomass and thereby carbon pools; however, little work has evaluated the efficacy of repeat LiDAR...

  14. Carbon stock in forest aboveground biomass –comparison based on Landsat data

    Czech Academy of Sciences Publication Activity Database

    Pechanec, V.; Stržínek, F.; Purkyt, Jan; Štěrbová, Lenka; Cudlín, Pavel

    2017-01-01

    Roč. 63, 2-3 (2017), s. 126-132 ISSN 2454-0358 R&D Projects: GA MŠk(CZ) LO1415 Grant - others:EHP,MF ČR(CZ) EHP-CZ02-OV-1-014-2014 Program:CZ02 Institutional support: RVO:67179843 Keywords : aboveground biomass * carbon stock * remote sensing data * vegetation indices * Czech Republic Subject RIV: EH - Ecology, Behaviour OBOR OECD: Environmental sciences (social aspects to be 5.7)

  15. Changes in carbon allocation to aboveground versus belowground forest components is driven by a trade-off involving mycorrhizal fungi, not fine roots

    Science.gov (United States)

    Ouimette, A.; Ollinger, S. V.; Hobbie, E. A.; Lepine, L. C.; Stephens, R.; Rowe, R.; Vadeboncoeur, M. A.; Tumber-Davila, S. J.

    2017-12-01

    Species composition and resource availability exert a strong influence on the dynamics of carbon allocation among different forest ecosystem components. Recent work in temperate forests has highlighted a tradeoff between carbon allocation to aboveground woody tissues (access to light), and belowground to fine roots (access to soil nutrients). Although root-associated mycorrhizal fungi are crucial for N acquisition and can receive 20% or more of annual net primary production, most studies fail to explicitly include carbon allocation to mycorrhizal fungi. In part, this is due to the inherent difficulties in accurately quantifying fungal production. We took several approaches to quantify production of mycorrhizal fungi, including a carbon budget approach and isotopic techniques. Here we present data on patterns of carbon allocation to aboveground (wood and foliar production), and belowground components (production of fine roots and mycorrhizal fungi), across temperate forest stands spanning a range of nitrogen availability and species composition. We found that as the proportion of conifer species decreased, and stand nitrogen availability increased, both the absolute amount and the fraction of net primary production increased for foliage, aboveground wood, and fine roots ("a rising tide lifts all boats"). While allocation to plant pools increased, allocation to mycorrhizal fungi significantly decreased with decreasing conifer dominance and increasing soil nitrogen availability. We did not find a strong trade-off between carbon allocation to fine roots and aboveground wood or foliage. Instead, a negative relationship is seen between allocation to mycorrhizal fungi and other plant pools. Effort to estimate carbon allocation to mycorrhizal fungi is important for gaining a more complete understanding of how ecosystems respond to changes in growth-limiting resources.

  16. Mapping aboveground carbon stocks using LiDAR data in Eucalyptus spp. plantations in the state of Sao Paulo, Brazil

    Science.gov (United States)

    Carlos Alberto Silva; Carine Klauberg; Samuel de Padua Chaves e Carvalho; Andrew T. Hudak; e Luiz Carlos Estraviz. Rodriguez

    2014-01-01

    Fast growing plantation forests provide a low-cost means to sequester carbon for greenhouse gas abatement. The aim of this study was to evaluate airborne LiDAR (Light Detection And Ranging) to predict aboveground carbon (AGC) stocks in Eucalyptus spp. plantations. Biometric parameters (tree height (Ht) and diameter at breast height (DBH)) were collected from...

  17. Effects of thinning on aboveground carbon sequestration by a 45-year-old eastern white pine plantation: A case study

    Science.gov (United States)

    W. Henry McNab

    2012-01-01

    Aboveground carbon sequestration by a 45-year-old plantation of eastern white pines was determined in response to thinning to three levels of residual basal area: (1) Control (no thinning), (2) light thinning to 120 feet2/acre and (3) heavy thinning to 80 feet2/acre. After 11 years carbon stocks were lowest on the heavily...

  18. Dry matter yield and Carbon partitioning in the aboveground part of switchgrass ( panicum virgatum l.) germplasm

    Energy Technology Data Exchange (ETDEWEB)

    Butkutė, B.; Lemežien ė, N.; Cesevičienė, J.; Liaudanskienė, I., E-mail: brone@lzi.lt [Institute of Agriculture, Lithuanian Research Centre for Agriculture and Forestry, Akademija, Kėdainiai distr. (Lithuania)

    2013-07-01

    Carbon (C) accumulated in biomass can be converted into usable forms of energy like methane, bioethanol or solid fuel. Understanding the partitioning of aboveground biomass and C plays an important role in optimizing its pre-treatment technologies. Our objectives were to determine dry matter yield (DMY) and C partitioning in switch grass germplasm. Plants were sampled at heading (HS) and seed filling (SFS) stages. The biomass of the SFS-sampled plants was separated into leaves (blades+sheaths), stems, and panicles. C content was determined by dry combustion. C yield per plant (CY) at HS ranged from 25.9 to 171 g (37.3 g on average for plants in the first harvest year, and 147 for those in the second harvest year), at SFS CY varied within a range of 79.8 ‒ 295g and averaged 119 and 252g depending on the year of growth. DMY was a weighted factor for such results. At SFS, DMY of stems accounted on average for 46.3%, leaves for 40.5%, and panicles for 13.2% of the aboveground biomass of whole plant with respective C concentrations of 462, 439 and 459 g kg -1 DM. (author)

  19. The effect of cassava-based bioethanol production on above-ground carbon stocks: A case study from Southern Mali

    International Nuclear Information System (INIS)

    Vang Rasmussen, Laura; Rasmussen, Kjeld; Birch-Thomsen, Torben; Kristensen, Søren B.P.; Traoré, Oumar

    2012-01-01

    Increasing energy use and the need to mitigate climate change make production of liquid biofuels a high priority. Farmers respond worldwide to this increasing demand by converting forests and grassland into biofuel crops, but whether biofuels offer carbon savings depends on the carbon emissions that occur when land use is changed to biofuel crops. This paper reports the results of a study on cassava-based bioethanol production undertaken in the Sikasso region in Southern Mali. The paper outlines the estimated impacts on above-ground carbon stocks when land use is changed to increase cassava production. The results show that expansion of cassava production for bioethanol will most likely lead to the conversion of fallow areas to cassava. A land use change from fallow to cassava creates a reduction in the above-ground carbon stocks in the order of 4–13 Mg C ha −1 , depending on (a) the age of the fallow, (b) the allometric equation used and (c) whether all trees are removed or the larger, useful trees are preserved. This ‘carbon debt’ associated with the above-ground biomass loss would take 8–25 years to repay if fossil fuels are replaced with cassava-based bioethanol. - Highlights: ► Demands for biofuels make production of cassava-based bioethanol a priority. ► Farmers in Southern Mali are likely to convert fallow areas to cassava production. ► Converting fallow to cassava creates reductions in above-ground carbon stocks. ► Estimates of carbon stock reductions include that farmers preserve useful trees. ► The carbon debt associated with above-ground biomass loss takes 8–25 years to repay.

  20. Estimating Aboveground Biomass and Carbon Stocks in Periurban Andean Secondary Forests Using Very High Resolution Imagery

    Directory of Open Access Journals (Sweden)

    Nicola Clerici

    2016-07-01

    Full Text Available Periurban forests are key to offsetting anthropogenic carbon emissions, but they are under constant threat from urbanization. In particular, secondary Neotropical forest types in Andean periurban areas have a high potential to store carbon, but are currently poorly characterized. To address this lack of information, we developed a method to estimate periurban aboveground biomass (AGB—a proxy for multiple ecosystem services—of secondary Andean forests near Bogotá, Colombia, based on very high resolution (VHR GeoEye-1, Pleiades-1A imagery and field-measured plot data. Specifically, we tested a series of different pre-processing workflows to derive six vegetation indices that were regressed against in situ estimates of AGB. Overall, the coupling of linear models and the Ratio Vegetation Index produced the most satisfactory results. Atmospheric and topographic correction proved to be key in improving model fit, especially in high aerosol and rugged terrain such as the Andes. Methods and findings provide baseline AGB and carbon stock information for little studied periurban Andean secondary forests. The methodological approach can also be used for integrating limited forest monitoring plot AGB data with very high resolution imagery for cost-effective modelling of ecosystem service provision from forests, monitoring reforestation and forest cover change, and for carbon offset assessments.

  1. Observations and modeling of aboveground tree carbon stocks and fluxes following a bark beetle outbreak in the western United States

    Science.gov (United States)

    Eric M. Pfeifer; Jeffrey A. Hicke; Arjan J.H. Meddens

    2011-01-01

    Bark beetle epidemics result in tree mortality across millions of hectares in North America. However, few studies have quantified impacts on carbon (C) cycling. In this study, we quantified the immediate response and subsequent trajectories of stand-level aboveground tree C stocks and fluxes using field measurements and modeling for a location in central Idaho, USA...

  2. Methods and equations for estimating aboveground volume, biomass, and carbon for trees in the U.S. forest inventory, 2010

    Science.gov (United States)

    Christopher W. Woodall; Linda S. Heath; Grant M. Domke; Michael C. Nichols

    2011-01-01

    The U.S. Forest Service, Forest Inventory and Analysis (FIA) program uses numerous models and associated coefficients to estimate aboveground volume, biomass, and carbon for live and standing dead trees for most tree species in forests of the United States. The tree attribute models are coupled with FIA's national inventory of sampled trees to produce estimates of...

  3. Economically important species dominate aboveground carbon storage in forests of southwestern Amazonia

    Directory of Open Access Journals (Sweden)

    N. Galia Selaya

    2017-06-01

    Full Text Available Tree species in tropical forests provide economically important goods and ecosystem services. In submontane forests of southwestern Amazonia, we investigated the degree to which tree species important for subsistence and trade contribute to aboveground carbon storage (AGC. We used 41 1-hectare plots to determine the species abundance, basal area, and AGC of stems > 10 cm diameter at breast height (dbh. Economically important taxa were classified using ethnobotanical studies and according to their stem density. These taxa (n = 263 accounted for 45% of total stems, 53% of total basal area, and 56% of total AGC, significantly more than taxa with minor or unknown uses (Welch test at p 40 cm and few stems in regeneration classes of dbh < 10 to 20 cm (e.g., Bertholletia excelsa, Cariniana spp., Cedrelinga spp., Ceiba spp., Dipteryx spp., whereas dominant Tetragastris spp., and Pseudolmedia spp. had most stems in low diameter classes and a median diameter of < 30 cm. Bertholletia excelsa, with 1.5 stems per hectare, showed the highest basal area of any species and accounted for 9% of AGC (11 Mg/ha, twice that of the second-ranking species. Our study shows that economic importance and carbon stocks in trees are closely linked in southwestern Amazonia. Unplanned harvests can disrupt synergistic dual roles altering carbon stocks temporally or permanently. Precautionary measures based on species ecology, demography, and regeneration traits should be at the forefront of REDD+ to reconcile maximum harvesting limits, biodiversity conservation, and sustainable forest management.

  4. Response of aboveground carbon balance to long-term, experimental shifts in precipitation seasonality is contingent on plant community type in cold-desert rangelands

    Science.gov (United States)

    Reinhardt, K.; McAbee, K.; Germino, M. J.; Bosworth, A.

    2016-12-01

    Semi-arid rangelands have been identified as potential carbon (C) sinks. However, the degree of net C storage or release in water-limited systems is a function of precipitation amount and timing, as well as plant community composition. In northern latitudes of western North America, climate models predict increases in wintertime precipitation and decreases in summertime precipitation. In theory, this should boost C storage in cold-desert ecosystems that have deep-rooted woody plants due to greater wintertime soil water storage that enhances summertime productivity. However, there are few long-term, manipulative field-based studies investigating how shrub- and grass-dominated rangelands will respond to changing precipitation patterns. We measured aboveground C pools and fluxes at leaf, soil, and ecosystem scales over the 2014 growing season on plots that had supplemental precipitation added in either winter or summer for 21 years, in shrub- and exotic-bunchgrass-dominated plots. We hypothesized that increased winter precipitation would stimulate aboveground C uptake and storage relative to ambient conditions, in our cold-desert-adapted plant species. We further hypothesized that long-term gains in aboveground C storage due to precipitation manipulations would be greater in plots containing shrubs. Our hypotheses were generally supported: ecosystem C uptake and long-term biomass accumulation were greater in winter- and summer-irrigated plots compared to control plots in both vegetation communities. However, substantial increases in aboveground biomass occurred only in winter-irrigated plots that contained shrubs. Our findings suggest that increases in winter precipitation will enhance C storage of this widespread ecosystem, provided that the ecosystems have resisted conversion to exotic grassland.

  5. A remote sensing-based model of tidal marsh aboveground carbon stocks for the conterminous United States

    Science.gov (United States)

    Byrd, Kristin B.; Ballanti, Laurel; Thomas, Nathan; Nguyen, Dung; Holmquist, James R.; Simard, Marc; Windham-Myers, Lisamarie

    2018-05-01

    Remote sensing based maps of tidal marshes, both of their extents and carbon stocks, have the potential to play a key role in conducting greenhouse gas inventories and implementing climate mitigation policies. Our objective was to generate a single remote sensing model of tidal marsh aboveground biomass and carbon that represents nationally diverse tidal marshes within the conterminous United States (CONUS). We developed the first calibration-grade, national-scale dataset of aboveground tidal marsh biomass, species composition, and aboveground plant carbon content (%C) from six CONUS regions: Cape Cod, MA, Chesapeake Bay, MD, Everglades, FL, Mississippi Delta, LA, San Francisco Bay, CA, and Puget Sound, WA. Using the random forest machine learning algorithm, we tested whether imagery from multiple sensors, Sentinel-1 C-band synthetic aperture radar, Landsat, and the National Agriculture Imagery Program (NAIP), can improve model performance. The final model, driven by six Landsat vegetation indices and with the soil adjusted vegetation index as the most important (n = 409, RMSE = 310 g/m2, 10.3% normalized RMSE), successfully predicted biomass for a range of marsh plant functional types defined by height, leaf angle and growth form. Model results were improved by scaling field-measured biomass calibration data by NAIP-derived 30 m fraction green vegetation. With a mean plant carbon content of 44.1% (n = 1384, 95% C.I. = 43.99%-44.37%), we generated regional 30 m aboveground carbon density maps for estuarine and palustrine emergent tidal marshes as indicated by a modified NOAA Coastal Change Analysis Program map. We applied a multivariate delta method to calculate uncertainties in regional carbon densities and stocks that considered standard error in map area, mean biomass and mean %C. Louisiana palustrine emergent marshes had the highest C density (2.67 ± 0.004 Mg/ha) of all regions, while San Francisco Bay brackish/saline marshes had the highest C density of all

  6. Identification of fine scale and landscape scale drivers of urban aboveground carbon stocks using high-resolution modeling and mapping.

    Science.gov (United States)

    Mitchell, Matthew G E; Johansen, Kasper; Maron, Martine; McAlpine, Clive A; Wu, Dan; Rhodes, Jonathan R

    2018-05-01

    Urban areas are sources of land use change and CO 2 emissions that contribute to global climate change. Despite this, assessments of urban vegetation carbon stocks often fail to identify important landscape-scale drivers of variation in urban carbon, especially the potential effects of landscape structure variables at different spatial scales. We combined field measurements with Light Detection And Ranging (LiDAR) data to build high-resolution models of woody plant aboveground carbon across the urban portion of Brisbane, Australia, and then identified landscape scale drivers of these carbon stocks. First, we used LiDAR data to quantify the extent and vertical structure of vegetation across the city at high resolution (5×5m). Next, we paired this data with aboveground carbon measurements at 219 sites to create boosted regression tree models and map aboveground carbon across the city. We then used these maps to determine how spatial variation in land cover/land use and landscape structure affects these carbon stocks. Foliage densities above 5m height, tree canopy height, and the presence of ground openings had the strongest relationships with aboveground carbon. Using these fine-scale relationships, we estimate that 2.2±0.4 TgC are stored aboveground in the urban portion of Brisbane, with mean densities of 32.6±5.8MgCha -1 calculated across the entire urban land area, and 110.9±19.7MgCha -1 calculated within treed areas. Predicted carbon densities within treed areas showed strong positive relationships with the proportion of surrounding tree cover and how clumped that tree cover was at both 1km 2 and 1ha resolutions. Our models predict that even dense urban areas with low tree cover can have high carbon densities at fine scales. We conclude that actions and policies aimed at increasing urban carbon should focus on those areas where urban tree cover is most fragmented. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Landscape-scale analysis of aboveground tree carbon stocks affected by mountain pine beetles in Idaho

    International Nuclear Information System (INIS)

    Bright, B C; Hicke, J A; Hudak, A T

    2012-01-01

    Bark beetle outbreaks kill billions of trees in western North America, and the resulting tree mortality can significantly impact local and regional carbon cycling. However, substantial variability in mortality occurs within outbreak areas. Our objective was to quantify landscape-scale effects of beetle infestations on aboveground carbon (AGC) stocks using field observations and remotely sensed data across a 5054 ha study area that had experienced a mountain pine beetle outbreak. Tree mortality was classified using multispectral imagery that separated green, red, and gray trees, and models relating field observations of AGC to LiDAR data were used to map AGC. We combined mortality and AGC maps to quantify AGC in beetle-killed trees. Thirty-nine per cent of the forested area was killed by beetles, with large spatial variability in mortality severity. For the entire study area, 40–50% of AGC was contained in beetle-killed trees. When considered on a per-hectare basis, 75–89% of the study area had >25% AGC in killed trees and 3–6% of the study area had >75% of the AGC in killed trees. Our results show that despite high variability in tree mortality within an outbreak area, bark beetle epidemics can have a large impact on AGC stocks at the landscape scale. (letter)

  8. Aboveground carbon loss in natural and managed tropical forests from 2000 to 2012

    International Nuclear Information System (INIS)

    Tyukavina, A; Hansen, M C; Potapov, P V; Krylov, A M; Turubanova, S; Baccini, A; Houghton, R A; Goetz, S J; Stehman, S V

    2015-01-01

    Tropical forests provide global climate regulation ecosystem services and their clearing is a significant source of anthropogenic greenhouse gas (GHG) emissions and resultant radiative forcing of climate change. However, consensus on pan-tropical forest carbon dynamics is lacking. We present a new estimate that employs recommended good practices to quantify gross tropical forest aboveground carbon (AGC) loss from 2000 to 2012 through the integration of Landsat-derived tree canopy cover, height, intactness and forest cover loss and GLAS-lidar derived forest biomass. An unbiased estimate of forest loss area is produced using a stratified random sample with strata derived from a wall-to-wall 30 m forest cover loss map. Our sample-based results separate the gross loss of forest AGC into losses from natural forests (0.59 PgC yr −1 ) and losses from managed forests (0.43 PgC yr −1 ) including plantations, agroforestry systems and subsistence agriculture. Latin America accounts for 43% of gross AGC loss and 54% of natural forest AGC loss, with Brazil experiencing the highest AGC loss for both categories at national scales. We estimate gross tropical forest AGC loss and natural forest loss to account for 11% and 6% of global year 2012 CO 2 emissions, respectively. Given recent trends, natural forests will likely constitute an increasingly smaller proportion of tropical forest GHG emissions and of global emissions as fossil fuel consumption increases, with implications for the valuation of co-benefits in tropical forest conservation. (letter)

  9. Carbon gains by conservation projects overbalance carbon losses by degradation in China's karst ecoregions

    Science.gov (United States)

    Tong, X.; Yue, Y.; Fensholt, R.; Brandt, M.

    2017-12-01

    China's ecological restoration projects are considered as "mega-engineering" activities and the most ambitious afforestation and conservation projects in human history. The highly sensitive and vulnerable karst ecosystem in Southwest China is one of the largest exposed carbonate rock areas (more than 0.54 million km2) in the world. Accelerating desertification has been reported during the last half century, caused by the increasing intensity of human exploitation of natural resources. As a result, vast karst areas (approximately 0.12 million km2) previously covered by vegetation and soil were turned into a rocky landscape. To combat this severe form of land degradation, more than 19 billion USD have been invested in mitigation initiatives since the end of the 1990s. The costs of mega-engineering as a climate change mitigation measure are however only justified if ecosystem properties can be affected at large scales. Here we study the carbon balance of the karst regions of 8 Chinese provinces over four decades, using optical and passive microwave satellite data, supported by statistical data on project implementations. We find that most areas experiencing losses in aboveground biomass carbon are located in areas with a high standing biomass ( 95 Mg C ha-1), whereas areas with a carbon gain are mostly located in regions with a low standing biomass ( 45 Mg C ha-1). However, the overall gains in carbon stocks overbalance the losses, with an average gross loss of -0.8 Pg C and a gross gain of +2.4 Pg C (1980s to 2016), resulting in a net gain of 1.6 Pg C. Areas of carbon gains are widespread and spatially coherent with conservation projects implemented after 2001, whereas areas of carbon losses show that ongoing degradation is still happening in the western parts of the karst regions. We conclude that the impact of conservation projects on the carbon balance of China's karst ecoregions is remarkable, but biomass carbon losses caused by ongoing degradation can not be

  10. Compatible above-ground biomass equations and carbon stock estimation for small diameter Turkish pine (Pinus brutia Ten.).

    Science.gov (United States)

    Sakici, Oytun Emre; Kucuk, Omer; Ashraf, Muhammad Irfan

    2018-04-15

    Small trees and saplings are important for forest management, carbon stock estimation, ecological modeling, and fire management planning. Turkish pine (Pinus brutia Ten.) is a common coniferous species and comprises 25.1% of total forest area of Turkey. Turkish pine is also important due to its flammable fuel characteristics. In this study, compatible above-ground biomass equations were developed to predict needle, branch, stem wood, and above-ground total biomass, and carbon stock assessment was also described for Turkish pine which is smaller than 8 cm diameter at breast height or shorter than breast height. Compatible biomass equations are useful for biomass prediction of small diameter individuals of Turkish pine. These equations will also be helpful in determining fire behavior characteristics and calculating their carbon stock. Overall, present study will be useful for developing ecological models, forest management plans, silvicultural plans, and fire management plans.

  11. QUANTIFYING FOREST ABOVEGROUND CARBON POOLS AND FLUXES USING MULTI-TEMPORAL LIDAR A report on field monitoring, remote sensing MMV, GIS integration, and modeling results for forestry field validation test to quantify aboveground tree biomass and carbon

    Energy Technology Data Exchange (ETDEWEB)

    Lee Spangler; Lee A. Vierling; Eva K. Stand; Andrew T. Hudak; Jan U.H. Eitel; Sebastian Martinuzzi

    2012-04-01

    Sound policy recommendations relating to the role of forest management in mitigating atmospheric carbon dioxide (CO{sub 2}) depend upon establishing accurate methodologies for quantifying forest carbon pools for large tracts of land that can be dynamically updated over time. Light Detection and Ranging (LiDAR) remote sensing is a promising technology for achieving accurate estimates of aboveground biomass and thereby carbon pools; however, not much is known about the accuracy of estimating biomass change and carbon flux from repeat LiDAR acquisitions containing different data sampling characteristics. In this study, discrete return airborne LiDAR data was collected in 2003 and 2009 across {approx}20,000 hectares (ha) of an actively managed, mixed conifer forest landscape in northern Idaho, USA. Forest inventory plots, established via a random stratified sampling design, were established and sampled in 2003 and 2009. The Random Forest machine learning algorithm was used to establish statistical relationships between inventory data and forest structural metrics derived from the LiDAR acquisitions. Aboveground biomass maps were created for the study area based on statistical relationships developed at the plot level. Over this 6-year period, we found that the mean increase in biomass due to forest growth across the non-harvested portions of the study area was 4.8 metric ton/hectare (Mg/ha). In these non-harvested areas, we found a significant difference in biomass increase among forest successional stages, with a higher biomass increase in mature and old forest compared to stand initiation and young forest. Approximately 20% of the landscape had been disturbed by harvest activities during the six-year time period, representing a biomass loss of >70 Mg/ha in these areas. During the study period, these harvest activities outweighed growth at the landscape scale, resulting in an overall loss in aboveground carbon at this site. The 30-fold increase in sampling density

  12. Tree species diversity promotes aboveground carbon storage through functional diversity and functional dominance.

    Science.gov (United States)

    Mensah, Sylvanus; Veldtman, Ruan; Assogbadjo, Achille E; Glèlè Kakaï, Romain; Seifert, Thomas

    2016-10-01

    The relationship between biodiversity and ecosystem function has increasingly been debated as the cornerstone of the processes behind ecosystem services delivery. Experimental and natural field-based studies have come up with nonconsistent patterns of biodiversity-ecosystem function, supporting either niche complementarity or selection effects hypothesis. Here, we used aboveground carbon (AGC) storage as proxy for ecosystem function in a South African mistbelt forest, and analyzed its relationship with species diversity, through functional diversity and functional dominance. We hypothesized that (1) diversity influences AGC through functional diversity and functional dominance effects; and (2) effects of diversity on AGC would be greater for functional dominance than for functional diversity. Community weight mean (CWM) of functional traits (wood density, specific leaf area, and maximum plant height) were calculated to assess functional dominance (selection effects). As for functional diversity (complementarity effects), multitrait functional diversity indices were computed. The first hypothesis was tested using structural equation modeling. For the second hypothesis, effects of environmental variables such as slope and altitude were tested first, and separate linear mixed-effects models were fitted afterward for functional diversity, functional dominance, and both. Results showed that AGC varied significantly along the slope gradient, with lower values at steeper sites. Species diversity (richness) had positive relationship with AGC, even when slope effects were considered. As predicted, diversity effects on AGC were mediated through functional diversity and functional dominance, suggesting that both the niche complementarity and the selection effects are not exclusively affecting carbon storage. However, the effects were greater for functional diversity than for functional dominance. Furthermore, functional dominance effects were strongly transmitted by CWM of

  13. A forward-looking, national-scale remote sensing-based model of tidal marsh aboveground carbon stocks

    Science.gov (United States)

    Holmquist, J. R.; Byrd, K. B.; Ballanti, L.; Nguyen, D.; Simard, M.; Windham-Myers, L.; Thomas, N.

    2017-12-01

    Remote sensing based maps of tidal marshes, both of their extents and carbon stocks, have the potential to play a key role in conducting greenhouse gas inventories and implementing climate mitigation policies. Our goal was to generate a single remote sensing model of tidal marsh aboveground biomass and carbon that represents nationally diverse tidal marshes within the conterminous United States (CONUS). To meet this objective we developed the first national-scale dataset of aboveground tidal marsh biomass, species composition, and aboveground plant carbon content (%C) from six CONUS regions: Cape Cod, MA, Chesapeake Bay, MD, Everglades, FL, Mississippi Delta, LA, San Francisco Bay, CA, and Puget Sound, WA. Using the random forest algorithm we tested Sentinel-1 radar backscatter metrics and Landsat vegetation indices as predictors of biomass. The final model, driven by six Landsat vegetation indices and with the soil adjusted vegetation index as the most important (n=409, RMSE=310 g/m2, 10.3% normalized RMSE), successfully predicted biomass and carbon for a range of marsh plant functional types defined by height, leaf angle and growth form. Model error was reduced by scaling field measured biomass by Landsat fraction green vegetation derived from object-based classification of National Agriculture Imagery Program imagery. We generated 30m resolution biomass maps for estuarine and palustrine emergent tidal marshes as indicated by a modified NOAA Coastal Change Analysis Program map for each region. With a mean plant %C of 44.1% (n=1384, 95% C.I.=43.99% - 44.37%) we estimated mean aboveground carbon densities (Mg/ha) and total carbon stocks for each wetland type for each region. Louisiana palustrine emergent marshes had the highest C density (2.67 ±0.08 Mg/ha) of all regions, while San Francisco Bay brackish/saline marshes had the highest C density of all estuarine emergent marshes (2.03 ±0.06 Mg/ha). This modeling and data synthesis effort will allow for aboveground

  14. Aboveground Biomass and Carbon in a South African Mistbelt Forest and the Relationships with Tree Species Diversity and Forest Structures

    Directory of Open Access Journals (Sweden)

    Sylvanus Mensah

    2016-04-01

    Full Text Available Biomass and carbon stocks are key information criteria to understand the role of forests in regulating global climate. However, for a bio-rich continent like Africa, ground-based measurements for accurate estimation of carbon are scarce, and the variables affecting the forest carbon are not well understood. Here, we present the first biomass study conducted in South Africa Mistbelt forests. Using data from a non-destructive sampling of 59 trees of four species, we (1 evaluated the accuracy of multispecies aboveground biomass (AGB models, using predictors such as diameter at breast height (DBH, total height (H and wood density; (2 estimated the amount of biomass and carbon stored in the aboveground compartment of Mistbelt forests and (3 explored the variation of aboveground carbon (AGC in relation to tree species diversity and structural variables. We found significant effects of species on wood density and AGB. Among the candidate models, the model that incorporated DBH and H as a compound variable (DBH2 × H was the best fitting. AGB and AGC values were highly variable across all plots, with average values of 358.1 Mg·ha−1 and 179.0 Mg·C·ha−1, respectively. Few species contributed 80% of AGC stock, probably as a result of selection effect. Stand basal area, basal area of the ten most important species and basal area of the largest trees were the most influencing variables. Tree species richness was also positively correlated with AGC, but the basal area of smaller trees was not. These results enable insights into the role of biodiversity in maintaining carbon storage and the possibilities for sustainable strategies for timber harvesting without risk of significant biomass decline.

  15. Linking aboveground net primary productivity to soil carbon and dissolved organic carbon in complex terrain

    Science.gov (United States)

    F.S. Peterson; K. Lajtha

    2013-01-01

    Factors influencing soil organic matter (SOM) stabilization and dissolved organic carbon (DOC) content in complex terrain, where vegetation, climate, and topography vary over the scale of a few meters, are not well understood. We examined the spatial correlations of lidar and geographic information system-derived landscape topography, empirically measured soil...

  16. A remote sensing-based model of tidal marsh aboveground carbon stocks for the conterminous United States

    Science.gov (United States)

    Byrd, Kristin B.; Ballanti, Laurel; Thomas, Nathan; Nguyen, Dung; Holmquist, James R.; Simard, Marc; Windham-Myers, Lisamarie

    2018-01-01

    Remote sensing based maps of tidal marshes, both of their extents and carbon stocks, have the potential to play a key role in conducting greenhouse gas inventories and implementing climate mitigation policies. Our objective was to generate a single remote sensing model of tidal marsh aboveground biomass and carbon that represents nationally diverse tidal marshes within the conterminous United States (CONUS). We developed the first calibration-grade, national-scale dataset of aboveground tidal marsh biomass, species composition, and aboveground plant carbon content (%C) from six CONUS regions: Cape Cod, MA, Chesapeake Bay, MD, Everglades, FL, Mississippi Delta, LA, San Francisco Bay, CA, and Puget Sound, WA. Using the random forest machine learning algorithm, we tested whether imagery from multiple sensors, Sentinel-1 C-band synthetic aperture radar, Landsat, and the National Agriculture Imagery Program (NAIP), can improve model performance. The final model, driven by six Landsat vegetation indices and with the soil adjusted vegetation index as the most important (n = 409, RMSE = 310 g/m2, 10.3% normalized RMSE), successfully predicted biomass for a range of marsh plant functional types defined by height, leaf angle and growth form. Model results were improved by scaling field-measured biomass calibration data by NAIP-derived 30 m fraction green vegetation. With a mean plant carbon content of 44.1% (n = 1384, 95% C.I. = 43.99%–44.37%), we generated regional 30 m aboveground carbon density maps for estuarine and palustrine emergent tidal marshes as indicated by a modified NOAA Coastal Change Analysis Program map. We applied a multivariate delta method to calculate uncertainties in regional carbon densities and stocks that considered standard error in map area, mean biomass and mean %C. Louisiana palustrine emergent marshes had the highest C density (2.67 ± 0.004 Mg/ha) of all regions, while San Francisco Bay brackish/saline marshes had

  17. Examining spectral properties of Landsat 8 OLI for predicting above-ground carbon of Labanan Forest, Berau

    Science.gov (United States)

    Suhardiman, A.; Tampubolon, B. A.; Sumaryono, M.

    2018-04-01

    Many studies revealed significant correlation between satellite image properties and forest data attributes such as stand volume, biomass or carbon stock. However, further study is still relevant due to advancement of remote sensing technology as well as improvement on methods of data analysis. In this study, the properties of three vegetation indices derived from Landsat 8 OLI were tested upon above-ground carbon stock data from 50 circular sample plots (30-meter radius) from ground survey in PT. Inhutani I forest concession in Labanan, Berau, East Kalimantan. Correlation analysis using Pearson method exhibited a promising results when the coefficient of correlation (r-value) was higher than 0.5. Further regression analysis was carried out to develop mathematical model describing the correlation between sample plots data and vegetation index image using various mathematical models.Power and exponential model were demonstrated a good result for all vegetation indices. In order to choose the most adequate mathematical model for predicting Above-ground Carbon (AGC), the Bayesian Information Criterion (BIC) was applied. The lowest BIC value (i.e. -376.41) shown by Transformed Vegetation Index (TVI) indicates this formula, AGC = 9.608*TVI21.54, is the best predictor of AGC of study area.

  18. Seeing the Forest through the Trees: Citizen Scientists Provide Critical Data to Refine Aboveground Carbon Estimates in Restored Riparian Forests

    Science.gov (United States)

    Viers, J. H.

    2013-12-01

    Integrating citizen scientists into ecological informatics research can be difficult due to limited opportunities for meaningful engagement given vast data streams. This is particularly true for analysis of remotely sensed data, which are increasingly being used to quantify ecosystem services over space and time, and to understand how land uses deliver differing values to humans and thus inform choices about future human actions. Carbon storage and sequestration are such ecosystem services, and recent environmental policy advances in California (i.e., AB 32) have resulted in a nascent carbon market that is helping fuel the restoration of riparian forests in agricultural landscapes. Methods to inventory and monitor aboveground carbon for market accounting are increasingly relying on hyperspatial remotely sensed data, particularly the use of light detection and ranging (LiDAR) technologies, to estimate biomass. Because airborne discrete return LiDAR can inexpensively capture vegetation structural differences at high spatial resolution ( 1000 ha), its use is rapidly increasing, resulting in vast stores of point cloud and derived surface raster data. While established algorithms can quantify forest canopy structure efficiently, the highly complex nature of native riparian forests can result in highly uncertain estimates of biomass due to differences in composition (e.g., species richness, age class) and structure (e.g., stem density). This study presents the comparative results of standing carbon estimates refined with field data collected by citizen scientists at three different sites, each capturing a range of agricultural, remnant forest, and restored forest cover types. These citizen science data resolve uncertainty in composition and structure, and improve allometric scaling models of biomass and thus estimates of aboveground carbon. Results indicate that agricultural land and horticulturally restored riparian forests store similar amounts of aboveground carbon

  19. Stand restoration burning in oak-pine forests in the southern Applachians: effects on aboveground biomass and carbon and nitrogen cycling

    Science.gov (United States)

    Robert M. Hubbard; James M. Vose; Barton D. Clinton; Katherine J. Elliott; Jennifer D. Knoepp

    2004-01-01

    Understory prescribed burning is being suggested as a viable management tool for restoring degraded oak–pine forest communities in the southern Appalachians yet information is lacking on how this will affect ecosystem processes. Our objectives in this study were to evaluate the watershed scale effects of understory burning on total aboveground biomass, and the carbon...

  20. Partitioning Uncertainty In Aboveground Carbon Density Estimates: Relative Contributions From Lidar and Forest Inventory In The Brazilian Amazon.

    Science.gov (United States)

    Duffy, P.; Keller, M. M.; Morton, D. C.

    2016-12-01

    Carbon accounting for REDD+ requires knowledge of deforestation, degradation, and associated changes in forest carbon stocks. Degradation is more difficult to detect than deforestation so SilvaCarbon, an US inter-agency effort, has set a priority to better characterize forest degradation effects on carbon loss. By combining information from forest inventory and lidar data products, impacts of deforestation, degradation, and associated changes in forest carbon stocks can be more accurately characterized across space. Our approach employs a hierarchical Bayesian modeling (HBM) framework where the assimilation of information from multiple sources is accomplished using a change of support (COS) technique. The COS formulation allows data from multiple spatial resolutions to be assimilated into an intermediate resolution. This approach is being applied in Paragominas, a jurisdiction in the eastern Brazilian Amazon with a high proportion of logged and burned degraded forests where political change has opened the way for REDD+. We build on a long history of research including our extensive studies of logging damage. Our primary objective is to quantify above-ground carbon stocks and corresponding uncertainty in a spatially explicit manner. A secondary objective is to quantify the relative contribution of lower level data products to the overall uncertainty, allowing for more focused subsequent data collection in the context of uncertainty reduction. This approach provides a mechanism to assimilate information from multiple sources to produce spatially-explicit maps of carbon stocks and changes with corresponding spatially explicit maps of uncertainty. Importantly, this approach also provides a mechanism that can be used to assess the value of information from specific data products.

  1. National-scale estimation of gross forest aboveground carbon loss: a case study of the Democratic Republic of the Congo

    International Nuclear Information System (INIS)

    Tyukavina, A; Potapov, P V; Turubanova, S A; Hansen, M C; Stehman, S V; Baccini, A; Goetz, S J; Laporte, N T; Houghton, R A

    2013-01-01

    Recent advances in remote sensing enable the mapping and monitoring of carbon stocks without relying on extensive in situ measurements. The Democratic Republic of the Congo (DRC) is among the countries where national forest inventories (NFI) are either non-existent or out of date. Here we demonstrate a method for estimating national-scale gross forest aboveground carbon (AGC) loss and associated uncertainties using remotely sensed-derived forest cover loss and biomass carbon density data. Lidar data were used as a surrogate for NFI plot measurements to estimate carbon stocks and AGC loss based on forest type and activity data derived using time-series multispectral imagery. Specifically, DRC forest type and loss from the FACET (Forêts d’Afrique Centrale Evaluées par Télédétection) product, created using Landsat data, were related to carbon data derived from the Geoscience Laser Altimeter System (GLAS). Validation data for FACET forest area loss were created at a 30-m spatial resolution and compared to the 60-m spatial resolution FACET map. We produced two gross AGC loss estimates for the DRC for the last decade (2000–2010): a map-scale estimate (53.3 ± 9.8 Tg C yr −1 ) accounting for whole-pixel classification errors in the 60-m resolution FACET forest cover change product, and a sub-grid estimate (72.1 ± 12.7 Tg C yr −1 ) that took into account 60-m cells that experienced partial forest loss. Our sub-grid forest cover and AGC loss estimates, which included smaller-scale forest disturbances, exceed published assessments. Results raise the issue of scale in forest cover change mapping and validation, and subsequent impacts on remotely sensed carbon stock change estimation, particularly for smallholder dominated systems such as the DRC. (letter)

  2. Using basal area to estimate aboveground carbon stocks in forests: La Primavera Biosphere's Reserve, Mexico

    NARCIS (Netherlands)

    Balderas Torres, Arturo; Lovett, Jonathan Cranidge

    2012-01-01

    Increasing use of woody plants for greenhouse gas mitigation has led to demand for rapid, cost-effective estimation of forest carbon stocks. Bole diameter is readily measured and basal area can be correlated to biomass and carbon through application of allometric equations. We explore different

  3. Predicting Impacts of Climate Change on the Aboveground Carbon Sequestration Rate of a Temperate Forest in Northeastern China

    Science.gov (United States)

    Ma, Jun; Hu, Yuanman; Bu, Rencang; Chang, Yu; Deng, Huawei; Qin, Qin

    2014-01-01

    The aboveground carbon sequestration rate (ACSR) reflects the influence of climate change on forest dynamics. To reveal the long-term effects of climate change on forest succession and carbon sequestration, a forest landscape succession and disturbance model (LANDIS Pro7.0) was used to simulate the ACSR of a temperate forest at the community and species levels in northeastern China based on both current and predicted climatic data. On the community level, the ACSR of mixed Korean pine hardwood forests and mixed larch hardwood forests, fluctuated during the entire simulation, while a large decline of ACSR emerged in interim of simulation in spruce-fir forest and aspen-white birch forests, respectively. On the species level, the ACSR of all conifers declined greatly around 2070s except for Korean pine. The ACSR of dominant hardwoods in the Lesser Khingan Mountains area, such as Manchurian ash, Amur cork, black elm, and ribbed birch fluctuated with broad ranges, respectively. Pioneer species experienced a sharp decline around 2080s, and they would finally disappear in the simulation. The differences of the ACSR among various climates were mainly identified in mixed Korean pine hardwood forests, in all conifers, and in a few hardwoods in the last quarter of simulation. These results indicate that climate warming can influence the ACSR in the Lesser Khingan Mountains area, and the largest impact commonly emerged in the A2 scenario. The ACSR of coniferous species experienced higher impact by climate change than that of deciduous species. PMID:24763409

  4. Predicting impacts of climate change on the aboveground carbon sequestration rate of a temperate forest in northeastern China.

    Science.gov (United States)

    Ma, Jun; Hu, Yuanman; Bu, Rencang; Chang, Yu; Deng, Huawei; Qin, Qin

    2014-01-01

    The aboveground carbon sequestration rate (ACSR) reflects the influence of climate change on forest dynamics. To reveal the long-term effects of climate change on forest succession and carbon sequestration, a forest landscape succession and disturbance model (LANDIS Pro7.0) was used to simulate the ACSR of a temperate forest at the community and species levels in northeastern China based on both current and predicted climatic data. On the community level, the ACSR of mixed Korean pine hardwood forests and mixed larch hardwood forests, fluctuated during the entire simulation, while a large decline of ACSR emerged in interim of simulation in spruce-fir forest and aspen-white birch forests, respectively. On the species level, the ACSR of all conifers declined greatly around 2070s except for Korean pine. The ACSR of dominant hardwoods in the Lesser Khingan Mountains area, such as Manchurian ash, Amur cork, black elm, and ribbed birch fluctuated with broad ranges, respectively. Pioneer species experienced a sharp decline around 2080s, and they would finally disappear in the simulation. The differences of the ACSR among various climates were mainly identified in mixed Korean pine hardwood forests, in all conifers, and in a few hardwoods in the last quarter of simulation. These results indicate that climate warming can influence the ACSR in the Lesser Khingan Mountains area, and the largest impact commonly emerged in the A2 scenario. The ACSR of coniferous species experienced higher impact by climate change than that of deciduous species.

  5. Predicting impacts of climate change on the aboveground carbon sequestration rate of a temperate forest in northeastern China.

    Directory of Open Access Journals (Sweden)

    Jun Ma

    Full Text Available The aboveground carbon sequestration rate (ACSR reflects the influence of climate change on forest dynamics. To reveal the long-term effects of climate change on forest succession and carbon sequestration, a forest landscape succession and disturbance model (LANDIS Pro7.0 was used to simulate the ACSR of a temperate forest at the community and species levels in northeastern China based on both current and predicted climatic data. On the community level, the ACSR of mixed Korean pine hardwood forests and mixed larch hardwood forests, fluctuated during the entire simulation, while a large decline of ACSR emerged in interim of simulation in spruce-fir forest and aspen-white birch forests, respectively. On the species level, the ACSR of all conifers declined greatly around 2070s except for Korean pine. The ACSR of dominant hardwoods in the Lesser Khingan Mountains area, such as Manchurian ash, Amur cork, black elm, and ribbed birch fluctuated with broad ranges, respectively. Pioneer species experienced a sharp decline around 2080s, and they would finally disappear in the simulation. The differences of the ACSR among various climates were mainly identified in mixed Korean pine hardwood forests, in all conifers, and in a few hardwoods in the last quarter of simulation. These results indicate that climate warming can influence the ACSR in the Lesser Khingan Mountains area, and the largest impact commonly emerged in the A2 scenario. The ACSR of coniferous species experienced higher impact by climate change than that of deciduous species.

  6. Aboveground stock of biomass and organic carbon in stands of Pinus taeda L.

    Directory of Open Access Journals (Sweden)

    Luciano Farinha Watzlawick

    2013-09-01

    Full Text Available This study aimed to estimate biomass and organic carbon in stands of Pinus taeda L. at different ages (14, 16, 19, 21, 22, 23 and 32 years and located in the municipality of General Carneiro (PR. In order to estimate biomass and organic carbon in different tree components (needles, live branches, dead branches, bark and stem wood, the destructive quantification method was used in which seven trees from each age category were randomly sampled across the stand. Stocks of biomass and organic carbon were found to vary between the different age categories, mainly as a result of existing dissimilarities between ages in association with forest management practices such as thinning, pruning and tree density per hectare.

  7. [Tree above-ground biomass allometries for carbon stocks estimation in the Caribbean mangroves in Colombia].

    Science.gov (United States)

    Yepes, Adriana; Zapata, Mauricio; Bolivar, Jhoanata; Monsalve, Alejandra; Espinosa, Sandra Milena; Sierra-Correa, Paula Cristina; Sierra, Andrés

    2016-06-01

    The distribution of carbon in “Blue Carbon” ecosystems such as mangroves is little known, when compared with the highly known terrestrial forests, despite its particular and recognized high productivity and carbon storage capacity. The objective of this study was to analyze the above ground biomass (AGB) of the species Rhizophora mangle and Avicennia germinans from the Marine Protected Area of Distrito de Manejo Integrado (DMI), Cispatá-Tinajones-La Balsa, Caribbean Colombian coast. With official authorization, we harvested and studied 30 individuals of each species, and built allometric models in order to estimate AGB. Our AGB results indicated that the studied mangrove forests of the DMI Colombian Caribbean was of 129.69 ± 20.24 Mg/ha, equivalent to 64.85 ± 10.12 MgC/ha. The DMI has an area of 8 570.9 ha in mangrove forests, and we estimated that the total carbon potential stored was about 555 795.93 Mg C. The equations generated in this study can be considered as an alternative for the assessment of carbon stocks in AGB of mangrove forests in Colombia; as other available AGB allometric models do not discriminate mangrove forests, despite being particular ecosystems. They can be used for analysis at a more detailed scale and are considered useful to determine the carbon storage potential of mangrove forests, as a country alternative to support forest conservation and emission reduction strategies. In general, the potential of carbon storage from Colombian Caribbean mangrove forests is important and could promote the country leadership of the “blue carbon” stored.

  8. Consequences of long-term severe industrial pollution for aboveground carbon and nitrogen pools in northern taiga forests at local and regional scales.

    Science.gov (United States)

    Manninen, Sirkku; Zverev, Vitali; Bergman, Igor; Kozlov, Mikhail V

    2015-12-01

    Boreal coniferous forests act as an important sink for atmospheric carbon dioxide. The overall tree carbon (C) sink in the forests of Europe has increased during the past decades, especially due to management and elevated nitrogen (N) deposition; however, industrial atmospheric pollution, primarily sulphur dioxide and heavy metals, still negatively affect forest biomass production at different spatial scales. We report local and regional changes in forest aboveground biomass, C and N concentrations in plant tissues, and C and N pools caused by long-term atmospheric emissions from a large point source, the nickel-copper smelter in Monchegorsk, in north-western Russia. An increase in pollution load (assessed as Cu concentration in forest litter) caused C to increase in foliage but C remained unchanged in wood, while N decreased in foliage and increased in wood, demonstrating strong effects of pollution on resource translocation between green and woody tissues. The aboveground C and N pools were primarily governed by plant biomass, which strongly decreased with an increase in pollution load. In our study sites (located 1.6-39.7 km from the smelter) living aboveground plant biomass was 76 to 4888 gm(-2), and C and N pools ranged 35-2333 g C m(-2) and 0.5-35.1 g N m(-2), respectively. We estimate that the aboveground plant biomass is reduced due to chronic exposure to industrial air pollution over an area of about 107,200 km2, and the total (aboveground and belowground) loss of phytomass C stock amounts to 4.24×10(13) g C. Our results emphasize the need to account for the overall impact of industrial polluters on ecosystem C and N pools when assessing the C and N dynamics in northern boreal forests because of the marked long-term negative effects of their emissions on structure and productivity of plant communities. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. [Influence of fire disturbance on aboveground deadwood debris carbon storage in Huzhong forest region of Great Xing'an Mountains, Northeast China].

    Science.gov (United States)

    Yang, Da; He, Hong-shi; Wu, Zhi-wei; Liang, Yu; Huang, Chao; Luo, Xu; Xiao, Jiang-tao; Zhang, Qing-long

    2015-02-01

    Based on the field inventory data, the aboveground deadwood debris carbon storage under different fire severities was analyzed in Huzhong forest region of Great Xing' an Mountains. The results showed that the fire severity had a significant effect on aboveground deadwood debris carbon storage. The deadwood debris carbon storage was in the order of high-severity > low-severity > unburned in Larix gmelinii stands, and mixed conifer-broadleaf stands ( L. gmelinii and Betula platyphylla), and in the order of high severity > unburned > low-severity in B. platyphylla stands. Fire disturbance significantly changed the component percentage of the deadwood debris carbon storage. The component percentage of snags increased and litter decreased with the increasing fire severity. Logs and stumps did not change significantly with the increasing fire severity. The spatial variation of deadwood debris carbon storage in forests burned with low-severity fire was higher than that in unburned forests. The spatial variation of deadwood debris carbon storage with high-severity fires was lowest. This spatial variation needed to be accounted when calculating forest deadwood debris carbon storage.

  10. Complex mountain terrain and disturbance history drive variation in forest aboveground live carbon density in the western Oregon Cascades, USA

    Science.gov (United States)

    Zald, Harold S.J.; Spies, Thomas A.; Seidl, Rupert; Pabst, Robert J.; Olsen, Keith A.; Steel, E. Ashley

    2016-01-01

    Forest carbon (C) density varies tremendously across space due to the inherent heterogeneity of forest ecosystems. Variation of forest C density is especially pronounced in mountainous terrain, where environmental gradients are compressed and vary at multiple spatial scales. Additionally, the influence of environmental gradients may vary with forest age and developmental stage, an important consideration as forest landscapes often have a diversity of stand ages from past management and other disturbance agents. Quantifying forest C density and its underlying environmental determinants in mountain terrain has remained challenging because many available data sources lack the spatial grain and ecological resolution needed at both stand and landscape scales. The objective of this study was to determine if environmental factors influencing aboveground live carbon (ALC) density differed between young versus old forests. We integrated aerial light detection and ranging (lidar) data with 702 field plots to map forest ALC density at a grain of 25 m across the H.J. Andrews Experimental Forest, a 6369 ha watershed in the Cascade Mountains of Oregon, USA. We used linear regressions, random forest ensemble learning (RF) and sequential autoregressive modeling (SAR) to reveal how mapped forest ALC density was related to climate, topography, soils, and past disturbance history (timber harvesting and wildfires). ALC increased with stand age in young managed forests, with much greater variation of ALC in relation to years since wildfire in old unmanaged forests. Timber harvesting was the most important driver of ALC across the entire watershed, despite occurring on only 23% of the landscape. More variation in forest ALC density was explained in models of young managed forests than in models of old unmanaged forests. Besides stand age, ALC density in young managed forests was driven by factors influencing site productivity, whereas variation in ALC density in old unmanaged forests

  11. Measuring and modelling above-ground carbon and tree allometry along a tropical elevation gradient

    DEFF Research Database (Denmark)

    Marshall, A.R.; Willcock, S.; Platts, P.J.

    2012-01-01

    of physical, climatic and edaphic predictors of AGC and tree stature. AGC estimates using stem diameter, height and wood density, gave a mean value of 174.6 t ha−1, compared with 229.6 t ha−1 when height was excluded. Regression models revealed that stems were tallest for a given diameter at mid......:benefit of different measurements and recommend a tiered approach to AGC monitoring, depending on available resources. AGC assessments in African forests could exclude small stems, but should aim to record disturbance, topography and species. Stem height is vital for AGC estimation and valuation; when excluding height...... our 55 t ha−1 over-estimation of AGC would have over-valued the carbon resource by 24% (US$3300 ha−1)....

  12. Ecosystem carbon partitioning: aboveground net primary productivity correlates with the root carbon input in different land use types of Southern Alps

    Science.gov (United States)

    Rodeghiero, Mirco; Martinez, Cristina; Gianelle, Damiano; Camin, Federica; Zanotelli, Damiano; Magnani, Federico

    2013-04-01

    Terrestrial plant carbon partitioning to above- and below-ground compartments can be better understood by integrating studies on biomass allocation and estimates of root carbon input based on the use of stable isotopes. These experiments are essential to model ecosystem's metabolism and predict the effects of global change on carbon cycling. Using in-growth soil cores in conjunction with the 13C natural abundance method we quantified net plant-derived root carbon input into the soil, which has been pointed out as the main unaccounted NPP (net primary productivity) component. Four land use types located in the Trentino Region (northern Italy) and representing a range of aboveground net primary productivity (ANPP) values (155-868 gC m-2 y-1) were investigated: conifer forest, apple orchard, vineyard and grassland. Cores, filled with soil of a known C4 isotopic signature were inserted at 18 sampling points for each site and left in place for twelve months. After extraction, cores were analysed for %C and d13C, which were used to calculate the proportion of new plant-derived root C input by applying a mass balance equation. The GPP (gross primary productivity) of each ecosystem was determined by the eddy covariance technique whereas ANPP was quantified with a repeated inventory approach. We found a strong and significant relationship (R2 = 0.93; p=0.03) between ANPP and the fraction of GPP transferred to the soil as root C input across the investigated sites. This percentage varied between 10 and 25% of GPP with the grassland having the lowest value and the apple orchard the highest. Mechanistic ecosystem carbon balance models could benefit from this general relationship since ANPP is routinely and easily measured at many sites. This result also suggests that by quantifying site-specific ANPP, root carbon input can be reliably estimated, as opposed to using arbitrary root/shoot ratios which may under- or over-estimate C partitioning.

  13. Above-ground woody carbon sequestration measured from tree rings is coherent with net ecosystem productivity at five eddy-covariance sites.

    Science.gov (United States)

    Babst, Flurin; Bouriaud, Olivier; Papale, Dario; Gielen, Bert; Janssens, Ivan A; Nikinmaa, Eero; Ibrom, Andreas; Wu, Jian; Bernhofer, Christian; Köstner, Barbara; Grünwald, Thomas; Seufert, Günther; Ciais, Philippe; Frank, David

    2014-03-01

    • Attempts to combine biometric and eddy-covariance (EC) quantifications of carbon allocation to different storage pools in forests have been inconsistent and variably successful in the past. • We assessed above-ground biomass changes at five long-term EC forest stations based on tree-ring width and wood density measurements, together with multiple allometric models. Measurements were validated with site-specific biomass estimates and compared with the sum of monthly CO₂ fluxes between 1997 and 2009. • Biometric measurements and seasonal net ecosystem productivity (NEP) proved largely compatible and suggested that carbon sequestered between January and July is mainly used for volume increase, whereas that taken up between August and September supports a combination of cell wall thickening and storage. The inter-annual variability in above-ground woody carbon uptake was significantly linked with wood production at the sites, ranging between 110 and 370 g C m(-2) yr(-1) , thereby accounting for 10-25% of gross primary productivity (GPP), 15-32% of terrestrial ecosystem respiration (TER) and 25-80% of NEP. • The observed seasonal partitioning of carbon used to support different wood formation processes refines our knowledge on the dynamics and magnitude of carbon allocation in forests across the major European climatic zones. It may thus contribute, for example, to improved vegetation model parameterization and provides an enhanced framework to link tree-ring parameters with EC measurements. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  14. Improving estimation of tree carbon stocks by harvesting aboveground woody biomass within airborne LiDAR flight areas

    Science.gov (United States)

    Colgan, M.; Asner, G. P.; Swemmer, A. M.

    2011-12-01

    The accurate estimation of carbon stored in a tree is essential to accounting for the carbon emissions due to deforestation and degradation. Airborne LiDAR (Light Detection and Ranging) has been successful in estimating aboveground carbon density (ACD) by correlating airborne metrics, such as canopy height, to field-estimated biomass. This latter step is reliant on field allometry which is applied to forest inventory quantities, such as stem diameter and height, to predict the biomass of a given tree stem. Constructing such allometry is expensive, time consuming, and requires destructive sampling. Consequently, the sample sizes used to construct such allometry are often small, and the largest tree sampled is often much smaller than the largest in the forest population. The uncertainty resulting from these sampling errors can lead to severe biases when the allometry is applied to stems larger than those harvested to construct the allometry, which is then subsequently propagated to airborne ACD estimates. The Kruger National Park (KNP) mission of maintaining biodiversity coincides with preserving ecosystem carbon stocks. However, one hurdle to accurately quantifying carbon density in savannas is that small stems are typically harvested to construct woody biomass allometry, yet they are not representative of Kruger's distribution of biomass. Consequently, these equations inadequately capture large tree variation in sapwood/hardwood composition, root/shoot/leaf allocation, branch fall, and stem rot. This study eliminates the "middleman" of field allometry by directly measuring, or harvesting, tree biomass within the extent of airborne LiDAR. This enables comparisons of field and airborne ACD estimates, and also enables creation of new airborne algorithms to estimate biomass at the scale of individual trees. A field campaign was conducted at Pompey Silica Mine 5km outside Kruger National Park, South Africa, in Mar-Aug 2010 to harvest and weigh tree mass. Since

  15. Spatial Distribution of Aboveground Carbon Stock of the Arboreal Vegetation in Brazilian Biomes of Savanna, Atlantic Forest and Semi-Arid Woodland.

    Science.gov (United States)

    Scolforo, Henrique Ferraco; Scolforo, Jose Roberto Soares; Mello, Carlos Rogerio; Mello, Jose Marcio; Ferraz Filho, Antonio Carlos

    2015-01-01

    The objective of this study was to map the spatial distribution of aboveground carbon stock (using Regression-kriging) of arboreal plants in the Atlantic Forest, Semi-arid woodland, and Savanna Biomes in Minas Gerais State, southeastern Brazil. The database used in this study was obtained from 163 forest fragments, totaling 4,146 plots of 1,000 m2 distributed in these Biomes. A geographical model for carbon stock estimation was parameterized as a function of Biome, latitude and altitude. This model was applied over the samples and the residuals generated were mapped based on geostatistical procedures, selecting the exponential semivariogram theoretical model for conducting ordinary Kriging. The aboveground carbon stock was found to have a greater concentration in the north of the State, where the largest contingent of native vegetation is located, mainly the Savanna Biome, with Wooded Savanna and Shrub Savanna phytophysiognomes. The largest weighted averages of carbon stock per hectare were found in the south-center region (48.6 Mg/ha) and in the southern part of the eastern region (48.4 Mg/ha) of Minas Gerais State, due to the greatest predominance of Atlantic Forest Biome forest fragments. The smallest weighted averages per hectare were found in the central (21.2 Mg/ha), northern (20.4 Mg/ha), and northwestern (20.7 Mg/ha) regions of Minas Gerais State, where Savanna Biome fragments are predominant, in the phytophysiognomes Wooded Savanna and Shrub Savanna.

  16. Mixed-species allometric equations and estimation of aboveground biomass and carbon stocks in restoring degraded landscape in northern Ethiopia

    Science.gov (United States)

    Mokria, Mulugeta; Mekuria, Wolde; Gebrekirstos, Aster; Aynekulu, Ermias; Belay, Beyene; Gashaw, Tadesse; Bräuning, Achim

    2018-02-01

    Accurate biomass estimation is critical to quantify the changes in biomass and carbon stocks following the restoration of degraded landscapes. However, there is lack of site-specific allometric equations for the estimation of aboveground biomass (AGB), which consequently limits our understanding of the contributions of restoration efforts in mitigating climate change. This study was conducted in northwestern Ethiopia to develop a multi-species allometric equation and investigate the spatial and temporal variation of C-stocks following the restoration of degraded landscapes. We harvested and weighed 84 trees from eleven dominant species from six grazing exclosures and adjacent communal grazing land. We observed that AGB correlates significantly with diameter at stump height D 30 (R 2 = 0.78 P < 0.01), and tree height H (R 2 = 0.41, P < 0.05). Our best model, which includes D 30 and H as predictors explained 82% of the variations in AGB. This model produced the lowest bias with narrow ranges of errors across different diameter classes. Estimated C-stock showed a significant positive correlation with stem density (R 2 = 0.80, P < 0.01) and basal area (R 2 = 0.84, P < 0.01). At the watershed level, the mean C-stock was 3.8 (±0.5) Mg C ha-1. Plot-level C-stocks varied between 0.1 and 13.7 Mg C ha-1. Estimated C-stocks in three- and seven-year-old exclosures exceeded estimated C-stock in the communal grazing land by 50%. The species that contribute most to C-stocks were Leucaena sp. (28%), Calpurnia aurea (21%), Euclea racemosa (20.9%), and Dodonaea angustifolia (15.8%). The equations developed in this study allow monitoring changes in C-stocks and C-sequestration following the implementation of restoration practices in northern Ethiopia over space and time. The estimated C-stocks can be used as a reference against which future changes in C-stocks can be compared.

  17. Measurement of population inversions and gain in carbon fiber plasmas

    International Nuclear Information System (INIS)

    Milchberg, H.; Skinner, C.H.; Suckewer, S.; Voorhees, D.

    1985-10-01

    A CO 2 laser (approx.0.5 kJ energy, 70 nsec pulse width) was focussed onto the end of an axially oriented, thick (35 to 350 μ) carbon fiber with or without a magnetic field present along the laser-fiber axis. We present evidence for axial-to-transverse enhancement of the CVI 182A (n = 3 → 2) transition, which is correlated with the appearance of a population inversion between levels n = 3 and 2. For the B = 0 kG, zero field case, the maximum gain-length product of kl approx. =3 (k approx. =6 cm -1 ) was measured for a carbon fiber coated with a thin layer of aluminum (for additional radiation cooling). The results are interpreted in terms of fast recombination due mostly to thermal conduction from the plasma to the cold fiber core

  18. WELFARE GAIN FROM CARBON TAX APPLIED TO LEISURE AIR TRAFFIC

    Directory of Open Access Journals (Sweden)

    Roberto Rendeiro Martín-Cejas

    2017-12-01

    Full Text Available ABSTRACTThe rapid growth in the air transport required satisfying the increased demand for tourism become a factor of unsustainability due to the substantial environmental impact that supports such a development. There is the need to establish an alternative to the traditional air transport pricing structure that reflects the true cost that air market operators impose on others. This paper analyses one application of a Carbon tax by considering the CO2 emission costs as a valuable input. A tentative tax on CO2 emissions from air transport is calculated considering its applications in leisure air transport market. Finally, one of the main conclusions of the analysis performed is that the available evidence suggests that international aviation emissions should be restricted. In this case, a Ramsey pricing structure, which involved aviation users bearing the environmental costs, would work reasonably well at restricting inefficient demand and produce a reasonable welfare gain respect to the do-nothing scenerywill be pointed out.

  19. Above-ground woody biomass allocation and within tree carbon and nutrient distribution of wild cherry (Prunus avium L. – a case study

    Directory of Open Access Journals (Sweden)

    Christopher Morhart

    2016-02-01

    Full Text Available Background: The global search for new ways to sequester carbon has already reached agricultural lands. Such land constitutes a major potential carbon sink. The production of high value timber within agroforestry systems can facilitate an in-situ carbon storage function. This is followed by a potential long term ex- situ carbon sinkwithin long lasting products such as veneer and furniture. For this purpose wild cherry (Prunus avium L. is an interesting option for middle Europe, yielding high prices on the timber market. Methods: A total number of 39 wild cherry were sampled in 2012 and 2013 to assess the leafless above ground biomass. The complete trees including stem and branches were separated into 1 cm diameter classes. Wood and bark from sub-samples were analysed separately and nutrient content was derived. Models for biomass estimation were constructed for all tree compartments. Results: The smallest diameter classes possess the highest proportion of bark due to smaller cross sectional area. Tree boles with a greater amount of stem wood above 10 cm in diameter will have a more constant bark proportion. Total branch bark proportion also remains relatively constant above d1.3m measurements of 8 cm. A balance is evident between the production of new branches with a low diameter and high bark proportion offset by the thickening and a relative reduction in bark proportion in larger branches. The results show that a single tree with an age of 17 and 18 years can store up to 85 kg of carbon within the aboveground biomass portion, an amount that will increase as the tree matures. Branches display greater nutrient content than stem sections per volume unit which can be attributed to a greater bark proportion. Conclusions: Using the derived models the carbon and the nutrient content of above-ground woody biomass of whole trees can be calculated. Suggested values for carbon with other major and minor nutrients held within relatively immature trees

  20. Timber volume and aboveground live tree biomass estimations for landscape analyses in the Pacific Northwest

    Science.gov (United States)

    Xiaoping Zhou; Miles A. Hemstrom

    2010-01-01

    Timber availability, aboveground tree biomass, and changes in aboveground carbon pools are important consequences of landscape management. There are several models available for calculating tree volume and aboveground tree biomass pools. This paper documents species-specific regional equations for tree volume and aboveground live tree biomass estimation that might be...

  1. [Simulating climate change effect on aboveground carbon sequestration rates of main broadleaved trees in the Xiaoxing'an Mountains area, Northeast China].

    Science.gov (United States)

    Ma, Jun; Bu, Rencang; Deng, Hua-Wei; Hu, Yuan-Man; Qin, Qin; Han, Feng-Lin

    2014-09-01

    LANDIS Pro 7.0 model was used to simulate the dynamics of aboveground biomass of ten broadleaved tree species in the Xiao Xing' an Mountains area under current and various climate change scenarios from 2000 to 2200, and carbon content coefficients (CCCs) were coupled to cal- culate the aboveground carbon sequestration rates (ACSRs) of these species. The results showed that in the initial year of simulation, the biomasses and their proportions of Fraxinus mandshurica, Phellodendron amurense, Quercus mongolica, Ulmus propinqua, and Acer mono were relatively low, while those of Betula costata, Betula platyphylla, and Populus davidiana were higher. A trend of rise after decline occurred in ACSR for pioneer species in the mid and late periods of simulation years, but ACSRs for the other broadleaved tree species were considerably complex. The ACSRs of Q. mongolica and Tilla amurensis fluctuated in the ranges of -0.05-0.25 t · hm(-2) · 10 a(-1) and 0.16-1.29 t · hm(-2) · 10 a(-1) in simulation years, respectively. The ACSRs of F. mandshurica, U. propinqua, A. mono, and B. costata showed a trend of decline after rise in late simulation years. There were significant differences in ACSR for P. amurense and B. davurica among various climate change scenarios in the periods of 2050-2100 and 2150-2200, while no significant difference in ACSR for the other species would be detected. Difference of sensitivity of various species in ACSR for future climate scenarios in the Small Khingan Mountains area existed. However, the un- certainty of future climates would not yield significant difference in ACSR for most broadleaved tree species. Moreover, a time lag would exist in the process of climate change effects on temperate forest's ACSR.

  2. Shade tree diversity and aboveground carbon stocks in Theobroma cacao agroforestry systems: implications for REDD+ implementation in a West African cacao landscape.

    Science.gov (United States)

    Dawoe, Evans; Asante, Winston; Acheampong, Emmanuel; Bosu, Paul

    2016-12-01

    The promotion of cacao agroforestry is one of the ways of diversifying farmer income and creating incentives through their inclusion in REDD+ interventions. We estimated the aboveground carbon stocks in cacao and shade trees, determined the floristic diversity of shade trees and explored the possibility of implementing REDD+ interventions in cacao landscapes. Using replicated multi-site transect approach, data were collected from nine 1-ha plots established on 5 km long transects in ten cacao growing districts in Ghana West Africa. Biomass of cacao and shade trees was determined using allometric equations. One thousand four hundred and one (1401) shade trees comprising 109 species from 33 families were recorded. Total number of species ranged from 34 to 49. Newbouldia laevis (Bignoniacea) was the most frequently occurring specie and constituted 43.2 % of all shade trees. The most predominant families were Sterculiaceae and Moraceae (10 species each), followed by Meliaceae and Mimosaceae (8 species each) and Caesalpiniacaea (6 species). Shannon diversity indices (H', H max and J') and species richness were low compared to other similar studies. Shade tree densities ranged from 16.2 ± 3.0 to 22.8 ± 1.7 stems ha -1 and differed significantly between sites. Carbon stocks of shade trees differed between sites but were similar in cacao trees. The average C stock in cacao trees was 7.45 ± 0.41 Mg C ha -1 compared with 8.32 ± 1.15 Mg C ha -1 in the shade trees. Cacao landscapes in Ghana have the potential of contributing to forest carbon stocks enhancement by increasing the stocking density of shade trees to recommended levels.

  3. Impacts of fire management on aboveground tree carbon stocks in Yosemite and Sequoia & Kings Canyon National Parks

    Science.gov (United States)

    Matchett, John R.; Lutz, James A.; Tarnay, Leland W.; Smith, Douglas G.; Becker, Kendall M.L.; Brooks, Matthew L.

    2015-01-01

    Forest biomass on Sierra Nevada landscapes constitutes one of the largest carbon stocks in California, and its stability is tightly linked to the factors driving fire regimes. Research suggests that fire suppression, logging, climate change, and present management practices in Sierra Nevada forests have altered historic patterns of landscape carbon storage, and over a century of fire suppression and the resulting accumulation in surface fuels have been implicated in contributing to recent increases in high severity, stand-replacing fires. For over 30 years, fire management at Yosemite (YOSE) and Sequoia & Kings Canyon (SEKI) national parks has led the nation in restoring fire to park landscapes; however, the impacts on the stability and magnitude of carbon stocks have not been thoroughly examined.

  4. Estimating Aboveground Forest Carbon Stock of Major Tropical Forest Land Uses Using Airborne Lidar and Field Measurement Data in Central Sumatra

    Science.gov (United States)

    Thapa, R. B.; Watanabe, M.; Motohka, T.; Shiraishi, T.; shimada, M.

    2013-12-01

    Tropical forests are providing environmental goods and services including carbon sequestration, energy regulation, water fluxes, wildlife habitats, fuel, and building materials. Despite the policy attention, the tropical forest reserve in Southeast Asian region is releasing vast amount of carbon to the atmosphere due to deforestation. Establishing quality forest statistics and documenting aboveground forest carbon stocks (AFCS) are emerging in the region. Airborne and satellite based large area monitoring methods are developed to compliment conventional plot based field measurement methods as they are costly, time consuming, and difficult to implement for large regions. But these methods still require adequate ground measurements for calibrating accurate AFCS model. Furthermore, tropical region comprised of varieties of natural and plantation forests capping higher variability of forest structures and biomass volumes. To address this issue and the needs for ground data, we propose the systematic collection of ground data integrated with airborne light detection and ranging (LiDAR) data. Airborne LiDAR enables accurate measures of vertical forest structure, including canopy height and volume demanding less ground measurement plots. Using an appropriate forest type based LiDAR sampling framework, structural properties of forest can be quantified and treated similar to ground measurement plots, producing locally relevant information to use independently with satellite data sources including synthetic aperture radar (SAR). In this study, we examined LiDAR derived forest parameters with field measured data and developed general and specific AFCS models for tropical forests in central Sumatra. The general model is fitted for all types of natural and plantation forests while the specific model is fitted to the specific forest type. The study region consists of natural forests including peat swamp and dry moist forests, regrowth, and mangrove and plantation forests

  5. Estimating aboveground forest biomass carbon and fire consumption in the U.S. Utah High Plateaus using data from the Forest Inventory and Analysis program, Landsat, and LANDFIRE

    Science.gov (United States)

    Chen, Xuexia; Liu, Shuguang; Zhu, Zhiliang; Vogelmann, James E.; Li, Zhengpeng; Ohlen, Donald O.

    2011-01-01

    The concentrations of CO2 and other greenhouse gases in the atmosphere have been increasing and greatly affecting global climate and socio-economic systems. Actively growing forests are generally considered to be a major carbon sink, but forest wildfires lead to large releases of biomass carbon into the atmosphere. Aboveground forest biomass carbon (AFBC), an important ecological indicator, and fire-induced carbon emissions at regional scales are highly relevant to forest sustainable management and climate change. It is challenging to accurately estimate the spatial distribution of AFBC across large areas because of the spatial heterogeneity of forest cover types and canopy structure. In this study, Forest Inventory and Analysis (FIA) data, Landsat, and Landscape Fire and Resource Management Planning Tools Project (LANDFIRE) data were integrated in a regression tree model for estimating AFBC at a 30-m resolution in the Utah High Plateaus. AFBC were calculated from 225 FIA field plots and used as the dependent variable in the model. Of these plots, 10% were held out for model evaluation with stratified random sampling, and the other 90% were used as training data to develop the regression tree model. Independent variable layers included Landsat imagery and the derived spectral indicators, digital elevation model (DEM) data and derivatives, biophysical gradient data, existing vegetation cover type and vegetation structure. The cross-validation correlation coefficient (r value) was 0.81 for the training model. Independent validation using withheld plot data was similar with r value of 0.82. This validated regression tree model was applied to map AFBC in the Utah High Plateaus and then combined with burn severity information to estimate loss of AFBC in the Longston fire of Zion National Park in 2001. The final dataset represented 24 forest cover types for a 4 million ha forested area. We estimated a total of 353 Tg AFBC with an average of 87 MgC/ha in the Utah High

  6. Antarctic sea ice losses drive gains in benthic carbon drawdown.

    Science.gov (United States)

    Barnes, D K A

    2015-09-21

    Climate forcing of sea-ice losses from the Arctic and West Antarctic are blueing the poles. These losses are accelerating, reducing Earth's albedo and increasing heat absorption. Subarctic forest (area expansion and increased growth) and ice-shelf losses (resulting in new phytoplankton blooms which are eaten by benthos) are the only significant described negative feedbacks acting to counteract the effects of increasing CO2 on a warming planet, together accounting for uptake of ∼10(7) tonnes of carbon per year. Most sea-ice loss to date has occurred over polar continental shelves, which are richly, but patchily, colonised by benthic animals. Most polar benthos feeds on microscopic algae (phytoplankton), which has shown increased blooms coincident with sea-ice losses. Here, growth responses of Antarctic shelf benthos to sea-ice losses and phytoplankton increases were investigated. Analysis of two decades of benthic collections showed strong increases in annual production of shelf seabed carbon in West Antarctic bryozoans. These were calculated to have nearly doubled to >2x10(5) tonnes of carbon per year since the 1980s. Annual production of bryozoans is median within wider Antarctic benthos, so upscaling to include other benthos (combined study species typically constitute ∼3% benthic biomass) suggests an increased drawdown of ∼2.9x10(6) tonnes of carbon per year. This drawdown could become sequestration because polar continental shelves are typically deeper than most modern iceberg scouring, bacterial breakdown rates are slow, and benthos is easily buried. To date, most sea-ice losses have been Arctic, so, if hyperboreal benthos shows a similar increase in drawdown, polar continental shelves would represent Earth's largest negative feedback to climate change. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Below and above-ground carbon distribution along a rainfall gradient. A case of the Zambezi teak forests, Zambia

    Science.gov (United States)

    Ngoma, Justine; Moors, Eddy; Kruijt, Bart; Speer, James H.; Vinya, Royd; Chidumayo, Emmanuel N.; Leemans, Rik

    2018-02-01

    Understanding carbon (C) stocks or biomass in forests is important to examine how forests mitigate climate change. To estimate biomass in stems, branches and roots takes intensive fieldwork to uproot, cut and weigh the mass of each component. Different models or equations are also required. Our research focussed on the dry tropical Zambezi teak forests and we studied their structure at three sites following a rainfall gradient in Zambia. We sampled 3558 trees at 42 plots covering a combined area of 15ha. Using data from destructive tree samples, we developed mixed-species biomass models to estimate above ground biomass for small (forests, thereby adversely affecting their mitigating role in climate change.

  8. Aboveground storage tanks

    International Nuclear Information System (INIS)

    Rizzo, J.A.

    1992-01-01

    With the 1988 promulgation of the comprehensive Resource Conservation and Recovery Act (RCRA) regulations for underground storage of petroleum and hazardous substances, many existing underground storage tank (UST) owners have been considering making the move to aboveground storage. While on the surface, this may appear to be the cure-all to avoiding the underground leakage dilemma, there are many other new and different issues to consider with aboveground storage. The greatest misconception is that by storing materials above ground, there is no risk of subsurface environmental problems. it should be noted that with the aboveground storage tank (AGST) systems, there is still considerable risk of environmental contamination, either by the failure of onground tank bottoms or the spillage of product onto the ground surface where it subsequently finds its way to the ground water. In addition, there are added safety concerns that must be addressed. So what are the other specific areas of concern besides environmental to be addressed when making the decision between underground and aboveground tanks? The primary issues that will be addressed in this paper are: Safety, Product Losses, Cost Comparison of USTs vs AGSTs, Space Availability/Accessibility, Precipitation Handling, Aesthetics and Security, Pending and Existing Regulations

  9. Spatial complexities in aboveground carbon stocks of a semi-arid mangrove community: A remote sensing height-biomass-carbon approach

    KAUST Repository

    Hickey, S.M.; Callow, N.J.; Phinn, S.; Lovelock, C.E.; Duarte, Carlos M.

    2017-01-01

    Mangroves are integral to ecosystem services provided by the coastal zone, in particular carbon (C) sequestration and storage. Allometric relationships linking mangrove height to estimated biomass and C stocks have been developed from field sampling

  10. Combined effect of pulse density and grid cell size on predicting and mapping aboveground carbon in fast-growing Eucalyptus forest plantation using airborne LiDAR data.

    Science.gov (United States)

    Silva, Carlos Alberto; Hudak, Andrew Thomas; Klauberg, Carine; Vierling, Lee Alexandre; Gonzalez-Benecke, Carlos; de Padua Chaves Carvalho, Samuel; Rodriguez, Luiz Carlos Estraviz; Cardil, Adrián

    2017-12-01

    LiDAR remote sensing is a rapidly evolving technology for quantifying a variety of forest attributes, including aboveground carbon (AGC). Pulse density influences the acquisition cost of LiDAR, and grid cell size influences AGC prediction using plot-based methods; however, little work has evaluated the effects of LiDAR pulse density and cell size for predicting and mapping AGC in fast-growing Eucalyptus forest plantations. The aim of this study was to evaluate the effect of LiDAR pulse density and grid cell size on AGC prediction accuracy at plot and stand-levels using airborne LiDAR and field data. We used the Random Forest (RF) machine learning algorithm to model AGC using LiDAR-derived metrics from LiDAR collections of 5 and 10 pulses m -2 (RF5 and RF10) and grid cell sizes of 5, 10, 15 and 20 m. The results show that LiDAR pulse density of 5 pulses m -2 provides metrics with similar prediction accuracy for AGC as when using a dataset with 10 pulses m -2 in these fast-growing plantations. Relative root mean square errors (RMSEs) for the RF5 and RF10 were 6.14 and 6.01%, respectively. Equivalence tests showed that the predicted AGC from the training and validation models were equivalent to the observed AGC measurements. The grid cell sizes for mapping ranging from 5 to 20 also did not significantly affect the prediction accuracy of AGC at stand level in this system. LiDAR measurements can be used to predict and map AGC across variable-age Eucalyptus plantations with adequate levels of precision and accuracy using 5 pulses m -2 and a grid cell size of 5 m. The promising results for AGC modeling in this study will allow for greater confidence in comparing AGC estimates with varying LiDAR sampling densities for Eucalyptus plantations and assist in decision making towards more cost effective and efficient forest inventory.

  11. Convergent evolution towards high net carbon gain efficiency contributes to the shade tolerance of palms (Arecaceae)

    NARCIS (Netherlands)

    Ma, Ren Yi; Zhang, Jiao Lin; Cavaleri, Molly A.; Sterck, Frank; Strijk, J.S.; Cao, Kun Fang

    2015-01-01

    Most palm species occur in the shaded lower strata of tropical rain forests, but how their traits relate to shade adaptation is poorly understood. We hypothesized that palms are adapted to the shade of their native habitats by convergent evolution towards high net carbon gain efficiency (CGEn),

  12. Estimates of forest canopy height and aboveground biomass using ICESat.

    Science.gov (United States)

    Michael A. Lefsky; David J. Harding; Michael Keller; Warren B. Cohen; Claudia C. Carabajal; Fernando Del Bom; Maria O. Hunter; Raimundo Jr. de Oliveira

    2005-01-01

    Exchange of carbon between forests and the atmosphere is a vital component of the global carbon cycle. Satellite laser altimetry has a unique capability for estimating forest canopy height, which has a direct and increasingly well understood relationship to aboveground carbon storage. While the Geoscience Laser Altimeter System (GLAS) onboard the Ice, Cloud and land...

  13. Spatial complexities in aboveground carbon stocks of a semi-arid mangrove community: A remote sensing height-biomass-carbon approach

    Science.gov (United States)

    Hickey, S. M.; Callow, N. J.; Phinn, S.; Lovelock, C. E.; Duarte, C. M.

    2018-01-01

    Mangroves are integral to ecosystem services provided by the coastal zone, in particular carbon (C) sequestration and storage. Allometric relationships linking mangrove height to estimated biomass and C stocks have been developed from field sampling, while various forms of remote sensing has been used to map vegetation height and biomass. Here we combine both these approaches to investigate spatial patterns in living biomass of mangrove forests in a small area of mangrove in north-west Australia. This study used LiDAR data and Landsat 8 OLI (Operational Land Imager) with allometric equations to derive mangrove height, biomass, and C stock estimates. We estimated the study site, Mangrove Bay, a semi-arid site in north-western Australia, contained 70 Mg ha-1 biomass and 45 Mg C ha-1 organic C, with total stocks of 2417 Mg biomass and 778 Mg organic C. Using spatial statistics to identify the scale of clustering of mangrove pixels, we found that living biomass and C stock declined with increasing distance from hydrological features (creek entrance: 0-150 m; y = -0.00041x + 0.9613, R2 = 0.96; 150-770 m; y = -0.0008x + 1.6808, R2 = 0.73; lagoon: y = -0.0041x + 3.7943, R2 = 0.78). Our results illustrate a set pattern of living C distribution within the mangrove forest, and then highlight the role hydrologic features play in determining C stock distribution in the arid zone.

  14. How closely does stem growth of adult beech (Fagus sylvatica) relate to net carbon gain under experimentally enhanced ozone stress?

    International Nuclear Information System (INIS)

    Kitao, Mitsutoshi; Winkler, J. Barbro; Löw, Markus; Nunn, Angela J.; Kuptz, Daniel; Häberle, Karl-Heinz; Reiter, Ilja M.; Matyssek, Rainer

    2012-01-01

    The hypothesis was tested that O 3 -induced changes in leaf-level photosynthetic parameters have the capacity of limiting the seasonal photosynthetic carbon gain of adult beech trees. To this end, canopy-level photosynthetic carbon gain and respiratory carbon loss were assessed in European beech (Fagus sylvatica) by using a physiologically based model, integrating environmental and photosynthetic parameters. The latter were derived from leaves at various canopy positions under the ambient O 3 regime, as prevailing at the forest site (control), or under an experimental twice-ambient O 3 regime (elevated O 3 ), as released through a free-air canopy O 3 fumigation system. Gross carbon gain at the canopy-level declined by 1.7%, while respiratory carbon loss increased by 4.6% under elevated O 3 . As this outcome only partly accounts for the decline in stem growth, O 3 -induced changes in allocation are referred to and discussed as crucial in quantitatively linking carbon gain with stem growth. - Highlights: ► We model O 3 -induced changes in the photosynthetic carbon gain of adult beech trees. ► Elevated O 3 decreases gross carbon gain but increases respiratory carbon loss. ► Reduction in net carbon gain only partly accounts for the decline in stem growth. ► O 3 effects on the whole-tree allocation is crucial in addition to carbon gains. - Reduction in net carbon gain at the canopy level only partly accounts for the decline in stem growth under elevated ozone.

  15. Spatial complexities in aboveground carbon stocks of a semi-arid mangrove community: A remote sensing height-biomass-carbon approach

    KAUST Repository

    Hickey, S.M.

    2017-11-10

    Mangroves are integral to ecosystem services provided by the coastal zone, in particular carbon (C) sequestration and storage. Allometric relationships linking mangrove height to estimated biomass and C stocks have been developed from field sampling, while various forms of remote sensing has been used to map vegetation height and biomass. Here we combine both these approaches to investigate spatial patterns in living biomass of mangrove forests in a small area of mangrove in north-west Australia. This study used LiDAR data and Landsat 8 OLI (Operational Land Imager) with allometric equations to derive mangrove height, biomass, and C stock estimates. We estimated the study site, Mangrove Bay, a semi-arid site in north-western Australia, contained 70 Mg ha−1 biomass and 45 Mg C ha−1 organic C, with total stocks of 2417 Mg biomass and 778 Mg organic C. Using spatial statistics to identify the scale of clustering of mangrove pixels, we found that living biomass and C stock declined with increasing distance from hydrological features (creek entrance: 0–150 m; y = −0.00041x + 0.9613, R2 = 0.96; 150–770 m; y = −0.0008x + 1.6808, R2 = 0.73; lagoon: y = −0.0041x + 3.7943, R2 = 0.78). Our results illustrate a set pattern of living C distribution within the mangrove forest, and then highlight the role hydrologic features play in determining C stock distribution in arid zone.

  16. Monitoring CO2 emissions to gain a dynamic view of carbon allocation to arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Slavíková, Renata; Püschel, David; Janoušková, Martina; Hujslová, Martina; Konvalinková, Tereza; Gryndlerová, Hana; Gryndler, Milan; Weiser, Martin; Jansa, Jan

    2017-01-01

    Quantification of carbon (C) fluxes in mycorrhizal plants is one of the important yet little explored tasks of mycorrhizal physiology and ecology. 13 CO 2 pulse-chase labelling experiments are increasingly being used to track the fate of C in these plant-microbial symbioses. Nevertheless, continuous monitoring of both the below- and aboveground CO 2 emissions remains a challenge, although it is necessary to establish the full C budget of mycorrhizal plants. Here, a novel CO 2 collection system is presented which allows assessment of gaseous CO 2 emissions (including isotopic composition of their C) from both belowground and shoot compartments. This system then is used to quantify the allocation of recently fixed C in mycorrhizal versus nonmycorrhizal Medicago truncatula plants with comparable biomass and mineral nutrition. Using this system, we confirmed substantially greater belowground C drain in mycorrhizal versus nonmycorrhizal plants, with the belowground CO 2 emissions showing large variation because of fluctuating environmental conditions in the glasshouse. Based on the assembled 13 C budget, the C allocation to the mycorrhizal fungus was between 2.3% (increased 13 C allocation to mycorrhizal substrate) and 2.9% (reduction of 13 C allocation to mycorrhizal shoots) of the plant gross photosynthetic production. Although the C allocation to shoot respiration (measured during one night only) did not differ between the mycorrhizal and nonmycorrhizal plants under our experimental conditions, it presented a substantial part (∼10%) of the plant C budget, comparable to the amount of CO 2 released belowground. These results advocate quantification of both above- and belowground CO 2 emissions in future studies.

  17. Carbon print: in 20 years, French gained weight. Carbon Newsletter Nr 2

    International Nuclear Information System (INIS)

    Grandjean, Alain; Jancovici, Jean-Marc; Paillat, Emmanuelle; Adam, Julien; Wilmotte, Jean-Yves

    2011-09-01

    This publication proposes another approach (ECO_2 Climat) than a simple rate between direct emissions and population to assess the average carbon emission by a French person: to calculate, not direct emissions made by the country, but emissions necessary to the fabrication of all what is consumed by French people in France, whether this fabrication is made in France or anywhere else. As, with respect to the preceding method, the assessment seems quite good (direct emissions are almost steady whereas population increases, and the individual carbon print therefore decreases), the obtained result is not so flattering. This approach is thus described, and some aspects are highlighted: average individual greenhouse gas emissions, most impacting items (food, and then manufactured products, and individual mobility), evolution of the indicator during the last 20 years, comparison with the national inventory of greenhouse gas emissions. The main variations of emissions between 1990 and 2010 are discussed: energy in housing, food, manufactured products, individual mobility, and services. A brief discussion is proposed in terms of social-professional category. Some ways to face the challenge for a transition towards a low carbon economy are highlighted

  18. Gas Gain Measurement Of GEM-Foil In Argon-Carbon Dioxide Mixture

    International Nuclear Information System (INIS)

    Nguyen Ngoc Duy; Vuong Huu Tan; Le Hong Khiem

    2011-01-01

    Nuclear reaction measurement with radioactive beam at low energy plays an important role in nuclear astrophysics and nuclear structure. The trajectory of particle beams can be obtained by using an active gas target, multiple-sampling and tracking proportional chamber (MSTPC), as a proportional counter. Because of intensity of low energy radioactive beam, in the stellar reaction such as (α, p), (p, α), it is necessary to increase the gain for the counter. In this case, a gas electrons multiplier (GEM) foil will be used, so the proportional counter is called GEM-MSTPC. The efficient gas gain of GEM foils which relates to foil thickness and operating pressure was investigated with two type of the foils, 400 μm and 200 μm, in Argon (70%) + Carbon dioxide (30%) mixture. (author)

  19. Economic innovation and efficiency gains as the driving force for accelerating carbon dioxide emissions

    Science.gov (United States)

    Garrett, T. J.

    2012-12-01

    It is normally assumed that gains in energy efficiency are one of the best routes that society has available to it for stabilizing future carbon dioxide emissions. For a given degree of economic productivity less energy is consumed and a smaller quantity of fossil fuels is required. While certainly this observation is true in the instant, it ignores feedbacks in the economic system such that efficiency gains ultimately lead to greater energy consumption: taken as a global whole, they permit civilization to accelerate its expansion into the energy reserves that sustain it. Here this argument is formalized from a general thermodynamic perspective. The core result is that there exists a fixed, time-independent link between a very general representation of global inflation-adjusted economic wealth (units currency) and civilization's total capacity to consume power (units energy per time). Based on 40 years of available statistics covering more than a tripling of global GDP and a doubling of wealth, this constant has a value of 7.1 +/- 0.01 Watts per one thousand 2005 US dollars. Essentially, wealth is power. Civilization grows by dissipating power in order to sustain all its current activities and to incorporate more raw material into its existing structure. Growth of its structure is related to economic production, so more energy efficient economic production facilitates growth. Growth is into the reserves that sustain civilization, in which case there is a positive feedback in the economic system whereby energy efficiency gains ultimately "backfire" if their intended purpose is to reduce energy consumption and carbon dioxide emissions. The analogy that can be made is to a growing child: a healthy child who efficiently incorporates food into her structure grows quickly and is able to consume more in following years. Economically, an argument is made that, for a range of reasons, there are good reasons to refer to efficiency gains as economic "innovation", both for

  20. Effects of high CO2 levels on dynamic photosynthesis: carbon gain, mechanisms, and environmental interactions.

    Science.gov (United States)

    Tomimatsu, Hajime; Tang, Yanhong

    2016-05-01

    Understanding the photosynthetic responses of terrestrial plants to environments with high levels of CO2 is essential to address the ecological effects of elevated atmospheric CO2. Most photosynthetic models used for global carbon issues are based on steady-state photosynthesis, whereby photosynthesis is measured under constant environmental conditions; however, terrestrial plant photosynthesis under natural conditions is highly dynamic, and photosynthetic rates change in response to rapid changes in environmental factors. To predict future contributions of photosynthesis to the global carbon cycle, it is necessary to understand the dynamic nature of photosynthesis in relation to high CO2 levels. In this review, we summarize the current body of knowledge on the photosynthetic response to changes in light intensity under experimentally elevated CO2 conditions. We found that short-term exposure to high CO2 enhances photosynthetic rate, reduces photosynthetic induction time, and reduces post-illumination CO2 burst, resulting in increased leaf carbon gain during dynamic photosynthesis. However, long-term exposure to high CO2 during plant growth has varying effects on dynamic photosynthesis. High levels of CO2 increase the carbon gain in photosynthetic induction in some species, but have no significant effects in other species. Some studies have shown that high CO2 levels reduce the biochemical limitation on RuBP regeneration and Rubisco activation during photosynthetic induction, whereas the effects of high levels of CO2 on stomatal conductance differ among species. Few studies have examined the influence of environmental factors on effects of high levels of CO2 on dynamic photosynthesis. We identified several knowledge gaps that should be addressed to aid future predictions of photosynthesis in high-CO2 environments.

  1. Discovery of natural gain amplification in the 10-micrometer carbon dioxide laser bands on Mars - A natural laser

    Science.gov (United States)

    Mumma, M. J.; Buhl, D.; Chin, G.; Deming, D.; Espenak, F.; Kostiuk, T.; Zipoy, D.

    1981-01-01

    Fully resolved intensity profiles of various lines in the carbon dioxide band at 10.4 micrometers have been measured on Mars with an infrared heterodyne spectrometer. Analysis of the line shapes shows that the Mars atmosphere exhibits positive gain in these lines. The detection of natural optical gain amplification enables identification of these lines as a definite natural laser.

  2. Effects of gamma radiation on stem diameter growth, carbon gain and biomass partitioning in Helianthus annuus

    International Nuclear Information System (INIS)

    Thiede, M.E.; Link, S.O.; Fellows, R.J.; Beedlow, P.A.

    1995-01-01

    To determine the effects of gamma radiation on stem diameter growth, carbon gain, and biomass partitioning, 19-day-old dwarf sunflower plants (Helianthus annuus, variety NK894) were given variable doses (0–40 Gy) from a 60Co gamma source. Exposure of plants to gamma radiation caused a significant reduction in stem growth and root biomass. Doses as low as 5 Gy resulted in a significant increase in leaf density, suggesting that very low doses of radiation could induce morphological growth changes. Carbohydrate analysis of plants exposed to 40 Gy demonstrated significantly more starch content in leaves and significantly less in stems 18 days after exposure compared with control plants. In contrast, the carbohydrate content of the roots of plants exposed to 40 Gy was not significantly different from non-irradiated plants 18 days after exposure. (author)

  3. Convergent Evolution towards High Net Carbon Gain Efficiency Contributes to the Shade Tolerance of Palms (Arecaceae.

    Directory of Open Access Journals (Sweden)

    Ren-Yi Ma

    Full Text Available Most palm species occur in the shaded lower strata of tropical rain forests, but how their traits relate to shade adaptation is poorly understood. We hypothesized that palms are adapted to the shade of their native habitats by convergent evolution towards high net carbon gain efficiency (CGEn, which is given by the maximum photosynthetic rate to dark respiration rate ratio. Leaf mass per area, maximum photosynthetic rate, dark respiration and N and P concentrations were measured in 80 palm species grown in a common garden, and combined with data of 30 palm species growing in their native habitats. Compared to other species from the global leaf economics data, dicotyledonous broad-leaved trees in tropical rainforest or other monocots in the global leaf economics data, palms possessed consistently higher CGEn, achieved by lowered dark respiration and fairly high foliar P concentration. Combined phylogenetic analyses of evolutionary signal and trait evolution revealed convergent evolution towards high CGEn in palms. We conclude that high CGEn is an evolutionary strategy that enables palms to better adapt to shady environments than coexisting dicot tree species, and may convey advantages in competing with them in the tropical forest understory. These findings provide important insights for understanding the evolution and ecology of palms, and for understanding plant shade adaptations of lower rainforest strata. Moreover, given the dominant role of palms in tropical forests, these findings are important for modelling carbon and nutrient cycling in tropical forest ecosystems.

  4. MODIS Based Estimation of Forest Aboveground Biomass in China

    Science.gov (United States)

    Sun, Yan; Wang, Tao; Zeng, Zhenzhong; Piao, Shilong

    2015-01-01

    Accurate estimation of forest biomass C stock is essential to understand carbon cycles. However, current estimates of Chinese forest biomass are mostly based on inventory-based timber volumes and empirical conversion factors at the provincial scale, which could introduce large uncertainties in forest biomass estimation. Here we provide a data-driven estimate of Chinese forest aboveground biomass from 2001 to 2013 at a spatial resolution of 1 km by integrating a recently reviewed plot-level ground-measured forest aboveground biomass database with geospatial information from 1-km Moderate-Resolution Imaging Spectroradiometer (MODIS) dataset in a machine learning algorithm (the model tree ensemble, MTE). We show that Chinese forest aboveground biomass is 8.56 Pg C, which is mainly contributed by evergreen needle-leaf forests and deciduous broadleaf forests. The mean forest aboveground biomass density is 56.1 Mg C ha−1, with high values observed in temperate humid regions. The responses of forest aboveground biomass density to mean annual temperature are closely tied to water conditions; that is, negative responses dominate regions with mean annual precipitation less than 1300 mm y−1 and positive responses prevail in regions with mean annual precipitation higher than 2800 mm y−1. During the 2000s, the forests in China sequestered C by 61.9 Tg C y−1, and this C sink is mainly distributed in north China and may be attributed to warming climate, rising CO2 concentration, N deposition, and growth of young forests. PMID:26115195

  5. MODIS Based Estimation of Forest Aboveground Biomass in China.

    Science.gov (United States)

    Yin, Guodong; Zhang, Yuan; Sun, Yan; Wang, Tao; Zeng, Zhenzhong; Piao, Shilong

    2015-01-01

    Accurate estimation of forest biomass C stock is essential to understand carbon cycles. However, current estimates of Chinese forest biomass are mostly based on inventory-based timber volumes and empirical conversion factors at the provincial scale, which could introduce large uncertainties in forest biomass estimation. Here we provide a data-driven estimate of Chinese forest aboveground biomass from 2001 to 2013 at a spatial resolution of 1 km by integrating a recently reviewed plot-level ground-measured forest aboveground biomass database with geospatial information from 1-km Moderate-Resolution Imaging Spectroradiometer (MODIS) dataset in a machine learning algorithm (the model tree ensemble, MTE). We show that Chinese forest aboveground biomass is 8.56 Pg C, which is mainly contributed by evergreen needle-leaf forests and deciduous broadleaf forests. The mean forest aboveground biomass density is 56.1 Mg C ha-1, with high values observed in temperate humid regions. The responses of forest aboveground biomass density to mean annual temperature are closely tied to water conditions; that is, negative responses dominate regions with mean annual precipitation less than 1300 mm y-1 and positive responses prevail in regions with mean annual precipitation higher than 2800 mm y-1. During the 2000s, the forests in China sequestered C by 61.9 Tg C y-1, and this C sink is mainly distributed in north China and may be attributed to warming climate, rising CO2 concentration, N deposition, and growth of young forests.

  6. MODIS Based Estimation of Forest Aboveground Biomass in China.

    Directory of Open Access Journals (Sweden)

    Guodong Yin

    Full Text Available Accurate estimation of forest biomass C stock is essential to understand carbon cycles. However, current estimates of Chinese forest biomass are mostly based on inventory-based timber volumes and empirical conversion factors at the provincial scale, which could introduce large uncertainties in forest biomass estimation. Here we provide a data-driven estimate of Chinese forest aboveground biomass from 2001 to 2013 at a spatial resolution of 1 km by integrating a recently reviewed plot-level ground-measured forest aboveground biomass database with geospatial information from 1-km Moderate-Resolution Imaging Spectroradiometer (MODIS dataset in a machine learning algorithm (the model tree ensemble, MTE. We show that Chinese forest aboveground biomass is 8.56 Pg C, which is mainly contributed by evergreen needle-leaf forests and deciduous broadleaf forests. The mean forest aboveground biomass density is 56.1 Mg C ha-1, with high values observed in temperate humid regions. The responses of forest aboveground biomass density to mean annual temperature are closely tied to water conditions; that is, negative responses dominate regions with mean annual precipitation less than 1300 mm y-1 and positive responses prevail in regions with mean annual precipitation higher than 2800 mm y-1. During the 2000s, the forests in China sequestered C by 61.9 Tg C y-1, and this C sink is mainly distributed in north China and may be attributed to warming climate, rising CO2 concentration, N deposition, and growth of young forests.

  7. Aging yeast gain a competitive advantage on non-optimal carbon sources.

    Science.gov (United States)

    Frenk, Stephen; Pizza, Grazia; Walker, Rachael V; Houseley, Jonathan

    2017-06-01

    Animals, plants and fungi undergo an aging process with remarkable physiological and molecular similarities, suggesting that aging has long been a fact of life for eukaryotes and one to which our unicellular ancestors were subject. Key biochemical pathways that impact longevity evolved prior to multicellularity, and the interactions between these pathways and the aging process therefore emerged in ancient single-celled eukaryotes. Nevertheless, we do not fully understand how aging impacts the fitness of unicellular organisms, and whether such cells gain a benefit from modulating rather than simply suppressing the aging process. We hypothesized that age-related loss of fitness in single-celled eukaryotes may be counterbalanced, partly or wholly, by a transition from a specialist to a generalist life-history strategy that enhances adaptability to other environments. We tested this hypothesis in budding yeast using competition assays and found that while young cells are more successful in glucose, highly aged cells outcompete young cells on other carbon sources such as galactose. This occurs because aged yeast divide faster than young cells in galactose, reversing the normal association between age and fitness. The impact of aging on single-celled organisms is therefore complex and may be regulated in ways that anticipate changing nutrient availability. We propose that pathways connecting nutrient availability with aging arose in unicellular eukaryotes to capitalize on age-linked diversity in growth strategy and that individual cells in higher eukaryotes may similarly diversify during aging to the detriment of the organism as a whole. © 2017 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

  8. Seagrass blue carbon dynamics in the Gulf of Mexico: Stocks, losses from anthropogenic disturbance, and gains through seagrass restoration.

    Science.gov (United States)

    Thorhaug, Anitra; Poulos, Helen M; López-Portillo, Jorge; Ku, Timothy C W; Berlyn, Graeme P

    2017-12-15

    Seagrasses comprise a substantive North American and Caribbean Sea blue carbon sink. Yet fine-scale estimates of seagrass carbon stocks, fluxes from anthropogenic disturbances, and potential gains in sedimentary carbon from seagrass restoration are lacking for most of the Western Hemisphere. To begin to fill this knowledge gap in the subtropics and tropics, we quantified organic carbon (C org ) stocks, losses, and gains from restorations at 8 previously-disturbed seagrass sites around the Gulf of Mexico (GoM) (n=128 cores). Mean natural seagrass C org stocks were 25.7±6.7MgC org ha -1 around the GoM, while mean C org stocks at adjacent barren sites that had previously hosted seagrass were 17.8MgC org ha -1 . Restored seagrass beds contained a mean of 38.7±13.1MgC org ha -1 . Mean C org losses differed by anthropogenic impact type, but averaged 20.98±7.14MgC org ha -1 . C org gains from seagrass restoration averaged 20.96±8.59Mgha -1 . These results, when combined with the similarity between natural and restored C org content, highlight the potential of seagrass restoration for mitigating seagrass C org losses from prior impact events. Our GoM basin-wide estimates of natural C org totaled ~36.4Tg for the 947,327ha for the USA-GoM. Including Mexico, the total basin contained an estimated 37.2-37.5Tg C org . Regional US-GoM losses totaled 21.69Tg C org . C org losses differed significantly among anthropogenic impacts. Yet, seagrass restoration appears to be an important climate change mitigation strategy that could be implemented elsewhere throughout the tropics and subtropics. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Different growth strategies determine the carbon gain and productivity of aspen collectives to be used in short-rotation plantations

    International Nuclear Information System (INIS)

    Müller, Annika; Horna, Viviana; Zhang, Chunxia; Leuschner, Christoph

    2012-01-01

    Populus tremula is a favoured tree species in short-rotation forestry with a recognised large intraspecific variation in productivity. We compared the growth potential of 1-yr-old saplings of four Central European aspen collectives with different climate adaptation on a low-fertility site and searched for growth-determining physiological and morphological traits and their dependence on genetic constitution. Among the 35 investigated traits were photosynthetic capacity and mean assimilation rate, quantum yield and carboxylation efficiency, leaf water potential, leaf phaenology and the ratio of leaves lost to leaves produced (LP ratio), leaf size and total leaf area, axes length growth and canopy carbon gain as an estimate of productivity. The collectives differed by more than 30% in cumulative carbon gain with a large genotype effect, while mean assimilation rate and most photosynthetic and water status traits showed a relatively small intraspecific variation with no significant influence on the variation in C gain. The timing of the beginning of net leaf loss (leaf abscission > leaf production) in August differed between the four collectives and resulted in different maximum leaf areas and LP ratios, which were identified as key factors controlling C gain. Mean assimilation rate, though not related to cumulative C gain, was positively correlated with the light, CO 2 and water use efficiencies of photosynthesis. We conclude that genotype selection for high-yielding aspen in short-rotation forestry at low-fertility sites should focus on the parameters leaf phaenology, LP ratio at the end of the growing season, and the resulting total leaf area as key traits.

  10. Linking aboveground and belowground inducible plant resistance

    NARCIS (Netherlands)

    Bezemer, T.M.

    2009-01-01

    Induced resistance of plants against pests and diseases via plant defense responses is well documented and can occur aboveground, in the leaves, and belowground in the roots. A number of recent studies have shown that soil-borne pests can also induce plant resistance aboveground and vice versa.

  11. Ecophysiological differences in tree carbon gain and water use for two fast growing loblolly pine ideotypes that differ in carbon allocation

    Science.gov (United States)

    Maier, C. A.; Johnsen, K. H.; Dougherty, P.; Albaugh, T.; Patterson, S.

    2013-12-01

    We examined the ecophysiological basis for differences in growth efficiency and water-use for two contrasting Pinus taeda (L.) ideotypes: a ';broad-crown' (BC) and a ';narrow crown' (NC) clone, which allocate more growth to leaves and wood, respectively. Tree growth, above and belowground biomass production, fine root turnover, light use efficiency (LUE), and transpiration on a ground (Et) and leaf (EL) basis were measured periodically over eight years. Silviculture treatments were a control consisting of shearing and bedding following local commercial operations and a mulch treatment where chipped logging residue (C/N≈700) was incorporated into the soil during bedding at a rate of 25 Mg ha-1. We hypothesized that: 1) the NC and BC clone would display similar aboveground productivity in the control treatment, but because of lower leaf area and thus lower nitrogen demand, the NC would display higher productivity than BC on the mulch treatment, 2) the NC would have higher LUE, and 3) the NC clone would have lower Et and EL. There were no treatment, clone, or interaction effects on stemwood production. At age eight, standing stem biomass was 80.7 and 86.0 Mg ha-1 (p=0.33), for the NC and BC, respectively. However, there were significant clone effects on carbon allocation. The BC had greater foliage (BC: 8.1, NC: 6.6 Mg ha-1, se=0.2, p=0.01) and branch (BC: 15.0, NC: 12.4 Mg ha-1, se=0.4, p2mm) (BC: 9.7, NC: 11.23 Mg ha-1, se=0.2, Parea to conducting sapwood area (AL/AS) (BC: 0.175 m2 cm-2, NC: 0.150 m2 cm-2) than the NC clone. Growth efficiency, defined as annual stem increment per unit leaf area was 5.36 and 4.70 Mg ha-1 yr-1 LAI-1 in the NC and BC, respectively (parea, which confers greater nutrient use efficiency. In addition, the NC had significantly greater belowground carbon allocation, which could have long-term implications for soil carbon sequestration.

  12. Mineral carbonation: energy costs of pretreatment options and insights gained from flow loop reaction studies

    Energy Technology Data Exchange (ETDEWEB)

    Penner, Larry R.; O' Connor, William K.; Dahlin, David C.; Gerdemann, Stephen J.; Rush, Gilbert E.

    2004-01-01

    Sequestration of carbon as a stable mineral carbonate has been proposed to mitigate environmental concerns that carbon dioxide may with time escape from its sequestered matrix using alternative sequestration technologies. A method has been developed to prepare stable carbonate products by reacting CO2 with magnesium silicate minerals in aqueous bicarbonate/chloride media at high temperature and pressure. Because this approach is inherently expensive due to slow reaction rates and high capital costs, studies were conducted to improve the reaction rates through mineral pretreatment steps and to cut expenses through improved reactor technology. An overview is given for the estimated cost of the process including sensitivity to grinding and heating as pretreatment options for several mineral feedstocks. The energy costs are evaluated for each pretreatment in terms of net carbon avoided. New studies with a high-temperature, high-pressure flow-loop reactor have yielded information on overcoming kinetic barriers experienced with processing in stirred autoclave reactors. Repeated tests with the flow-loop reactor have yielded insights on wear and failure of system components, on challenges to maintain and measure flow, and for better understanding of the reaction mechanism.

  13. Mineral carbonation: energy costs of pretreatment options and insights gained from flow loop reaction studies

    International Nuclear Information System (INIS)

    Penner, Larry R.; O'Connor, William K.; Dahlin, David C.; Gerdemann, Stephen J.; Rush, Gilbert E.

    2004-01-01

    Sequestration of carbon as a stable mineral carbonate has been proposed to mitigate environmental concerns that carbon dioxide may with time escape from its sequestered matrix using alternative sequestration technologies. A method has been developed to prepare stable carbonate products by reacting CO2 with magnesium silicate minerals in aqueous bicarbonate/chloride media at high temperature and pressure. Because this approach is inherently expensive due to slow reaction rates and high capital costs, studies were conducted to improve the reaction rates through mineral pretreatment steps and to cut expenses through improved reactor technology. An overview is given for the estimated cost of the process including sensitivity to grinding and heating as pretreatment options for several mineral feedstocks. The energy costs are evaluated for each pretreatment in terms of net carbon avoided. New studies with a high-temperature, high-pressure flow-loop reactor have yielded information on overcoming kinetic barriers experienced with processing in stirred autoclave reactors. Repeated tests with the flow-loop reactor have yielded insights on wear and failure of system components, on challenges to maintain and measure flow, and for better understanding of the reaction mechanism

  14. Modeling loblolly pine aboveground live biomass in a mature pine-hardwood stand: a cautionary tale

    Science.gov (United States)

    D. C. Bragg

    2011-01-01

    Carbon sequestration in forests is a growing area of interest for researchers and land managers. Calculating the quantity of carbon stored in forest biomass seems to be a straightforward task, but it is highly dependent on the function(s) used to construct the stand. For instance, there are a number of possible equations to predict aboveground live biomass for loblolly...

  15. Estimating aboveground tree biomass on forest land in the Pacific Northwest: a comparison of approaches

    Science.gov (United States)

    Xiaoping Zhou; Miles A. Hemstrom

    2009-01-01

    Live tree biomass estimates are essential for carbon accounting, bioenergy feasibility studies, and other analyses. Several models are currently used for estimating tree biomass. Each of these incorporates different calculation methods that may significantly impact the estimates of total aboveground tree biomass, merchantable biomass, and carbon pools. Consequently,...

  16. Monitoring CO2 emissions to gain a dynamic view of carbon allocation to arbuscular mycorrhizal fungi

    Czech Academy of Sciences Publication Activity Database

    Slavíková, R.; Püschel, David; Janoušková, Martina; Hujslová, M.; Konvalinková, T.; Gryndlerová, H.; Gryndler, M.; Weiser, M.; Jansa, J.

    2017-01-01

    Roč. 27, č. 1 (2017), s. 35-51 ISSN 0940-6360 Institutional support: RVO:67985939 Keywords : belowground carbon allocation * 13C isotope labelling * Medicago truncatula * Glomeromycota * shade * Rhizophagus irregularis Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 3.047, year: 2016

  17. Monitoring CO2 emissions to gain a dynamic view of carbon allocation to arbuscular mycorrhizal fungi

    Czech Academy of Sciences Publication Activity Database

    Slavíková, Renata; Püschel, David; Janoušková, Martina; Hujslová, Martina; Konvalinková, Tereza; Gryndlerová, Hana; Gryndler, Milan; Weiser, M.; Jansa, Jan

    2017-01-01

    Roč. 27, č. 1 (2017), s. 35-51 ISSN 0940-6360 R&D Projects: GA MŠk(CZ) LK11224; GA ČR(CZ) GA14-19191S Grant - others:AV ČR(CZ) Fellowship J. E. Purkyně Institutional support: RVO:61388971 Keywords : Belowground carbon (C) allocation * C-13 isotope labelling * Glomeromycota Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 3.047, year: 2016

  18. Bioenergy production potential for aboveground biomass from a subtropical constructed wetland

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yi-Chung [Department of Forestry and Nature Conservation, Chinese Culture University, Taipei 11114 (China); Ko, Chun-Han [School of Forestry and Resource Conservation, National Taiwan University, Taipei 10617 (China); Bioenergy Research Center, National Taiwan University, Taipei 10617 (China); Chang, Fang-Chih [The Instrument Center, National Cheng Kung University, No.1, University Road, Tainan City 70101 (China); Chen, Pen-Yuan [Department of Landscape Architecture, National Chiayi University, Chiayi City 60004 (China); Liu, Tzu-Fen [School of Forestry and Resource Conservation, National Taiwan University, Taipei 10617 (China); Sheu, Yiong-Shing [Department of Water Quality Protection, Environmental Protection Administration, Executive Yuan, Taipei 10042 (China); Shih, Tzenge-Lien [Department of Chemistry, Tamkang University, Tamsui, Taipei 25137 (China); Teng, Chia-Ji [Environmental Protection Bureau, Taipei County Government, Taipei 22001 (China)

    2011-01-15

    Wetland biomass has potentials for bioenergy production and carbon sequestration. Planted with multiple species macrophytes to promote biodiversity, the 3.29 ha constructed wetland has been treated 4000 cubic meter per day (CMD) domestic wastewater and urban runoff. This study investigated the seasonal variations of aboveground biomass of the constructed wetland, from March 2007 to March 2008. The overall aboveground biomass was 16,737 kg and total carbon content 6185 kg at the peak of aboveground accumulation for the system emergent macrophyte at September 2007. Typhoon Korsa flood this constructed wetland at October 2007, however, significant recovery for emergent macrophyte was observed without human intervention. Endemic Ludwigia sp. recovered much faster, compared to previously dominated typha. Self-recovery ability of the macrophyte community after typhoon validated the feasibility of biomass harvesting. Incinerating of 80% biomass harvested of experimental area in a nearby incineration plant could produce 11,846 kWh for one month. (author)

  19. Enhanced growth of Juniperus thurifera under a warmer climate is explained by a positive carbon gain under cold and drought.

    Science.gov (United States)

    Gimeno, Teresa E; Camarero, J Julio; Granda, Elena; Pías, Beatriz; Valladares, Fernando

    2012-03-01

    Juniperus thurifera L. is an endemic conifer of the western Mediterranean Basin where it is subjected to a severe climatic stress characterized by low winter temperatures and summer drought. Given the trend of increased warming-induced drought stress in this area and the climatic sensitivity of this species, we expect a negative impact of climate change on growth and ecophysiological performance of J. thurifera in the harsh environments where it dominates. To evaluate this, we measured long- and short-term radial growth using dendrochronology, photosynthesis and water-use efficiency in males, females and juveniles in three sites in Central Spain. Climate was monitored and completed with historical records. Mean annual temperature has increased +0.2 °C per decade in the study area, and the main warming trends corresponded to spring (+0.2 °C per decade) and summer (+0.3 °C per decade). Radial growth and maximum photosynthesis peaked in spring and autumn. Positive photosynthetic rates were maintained all year long, albeit at reduced rates in winter and summer. Radial growth was enhanced by wet conditions in the previous autumn and by warm springs and high precipitation in summer of the year of tree-ring formation. Cloud cover during the summer increased growth, while cloudy winters led to impaired carbon gain and reduced growth in the long term. We argue that maintenance of carbon gain under harsh conditions (low winter temperatures and dry summer months) and plastic xylogenesis underlie J. thurifera's ability to profit from changing climatic conditions such as earlier spring onset and erratic summer rainfall. Our results highlight that not only the magnitude but also the sign of the impact of climate change on growth and persistence of Mediterranean trees is species specific.

  20. Response of photosynthetic carbon gain to ecosystem retrogression of vascular plants and mosses in the boreal forest.

    Science.gov (United States)

    Bansal, Sheel; Nilsson, Marie-Charlotte; Wardle, David A

    2012-07-01

    In the long-term absence of rejuvenating disturbances, forest succession frequently proceeds from a maximal biomass phase to a retrogressive phase characterized by reduced nutrient availability [notably nitrogen (N) and phosphorus (P)] and net primary productivity. Few studies have considered how retrogression induces changes in ecophysiological responses associated with photosynthetic carbon (C) gain, and only for trees. We tested the hypothesis that retrogression would negatively impact photosynthetic C gain of four contrasting species, and that this impact would be greater for vascular plants (i.e., trees and shrubs) than for non-vascular plants (i.e., mosses). We used a 5,000-year-old chronosequence of forested islands in Sweden, where retrogression occurs in the long-term absence of lightning-ignited wildfires. Despite fundamental differences in plant form and ecological niche among species, vascular plants and mosses showed similar ecophysiological responses to retrogression. The most common effects of retrogression were reductions in photosynthesis and respiration per unit foliar N, increases in foliar N, δ(13)C and δ(15)N, and decreases in specific leaf areas. In contrast, photosynthesis per unit mass or area generally did not change along the chronosequence, but did vary many-fold between vascular plants and mosses. The consistent increases in foliar N without corresponding increases in mass- or area-based photosynthesis suggest that other factor(s), such as P co-limitation, light conditions or water availability, may co-regulate C gain in retrogressive boreal forests. Against our predictions, traits of mosses associated with C and N were generally highly responsive to retrogression, which has implications for how mosses influence ecosystem processes in boreal forests.

  1. Modeling and Mapping Agroforestry Aboveground Biomass in the Brazilian Amazon Using Airborne Lidar Data

    Science.gov (United States)

    Qi Chen; Dengsheng Lu; Michael Keller; Maiza dos-Santos; Edson Bolfe; Yunyun Feng; Changwei Wang

    2015-01-01

    Agroforestry has large potential for carbon (C) sequestration while providing many economical, social, and ecological benefits via its diversified products. Airborne lidar is considered as the most accurate technology for mapping aboveground biomass (AGB) over landscape levels. However, little research in the past has been done to study AGB of agroforestry systems...

  2. Long-term above-ground biomass production in a red oak-pecan agroforestry system

    Science.gov (United States)

    Agroforestry systems have widely been recognized for their potential to foster long-term carbon sequestration in woody perennials. This study aims to determine the above-ground biomass in a 16-year-old red oak (Quercus rubra) - pecan (Carya illinoinensis) silvopastoral planting (141 and 53 trees ha-...

  3. Aboveground biomass variability across intact and degraded forests in the Brazilian Amazon

    Science.gov (United States)

    Marcos Longo; Michael Keller; Maiza N. dos-Santos; Veronika Leitold; Ekena R. Pinagé; Alessandro Baccini; Sassan Saatchi; Euler M. Nogueira; Mateus Batistella; Douglas C. Morton

    2016-01-01

    Deforestation rates have declined in the Brazilian Amazon since 2005, yet degradation from logging, fire, and fragmentation has continued in frontier forests. In this study we quantified the aboveground carbon density (ACD) in intact and degraded forests using the largest data set of integrated forest inventory plots (n = 359) and airborne lidar data (18,000 ha)...

  4. Carbonated water (CW) process waste reuse for ammonium-uranyl-carbonate (AUC) production and its gains on the environmental, economic and social aspects

    International Nuclear Information System (INIS)

    Carnaval, Joao Paulo R.; Santos, Rafael D. dos; Barbosa, Rodrigo A.; Lauer, Sergio

    2013-01-01

    In the INB nuclear fuel cycle, the pellets production is based on UO 2 powder made by AUC (Ammonium-Uranyl-Carbonate) route. AUC formation occurs by fluidising of UF 6 , NH 3 and CO 2 in a vase containing usually pure water, and this exothermal reaction has AUC as direct product. The mass formed is filtered, washed with CW, washed again with methano solution, dried with air and conducted to the fluidized bed furnace, to be converted to UO 2 powder. At this point, the dried AUC decompounds to UO 3 , NH 3 and C0 2 , these 2 gases are absorbed at the gases washer, formin go the carbonated water (CW), whit is basically a (NH 4 ) 2 CO 3 solution. The UO 2+x is reduced and stabilized to UO 2 powder, which is conducted to pellets production. During the process, a considerable amount of this aqueous waste is generated and goes for effluent treatment. After that, the solution is sent for spray-dryer for power formation, and stock. This treatment demands equipment, energy and time, representing considerable costs of the company beyond the human risks involved on the drying step. The purpose of this work is to present a study of the carbonated water use as substitute of pure water in the AUC formation step. At this point, tests were made varying the CW loads for the AUC precipitation, and the control was made by the UO 2 powder properties. The carbonated water used for AUC precipitation has been tested at several levels and the results has demonstrated full viability to become a definitive process step (INB, Resende site). It has been demonstrated the great resources economy caused by the waste reuse and the guarantee product quality. This represents such an environmental gain and also economic and social aspects got improved. (author)

  5. Carbonated water (CW) process waste reuse for ammonium-uranyl-carbonate (AUC) production and its gains on the environmental, economic and social aspects

    Energy Technology Data Exchange (ETDEWEB)

    Carnaval, Joao Paulo R.; Santos, Rafael D. dos; Barbosa, Rodrigo A.; Lauer, Sergio, E-mail: joaocarnaval@inb.gov.br, E-mail: rafaelsantos@inb.gov.br, E-mail: rodrigobarbosa@inb.gov.br, E-mail: lauer@inb.gov.br [Industias Nucleares do Brasil S.A. (INB), Resende, RJ (Brazil)

    2013-07-01

    In the INB nuclear fuel cycle, the pellets production is based on UO{sub 2} powder made by AUC (Ammonium-Uranyl-Carbonate) route. AUC formation occurs by fluidising of UF{sub 6}, NH{sub 3} and CO{sub 2} in a vase containing usually pure water, and this exothermal reaction has AUC as direct product. The mass formed is filtered, washed with CW, washed again with methano solution, dried with air and conducted to the fluidized bed furnace, to be converted to UO{sub 2} powder. At this point, the dried AUC decompounds to UO{sub 3}, NH{sub 3} and C0{sub 2}, these 2 gases are absorbed at the gases washer, formin go the carbonated water (CW), whit is basically a (NH{sub 4}){sub 2}CO{sub 3} solution. The UO{sub 2+x} is reduced and stabilized to UO{sub 2} powder, which is conducted to pellets production. During the process, a considerable amount of this aqueous waste is generated and goes for effluent treatment. After that, the solution is sent for spray-dryer for power formation, and stock. This treatment demands equipment, energy and time, representing considerable costs of the company beyond the human risks involved on the drying step. The purpose of this work is to present a study of the carbonated water use as substitute of pure water in the AUC formation step. At this point, tests were made varying the CW loads for the AUC precipitation, and the control was made by the UO{sub 2} powder properties. The carbonated water used for AUC precipitation has been tested at several levels and the results has demonstrated full viability to become a definitive process step (INB, Resende site). It has been demonstrated the great resources economy caused by the waste reuse and the guarantee product quality. This represents such an environmental gain and also economic and social aspects got improved. (author)

  6. Ecological linkages between aboveground and belowground biota

    NARCIS (Netherlands)

    Wardle, D.A.; Bardgett, R.D.; Klironomos, J.N.; Setälä, H.; Putten, van der W.H.; Wall, D.H.

    2004-01-01

    All terrestrial ecosystems consist of aboveground and belowground components that interact to influence community- and ecosystem-level processes and properties. Here we show how these components are closely interlinked at the community level, reinforced by a greater degree of specificity between

  7. Modeling aboveground tree woody biomass using national-scale allometric methods and airborne lidar

    Science.gov (United States)

    Chen, Qi

    2015-08-01

    Estimating tree aboveground biomass (AGB) and carbon (C) stocks using remote sensing is a critical component for understanding the global C cycle and mitigating climate change. However, the importance of allometry for remote sensing of AGB has not been recognized until recently. The overarching goals of this study are to understand the differences and relationships among three national-scale allometric methods (CRM, Jenkins, and the regional models) of the Forest Inventory and Analysis (FIA) program in the U.S. and to examine the impacts of using alternative allometry on the fitting statistics of remote sensing-based woody AGB models. Airborne lidar data from three study sites in the Pacific Northwest, USA were used to predict woody AGB estimated from the different allometric methods. It was found that the CRM and Jenkins estimates of woody AGB are related via the CRM adjustment factor. In terms of lidar-biomass modeling, CRM had the smallest model errors, while the Jenkins method had the largest ones and the regional method was between. The best model fitting from CRM is attributed to its inclusion of tree height in calculating merchantable stem volume and the strong dependence of non-merchantable stem biomass on merchantable stem biomass. This study also argues that it is important to characterize the allometric model errors for gaining a complete understanding of the remotely-sensed AGB prediction errors.

  8. Control of Growth Efficiency in Young Plantation Loblolly Pine and Sweetgum through Irrigation and Fertigation Enhancement of Leaf Carbon Gain; FINAL

    International Nuclear Information System (INIS)

    L. Samuelson

    1999-01-01

    The overall objective of this study was to determine if growth efficiency of young plantation loblolly pine and sweetgum can be maintained by intensive forest management and whether increased carbon gain is the mechanism controlling growth efficiency response to resource augmentation. Key leaf physiological processes were examined over two growing seasons in response to irrigation, fertigation (irrigation with a fertilizer solution), and fertigation plus pest control (pine only). Although irrigation improved leaf net photosynthesis in pine and decreased stomatal sensitivity to vapor pressure deficit in sweetgum, no consistent physiological responses to fertigation were detected in either species. After 4 years of treatment, a 3-fold increase in woody net primary productivity was observed in both species in response to fertigation. Trees supplemented with fertigation and fertigation plus pest control exhibited the largest increases in growth and biomass. Furthermore, growth efficiency was maintained by fertigation and fertigation plus pest control, despite large increases in crown development and self-shading. Greater growth in response to intensive culture was facilitated by significant gains in leaf mass and whole tree carbon gain rather than detectable increases in leaf level processes. Growth efficiency was not maintained by significant increases in leaf level carbon gain but was possibly influenced by changes in carbon allocation to root versus shoot processes

  9. Modelling functional trait acclimation for trees of different height in a forest light gradient: emergent patterns driven by carbon gain maximization

    NARCIS (Netherlands)

    Sterck, F.J.; Schieving, F.

    2011-01-01

    Forest trees show large changes in functional traits as they develop from a sapling in the shaded understorey to an adult in the light-exposed canopy. The adaptive function of such changes remains poorly understood. The carbon gain hypothesis suggests that these changes should be adaptive

  10. Regional contingencies in the relationship between aboveground Bbomass and litter in the world’s grasslands

    Science.gov (United States)

    O’Halloran, Lydia R.; Borer, Elizabeth T.; Seabloom, Eric W.; MacDougall, Andrew S.; Cleland, Elsa E.; McCulley, Rebecca L.; Hobbie, Sarah; Harpole, W. Stan; DeCrappeo, Nicole M.; Chu, Cheng-Jin; Bakker, Jonathan D.; Davies, Kendi F.; Du, Guozhen; Firn, Jennifer; Hagenah, Nicole; Hofmockel, Kirsten S.; Knops, Johannes M.H.; Li, Wei; Melbourne, Brett A.; Morgan, John W.; Orrock, John L.; Prober, Suzanne M.; Stevens, Carly J.

    2013-01-01

    Based on regional-scale studies, aboveground production and litter decomposition are thought to positively covary, because they are driven by shared biotic and climatic factors. Until now we have been unable to test whether production and decomposition are generally coupled across climatically dissimilar regions, because we lacked replicated data collected within a single vegetation type across multiple regions, obfuscating the drivers and generality of the association between production and decomposition. Furthermore, our understanding of the relationships between production and decomposition rests heavily on separate meta-analyses of each response, because no studies have simultaneously measured production and the accumulation or decomposition of litter using consistent methods at globally relevant scales. Here, we use a multi-country grassland dataset collected using a standardized protocol to show that live plant biomass (an estimate of aboveground net primary production) and litter disappearance (represented by mass loss of aboveground litter) do not strongly covary. Live biomass and litter disappearance varied at different spatial scales. There was substantial variation in live biomass among continents, sites and plots whereas among continent differences accounted for most of the variation in litter disappearance rates. Although there were strong associations among aboveground biomass, litter disappearance and climatic factors in some regions (e.g. U.S. Great Plains), these relationships were inconsistent within and among the regions represented by this study. These results highlight the importance of replication among regions and continents when characterizing the correlations between ecosystem processes and interpreting their global-scale implications for carbon flux. We must exercise caution in parameterizing litter decomposition and aboveground production in future regional and global carbon models as their relationship is complex.

  11. ALLOMETRIC EQUATIONS FOR ESTIMATING ABOVEGROUND BIOMASS IN PAPUA TROPICAL FOREST

    Directory of Open Access Journals (Sweden)

    Sandhi Imam Maulana

    2014-10-01

    Full Text Available Allometric equations can be used to estimate biomass and carbon stock of  the forest. However, so far the allometric equations for commercial species in Papua tropical forests have not been appropriately developed. In this research, allometric equations are presented based on the genera of  commercial species. Few equations have been developed for the commercial species of  Intsia, Pometia, Palaquium and Vatica genera and an equation of  a mix of  these genera. The number of  trees sampled in this research was 49, with diameters (1.30 m above-ground or above buttresses ranging from 5 to 40 cm. Destructive sampling was used to collect the samples where Diameter at Breast Height (DBH and Wood Density (WD were used as predictors for dry weight of  Total Above-Ground Biomass (TAGB. Model comparison and selection were based on the values of  F-statistics, R-sq, R-sq (adj, and average deviation. Based on these statistical indicators, the most suitable model for Intsia, Pometia, Palaquium and Vatica genera respectively are Log(TAGB = -0.76 + 2.51Log(DBH, Log(TAGB = -0.84 + 2.57Log(DBH, Log(TAGB = -1.52 + 2.96Log(DBH, and Log(TAGB = -0.09 + 2.08Log(DBH. Additional explanatory variables such as Commercial Bole Height (CBH do not really increase the indicators’ goodness of  fit for the equation. An alternative model to incorporate wood density should  be considered for estimating the above-ground biomass for mixed genera. Comparing the presented mixed-genera equation; Log(TAGB = 0.205 + 2.08Log(DBH + 1.75Log(WD, R-sq: 97.0%, R-sq (adj: 96.9%, F statistics 750.67, average deviation: 3.5%; to previously published datashows that this local species specific equation differs substantially from previously published equations and this site-specific equation is  considered to give a better estimation of  biomass.

  12. Does functional trait diversity predict aboveground biomass and productivity of tropical forests? Testing three alternative hypotheses

    OpenAIRE

    Finegan, B.; Pena Claros, M.; Silva de Oliveira, A.; Ascarrunz, N.; Bret-Harte, M.S.; Carreño Rocabado, I.G.; Casanoves, F.; Diaz, S.; Eguiguren Velepucha, P.; Fernandez, F.; Licona, J.C.; Lorenzo, L.; Salgado Negret, B.; Vaz, M.; Poorter, L.

    2014-01-01

    1. Tropical forests are globally important, but it is not clear whether biodiversity enhances carbon storage and sequestration in them. We tested this relationship focusing on components of functional trait biodiversity as predictors. 2. Data are presented for three rain forests in Bolivia, Brazil and Costa Rica. Initial above-ground biomass and biomass increments of survivors, recruits and survivors + recruits (total) were estimated for trees ≥10 cm d.b.h. in 62 and 21 1.0-ha plots, respecti...

  13. Radio Frequency Transistors Using Aligned Semiconducting Carbon Nanotubes with Current-Gain Cutoff Frequency and Maximum Oscillation Frequency Simultaneously Greater than 70 GHz.

    Science.gov (United States)

    Cao, Yu; Brady, Gerald J; Gui, Hui; Rutherglen, Chris; Arnold, Michael S; Zhou, Chongwu

    2016-07-26

    In this paper, we report record radio frequency (RF) performance of carbon nanotube transistors based on combined use of a self-aligned T-shape gate structure, and well-aligned, high-semiconducting-purity, high-density polyfluorene-sorted semiconducting carbon nanotubes, which were deposited using dose-controlled, floating evaporative self-assembly method. These transistors show outstanding direct current (DC) performance with on-current density of 350 μA/μm, transconductance as high as 310 μS/μm, and superior current saturation with normalized output resistance greater than 100 kΩ·μm. These transistors create a record as carbon nanotube RF transistors that demonstrate both the current-gain cutoff frequency (ft) and the maximum oscillation frequency (fmax) greater than 70 GHz. Furthermore, these transistors exhibit good linearity performance with 1 dB gain compression point (P1dB) of 14 dBm and input third-order intercept point (IIP3) of 22 dBm. Our study advances state-of-the-art of carbon nanotube RF electronics, which have the potential to be made flexible and may find broad applications for signal amplification, wireless communication, and wearable/flexible electronics.

  14. Assessment of forest management influences on total live aboveground tree biomass in William B Bankhead National Forest, Alabama

    Science.gov (United States)

    Callie Schweitzer; Dawn Lemke; Wubishet Tadesse; Yong Wang

    2015-01-01

    Forests contain a large amount of carbon (C) stored as tree biomass (above and below ground), detritus, and soil organic material. The aboveground tree biomass is the most rapid change component in this forest C pool. Thus, management of forest resources can influence the net C exchange with the atmosphere by changing the amount of C stored, particularly in landscapes...

  15. Spatial distribution of forest aboveground biomass estimated from remote sensing and forest inventory data in New England, USA

    Science.gov (United States)

    Daolan Zheng; Linda S. Heath; Mark J. Ducey

    2008-01-01

    We combined satellite (Landsat 7 and Moderate Resolution Imaging Spectrometer) and U.S. Department of Agriculture forest inventory and analysis (FIA) data to estimate forest aboveground biomass (AGB) across New England, USA. This is practical for large-scale carbon studies and may reduce uncertainty of AGB estimates. We estimate that total regional forest AGB was 1,867...

  16. Validation databases for simulation models: aboveground biomass and net primary productive, (NPP) estimation using eastwide FIA data

    Science.gov (United States)

    Jennifer C. Jenkins; Richard A. Birdsey

    2000-01-01

    As interest grows in the role of forest growth in the carbon cycle, and as simulation models are applied to predict future forest productivity at large spatial scales, the need for reliable and field-based data for evaluation of model estimates is clear. We created estimates of potential forest biomass and annual aboveground production for the Chesapeake Bay watershed...

  17. Making C4 crops more water efficient under current and future climate: Tradeoffs between carbon gain and water loss

    Science.gov (United States)

    Srinivasan, V.; Pignon, C.

    2017-12-01

    C4 plants have a carbon concentrating mechanism that has evolved under historically low CO2 concentrations of around 200 ppm. However, increases in global CO2 concentrations in recent times (current CO2 concentrations are at 400 ppm and it is projected to be 550 ppm by mid-century) have diminished the relative advantage of C4 plants over C3 plants, which lack the expensive carbon concentrating machinery. Here we show by employing model simulations that under pre-historic CO2 concentrations, C4 plants are near optimal in their stomatal behavior and nitrogen partitioning between carbon concentrating machinery and carboxylation machinery, and they are significantly supra-optimal under current and future elevated CO2 concentrations. Model simulations performed at current CO2 concentrations of 400 ppm show that, under high light conditions, decreasing stomatal conductance by 20% results in a 15% increase in water use efficiency with negligible loss in photosynthesis. Under future elevated CO2 concentrations of 550 ppm, a 40% decrease in stomatal conductance produces a 35% increase in water use efficiency. Furthermore, stomatal closure is shown to be more effective in decreasing whole canopy transpiration compared to canopy top leaf transpiration, since shaded leaves are more supra-optimal than sunlit leaves. Model simulations for optimizing nitrogen distribution in C4 leaves show that under high light conditions, C4 plants over invest in carbon concentrating machinery and under invest in carboxylation machinery. A 20% redistribution in leaf nitrogen results in a 10% increase in leaf carbon assimilation without significant increases in transpiration under current CO2 concentrations of 400 ppm. Similarly, a 40% redistribution in leaf nitrogen results in a 15% increase in leaf carbon assimilation without significant increases in transpiration under future elevated CO2 concentrations of 550 ppm. Our model optimality simulations show that C4 leaves a supra optimal in their

  18. Responses of Carbon Dynamics to Nitrogen Deposition in Typical Freshwater Wetland of Sanjiang Plain

    Directory of Open Access Journals (Sweden)

    Yang Wang

    2014-01-01

    Full Text Available The effects of nitrogen deposition (N-deposition on the carbon dynamics in typical Calamagrostis angustifolia wetland of Sanjiang Plain were studied by a pot-culture experiment during two continuous plant growing seasons. Elevated atmospheric N-deposition caused significant increases in the aboveground net primary production and root biomass; moreover, a preferential partition of carbon to root was also observed. Different soil carbon fractions gained due to elevated N-deposition and their response intensities followed the sequence of labile carbon > dissolved organic carbon > microbial biomass carbon, and the interaction between N-deposition and flooded condition facilitated the release of different carbon fractions. Positive correlations were found between CO2 and CH4 fluxes and liable carbon contents with N-deposition, and flooded condition also tended to facilitate CH4 fluxes and to inhibit the CO2 fluxes with N-deposition. The increases in soil carbon fractions occurring in the nitrogen treatments were significantly correlated with increases in root, aboveground parts, total biomass, and their carbon uptake. Our results suggested that N-deposition could enhance the contents of active carbon fractions in soil system and carbon accumulation in plant of the freshwater wetlands.

  19. Topographically mediated controls on aboveground biomass across a mediterranean-type landscape

    Science.gov (United States)

    Dahlin, K.; Asner, G. P.; Field, C. B.

    2009-12-01

    Aboveground biomass accumulation is a useful metric for evaluating habitat restoration and ecosystem services projects, in addition to being a robust measure of carbon sequestration. However, at the landscape scale non-anthropogenic controls on biomass accumulation are poorly understood. In this study we combined field measurements, high resolution data from the NASA JPL Airborne Visible/Infrared Imaging Spectrometer (AVIRIS), and the Carnegie Airborne Observatory (CAO) airborne light detection and ranging (lidar) system to create a comprehensive map of aboveground biomass across a patchy mediterranean-type landscape (Jasper Ridge Biological Preserve, Stanford, CA). Candidate explanatory variables (e.g. slope, elevation, incident solar radiation) were developed using a geologic map and a digital elevation model derived from the lidar data. Finally, candidate variables were tested, and a model was produced to predict aboveground biomass from environmental data. Though many of the explanatory variables have only indirect effects on plant growth, the model permits inferences to be made about the relative importance of light, water, temperature, and edaphic characteristics on carbon accumulation in mediterranean-type systems.

  20. Mobile carbohydrates in Himalayan treeline trees I. Evidence for carbon gain limitation but not for growth limitation.

    Science.gov (United States)

    Li, Mai-He; Xiao, Wen-Fa; Wang, San-Gen; Cheng, Gen-Wei; Cherubini, Paolo; Cai, Xaio-Hu; Liu, Xing-Liang; Wang, Xiao-Dan; Zhu, Wan-Ze

    2008-08-01

    To test whether the altitudinal distribution of trees is determined by a carbon shortage or an insufficient sugar fraction (sugar:starch ratio) in treeline trees, we studied the status of nonstructural carbohydrates (NSC) and their components (total soluble sugars and starch) in Abies fabri (Mast.) Craib and Picea balfouriana var. hirtella Rehd. et Wils. trees along three elevational gradients, ranging from lower elevations to the alpine treeline, on the eastern edge of the Tibetan Plateau. For comparison, we investigated a low-altitude species (Tsuga yunnanensis (Franch.) Pritz.) which served as a warm-climate reference because it is distributed in closed montane forests below 3100 m a.s.l. in the study area. The carbon status of T. yunnanensis responded to altitude differently from that of the treeline species. At the species level, total NSC was not consistently more abundant in treeline trees than in trees of the same species growing at lower elevations. Thus there was no consistent evidence for carbon limitation of growth in treeline trees. For the three treeline species studied (P. balfouriana and A. fabri in the Kang-Ding Valley and A. fabri in the Mo-Xi Valley), winter NSC concentrations in treeline trees were significantly lower than in lower-elevation trees of the same species, suggesting that, in winter, carbon is limited in treeline trees. However, in no case was there total overwinter depletion of NSC or its components in treeline trees. Treeline and low-altitude species had similar sugar:starch ratios of about three at their upper-elevational limits in April. We conclude that survival and growth of trees at the elevational or latitudinal climate limit depend not only on NSC concentration in perennial tissues, but also on the maintenance of an overwintering sugar:starch ratio greater than three.

  1. Aboveground Tree Biomass for Pinus ponderosa in Northeastern California

    Directory of Open Access Journals (Sweden)

    Todd A. Hamilton

    2013-03-01

    Full Text Available Forest managers need accurate biomass equations to plan thinning for fuel reduction or energy production. Estimates of carbon sequestration also rely upon such equations. The current allometric equations for ponderosa pine (Pinus ponderosa commonly employed for California forests were developed elsewhere, and are often applied without consideration potential for spatial or temporal variability. Individual-tree aboveground biomass allometric equations are presented from an analysis of 79 felled trees from four separate management units at Blacks Mountain Experimental Forest: one unthinned and three separate thinned units. A simultaneous set of allometric equations for foliage, branch and bole biomass were developed as well as branch-level equations for wood and foliage. Foliage biomass relationships varied substantially between units while branch and bole biomass estimates were more stable across a range of stand conditions. Trees of a given breast height diameter and crown ratio in thinned stands had more foliage biomass, but slightly less branch biomass than those in an unthinned stand. The observed variability in biomass relationships within Blacks Mountain Experimental Forest suggests that users should consider how well the data used to develop a selected model relate to the conditions in any given application.

  2. Allometric models for estimating the aboveground biomass of the mangrove Rhizophora mangle

    Directory of Open Access Journals (Sweden)

    Heide Vanessa Souza Santos

    Full Text Available Abstract The development of species-specific allometric models is critical to the improvement of aboveground biomass estimates, as well as to the estimation of carbon stock and sequestration in mangrove forests. This study developed allometric equations for estimating aboveground biomass of Rhizophora mangle in the mangroves of the estuary of the São Francisco River, in northeastern Brazil. Using a sample of 74 trees, simple linear regression analysis was used to test the dependence of biomass (total and per plant part on size, considering both transformed (ln and not-transformed data. Best equations were considered as those with the lowest standard error of estimation (SEE and highest adjusted coefficient of determination (R2a. The ln-transformed equations showed better results, with R2a near 0.99 in most cases. The equations for reproductive parts presented low R2a values, probably attributed to the seasonal nature of this compartment. "Basal Area2 × Height" showed to be the best predictor, present in most of the best-fitted equations. The models presented here can be considered reliable predictors of the aboveground biomass of R. mangle in the NE-Brazilian mangroves as well as in any site were this widely distributed species present similar architecture to the trees used in the present study.

  3. Dynamics of aboveground phytomass of the circumpolar Arctic tundra during the past three decades

    International Nuclear Information System (INIS)

    Epstein, Howard E; Raynolds, Martha K; Walker, Donald A; Bhatt, Uma S; Tucker, Compton J; Pinzon, Jorge E

    2012-01-01

    Numerous studies have evaluated the dynamics of Arctic tundra vegetation throughout the past few decades, using remotely sensed proxies of vegetation, such as the normalized difference vegetation index (NDVI). While extremely useful, these coarse-scale satellite-derived measurements give us minimal information with regard to how these changes are being expressed on the ground, in terms of tundra structure and function. In this analysis, we used a strong regression model between NDVI and aboveground tundra phytomass, developed from extensive field-harvested measurements of vegetation biomass, to estimate the biomass dynamics of the circumpolar Arctic tundra over the period of continuous satellite records (1982–2010). We found that the southernmost tundra subzones (C–E) dominate the increases in biomass, ranging from 20 to 26%, although there was a high degree of heterogeneity across regions, floristic provinces, and vegetation types. The estimated increase in carbon of the aboveground live vegetation of 0.40 Pg C over the past three decades is substantial, although quite small relative to anthropogenic C emissions. However, a 19.8% average increase in aboveground biomass has major implications for nearly all aspects of tundra ecosystems including hydrology, active layer depths, permafrost regimes, wildlife and human use of Arctic landscapes. While spatially extensive on-the-ground measurements of tundra biomass were conducted in the development of this analysis, validation is still impossible without more repeated, long-term monitoring of Arctic tundra biomass in the field. (letter)

  4. Dynamics of Aboveground Phytomass of the Circumpolar Arctic Tundra During the Past Three Decades

    Science.gov (United States)

    Epstein, Howard E.; Raynolds, Martha K.; Walker, Donald A.; Bhatt, Uma S.; Tucker, Compton J.; Pinzon, Jorge E.

    2012-01-01

    Numerous studies have evaluated the dynamics of Arctic tundra vegetation throughout the past few decades, using remotely sensed proxies of vegetation, such as the normalized difference vegetation index (NDVI). While extremely useful, these coarse-scale satellite-derived measurements give us minimal information with regard to how these changes are being expressed on the ground, in terms of tundra structure and function. In this analysis, we used a strong regression model between NDVI and aboveground tundra phytomass, developed from extensive field-harvested measurements of vegetation biomass, to estimate the biomass dynamics of the circumpolar Arctic tundra over the period of continuous satellite records (1982-2010). We found that the southernmost tundra subzones (C-E) dominate the increases in biomass, ranging from 20 to 26%, although there was a high degree of heterogeneity across regions, floristic provinces, and vegetation types. The estimated increase in carbon of the aboveground live vegetation of 0.40 Pg C over the past three decades is substantial, although quite small relative to anthropogenic C emissions. However, a 19.8% average increase in aboveground biomass has major implications for nearly all aspects of tundra ecosystems including hydrology, active layer depths, permafrost regimes, wildlife and human use of Arctic landscapes. While spatially extensive on-the-ground measurements of tundra biomass were conducted in the development of this analysis, validation is still impossible without more repeated, long-term monitoring of Arctic tundra biomass in the field.

  5. Age-related effects on leaf area/sapwood area relationships, canopy transpiration and carbon gain of Norway spruce stands (Picea abies) in the Fichtelgebirge, Germany.

    Science.gov (United States)

    Köstner, B; Falge, E; Tenhunen, J D

    2002-06-01

    Stand age is an important structural determinant of canopy transpiration (E(c)) and carbon gain. Another more functional parameter of forest structure is the leaf area/sapwood area relationship, A(L)/A(S), which changes with site conditions and has been used to estimate leaf area index of forest canopies. The interpretation of age-related changes in A(L)/A(S) and the question of how A(L)/A(S) is related to forest functions are of current interest because they may help to explain forest canopy fluxes and growth. We conducted studies in mature stands of Picea abies (L.) Karst. varying in age from 40 to 140 years, in tree density from 1680 to 320 trees ha(-1), and in tree height from 15 to 30 m. Structural parameters were measured by biomass harvests of individual trees and stand biometry. We estimated E(c) from scaled-up xylem sap flux of trees, and canopy-level fluxes were predicted by a three-dimensional microclimate and gas exchange model (STANDFLUX). In contrast to pine species, A(L)/A(S) of P. abies increased with stand age from 0.26 to 0.48 m(2) cm(-2). Agreement between E(c) derived from scaled-up sap flux and modeled canopy transpiration was obtained with the same parameterization of needle physiology independent of stand age. Reduced light interception per leaf area and, as a consequence, reductions in net canopy photosynthesis (A(c)), canopy conductance (g(c)) and E(c) were predicted by the model in the older stands. Seasonal water-use efficiency (WUE = A(c)/E(c)), derived from scaled-up sap flux and stem growth as well as from model simulation, declined with increasing A(L)/A(S) and stand age. Based on the different behavior of age-related A(L)/A(S) in Norway spruce stands compared with other tree species, we conclude that WUE rather than A(L)/A(S) could represent a common age-related property of all species. We also conclude that, in addition to hydraulic limitations reducing carbon gain in old stands, a functional change in A(L)/A(S) that is related to

  6. Proven Alternatives for Aboveground Treatment of Arsenic in Groundwater

    Science.gov (United States)

    This issue paper, developed for EPA's Engineering Forum, identifies and summarizes experiences with proven aboveground treatment alternatives for arsenic in groundwater, and provides information on their relative effectiveness and cost.

  7. Eliciting maize defense pathways aboveground attracts belowground biocontrol agents.

    Science.gov (United States)

    Filgueiras, Camila Cramer; Willett, Denis S; Pereira, Ramom Vasconcelos; Moino Junior, Alcides; Pareja, Martin; Duncan, Larry W

    2016-11-04

    Plant defense pathways mediate multitrophic interactions above and belowground. Understanding the effects of these pathways on pests and natural enemies above and belowground holds great potential for designing effective control strategies. Here we investigate the effects of aboveground stimulation of plant defense pathways on the interactions between corn, the aboveground herbivore adult Diabrotica speciosa, the belowground herbivore larval D. speciosa, and the subterranean ento-mopathogenic nematode natural enemy Heterorhabditis amazonensis. We show that adult D. speciosa recruit to aboveground herbivory and methyl salicylate treatment, that larval D. speciosa are relatively indiscriminate, and that H. amazonensis en-tomopathogenic nematodes recruit to corn fed upon by adult D. speciosa. These results suggest that entomopathogenicnematodes belowground can be highly attuned to changes in the aboveground parts of plants and that biological control can be enhanced with induced plant defense in this and similar systems.

  8. an expansion of the aboveground biomass quantification model for ...

    African Journals Online (AJOL)

    Research Note BECVOL 3: an expansion of the aboveground biomass quantification model for ... African Journal of Range and Forage Science ... encroachment and estimation of food to browser herbivore species, was proposed during 1989.

  9. Changes in vegetation structure and aboveground biomass in ...

    African Journals Online (AJOL)

    Changes in vegetation structure and aboveground biomass in response to traditional rangeland management practices in Borana, southern Ethiopia. ... managed by prescribed fire for five years and grazed only post-fire during dry seasons.

  10. Eliciting maize defense pathways aboveground attracts belowground biocontrol agents

    Science.gov (United States)

    Filgueiras, Camila Cramer; Willett, Denis S.; Pereira, Ramom Vasconcelos; Moino Junior, Alcides; Pareja, Martin; Duncan, Larry W.

    2016-01-01

    Plant defense pathways mediate multitrophic interactions above and belowground. Understanding the effects of these pathways on pests and natural enemies above and belowground holds great potential for designing effective control strategies. Here we investigate the effects of aboveground stimulation of plant defense pathways on the interactions between corn, the aboveground herbivore adult Diabrotica speciosa, the belowground herbivore larval D. speciosa, and the subterranean ento-mopathogenic nematode natural enemy Heterorhabditis amazonensis. We show that adult D. speciosa recruit to aboveground herbivory and methyl salicylate treatment, that larval D. speciosa are relatively indiscriminate, and that H. amazonensis en-tomopathogenic nematodes recruit to corn fed upon by adult D. speciosa. These results suggest that entomopathogenicnematodes belowground can be highly attuned to changes in the aboveground parts of plants and that biological control can be enhanced with induced plant defense in this and similar systems. PMID:27811992

  11. Developing a generalized allometric equation for aboveground biomass estimation

    Science.gov (United States)

    Xu, Q.; Balamuta, J. J.; Greenberg, J. A.; Li, B.; Man, A.; Xu, Z.

    2015-12-01

    A key potential uncertainty in estimating carbon stocks across multiple scales stems from the use of empirically calibrated allometric equations, which estimate aboveground biomass (AGB) from plant characteristics such as diameter at breast height (DBH) and/or height (H). The equations themselves contain significant and, at times, poorly characterized errors. Species-specific equations may be missing. Plant responses to their local biophysical environment may lead to spatially varying allometric relationships. The structural predictor may be difficult or impossible to measure accurately, particularly when derived from remote sensing data. All of these issues may lead to significant and spatially varying uncertainties in the estimation of AGB that are unexplored in the literature. We sought to quantify the errors in predicting AGB at the tree and plot level for vegetation plots in California. To accomplish this, we derived a generalized allometric equation (GAE) which we used to model the AGB on a full set of tree information such as DBH, H, taxonomy, and biophysical environment. The GAE was derived using published allometric equations in the GlobAllomeTree database. The equations were sparse in details about the error since authors provide the coefficient of determination (R2) and the sample size. A more realistic simulation of tree AGB should also contain the noise that was not captured by the allometric equation. We derived an empirically corrected variance estimate for the amount of noise to represent the errors in the real biomass. Also, we accounted for the hierarchical relationship between different species by treating each taxonomic level as a covariate nested within a higher taxonomic level (e.g. species contribution of each different covariate in estimating the AGB of trees. Lastly, we applied the GAE to an existing vegetation plot database - Forest Inventory and Analysis database - to derive per-tree and per-plot AGB estimations, their errors, and how

  12. Quantification of live aboveground forest biomass dynamics with Landsat time-series and field inventory data: A comparison of empirical modeling approaches

    Science.gov (United States)

    Scott L. Powell; Warren B. Cohen; Sean P. Healey; Robert E. Kennedy; Gretchen G. Moisen; Kenneth B. Pierce; Janet L. Ohmann

    2010-01-01

    Spatially and temporally explicit knowledge of biomass dynamics at broad scales is critical to understanding how forest disturbance and regrowth processes influence carbon dynamics. We modeled live, aboveground tree biomass using Forest Inventory and Analysis (FIA) field data and applied the models to 20+ year time-series of Landsat satellite imagery to...

  13. Annual Removal of Aboveground Plant Biomass Alters Soil Microbial Responses to Warming

    Directory of Open Access Journals (Sweden)

    Kai Xue

    2016-09-01

    Full Text Available Clipping (i.e., harvesting aboveground plant biomass is common in agriculture and for bioenergy production. However, microbial responses to clipping in the context of climate warming are poorly understood. We investigated the interactive effects of grassland warming and clipping on soil properties and plant and microbial communities, in particular, on microbial functional genes. Clipping alone did not change the plant biomass production, but warming and clipping combined increased the C4 peak biomass by 47% and belowground net primary production by 110%. Clipping alone and in combination with warming decreased the soil carbon input from litter by 81% and 75%, respectively. With less carbon input, the abundances of genes involved in degrading relatively recalcitrant carbon increased by 38% to 137% in response to either clipping or the combined treatment, which could weaken long-term soil carbon stability and trigger positive feedback with respect to warming. Clipping alone also increased the abundance of genes for nitrogen fixation, mineralization, and denitrification by 32% to 39%. Such potentially stimulated nitrogen fixation could help compensate for the 20% decline in soil ammonium levels caused by clipping alone and could contribute to unchanged plant biomass levels. Moreover, clipping tended to interact antagonistically with warming, especially with respect to effects on nitrogen cycling genes, demonstrating that single-factor studies cannot predict multifactorial changes. These results revealed that clipping alone or in combination with warming altered soil and plant properties as well as the abundance and structure of soil microbial functional genes. Aboveground biomass removal for biofuel production needs to be reconsidered, as the long-term soil carbon stability may be weakened.

  14. A Global Database of Litterfall Mass and Litter Pool Carbon and Nutrients

    Data.gov (United States)

    National Aeronautics and Space Administration — Measurement data of aboveground litterfall and littermass and litter carbon, nitrogen, and nutrient concentrations were extracted from 685 original literature...

  15. Some metals in aboveground biomass of Scots pine in Lithuania

    DEFF Research Database (Denmark)

    Varnagiryte-Kabašinskiene, Iveta; Armolaitis, Kestutis; Stupak, Inge

    2014-01-01

    with stemwood and living branches. However, metal export with aboveground biomass represented relatively small proportion of metals in mineral sandy soil. The annual inputs of Fe and Zn with atmospheric deposition were over 10 times higher than the mean annual removals with total aboveground biomass....... The content of metals in forest biomass fuel ash was relatively small to compare with their total removals. The findings of this study have an important implications for future practice, i.e. the recommended maximum forest biomass fuel ash dose for the compensating fertilising could be increased with respect...... to balanced output - input in Lithuania....

  16. Interactions between aboveground herbivores and the mycorrhizal mutualists of plants.

    Science.gov (United States)

    Gehring, C A; Whitham, T G

    1994-07-01

    Plant growth, reproduction and survival can be affected both by mycorrhizal fungi and aboveground herbivores, but few studies have examined the interactive effects of these factors on plants. Most of the available data suggest that severe herbivory reduces root colonization by vesicular-arbuscular and ectomycorrhizal fungi. However, the reverse interaction has also been documented - mycorrhizal fungi deter herbivores and interact with fungal endophytes to influence herbivory. Although consistent patterns and mechanistic explanations are yet to emerge, it is likely that aboveground herbivore-mycorrhiza interactions have important implications for plant populations and communities. Copyright © 1994. Published by Elsevier Ltd.

  17. Large grazers modify effects of aboveground-belowground interactions on small-scale plant community composition

    NARCIS (Netherlands)

    Veen, G. F. (Ciska); Geuverink, Elzemiek; Olff, Han; Schmid, Bernhard

    Aboveground and belowground organisms influence plant community composition by local interactions, and their scale of impact may vary from millimeters belowground to kilometers aboveground. However, it still poorly understood how large grazers that select their forage on large spatial scales

  18. Aboveground vertebrate and invertebrate herbivore impact on net N mineralization in subalpine grasslands.

    Science.gov (United States)

    Risch, Anita C; Schotz, Martin; Vandegehuchte, Martijn L; Van Der Putten, Wim H; Duyts, Henk; Raschein, Ursina; Gwiazdowicz, Dariusz J; Busse, Matt D; Page-dumroese, Deborah S; Zimmermann, Stephan

    2015-12-01

    Aboveground herbivores have strong effects on grassland nitrogen (N) cycling. They can accelerate or slow down soil net N mineralization depending on ecosystem productivity and grazing intensity. Yet, most studies only consider either ungulates or invertebrate herbivores, but not the combined effect of several functionally different vertebrate and invertebrate herbivore species or guilds. We assessed how a diverse herbivore community affects net N mineralization in subalpine grasslands. By using size-selective fences, we progressively excluded large, medium, and small mammals, as well as invertebrates from two vegetation types, and assessed how the exclosure types (ET) affected net N mineralization. The two vegetation types differed in long-term management (centuries), forage quality, and grazing history and intensity. To gain a more mechanistic understanding of how herbivores affect net N mineralization, we linked mineralization to soil abiotic (temperature; moisture; NO3-, NH4+, and total inorganic N concentrations/pools; C, N, P concentrations; pH; bulk density), soil biotic (microbial biomass; abundance of collembolans, mites, and nematodes) and plant (shoot and root biomass; consumption; plant C, N, and fiber content; plant N pool) properties. Net N mineralization differed between ET, but not between vegetation types. Thus, short-term changes in herbivore community composition and, therefore, in grazing intensity had a stronger effect on net N mineralization than long-term management and grazing history. We found highest N mineralization values when only invertebrates were present, suggesting that mammals had a negative effect on net N mineralization. Of the variables included in our analyses, only mite abundance and aboveground plant biomass explained variation in net N mineralization among ET. Abundances of both mites and leaf-sucking invertebrates were positively correlated with aboveground plant biomass, and biomass increased with progressive exclusion

  19. Aboveground Biomass and Litterfall Dynamics in Secondary Forest ...

    African Journals Online (AJOL)

    The differences in aboveground biomass, litterfall patterns and the seasonality of litterfall in three secondary forest fields aged 1, 5 and 10 years of age regenerating from degraded abandoned rubber plantation and a mature forest were studied in southern Nigeria. This is with a view to understanding the possibility of ...

  20. Inventory of Tank Farm equipment stored or abandoned aboveground

    International Nuclear Information System (INIS)

    Hines, S.C.; Lakes, M.E.

    1994-01-01

    This document provides an inventory of Tank Farm equipment stored or abandoned aboveground and potentially subject to regulation. This inventory was conducted in part to ensure that Westinghouse Hanford Company (WHC) does not violate dangerous waste laws concerning storage of potentially contaminated equipment/debris that has been in contact with dangerous waste. The report identifies areas inventoried and provides photographs of equipment

  1. Steering soil microbiomes to suppress aboveground insect pests

    NARCIS (Netherlands)

    Pineda, Ana; Kaplan, Ian; Bezemer, T. Martijn

    2017-01-01

    Soil-borne microbes affect aboveground herbivorous insects through a cascade of molecular and chemical changes in the plant, but knowledge of these microbe?plant?insect interactions is mostly limited to one or a few microbial strains. Yet, the soil microbial community comprises thousands of unique

  2. Photosynthesis, Nitrogen, Their Adjustment and its Effects on Ecosystem Carbon Gain at Elevated CO(sub 2)l. A Comparison of Loblolly and Ponderosa Pines; FINAL

    International Nuclear Information System (INIS)

    Ball, J. Timothy; Eichelmann, Hillar Y.; Tissue, David T.; Lewis, James D.; Picone, Johnn B.; Ross, Peter D.

    1996-01-01

    A functional understanding of terrestrial ecosystem carbon processes is essential for two reasons. First, carbon flow is a most fundamental aspects of ecosystem function as it mediates most of the energy flow in these systems. Second, carbon flow also mediates the majority of energy flow in the global economy and will do for the foreseeable future. The increased atmospheric carbon dioxide and its inevitable flow through global ecosystems will influence ecosystem processes. There is, of course, great interest in the potential of ecosystems to sequester some of the carbon being loaded into the atmosphere by economic activity

  3. The role of crown architecture for light harvesting and carbon gain in extreme light environments assessed with a structurally realistic 3-D model

    Directory of Open Access Journals (Sweden)

    Valladares, Fernando

    2000-06-01

    Full Text Available Main results from different studies of crown architecture adaptation to extreme light environments are presented. Light capture and carbon gain by plants from low (forest understory and high (open Mediterranean-type ecosystems light environments were simulated with a 3-D model (YPLANT, which was developed specifically to analyse the structural features that determine light interception and photosynthesis at the whole plant level. Distantly related taxa with contrasting architectures exhibited similar efficiencies of light interception (functional convergence. Between habitats large differences in architecture existed depending on whether light capture must be maximised or whether excess photon flux density must be avoided. These differences are realised both at the species level and within a species because of plastic adjustments of crown architecture to the external light environment. Realistic, 3-D architectural models are indispensable tools in this kind of comparative studies due to the intrinsic complexity of plant architecture. Their efficient development requires a fluid exchange of ideas between botanists, ecologists and plant modellers.Se presentan los resultados principales de varios estudios sobre las adaptaciones del follaje a ambientes lumínicos extremos. Plantas de ambientes oscuros (sotobosques de bosques templados y tropicales y de ambientes muy luminosos (ecosistemas abiertos de tipo Mediterráneo han sido estudiadas mediante un modelo (YPLANT que permite la reconstrucción tridimensional de la parte aérea de las plantas e identificar los rasgos estructurales que determinan la interceptación de luz y la fotosíntesis y transpiraci6n potencial a nivel de toda la copa. Taxones no relacionados y con arquitecturas muy diferentes mostraron una eficiencia en la interceptaci6n de luz similar (convergencia funcional. La comparación entre hábitat revelo grandes diferencias arquitecturales dependiendo de si la absorción de luz deb

  4. Increased air temperature during simulated autumn conditions does not increase photosynthetic carbon gain but affects the dissipation of excess energy in seedlings of the evergreen conifer Jack pine.

    Science.gov (United States)

    Busch, Florian; Hüner, Norman P A; Ensminger, Ingo

    2007-03-01

    treatment as well as by changes in the abundance of thylakoid membrane proteins compared to the summer condition. We conclude that photoperiod control of dormancy in Jack pine appears to negate any potential for an increased carbon gain associated with higher temperatures during the autumn season.

  5. Assimilating satellite-based canopy height within an ecosystem model to estimate aboveground forest biomass

    Science.gov (United States)

    Joetzjer, E.; Pillet, M.; Ciais, P.; Barbier, N.; Chave, J.; Schlund, M.; Maignan, F.; Barichivich, J.; Luyssaert, S.; Hérault, B.; von Poncet, F.; Poulter, B.

    2017-07-01

    Despite advances in Earth observation and modeling, estimating tropical biomass remains a challenge. Recent work suggests that integrating satellite measurements of canopy height within ecosystem models is a promising approach to infer biomass. We tested the feasibility of this approach to retrieve aboveground biomass (AGB) at three tropical forest sites by assimilating remotely sensed canopy height derived from a texture analysis algorithm applied to the high-resolution Pleiades imager in the Organizing Carbon and Hydrology in Dynamic Ecosystems Canopy (ORCHIDEE-CAN) ecosystem model. While mean AGB could be estimated within 10% of AGB derived from census data in average across sites, canopy height derived from Pleiades product was spatially too smooth, thus unable to accurately resolve large height (and biomass) variations within the site considered. The error budget was evaluated in details, and systematic errors related to the ORCHIDEE-CAN structure contribute as a secondary source of error and could be overcome by using improved allometric equations.

  6. Testing the generality of above-ground biomass allometry across plant functional types at the continent scale.

    Science.gov (United States)

    Paul, Keryn I; Roxburgh, Stephen H; Chave, Jerome; England, Jacqueline R; Zerihun, Ayalsew; Specht, Alison; Lewis, Tom; Bennett, Lauren T; Baker, Thomas G; Adams, Mark A; Huxtable, Dan; Montagu, Kelvin D; Falster, Daniel S; Feller, Mike; Sochacki, Stan; Ritson, Peter; Bastin, Gary; Bartle, John; Wildy, Dan; Hobbs, Trevor; Larmour, John; Waterworth, Rob; Stewart, Hugh T L; Jonson, Justin; Forrester, David I; Applegate, Grahame; Mendham, Daniel; Bradford, Matt; O'Grady, Anthony; Green, Daryl; Sudmeyer, Rob; Rance, Stan J; Turner, John; Barton, Craig; Wenk, Elizabeth H; Grove, Tim; Attiwill, Peter M; Pinkard, Elizabeth; Butler, Don; Brooksbank, Kim; Spencer, Beren; Snowdon, Peter; O'Brien, Nick; Battaglia, Michael; Cameron, David M; Hamilton, Steve; McAuthur, Geoff; Sinclair, Jenny

    2016-06-01

    Accurate ground-based estimation of the carbon stored in terrestrial ecosystems is critical to quantifying the global carbon budget. Allometric models provide cost-effective methods for biomass prediction. But do such models vary with ecoregion or plant functional type? We compiled 15 054 measurements of individual tree or shrub biomass from across Australia to examine the generality of allometric models for above-ground biomass prediction. This provided a robust case study because Australia includes ecoregions ranging from arid shrublands to tropical rainforests, and has a rich history of biomass research, particularly in planted forests. Regardless of ecoregion, for five broad categories of plant functional type (shrubs; multistemmed trees; trees of the genus Eucalyptus and closely related genera; other trees of high wood density; and other trees of low wood density), relationships between biomass and stem diameter were generic. Simple power-law models explained 84-95% of the variation in biomass, with little improvement in model performance when other plant variables (height, bole wood density), or site characteristics (climate, age, management) were included. Predictions of stand-based biomass from allometric models of varying levels of generalization (species-specific, plant functional type) were validated using whole-plot harvest data from 17 contrasting stands (range: 9-356 Mg ha(-1) ). Losses in efficiency of prediction were <1% if generalized models were used in place of species-specific models. Furthermore, application of generalized multispecies models did not introduce significant bias in biomass prediction in 92% of the 53 species tested. Further, overall efficiency of stand-level biomass prediction was 99%, with a mean absolute prediction error of only 13%. Hence, for cost-effective prediction of biomass across a wide range of stands, we recommend use of generic allometric models based on plant functional types. Development of new species

  7. Response of Plant Height, Species Richness and Aboveground Biomass to Flooding Gradient along Vegetation Zones in Floodplain Wetlands, Northeast China.

    Science.gov (United States)

    Lou, Yanjing; Pan, Yanwen; Gao, Chuanyu; Jiang, Ming; Lu, Xianguo; Xu, Y Jun

    2016-01-01

    Flooding regime changes resulting from natural and human activity have been projected to affect wetland plant community structures and functions. It is therefore important to conduct investigations across a range of flooding gradients to assess the impact of flooding depth on wetland vegetation. We conducted this study to identify the pattern of plant height, species richness and aboveground biomass variation along the flooding gradient in floodplain wetlands located in Northeast China. We found that the response of dominant species height to the flooding gradient depends on specific species, i.e., a quadratic response for Carex lasiocarpa, a negative correlation for Calamagrostis angustifolia, and no response for Carex appendiculata. Species richness showed an intermediate effect along the vegetation zone from marsh to wet meadow while aboveground biomass increased. When the communities were analysed separately, only the water table depth had significant impact on species richness for two Carex communities and no variable for C. angustifolia community, while height of dominant species influenced aboveground biomass. When the three above-mentioned communities were grouped together, variations in species richness were mainly determined by community type, water table depth and community mean height, while variations in aboveground biomass were driven by community type and the height of dominant species. These findings indicate that if habitat drying of these herbaceous wetlands in this region continues, then two Carex marshes would be replaced gradually by C. angustifolia wet meadow in the near future. This will lead to a reduction in biodiversity and an increase in productivity and carbon budget. Meanwhile, functional traits must be considered, and should be a focus of attention in future studies on the species diversity and ecosystem function in this region.

  8. Response of Plant Height, Species Richness and Aboveground Biomass to Flooding Gradient along Vegetation Zones in Floodplain Wetlands, Northeast China

    Science.gov (United States)

    Lou, Yanjing; Pan, Yanwen; Gao, Chuanyu; Jiang, Ming; Lu, Xianguo; Xu, Y. Jun

    2016-01-01

    Flooding regime changes resulting from natural and human activity have been projected to affect wetland plant community structures and functions. It is therefore important to conduct investigations across a range of flooding gradients to assess the impact of flooding depth on wetland vegetation. We conducted this study to identify the pattern of plant height, species richness and aboveground biomass variation along the flooding gradient in floodplain wetlands located in Northeast China. We found that the response of dominant species height to the flooding gradient depends on specific species, i.e., a quadratic response for Carex lasiocarpa, a negative correlation for Calamagrostis angustifolia, and no response for Carex appendiculata. Species richness showed an intermediate effect along the vegetation zone from marsh to wet meadow while aboveground biomass increased. When the communities were analysed separately, only the water table depth had significant impact on species richness for two Carex communities and no variable for C. angustifolia community, while height of dominant species influenced aboveground biomass. When the three above-mentioned communities were grouped together, variations in species richness were mainly determined by community type, water table depth and community mean height, while variations in aboveground biomass were driven by community type and the height of dominant species. These findings indicate that if habitat drying of these herbaceous wetlands in this region continues, then two Carex marshes would be replaced gradually by C. angustifolia wet meadow in the near future. This will lead to a reduction in biodiversity and an increase in productivity and carbon budget. Meanwhile, functional traits must be considered, and should be a focus of attention in future studies on the species diversity and ecosystem function in this region. PMID:27097325

  9. Underground or aboveground storage tanks - A critical decision

    International Nuclear Information System (INIS)

    Rizzo, J.A.

    1992-01-01

    With the 1988 promulgation of the comprehensive Resource Conservation and Recovery Act (RCRA) regulations for underground storage of petroleum and hazardous substances, many existing underground storage tank (UST) owners have been considering making the move to aboveground storage. While on the surface, this may appear to be the cure-all to avoiding the underground leakage dilemma, there are many other new and different issues to consider with aboveground storage. The greatest misconception is that by storing materials above ground, there is no risk of subsurface environmental problems. It should be noted that with the aboveground storage tank (AGST) systems, there is still considerable risk of environmental contamination, either by the failure of onground tank bottoms or the spillage of product onto the ground surface where it subsequently finds its way to the ground water. In addition, there are added safety concerns that must be addressed. The greatest interest in AGSTs comes from managers with small volumes of used oil, fresh oil, solvents, chemicals, or heating oil. Dealing with small capacity tanks is not so different than large bulk storage - and, in fact, it lends itself to more options, such as portable storage, tank within tank configurations and inside installations. So what are the other specific areas of concern besides environmental to be addressed when making the decision between underground and aboveground tanks? The primary issues that will be addressed in this presentation are: (1) safety; (2) product losses; (3) cost comparison of USTs vs AGSTs; (4) space availability/accessibility; (5) precipitation handling; (6) aesthetics and security; (7) pending and existing regulations

  10. Proven Alternatives for Aboveground Treatment of Arsenic in Groundwater

    Science.gov (United States)

    2002-10-01

    issue paper does not address three technologies that have been used to treat water containing arsenic: • Biological treatment • Phytoremediation ...arsenic in water, and no aboveground treatments of groundwater conducted at full scale were found. Phytoremediation and electrokinetics are not...Roundtable. September 1998. http://www.frtr.gov/costperf.htm. 1.16 U.S. EPA. Office of Research and Development. Arsenic & Mercury - Workshop on Removal

  11. Cathodic Protection Design Algorithms for Refineries Aboveground Storage Tanks

    Directory of Open Access Journals (Sweden)

    Kosay Abdul sattar Majbor

    2017-12-01

    Full Text Available Storage tanks condition and integrity is maintained by joint application of coating and cathodic protection. Iraq southern region rich in oil and petroleum product refineries need and use plenty of aboveground storage tanks. Iraq went through conflicts over the past thirty five years resulting in holding the oil industry infrastructure behind regarding maintenance and modernization. The primary concern in this work is the design and implementation of cathodic protection systems for the aboveground storage tanks farm in the oil industry. Storage tank external base area and tank internal surface area are to be protected against corrosion using impressed current and sacrificial anode cathodic protection systems. Interactive versatile computer programs are developed to provide the necessary system parameters data including the anode requirements, composition, rating, configuration, etc. Microsoft-Excel datasheet and Visual Basic.Net developed software were used throughout the study in the design of both cathodic protection systems. The case study considered in this work is the eleven aboveground storage tanks farm situated in al-Shauiba refinery in southern IRAQ. The designed cathodic protection systems are to be installed and monitored realistically in the near future. Both systems were designed for a life span of (15-30 years, and all their parameters were within the internationally accepted standards.

  12. Allometric Models Based on Bayesian Frameworks Give Better Estimates of Aboveground Biomass in the Miombo Woodlands

    Directory of Open Access Journals (Sweden)

    Shem Kuyah

    2016-02-01

    Full Text Available The miombo woodland is the most extensive dry forest in the world, with the potential to store substantial amounts of biomass carbon. Efforts to obtain accurate estimates of carbon stocks in the miombo woodlands are limited by a general lack of biomass estimation models (BEMs. This study aimed to evaluate the accuracy of most commonly employed allometric models for estimating aboveground biomass (AGB in miombo woodlands, and to develop new models that enable more accurate estimation of biomass in the miombo woodlands. A generalizable mixed-species allometric model was developed from 88 trees belonging to 33 species ranging in diameter at breast height (DBH from 5 to 105 cm using Bayesian estimation. A power law model with DBH alone performed better than both a polynomial model with DBH and the square of DBH, and models including height and crown area as additional variables along with DBH. The accuracy of estimates from published models varied across different sites and trees of different diameter classes, and was lower than estimates from our model. The model developed in this study can be used to establish conservative carbon stocks required to determine avoided emissions in performance-based payment schemes, for example in afforestation and reforestation activities.

  13. Empirical and theoretical challenges in aboveground-belowground ecology

    DEFF Research Database (Denmark)

    W.H. van der Putten,; R.D. Bardgett; P.C. de Ruiter

    2009-01-01

    of the current conceptual succession models into more predictive models can help targeting empirical studies and generalising their results. Then, we discuss how understanding succession may help to enhance managing arable crops, grasslands and invasive plants, as well as provide insights into the effects...... and environmental settings, we explore where and how they can be supported by theoretical approaches to develop testable predictions and to generalise empirical results. We review four key areas where a combined aboveground-belowground approach offers perspectives for enhancing ecological understanding, namely...

  14. Decomposition of aboveground biomass of a herbaceous wetland stand

    OpenAIRE

    KLIMOVIČOVÁ, Lucie

    2010-01-01

    The master?s thesis is part of the project GA ČR č. P504/11/1151- Role of plants in the greenhouse gas budget of a sedge fen. This thesis deals with the decomposition of aboveground vegetation in a herbaceous wetland. The decomposition rate was established on the flooded part of the Wet Meadows near Třeboň. The rate of the decomposition processes was evaluated using the litter-bag method. Mesh bags filled with dry plant matter were located in the vicinity of the automatic meteorological stati...

  15. Carbon sequestration potential of second-growth forest regeneration in the Latin American tropics

    NARCIS (Netherlands)

    Chazdon, R.L.; Broadbent, E.N.; Rozendaal, Danae; Bongers, F.; Jakovac, A.C.; Braga Junqueira, A.; Lohbeck, M.W.M.; Pena Claros, M.; Poorter, L.

    2016-01-01

    Regrowth of tropical secondary forests following complete or nearly complete removal of forest vegetation actively stores carbon in aboveground biomass, partially counterbalancing carbon emissions from deforestation, forest degradation, burning of fossil fuels, and other anthropogenic sources. We

  16. Closure Report for Corrective Action Unit 134: Aboveground Storage Tanks, Nevada Test Site, Nevada

    International Nuclear Information System (INIS)

    2009-01-01

    Corrective Action Unit (CAU) 134 is identified in the Federal Facility Agreement and Consent Order (FFACO) as 'Aboveground Storage Tanks' and consists of the following four Corrective Action Sites (CASs), located in Areas 3, 15, and 29 of the Nevada Test Site: (1) CAS 03-01-03, Aboveground Storage Tank; (2) CAS 03-01-04, Tank; (3) CAS 15-01-05, Aboveground Storage Tank; and (4) CAS 29-01-01, Hydrocarbon Stain

  17. Terrestrial laser scanning to quantify above-ground biomass of structurally complex coastal wetland vegetation

    Science.gov (United States)

    Owers, Christopher J.; Rogers, Kerrylee; Woodroffe, Colin D.

    2018-05-01

    Above-ground biomass represents a small yet significant contributor to carbon storage in coastal wetlands. Despite this, above-ground biomass is often poorly quantified, particularly in areas where vegetation structure is complex. Traditional methods for providing accurate estimates involve harvesting vegetation to develop mangrove allometric equations and quantify saltmarsh biomass in quadrats. However broad scale application of these methods may not capture structural variability in vegetation resulting in a loss of detail and estimates with considerable uncertainty. Terrestrial laser scanning (TLS) collects high resolution three-dimensional point clouds capable of providing detailed structural morphology of vegetation. This study demonstrates that TLS is a suitable non-destructive method for estimating biomass of structurally complex coastal wetland vegetation. We compare volumetric models, 3-D surface reconstruction and rasterised volume, and point cloud elevation histogram modelling techniques to estimate biomass. Our results show that current volumetric modelling approaches for estimating TLS-derived biomass are comparable to traditional mangrove allometrics and saltmarsh harvesting. However, volumetric modelling approaches oversimplify vegetation structure by under-utilising the large amount of structural information provided by the point cloud. The point cloud elevation histogram model presented in this study, as an alternative to volumetric modelling, utilises all of the information within the point cloud, as opposed to sub-sampling based on specific criteria. This method is simple but highly effective for both mangrove (r2 = 0.95) and saltmarsh (r2 > 0.92) vegetation. Our results provide evidence that application of TLS in coastal wetlands is an effective non-destructive method to accurately quantify biomass for structurally complex vegetation.

  18. Non-Destructive, Laser-Based Individual Tree Aboveground Biomass Estimation in a Tropical Rainforest

    Directory of Open Access Journals (Sweden)

    Muhammad Zulkarnain Abd Rahman

    2017-03-01

    Full Text Available Recent methods for detailed and accurate biomass and carbon stock estimation of forests have been driven by advances in remote sensing technology. The conventional approach to biomass estimation heavily relies on the tree species and site-specific allometric equations, which are based on destructive methods. This paper introduces a non-destructive, laser-based approach (terrestrial laser scanner for individual tree aboveground biomass estimation in the Royal Belum forest reserve, Perak, Malaysia. The study area is in the state park, and it is believed to be one of the oldest rainforests in the world. The point clouds generated for 35 forest plots, using the terrestrial laser scanner, were geo-rectified and cleaned to produce separate point clouds for individual trees. The volumes of tree trunks were estimated based on a cylinder model fitted to the point clouds. The biomasses of tree trunks were calculated by multiplying the volume and the species wood density. The biomasses of branches and leaves were also estimated based on the estimated volume and density values. Branch and leaf volumes were estimated based on the fitted point clouds using an alpha-shape approach. The estimated individual biomass and the total above ground biomass were compared with the aboveground biomass (AGB value estimated using existing allometric equations and individual tree census data collected in the field. The results show that the combination of a simple single-tree stem reconstruction and wood density can be used to estimate stem biomass comparable to the results usually obtained through existing allometric equations. However, there are several issues associated with the data and method used for branch and leaf biomass estimations, which need further improvement.

  19. Aboveground Biomass Variability Across Intact and Degraded Forests in the Brazilian Amazon

    Science.gov (United States)

    Longo, Marcos; Keller, Michael; Dos-Santos, Maiza N.; Leitold, Veronika; Pinage, Ekena R.; Baccini, Alessandro; Saatchi, Sassan; Nogueira, Euler M.; Batistella, Mateus; Morton, Douglas C.

    2016-01-01

    Deforestation rates have declined in the Brazilian Amazon since 2005, yet degradation from logging, re, and fragmentation has continued in frontier forests. In this study we quantified the aboveground carbon density (ACD) in intact and degraded forests using the largest data set of integrated forest inventory plots (n 359) and airborne lidar data (18,000 ha) assembled to date for the Brazilian Amazon. We developed statistical models relating inventory ACD estimates to lidar metrics that explained70 of the variance across forest types. Airborne lidar-ACD estimates for intact forests ranged between 5.0 +/- 2.5 and 31.9 +/- 10.8 kg C m(exp -2). Degradation carbon losses were large and persistent. Sites that burned multiple times within a decade lost up to 15.0 +/- 0.7 kg C m(-2)(94%) of ACD. Forests that burned nearly15 years ago had between 4.1 +/- 0.5 and 6.8 +/- 0.3 kg C m(exp -2) (22-40%) less ACD than intact forests. Even for low-impact logging disturbances, ACD was between 0.7 +/- 0.3 and 4.4 +/- 0.4 kg C m(exp -2)(4-21%) lower than unlogged forests. Comparing biomass estimates from airborne lidar to existing biomass maps, we found that regional and pan-tropical products consistently overestimated ACD in degraded forests, under-estimated ACD in intact forests, and showed little sensitivity to res and logging. Fine-scale heterogeneity in ACD across intact and degraded forests highlights the benefits of airborne lidar for carbon mapping. Differences between airborne lidar and regional biomass maps underscore the need to improve and update biomass estimates for dynamic land use frontiers, to better characterize deforestation and degradation carbon emissions for regional carbon budgets and Reduce Emissions from Deforestation and forest Degradation(REDD+).

  20. Aboveground insect infestation attenuates belowground Agrobacterium-mediated genetic transformation.

    Science.gov (United States)

    Song, Geun Cheol; Lee, Soohyun; Hong, Jaehwa; Choi, Hye Kyung; Hong, Gun Hyong; Bae, Dong-Won; Mysore, Kirankumar S; Park, Yong-Soon; Ryu, Choong-Min

    2015-07-01

    Agrobacterium tumefaciens causes crown gall disease. Although Agrobacterium can be popularly used for genetic engineering, the influence of aboveground insect infestation on Agrobacterium induced gall formation has not been investigated. Nicotiana benthamiana leaves were exposed to a sucking insect (whitefly) infestation and benzothiadiazole (BTH) for 7 d, and these exposed plants were inoculated with a tumorigenic Agrobacterium strain. We evaluated, both in planta and in vitro, how whitefly infestation affects crown gall disease. Whitefly-infested plants exhibited at least a two-fold reduction in gall formation on both stem and crown root. Silencing of isochorismate synthase 1 (ICS1), required for salicylic acid (SA) synthesis, compromised gall formation indicating an involvement of SA in whitefly-derived plant defence against Agrobacterium. Endogenous SA content was augmented in whitefly-infested plants upon Agrobacterium inoculation. In addition, SA concentration was three times higher in root exudates from whitefly-infested plants. As a consequence, Agrobacterium-mediated transformation of roots of whitefly-infested plants was clearly inhibited when compared to control plants. These results suggest that aboveground whitefly infestation elicits systemic defence responses throughout the plant. Our findings provide new insights into insect-mediated leaf-root intra-communication and a framework to understand interactions between three organisms: whitefly, N. benthamiana and Agrobacterium. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  1. Modelling Growth and Partitioning of Annual Above-Ground Vegetative and Reproductive Biomass of Grapevine

    Science.gov (United States)

    Meggio, Franco; Vendrame, Nadia; Maniero, Giovanni; Pitacco, Andrea

    2014-05-01

    In the current climate change scenarios, both agriculture and forestry inherently may act as carbon sinks and consequently can play a key role in limiting global warming. An urgent need exists to understand which land uses and land resource types have the greatest potential to mitigate greenhouse gas (GHG) emissions contributing to global change. A common believe is that agricultural fields cannot be net carbon sinks due to many technical inputs and repeated disturbances of upper soil layers that all contribute to a substantial loss both of the old and newly-synthesized organic matter. Perennial tree crops (vineyards and orchards), however, can behave differently: they grow a permanent woody structure, stand undisturbed in the same field for decades, originate a woody pruning debris, and are often grass-covered. In this context, reliable methods for quantifying and modelling emissions and carbon sequestration are required. Carbon stock changes are calculated by multiplying the difference in oven dry weight of biomass increments and losses with the appropriate carbon fraction. These data are relatively scant, and more information is needed on vineyard management practices and how they impact vineyard C sequestration and GHG emissions in order to generate an accurate vineyard GHG footprint. During the last decades, research efforts have been made for estimating the vineyard carbon budget and its allocation pattern since it is crucial to better understand how grapevines control the distribution of acquired resources in response to variation in environmental growth conditions and agronomic practices. The objective of the present study was to model and compare the dynamics of current year's above-ground biomass among four grapevine varieties. Trials were carried out over three growing seasons in field conditions. The non-linear extra-sums-of-squares method demonstrated to be a feasible way of growth models comparison to statistically assess significant differences among

  2. Remote Sensing-based estimates of herbaceous aboveground biomass on the Mongolian Plateau

    Science.gov (United States)

    John, R.; Chen, J.; Kim, Y.; Ouyang, Z.; Park, H.; Shao, C.

    2015-12-01

    Grasslands comprise most of the land area on the Mongolian Plateau, which includes Mongolia (MG), and the province of Inner Mongolia (IM). Substantial land cover/use change in the recent past, driven by a combination of post-liberalization, socio-economic changes as well as extreme climatic events has resulted in degradation of grasslands in structure and function, for e.g., their carbon sequestration ability. Hence there is a need for precise estimation of above-ground biomass (AGB). In this study, we collected surface reflectance spectra from field radiometry and quadrats and line transects, which include percentage of ground cover, vegetation height, above ground biomass, and species richness, during the growing season, between the periods, 2006-2011 in IM and 2011-2015 in MG. The field sampling was stratified by the dominant vegetation types on the plateau, including the meadow steppe, typical steppe, and the desert steppe. These sampling data were used as training and validation data for developing and testing predictive models for total herbaceous vegetation, and AGB, using Landsat and MODIS-surface reflectance bands and derived vegetation indices optimized for low cover conditions. Our results show that the independent ground sampling data were significantly correlated with remotely sensed estimates. In addition to providing measures of carbon sequestration to the community, these predictive models offer decision makers and rangeland managers the ability to accurately monitor grassland dynamics, control livestock stocking rates in these remote and extensive grasslands.

  3. Aboveground Net Primary Production of tree cover at the post-disturbance area in the Tatra National Park, Slovakia

    Directory of Open Access Journals (Sweden)

    Konôpka Bohdan

    2015-09-01

    Full Text Available Large-scale disturbances under the conditions of Slovakia, caused especially by storm and bark beetle, bring dramatic decline in carbon budget of the country, besides other negative consequences. The largest disturbance in modern history of the Slovak forestry was the storm damage that occurred in November 2004. The Tatra National Park (TNP was one of the most affected regions. Thus, in this territory, two transects (T1 – the Danielov dom site and T2 – near the Horný Smokovec village were established to survey basic dendrometric properties of trees in young stands established after the disaster. The standing stock of aboveground biomass in tree cover for the spring and autumn 2014 was calculated using the recorded variables, i.e. tree height and diameter measured at the stem base, together with the region-specific allometric relations. Then, the Aboveground Net Primary Production (ANPP in tree cover was estimated with respect to its components (stem, branches and foliage. ANPP was 315 g m−2 per year (Transect T1, and 391 g m−2 per year (Transect T2. The differences in the structure of ANPP, i.e. contribution of tree components, were found between transects T1 and T2. They were caused by the contrasting tree species composition, specifically the ratios between Norway spruce and broadleaved species. Broadleaves allocated more biomass production to foliage than spruce. This phenomenon together with higher turnover (once a year of foliage caused that broadleaves manifest higher share of fast-cycling carbon in comparison to the amount of carbon sequestrated in woody parts (stem and branches. High variability of ANPP was found within the transects, i.e. among the plots (microsites. As for the representative estimation of the standing stock of aboveground part of tree cover as well as ANPP at the post-disturbance area in the TNP territory, the survey should be performed on a net of research plots. Only this approach enables reliable estimates

  4. Aboveground Biomass Monitoring over Siberian Boreal Forest Using Radar Remote Sensing Data

    Science.gov (United States)

    Stelmaszczuk-Gorska, M. A.; Thiel, C. J.; Schmullius, C.

    2014-12-01

    Aboveground biomass (AGB) plays an essential role in ecosystem research, global cycles, and is of vital importance in climate studies. AGB accumulated in the forests is of special monitoring interest as it contains the most of biomass comparing with other land biomes. The largest of the land biomes is boreal forest, which has a substantial carbon accumulation capability; carbon stock estimated to be 272 +/-23 Pg C (32%) [1]. Russian's forests are of particular concern, due to the largest source of uncertainty in global carbon stock calculations [1], and old inventory data that have not been updated in the last 25 years [2]. In this research new empirical models for AGB estimation are proposed. Using radar L-band data for AGB retrieval and optical data for an update of in situ data the processing scheme was developed. The approach was trained and validated in the Asian part of the boreal forest, in southern Russian Central Siberia; two Siberian Federal Districts: Krasnoyarsk Kray and Irkutsk Oblast. Together the training and testing forest territories cover an area of approximately 3,500 km2. ALOS PALSAR L-band single (HH - horizontal transmitted and received) and dual (HH and HV - horizontal transmitted, horizontal and vertical received) polarizations in Single Look Complex format (SLC) were used to calculate backscattering coefficient in gamma nought and coherence. In total more than 150 images acquired between 2006 and 2011 were available. The data were obtained through the ALOS Kyoto and Carbon Initiative Project (K&C). The data were used to calibrate a randomForest algorithm. Additionally, a simple linear and multiple-regression approach was used. The uncertainty of the AGB estimation at pixel and stand level were calculated approximately as 35% by validation against an independent dataset. The previous studies employing ALOS PALSAR data over boreal forests reported uncertainty of 39.4% using randomForest approach [2] or 42.8% using semi-empirical approach [3].

  5. Long-term organic farming fosters below and aboveground biota: Implications for soil quality, biological control and productivity

    DEFF Research Database (Denmark)

    Birkhofer, K.; Bezemer, TM; Bloem, J

    2008-01-01

     Organic farming may contribute substantially to future agricultural production worldwide by improving soil quality and pest control, thereby reducing environmental impacts of conventional farming. We investigated in a comprehensive way soil chemical, as well as below and aboveground biological...... with (CONFYM) or without manure (CONMIN) and herbicide application within a long-term agricultural experiment (DOK trial, Switzerland). Soil carbon content was significantly higher in systems receiving farmyard manure and concomitantly microbial biomass (fungi and bacteria) was increased. Microbial activity...... parameters, such as microbial basal respiration and nitrogen mineralization, showed an opposite pattern, suggesting that soil carbon in the conventional system (CONFYM) was more easily accessible to microorganisms than in organic systems. Bacterivorous nematodes and earthworms were most abundant in systems...

  6. Aboveground persistence of vascular plants in relationship to the levels of airborne nutrient deposition

    NARCIS (Netherlands)

    Hendriks, R.J.J.; Ozinga, W.A.; Berg, van den L.J.L.; Noordwijk, E.; Schaminee, J.H.J.; Groenendael, van J.M.

    2014-01-01

    This paper examines whether high atmospheric nitrogen deposition affects aboveground persistence of vascular plants. We combined information on local aboveground persistence of vascular plants in 245 permanent plots in the Netherlands with estimated level of nitrogen deposition at the time of

  7. Aboveground allometric models for freeze-affected black mangroves (Avicennia germinans): equations for a climate sensitive mangrove-marsh ecotone

    Science.gov (United States)

    Osland, Michael J.; Day, Richard H.; Larriviere, Jack C.; From, Andrew S.

    2014-01-01

    Across the globe, species distributions are changing in response to climate change and land use change. In parts of the southeastern United States, climate change is expected to result in the poleward range expansion of black mangroves (Avicennia germinans) at the expense of some salt marsh vegetation. The morphology of A. germinans at its northern range limit is more shrub-like than in tropical climes in part due to the aboveground structural damage and vigorous multi-stem regrowth triggered by extreme winter temperatures. In this study, we developed aboveground allometric equations for freeze-affected black mangroves which can be used to quantify: (1) total aboveground biomass; (2) leaf biomass; (3) stem plus branch biomass; and (4) leaf area. Plant volume (i.e., a combination of crown area and plant height) was selected as the optimal predictor of the four response variables. We expect that our simple measurements and equations can be adapted for use in other mangrove ecosystems located in abiotic settings that result in mangrove individuals with dwarf or shrub-like morphologies including oligotrophic and arid environments. Many important ecological functions and services are affected by changes in coastal wetland plant community structure and productivity including carbon storage, nutrient cycling, coastal protection, recreation, fish and avian habitat, and ecosystem response to sea level rise and extreme climatic events. Coastal scientists in the southeastern United States can use the identified allometric equations, in combination with easily obtained and non-destructive plant volume measurements, to better quantify and monitor ecological change within the dynamic, climate sensitive, and highly-productive mangrove-marsh ecotone.

  8. Aboveground allometric models for freeze-affected black mangroves (Avicennia germinans): equations for a climate sensitive mangrove-marsh ecotone.

    Science.gov (United States)

    Osland, Michael J; Day, Richard H; Larriviere, Jack C; From, Andrew S

    2014-01-01

    Across the globe, species distributions are changing in response to climate change and land use change. In parts of the southeastern United States, climate change is expected to result in the poleward range expansion of black mangroves (Avicennia germinans) at the expense of some salt marsh vegetation. The morphology of A. germinans at its northern range limit is more shrub-like than in tropical climes in part due to the aboveground structural damage and vigorous multi-stem regrowth triggered by extreme winter temperatures. In this study, we developed aboveground allometric equations for freeze-affected black mangroves which can be used to quantify: (1) total aboveground biomass; (2) leaf biomass; (3) stem plus branch biomass; and (4) leaf area. Plant volume (i.e., a combination of crown area and plant height) was selected as the optimal predictor of the four response variables. We expect that our simple measurements and equations can be adapted for use in other mangrove ecosystems located in abiotic settings that result in mangrove individuals with dwarf or shrub-like morphologies including oligotrophic and arid environments. Many important ecological functions and services are affected by changes in coastal wetland plant community structure and productivity including carbon storage, nutrient cycling, coastal protection, recreation, fish and avian habitat, and ecosystem response to sea level rise and extreme climatic events. Coastal scientists in the southeastern United States can use the identified allometric equations, in combination with easily obtained and non-destructive plant volume measurements, to better quantify and monitor ecological change within the dynamic, climate sensitive, and highly-productive mangrove-marsh ecotone.

  9. Aboveground allometric models for freeze-affected black mangroves (Avicennia germinans: equations for a climate sensitive mangrove-marsh ecotone.

    Directory of Open Access Journals (Sweden)

    Michael J Osland

    Full Text Available Across the globe, species distributions are changing in response to climate change and land use change. In parts of the southeastern United States, climate change is expected to result in the poleward range expansion of black mangroves (Avicennia germinans at the expense of some salt marsh vegetation. The morphology of A. germinans at its northern range limit is more shrub-like than in tropical climes in part due to the aboveground structural damage and vigorous multi-stem regrowth triggered by extreme winter temperatures. In this study, we developed aboveground allometric equations for freeze-affected black mangroves which can be used to quantify: (1 total aboveground biomass; (2 leaf biomass; (3 stem plus branch biomass; and (4 leaf area. Plant volume (i.e., a combination of crown area and plant height was selected as the optimal predictor of the four response variables. We expect that our simple measurements and equations can be adapted for use in other mangrove ecosystems located in abiotic settings that result in mangrove individuals with dwarf or shrub-like morphologies including oligotrophic and arid environments. Many important ecological functions and services are affected by changes in coastal wetland plant community structure and productivity including carbon storage, nutrient cycling, coastal protection, recreation, fish and avian habitat, and ecosystem response to sea level rise and extreme climatic events. Coastal scientists in the southeastern United States can use the identified allometric equations, in combination with easily obtained and non-destructive plant volume measurements, to better quantify and monitor ecological change within the dynamic, climate sensitive, and highly-productive mangrove-marsh ecotone.

  10. Should I Gain Weight?

    Science.gov (United States)

    ... Videos for Educators Search English Español Should I Gain Weight? KidsHealth / For Teens / Should I Gain Weight? ... something about it. Why Do People Want to Gain Weight? Some of the reasons people give for ...

  11. Evaluating lidar point densities for effective estimation of aboveground biomass

    Science.gov (United States)

    Wu, Zhuoting; Dye, Dennis G.; Stoker, Jason M.; Vogel, John M.; Velasco, Miguel G.; Middleton, Barry R.

    2016-01-01

    The U.S. Geological Survey (USGS) 3D Elevation Program (3DEP) was recently established to provide airborne lidar data coverage on a national scale. As part of a broader research effort of the USGS to develop an effective remote sensing-based methodology for the creation of an operational biomass Essential Climate Variable (Biomass ECV) data product, we evaluated the performance of airborne lidar data at various pulse densities against Landsat 8 satellite imagery in estimating above ground biomass for forests and woodlands in a study area in east-central Arizona, U.S. High point density airborne lidar data, were randomly sampled to produce five lidar datasets with reduced densities ranging from 0.5 to 8 point(s)/m2, corresponding to the point density range of 3DEP to provide national lidar coverage over time. Lidar-derived aboveground biomass estimate errors showed an overall decreasing trend as lidar point density increased from 0.5 to 8 points/m2. Landsat 8-based aboveground biomass estimates produced errors larger than the lowest lidar point density of 0.5 point/m2, and therefore Landsat 8 observations alone were ineffective relative to airborne lidar for generating a Biomass ECV product, at least for the forest and woodland vegetation types of the Southwestern U.S. While a national Biomass ECV product with optimal accuracy could potentially be achieved with 3DEP data at 8 points/m2, our results indicate that even lower density lidar data could be sufficient to provide a national Biomass ECV product with accuracies significantly higher than that from Landsat observations alone.

  12. High Throughput Determination of Plant Height, Ground Cover, and Above-Ground Biomass in Wheat with LiDAR.

    Science.gov (United States)

    Jimenez-Berni, Jose A; Deery, David M; Rozas-Larraondo, Pablo; Condon, Anthony Tony G; Rebetzke, Greg J; James, Richard A; Bovill, William D; Furbank, Robert T; Sirault, Xavier R R

    2018-01-01

    Crop improvement efforts are targeting increased above-ground biomass and radiation-use efficiency as drivers for greater yield. Early ground cover and canopy height contribute to biomass production, but manual measurements of these traits, and in particular above-ground biomass, are slow and labor-intensive, more so when made at multiple developmental stages. These constraints limit the ability to capture these data in a temporal fashion, hampering insights that could be gained from multi-dimensional data. Here we demonstrate the capacity of Light Detection and Ranging (LiDAR), mounted on a lightweight, mobile, ground-based platform, for rapid multi-temporal and non-destructive estimation of canopy height, ground cover and above-ground biomass. Field validation of LiDAR measurements is presented. For canopy height, strong relationships with LiDAR ( r 2 of 0.99 and root mean square error of 0.017 m) were obtained. Ground cover was estimated from LiDAR using two methodologies: red reflectance image and canopy height. In contrast to NDVI, LiDAR was not affected by saturation at high ground cover, and the comparison of both LiDAR methodologies showed strong association ( r 2 = 0.92 and slope = 1.02) at ground cover above 0.8. For above-ground biomass, a dedicated field experiment was performed with destructive biomass sampled eight times across different developmental stages. Two methodologies are presented for the estimation of biomass from LiDAR: 3D voxel index (3DVI) and 3D profile index (3DPI). The parameters involved in the calculation of 3DVI and 3DPI were optimized for each sample event from tillering to maturity, as well as generalized for any developmental stage. Individual sample point predictions were strong while predictions across all eight sample events, provided the strongest association with biomass ( r 2 = 0.93 and r 2 = 0.92) for 3DPI and 3DVI, respectively. Given these results, we believe that application of this system will provide new

  13. Amazon forest carbon dynamics predicted by profiles of canopy leaf area and light environment

    Science.gov (United States)

    S. C. Stark; V. Leitold; J. L. Wu; M. O. Hunter; C. V. de Castilho; F. R. C. Costa; S. M. McMahon; G. G. Parker; M. Takako Shimabukuro; M. A. Lefsky; M. Keller; L. F. Alves; J. Schietti; Y. E. Shimabukuro; D. O. Brandao; T. K. Woodcock; N. Higuchi; P. B de Camargo; R. C. de Oliveira; S. R. Saleska

    2012-01-01

    Tropical forest structural variation across heterogeneous landscapes may control above-ground carbon dynamics. We tested the hypothesis that canopy structure (leaf area and light availability) – remotely estimated from LiDAR – control variation in above-ground coarse wood production (biomass growth). Using a statistical model, these factors predicted biomass growth...

  14. Costs of jasmonic acid induced defense in aboveground and belowground parts of corn (Zea mays L.).

    Science.gov (United States)

    Feng, Yuanjiao; Wang, Jianwu; Luo, Shiming; Fan, Huizhi; Jin, Qiong

    2012-08-01

    Costs of jasmonic acid (JA) induced plant defense have gained increasing attention. In this study, JA was applied continuously to the aboveground (AG) or belowground (BG) parts, or AG plus BG parts of corn (Zea mays L.) to investigate whether JA exposure in one part of the plant would affect defense responses in another part, and whether or not JA induced defense would incur allocation costs. The results indicated that continuous JA application to AG parts systemically affected the quantities of defense chemicals in the roots, and vice versa. Quantities of DIMBOA and total amounts of phenolic compounds in leaves or roots generally increased 2 or 4 wk after the JA treatment to different plant parts. In the first 2 wk after application, the increase of defense chemicals in leaves and roots was accompanied by a significant decrease of root length, root surface area, and root biomass. Four weeks after the JA application, however, no such costs for the increase of defense chemicals in leaves and roots were detected. Instead, shoot biomass and root biomass increased. The results suggest that JA as a defense signal can be transferred from AG parts to BG parts of corn, and vice versa. Costs for induced defense elicited by continuous JA application were found in the early 2 wk, while distinct benefits were observed later, i.e., 4 wk after JA treatment.

  15. Over-expressing the C3 photosynthesis cycle enzyme Sedoheptulose-1-7 Bisphosphatase improves photosynthetic carbon gain and yield under fully open air CO2 fumigation (FACE)

    Science.gov (United States)

    2011-01-01

    Background Biochemical models predict that photosynthesis in C3 plants is most frequently limited by the slower of two processes, the maximum capacity of the enzyme Rubisco to carboxylate RuBP (Vc,max), or the regeneration of RuBP via electron transport (J). At current atmospheric [CO2] levels Rubisco is not saturated; consequently, elevating [CO2] increases the velocity of carboxylation and inhibits the competing oxygenation reaction which is also catalyzed by Rubisco. In the future, leaf photosynthesis (A) should be increasingly limited by RuBP regeneration, as [CO2] is predicted to exceed 550 ppm by 2050. The C3 cycle enzyme sedoheptulose-1,7 bisphosphatase (SBPase, EC 3.1.3.17) has been shown to exert strong metabolic control over RuBP regeneration at light saturation. Results We tested the hypothesis that tobacco transformed to overexpressing SBPase will exhibit greater stimulation of A than wild type (WT) tobacco when grown under field conditions at elevated [CO2] (585 ppm) under fully open air fumigation. Growth under elevated [CO2] stimulated instantaneous A and the diurnal photosynthetic integral (A') more in transformants than WT. There was evidence of photosynthetic acclimation to elevated [CO2] via downregulation of Vc,max in both WT and transformants. Nevertheless, greater carbon assimilation and electron transport rates (J and Jmax) for transformants led to greater yield increases than WT at elevated [CO2] compared to ambient grown plants. Conclusion These results provide proof of concept that increasing content and activity of a single photosynthesis enzyme can enhance carbon assimilation and yield of C3 crops grown at [CO2] expected by the middle of the 21st century. PMID:21884586

  16. LEAF AREA DYNAMICS AND ABOVEGROUND BIOMASS OF SPECIFIC VEGETATION TYPES OF A SEMI-ARID GRASSLAND IN SOUTHERN ETHIOPIA

    Directory of Open Access Journals (Sweden)

    Bosco Kidake Kisambo

    2016-12-01

    Full Text Available Leaf Area Index (LAI dynamics and aboveground biomass of a semi-arid grassland region in Southern Ethiopia were determined over a long rain season. The vegetation was categorized into four distinct vegetation types namely Grassland (G, Tree-Grassland (TG, Bushed-Grassland (BG and Bush-Tree grassland (BT. LAI was measured using a Plant Canopy Analyzer (LAI2000. Biomass dynamics of litter and herbaceous components were determined through clipping while the above ground biomass of trees and shrubs were estimated using species-specific allometric equations from literature. LAI showed a seasonal increase over the season with the maximum recorded in the BG vegetation (2.52. Total aboveground biomass for the different vegetation types ranged from 0.61 ton C/ha in areas where trees were non-existent to 8.80 ± 3.81ton C/ha in the Tree-Grassland vegetation in the study site. A correlation of LAI and AGB yielded a positive relationship with an R2 value of 0.55. The results demonstrate the importance of tropical semi-arid grasslands as carbon sinks hence their potential in mitigation of climate change.

  17. Modeling aboveground biomass of Tamarix ramosissima in the Arkansas River Basin of Southeastern Colorado, USA

    Science.gov (United States)

    Evangelista, P.; Kumar, S.; Stohlgren, T.J.; Crall, A.W.; Newman, G.J.

    2007-01-01

    Predictive models of aboveground biomass of nonnative Tamarix ramosissima of various sizes were developed using destructive sampling techniques on 50 individuals and four 100-m2 plots. Each sample was measured for average height (m) of stems and canopy area (m2) prior to cutting, drying, and weighing. Five competing regression models (P < 0.05) were developed to estimate aboveground biomass of T. ramosissima using average height and/or canopy area measurements and were evaluated using Akaike's Information Criterion corrected for small sample size (AICc). Our best model (AICc = -148.69, ??AICc = 0) successfully predicted T. ramosissima aboveground biomass (R2 = 0.97) and used average height and canopy area as predictors. Our 2nd-best model, using the same predictors, was also successful in predicting aboveground biomass (R2 = 0.97, AICc = -131.71, ??AICc = 16.98). A 3rd model demonstrated high correlation between only aboveground biomass and canopy area (R2 = 0.95), while 2 additional models found high correlations between aboveground biomass and average height measurements only (R2 = 0.90 and 0.70, respectively). These models illustrate how simple field measurements, such as height and canopy area, can be used in allometric relationships to accurately predict aboveground biomass of T. ramosissima. Although a correction factor may be necessary for predictions at larger scales, the models presented will prove useful for many research and management initiatives.

  18. Spatially explicit estimation of aboveground boreal forest biomass in the Yukon River Basin, Alaska

    Science.gov (United States)

    Ji, Lei; Wylie, Bruce K.; Brown, Dana R. N.; Peterson, Birgit E.; Alexander, Heather D.; Mack, Michelle C.; Rover, Jennifer R.; Waldrop, Mark P.; McFarland, Jack W.; Chen, Xuexia; Pastick, Neal J.

    2015-01-01

    Quantification of aboveground biomass (AGB) in Alaska’s boreal forest is essential to the accurate evaluation of terrestrial carbon stocks and dynamics in northern high-latitude ecosystems. Our goal was to map AGB at 30 m resolution for the boreal forest in the Yukon River Basin of Alaska using Landsat data and ground measurements. We acquired Landsat images to generate a 3-year (2008–2010) composite of top-of-atmosphere reflectance for six bands as well as the brightness temperature (BT). We constructed a multiple regression model using field-observed AGB and Landsat-derived reflectance, BT, and vegetation indices. A basin-wide boreal forest AGB map at 30 m resolution was generated by applying the regression model to the Landsat composite. The fivefold cross-validation with field measurements had a mean absolute error (MAE) of 25.7 Mg ha−1 (relative MAE 47.5%) and a mean bias error (MBE) of 4.3 Mg ha−1(relative MBE 7.9%). The boreal forest AGB product was compared with lidar-based vegetation height data; the comparison indicated that there was a significant correlation between the two data sets.

  19. Remote Sensing of Aboveground Biomass in Tropical Secondary Forests: A Review

    Directory of Open Access Journals (Sweden)

    J. M. Barbosa

    2014-01-01

    Full Text Available Tropical landscapes are, in general, a mosaic of pasture, agriculture, and forest undergoing various stages of succession. Forest succession is comprised of continuous structural changes over time and results in increases in aboveground biomass (AGB. New remote sensing methods, including sensors, image processing, statistical methods, and uncertainty evaluations, are constantly being developed to estimate biophysical forest changes. We review 318 peer-reviewed studies related to the use of remotely sensed AGB estimations in tropical forest succession studies and summarize their geographic distribution, sensors and methods used, and their most frequent ecological inferences. Remotely sensed AGB is broadly used in forest management studies, conservation status evaluations, carbon source and sink investigations, and for studies of the relationships between environmental conditions and forest structure. Uncertainties in AGB estimations were found to be heterogeneous with biases related to sensor type, processing methodology, ground truthing availability, and forest characteristics. Remotely sensed AGB of successional forests is more reliable for the study of spatial patterns of forest succession and over large time scales than that of individual stands. Remote sensing of temporal patterns in biomass requires further study, in particular, as it is critical for understanding forest regrowth at scales useful for regional or global analyses.

  20. Detrital carbon pools in temperate forests: magnitude and potential for landscape-scale assessment

    Science.gov (United States)

    John Bradford; Peter Weishampel; Marie-Louise Smith; Randall Kolka; Richard A. Birdsey; Scott V. Ollinger; Michael G. Ryan

    2009-01-01

    Reliably estimating carbon storage and cycling in detrital biomass is an obstacle to carbon accounting. We examined carbon pools and fluxes in three small temperate forest landscapes to assess the magnitude of carbon stored in detrital biomass and determine whether detrital carbon storage is related to stand structural properties (leaf area, aboveground biomass,...

  1. Extraction and textural characterization of above-ground areas from aerial stereo pairs: a quality assessment

    Science.gov (United States)

    Baillard, C.; Dissard, O.; Jamet, O.; Maître, H.

    Above-ground analysis is a key point to the reconstruction of urban scenes, but it is a difficult task because of the diversity of the involved objects. We propose a new method to above-ground extraction from an aerial stereo pair, which does not require any assumption about object shape or nature. A Digital Surface Model is first produced by a stereoscopic matching stage preserving discontinuities, and then processed by a region-based Markovian classification algorithm. The produced above-ground areas are finally characterized as man-made or natural according to the grey level information. The quality of the results is assessed and discussed.

  2. Aboveground mechanical stimuli affect belowground plant-plant communication.

    Science.gov (United States)

    Elhakeem, Ali; Markovic, Dimitrije; Broberg, Anders; Anten, Niels P R; Ninkovic, Velemir

    2018-01-01

    Plants can detect the presence of their neighbours and modify their growth behaviour accordingly. But the extent to which this neighbour detection is mediated by abiotic stressors is not well known. In this study we tested the acclimation response of Zea mays L. seedlings through belowground interactions to the presence of their siblings exposed to brief mechano stimuli. Maize seedling simultaneously shared the growth solution of touched plants or they were transferred to the growth solution of previously touched plants. We tested the growth preferences of newly germinated seedlings toward the growth solution of touched (T_solution) or untouched plants (C_solution). The primary root of the newly germinated seedlings grew significantly less towards T_solution than to C_solution. Plants transferred to T_solution allocated more biomass to shoots and less to roots. While plants that simultaneously shared their growth solution with the touched plants produced more biomass. Results show that plant responses to neighbours can be modified by aboveground abiotic stress to those neighbours and suggest that these modifications are mediated by belowground interactions.

  3. Aboveground mechanical stimuli affect belowground plant-plant communication.

    Directory of Open Access Journals (Sweden)

    Ali Elhakeem

    Full Text Available Plants can detect the presence of their neighbours and modify their growth behaviour accordingly. But the extent to which this neighbour detection is mediated by abiotic stressors is not well known. In this study we tested the acclimation response of Zea mays L. seedlings through belowground interactions to the presence of their siblings exposed to brief mechano stimuli. Maize seedling simultaneously shared the growth solution of touched plants or they were transferred to the growth solution of previously touched plants. We tested the growth preferences of newly germinated seedlings toward the growth solution of touched (T_solution or untouched plants (C_solution. The primary root of the newly germinated seedlings grew significantly less towards T_solution than to C_solution. Plants transferred to T_solution allocated more biomass to shoots and less to roots. While plants that simultaneously shared their growth solution with the touched plants produced more biomass. Results show that plant responses to neighbours can be modified by aboveground abiotic stress to those neighbours and suggest that these modifications are mediated by belowground interactions.

  4. Canopy area of large trees explains aboveground biomass variations across neotropical forest landscapes

    Science.gov (United States)

    Meyer, Victoria; Saatchi, Sassan; Clark, David B.; Keller, Michael; Vincent, Grégoire; Ferraz, António; Espírito-Santo, Fernando; d'Oliveira, Marcus V. N.; Kaki, Dahlia; Chave, Jérôme

    2018-06-01

    Large tropical trees store significant amounts of carbon in woody components and their distribution plays an important role in forest carbon stocks and dynamics. Here, we explore the properties of a new lidar-derived index, the large tree canopy area (LCA) defined as the area occupied by canopy above a reference height. We hypothesize that this simple measure of forest structure representing the crown area of large canopy trees could consistently explain the landscape variations in forest volume and aboveground biomass (AGB) across a range of climate and edaphic conditions. To test this hypothesis, we assembled a unique dataset of high-resolution airborne light detection and ranging (lidar) and ground inventory data in nine undisturbed old-growth Neotropical forests, of which four had plots large enough (1 ha) to calibrate our model. We found that the LCA for trees greater than 27 m (˜ 25-30 m) in height and at least 100 m2 crown size in a unit area (1 ha), explains more than 75 % of total forest volume variations, irrespective of the forest biogeographic conditions. When weighted by average wood density of the stand, LCA can be used as an unbiased estimator of AGB across sites (R2 = 0.78, RMSE = 46.02 Mg ha-1, bias = -0.63 Mg ha-1). Unlike other lidar-derived metrics with complex nonlinear relations to biomass, the relationship between LCA and AGB is linear and remains unique across forest types. A comparison with tree inventories across the study sites indicates that LCA correlates best with the crown area (or basal area) of trees with diameter greater than 50 cm. The spatial invariance of the LCA-AGB relationship across the Neotropics suggests a remarkable regularity of forest structure across the landscape and a new technique for systematic monitoring of large trees for their contribution to AGB and changes associated with selective logging, tree mortality and other types of tropical forest disturbance and dynamics.

  5. Landscape-level effects on aboveground biomass of tropical forests: A conceptual framework.

    Science.gov (United States)

    Melito, Melina; Metzger, Jean Paul; de Oliveira, Alexandre A

    2018-02-01

    Despite the general recognition that fragmentation can reduce forest biomass through edge effects, a systematic review of the literature does not reveal a clear role of edges in modulating biomass loss. Additionally, the edge effects appear to be constrained by matrix type, suggesting that landscape composition has an influence on biomass stocks. The lack of empirical evidence of pervasive edge-related biomass losses across tropical forests highlights the necessity for a general framework linking landscape structure with aboveground biomass. Here, we propose a conceptual model in which landscape composition and configuration mediate the magnitude of edge effects and seed-flux among forest patches, which ultimately has an influence on biomass. Our model hypothesizes that a rapid reduction of biomass can occur below a threshold of forest cover loss. Just below this threshold, we predict that changes in landscape configuration can strongly influence the patch's isolation, thus enhancing biomass loss. Moreover, we expect a synergism between landscape composition and patch attributes, where matrix type mediates the effects of edges on species decline, particularly for shade-tolerant species. To test our conceptual framework, we propose a sampling protocol where the effects of edges, forest amount, forest isolation, fragment size, and matrix type on biomass stocks can be assessed both collectively and individually. The proposed model unifies the combined effects of landscape and patch structure on biomass into a single framework, providing a new set of main drivers of biomass loss in human-modified landscapes. We argue that carbon trading agendas (e.g., REDD+) and carbon-conservation initiatives must go beyond the effects of forest loss and edges on biomass, considering the whole set of effects on biomass related to changes in landscape composition and configuration. © 2017 John Wiley & Sons Ltd.

  6. Weight Gain during Pregnancy

    Science.gov (United States)

    ... Global Map Premature Birth Report Cards Careers Archives Pregnancy Before or between pregnancies Nutrition, weight & fitness Prenatal ... fitness > Weight gain during pregnancy Weight gain during pregnancy E-mail to a friend Please fill in ...

  7. Preventing Weight Gain

    Science.gov (United States)

    ... Local Programs Related Topics Diabetes Nutrition Preventing Weight Gain Language: English (US) Español (Spanish) Recommend on Facebook ... cancer. Choosing an Eating Plan to Prevent Weight Gain So, how do you choose a healthful eating ...

  8. Siberian Boreal Forest Aboveground Biomass and Fire Scar Maps, Russia, 1969-2007

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides 30-meter resolution mapped estimates of Cajander larch (Larix cajanderi) aboveground biomass (AGB), circa 2007, and a map of burn perimeters...

  9. Relationships at the aboveground-belowground interface: plants, soil biota and soil processes

    NARCIS (Netherlands)

    Porazinska, D.L.; Bardgett, R.D.; Postma-Blaauw, M.B.; Hunt, H.W.; Parsons, A.N.; Seastedt, T.R.; Wall, D.M.

    2003-01-01

    Interactions at the aboveground-below ground interface provide important feedbacks that regulate ecosystem processes. Organisms within soil food webs are involved in processes of decomposition and nutrient mineralization, and their abundance and activity have been linked to plant ecophysiological

  10. Technical basis for the aboveground structure failure and associated represented hazardous conditions

    International Nuclear Information System (INIS)

    GOETZ, T.G.

    2003-01-01

    This technical basis document describes the risk binning process and the technical basis for assigning risk bins for the aboveground structure failure representative accident and associated represented hazardous conditions. This document was developed to support the documented safety analysis

  11. Improved Forest Biomass and Carbon Estimations Using Texture Measures from WorldView-2 Satellite Data

    Directory of Open Access Journals (Sweden)

    Sandra Eckert

    2012-03-01

    Full Text Available Accurate estimation of aboveground biomass and carbon stock has gained importance in the context of the United Nations Framework Convention on Climate Change (UNFCCC and the Kyoto Protocol. In order to develop improved forest stratum–specific aboveground biomass and carbon estimation models for humid rainforest in northeast Madagascar, this study analyzed texture measures derived from WorldView-2 satellite data. A forest inventory was conducted to develop stratum-specific allometric equations for dry biomass. On this basis, carbon was calculated by applying a conversion factor. After satellite data preprocessing, vegetation indices, principal components, and texture measures were calculated. The strength of their relationships with the stratum-specific plot data was analyzed using Pearson’s correlation. Biomass and carbon estimation models were developed by performing stepwise multiple linear regression. Pearson’s correlation coefficients revealed that (a texture measures correlated more with biomass and carbon than spectral parameters, and (b correlations were stronger for degraded forest than for non-degraded forest. For degraded forest, the texture measures of Correlation, Angular Second Moment, and Contrast, derived from the red band, contributed to the best estimation model, which explained 84% of the variability in the field data (relative RMSE = 6.8%. For non-degraded forest, the vegetation index EVI and the texture measures of Variance, Mean, and Correlation, derived from the newly introduced coastal blue band, both NIR bands, and the red band, contributed to the best model, which explained 81% of the variability in the field data (relative RMSE = 11.8%. These results indicate that estimation of tropical rainforest biomass/carbon, based on very high resolution satellite data, can be improved by (a developing and applying forest stratum–specific models, and (b including textural information in addition to spectral information.

  12. The importance of forest structure for carbon fluxes of the Amazon rainforest

    Science.gov (United States)

    Rödig, Edna; Cuntz, Matthias; Rammig, Anja; Fischer, Rico; Taubert, Franziska; Huth, Andreas

    2018-05-01

    Precise descriptions of forest productivity, biomass, and structure are essential for understanding ecosystem responses to climatic and anthropogenic changes. However, relations between these components are complex, in particular for tropical forests. We developed an approach to simulate carbon dynamics in the Amazon rainforest including around 410 billion individual trees within 7.8 million km2. We integrated canopy height observations from space-borne LIDAR in order to quantify spatial variations in forest state and structure reflecting small-scale to large-scale natural and anthropogenic disturbances. Under current conditions, we identified the Amazon rainforest as a carbon sink, gaining 0.56 GtC per year. This carbon sink is driven by an estimated mean gross primary productivity (GPP) of 25.1 tC ha‑1 a‑1, and a mean woody aboveground net primary productivity (wANPP) of 4.2 tC ha‑1 a‑1. We found that successional states play an important role for the relations between productivity and biomass. Forests in early to intermediate successional states are the most productive, and woody above-ground carbon use efficiencies are non-linear. Simulated values can be compared to observed carbon fluxes at various spatial resolutions (>40 m). Notably, we found that our GPP corresponds to the values derived from MODIS. For NPP, spatial differences can be observed due to the consideration of forest successional states in our approach. We conclude that forest structure has a substantial impact on productivity and biomass. It is an essential factor that should be taken into account when estimating current carbon budgets or analyzing climate change scenarios for the Amazon rainforest.

  13. Experimental effects of herbivore density on above-ground plant biomass in an alpine grassland ecosystem

    OpenAIRE

    Austrheim, Gunnar; Speed, James David Mervyn; Martinsen, Vegard; Mulder, Jan; Mysterud, Atle

    2014-01-01

    Herbivores may increase or decrease aboveground plant productivity depending on factors such as herbivore density and habitat productivity. The grazing optimization hypothesis predicts a peak in plant production at intermediate herbivore densities, but has rarely been tested experimentally in an alpine field setting. In an experimental design with three densities of sheep (high, low, and no sheep), we harvested aboveground plant biomass in alpine grasslands prior to treatment and after five y...

  14. [Spatial distribution of aboveground biomass of shrubs in Tianlaochi catchment of the Qilian Mountains].

    Science.gov (United States)

    Liang, Bei; Di, Li; Zhao, Chuan-Yan; Peng, Shou-Zhang; Peng, Huan-Hua; Wang, Chao

    2014-02-01

    This study estimated the spatial distribution of the aboveground biomass of shrubs in the Tianlaochi catchment of Qilian Mountains based on the field survey and remote sensing data. A relationship model of the aboveground biomass and its feasibly measured factors (i. e. , canopy perimeter and plant height) was built. The land use was classified by object-oriented technique with the high resolution image (GeoEye-1) of the study area, and the distribution of shrub coverage was extracted. Then the total aboveground biomass of shrubs in the study area was estimated by the relationship model with the distribution of shrub coverage. The results showed that the aboveground biomass of shrubs in the study area was 1.8 x 10(3) t and the aboveground biomass per unit area was 1598.45 kg x m(-2). The distribution of shrubs mainly was at altitudes of 3000-3700 m, and the aboveground biomass of shrubs on the sunny slope (1.15 x 10(3) t) was higher than that on the shady slope (0.65 x 10(3) t).

  15. Mapping Global Forest Aboveground Biomass with Spaceborne LiDAR, Optical Imagery, and Forest Inventory Data

    Directory of Open Access Journals (Sweden)

    Tianyu Hu

    2016-07-01

    Full Text Available As a large carbon pool, global forest ecosystems are a critical component of the global carbon cycle. Accurate estimations of global forest aboveground biomass (AGB can improve the understanding of global carbon dynamics and help to quantify anthropogenic carbon emissions. Light detection and ranging (LiDAR techniques have been proven that can accurately capture both horizontal and vertical forest structures and increase the accuracy of forest AGB estimation. In this study, we mapped the global forest AGB density at a 1-km resolution through the integration of ground inventory data, optical imagery, Geoscience Laser Altimeter System/Ice, Cloud, and Land Elevation Satellite data, climate surfaces, and topographic data. Over 4000 ground inventory records were collected from published literatures to train the forest AGB estimation model and validate the resulting global forest AGB product. Our wall-to-wall global forest AGB map showed that the global forest AGB density was 210.09 Mg/ha on average, with a standard deviation of 109.31 Mg/ha. At the continental level, Africa (333.34 ± 63.80 Mg/ha and South America (301.68 ± 67.43 Mg/ha had higher AGB density. The AGB density in Asia, North America and Europe were 172.28 ± 94.75, 166.48 ± 84.97, and 132.97 ± 50.70 Mg/ha, respectively. The wall-to-wall forest AGB map was evaluated at plot level using independent plot measurements. The adjusted coefficient of determination (R2 and root-mean-square error (RMSE between our predicted results and the validation plots were 0.56 and 87.53 Mg/ha, respectively. At the ecological zone level, the R2 and RMSE between our map and Intergovernmental Panel on Climate Change suggested values were 0.56 and 101.21 Mg/ha, respectively. Moreover, a comprehensive comparison was also conducted between our forest AGB map and other published regional AGB products. Overall, our forest AGB map showed good agreements with these regional AGB products, but some of the regional

  16. Aboveground Whitefly Infestation-Mediated Reshaping of the Root Microbiota.

    Science.gov (United States)

    Kong, Hyun G; Kim, Byung K; Song, Geun C; Lee, Soohyun; Ryu, Choong-Min

    2016-01-01

    study provides a new framework for investigating how aboveground insect feeding modulates the belowground microbiome.

  17. Aboveground Whitefly Infestation-mediated Reshaping of the Root Microbiota

    Directory of Open Access Journals (Sweden)

    Hyun Gi Kong

    2016-09-01

    framework for investigating how aboveground insect feeding modulates the belowground microbiome

  18. Dynamics, aboveground biomass and composition on permanent plots, Tambopata National Reserve. Madre de Dios, Peru

    Directory of Open Access Journals (Sweden)

    Nadir C. Pallqui

    2014-12-01

    Full Text Available In this study we evaluated the floristic composition and changes in stored biomass and dynamics over time in 9 permanent plots monitored by RAINFOR (Amazon Forest Inventory Network and located in the lowland Amazon rainforest of the Tambopata National Reserve. Data were acquired in the field using the standardized methodology of RAINFOR. The biomass was estimated using the equation for tropical moist forests of Chave et al. (2005. Biomass dynamics were analyzed, in three separated periods from 2003 to 2011. 64 families, 219 genera and 531 species were recorded. The tree floristic composition is very similar in all plots except for one swamp plot, although but it is also evident that two slightly different forest communities exist in the rest of landscape, apparently related to the age of the ancient river terraces in the area. Mortality and recruitment of individuals averaged 2.12 ± 0.52% and 1.92 ± 0.49%, respectively. The turnover rate is 2.02% per year. Aboveground biomass stored in these forests averages 296.2 ± 33.9 t ha-1. The biomass dynamics show a total net gain of 1.96, 1.69 and –1.23 t ha-1 for period respectively. Prior to the drought of 2010 a change in biomass was found 1.88 t ha-1 yr-1 and post drought was -0.18 t ha-1 yr-1 on average, though the difference is not significant. Demographic analysis suggests a dynamic equilibrium in the plots. The negative balance of biomass observed for the period 2008 – 2011 may be due to the drought of 2010, in which half of the monitored plots experienced negative net biomass change due to mortality of individuals selectively affecting the floristic composition.

  19. Net carbon exchange across the Arctic tundra-boreal forest transition in Alaska 1981-2000

    Science.gov (United States)

    Thompson, Catharine Copass; McGuire, A.D.; Clein, Joy S.; Chapin, F. S.; Beringer, J.

    2006-01-01

    Shifts in the carbon balance of high-latitude ecosystems could result from differential responses of vegetation and soil processes to changing moisture and temperature regimes and to a lengthening of the growing season. Although shrub expansion and northward movement of treeline should increase carbon inputs, the effects of these vegetation changes on net carbon exchange have not been evaluated. We selected low shrub, tall shrub, and forest tundra sites near treeline in northwestern Alaska, representing the major structural transitions expected in response to warming. In these sites, we measured aboveground net primary production (ANPP) and vegetation and soil carbon and nitrogen pools, and used these data to parameterize the Terrestrial Ecosystem Model. We simulated the response of carbon balance components to air temperature and precipitation trends during 1981-2000. In areas experiencing warmer and dryer conditions, Net Primary Production (NPP) decreased and heterotrophic respiration (R H ) increased, leading to a decrease in Net Ecosystem Production (NEP). In warmer and wetter conditions NPP increased, but the response was exceeded by an increase in R H ; therefore, NEP also decreased. Lastly, in colder and wetter regions, the increase in NPP exceeded a small decline in R H , leading to an increase in NEP. The net effect for the region was a slight gain in ecosystem carbon storage over the 20 year period. This research highlights the potential importance of spatial variability in ecosystem responses to climate change in assessing the response of carbon storage in northern Alaska over the last two decades. ?? Springer 2005.

  20. [Simulating the effects of climate change and fire disturbance on aboveground biomass of boreal forests in the Great Xing'an Mountains, Northeast China].

    Science.gov (United States)

    Luo, Xu; Wang, Yu Li; Zhang, Jin Quan

    2018-03-01

    Predicting the effects of climate warming and fire disturbance on forest aboveground biomass is a central task of studies in terrestrial ecosystem carbon cycle. The alteration of temperature, precipitation, and disturbance regimes induced by climate warming will affect the carbon dynamics of forest ecosystem. Boreal forest is an important forest type in China, the responses of which to climate warming and fire disturbance are increasingly obvious. In this study, we used a forest landscape model LANDIS PRO to simulate the effects of climate change on aboveground biomass of boreal forests in the Great Xing'an Mountains, and compared direct effects of climate warming and the effects of climate warming-induced fires on forest aboveground biomass. The results showed that the aboveground biomass in this area increased under climate warming scenarios and fire disturbance scenarios with increased intensity. Under the current climate and fire regime scenario, the aboveground biomass in this area was (97.14±5.78) t·hm -2 , and the value would increase up to (97.93±5.83) t·hm -2 under the B1F2 scenario. Under the A2F3 scenario, aboveground biomass at landscape scale was relatively higher at the simulated periods of year 100-150 and year 150-200, and the value were (100.02±3.76) t·hm -2 and (110.56±4.08) t·hm -2 , respectively. Compared to the current fire regime scenario, the predicted biomass at landscape scale was increased by (0.56±1.45) t·hm -2 under the CF2 scenario (fire intensity increased by 30%) at some simulated periods, and the aboveground biomass was reduced by (7.39±1.79) t·hm -2 in CF3 scenario (fire intensity increased by 230%) at the entire simulation period. There were significantly different responses between coniferous and broadleaved species under future climate warming scenarios, in that the simulated biomass for both Larix gmelinii and Betula platyphylla showed decreasing trend with climate change, whereas the simulated biomass for Pinus

  1. Growth Response of Aboveground and Belowground of Eustoma grandiflorum to Elevated Co2 in Hydroponic Culture

    Directory of Open Access Journals (Sweden)

    mahin nikoo

    2018-03-01

    Full Text Available Introduction: One of the climate change sign is variation in greenhouse gases in the Earth's atmosphere. Carbon dioxide is the most important greenhouse gas that is released into the atmosphere by humans. It is expected that addition of carbon dioxide could effect the energy balance and global climate. Climate change is effective on agricultural productions. It is clear that different plants have different responses to Co2 variation. These responses are consisting of yield, growth characteristic and variation in root/shoot ratio of plants. On the other hand, using growing media are expanding for plants because of their advantages such as plants nutrient control, reducing the incidence of diseases and pests and increasing the quantity and quality rather than soil cultivation. Properties of various materials as substrates influence directly or indirectly on plant growth and crop production., Hydroponic method can be considered as one of the important methods to optimize water use in agriculture, especially in many countries are located in arid and semi-arid regions that have water crisis. Lisianthus is one of the most beautiful flowers with folded petals in white, blue and purple. I-ts scientific name is Eustoma grandiflorum from the family of Gentianaceae and native to North America. It has variety of annual, biennial or short-lived perennial. The aim of this study was to explore the effect of Co2 enrichment on growth response of aboveground and belowground of Eustoma grandiflorum under increasing of Co2 greenhouse gases in hydroponic culture. Materials and Methods: The experiment was done as a split-plot based on completely randomized experimental design with three replications at greenhouse of Ferdowsi University of Mashhad. The treatments were consists of three concentrations of carbon dioxide (380 as controls, 750 and 1050 ppm as main plots and two cultivars Yodel white and GCREC-blue as subplots. Some characteristic such as plant height

  2. Gestational weight gain.

    Science.gov (United States)

    Kominiarek, Michelle A; Peaceman, Alan M

    2017-12-01

    Prenatal care providers are advised to evaluate maternal weight at each regularly scheduled prenatal visit, monitor progress toward meeting weight gain goals, and provide individualized counseling if significant deviations from a woman's goals occur. Today, nearly 50% of women exceed their weight gain goals with overweight and obese women having the highest prevalence of excessive weight gain. Risks of inadequate weight gain include low birthweight and failure to initiate breast-feeding whereas the risks of excessive weight gain include cesarean deliveries and postpartum weight retention for the mother and large-for-gestational-age infants, macrosomia, and childhood overweight or obesity for the offspring. Prenatal care providers have many resources and tools to incorporate weight and other health behavior counseling into routine prenatal practices. Because many women are motivated to improve health behaviors, pregnancy is often considered the optimal time to intervene for issues related to eating habits and physical activity to prevent excessive weight gain. Gestational weight gain is a potentially modifiable risk factor for a number of adverse maternal and neonatal outcomes and meta-analyses of randomized controlled trials report that diet or exercise interventions during pregnancy can help reduce excessive weight gain. However, health behavior interventions for gestational weight gain have not significantly improved other maternal and neonatal outcomes and have limited effectiveness in overweight and obese women. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Allometric Scaling and Resource Limitations Model of Total Aboveground Biomass in Forest Stands: Site-scale Test of Model

    Science.gov (United States)

    CHOI, S.; Shi, Y.; Ni, X.; Simard, M.; Myneni, R. B.

    2013-12-01

    Sparseness in in-situ observations has precluded the spatially explicit and accurate mapping of forest biomass. The need for large-scale maps has raised various approaches implementing conjugations between forest biomass and geospatial predictors such as climate, forest type, soil property, and topography. Despite the improved modeling techniques (e.g., machine learning and spatial statistics), a common limitation is that biophysical mechanisms governing tree growth are neglected in these black-box type models. The absence of a priori knowledge may lead to false interpretation of modeled results or unexplainable shifts in outputs due to the inconsistent training samples or study sites. Here, we present a gray-box approach combining known biophysical processes and geospatial predictors through parametric optimizations (inversion of reference measures). Total aboveground biomass in forest stands is estimated by incorporating the Forest Inventory and Analysis (FIA) and Parameter-elevation Regressions on Independent Slopes Model (PRISM). Two main premises of this research are: (a) The Allometric Scaling and Resource Limitations (ASRL) theory can provide a relationship between tree geometry and local resource availability constrained by environmental conditions; and (b) The zeroth order theory (size-frequency distribution) can expand individual tree allometry into total aboveground biomass at the forest stand level. In addition to the FIA estimates, two reference maps from the National Biomass and Carbon Dataset (NBCD) and U.S. Forest Service (USFS) were produced to evaluate the model. This research focuses on a site-scale test of the biomass model to explore the robustness of predictors, and to potentially improve models using additional geospatial predictors such as climatic variables, vegetation indices, soil properties, and lidar-/radar-derived altimetry products (or existing forest canopy height maps). As results, the optimized ASRL estimates satisfactorily

  4. Forest Aboveground Biomass Mapping and Canopy Cover Estimation from Simulated ICESat-2 Data

    Science.gov (United States)

    Narine, L.; Popescu, S. C.; Neuenschwander, A. L.

    2017-12-01

    The assessment of forest aboveground biomass (AGB) can contribute to reducing uncertainties associated with the amount and distribution of terrestrial carbon. With a planned launch date of July 2018, the Ice, Cloud and Land Elevation Satellite-2 (ICESat-2) will provide data which will offer the possibility of mapping AGB at global scales. In this study, we develop approaches for utilizing vegetation data that will be delivered in ICESat-2's land-vegetation along track product (ATL08). The specific objectives are to: (1) simulate ICESat-2 photon-counting lidar (PCL) data using airborne lidar data, (2) utilize simulated PCL data to estimate forest canopy cover and AGB and, (3) upscale AGB predictions to create a wall-to-wall AGB map at 30-m spatial resolution. Using existing airborne lidar data for Sam Houston National Forest (SHNF) located in southeastern Texas and known ICESat-2 beam locations, PCL data are simulated from discrete return lidar points. We use multiple linear regression models to relate simulated PCL metrics for 100 m segments along the ICESat-2 ground tracks to AGB from a biomass map developed using airborne lidar data and canopy cover calculated from the same. Random Forest is then used to create an AGB map from predicted estimates and explanatory data consisting of spectral metrics derived from Landsat TM imagery and land cover data from the National Land Cover Database (NLCD). Findings from this study will demonstrate how data that will be acquired by ICESat-2 can be used to estimate forest structure and characterize the spatial distribution of AGB.

  5. Estimation of aboveground biomass in Mediterranean forests by statistical modelling of ASTER fraction images

    Science.gov (United States)

    Fernández-Manso, O.; Fernández-Manso, A.; Quintano, C.

    2014-09-01

    Aboveground biomass (AGB) estimation from optical satellite data is usually based on regression models of original or synthetic bands. To overcome the poor relation between AGB and spectral bands due to mixed-pixels when a medium spatial resolution sensor is considered, we propose to base the AGB estimation on fraction images from Linear Spectral Mixture Analysis (LSMA). Our study area is a managed Mediterranean pine woodland (Pinus pinaster Ait.) in central Spain. A total of 1033 circular field plots were used to estimate AGB from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) optical data. We applied Pearson correlation statistics and stepwise multiple regression to identify suitable predictors from the set of variables of original bands, fraction imagery, Normalized Difference Vegetation Index and Tasselled Cap components. Four linear models and one nonlinear model were tested. A linear combination of ASTER band 2 (red, 0.630-0.690 μm), band 8 (short wave infrared 5, 2.295-2.365 μm) and green vegetation fraction (from LSMA) was the best AGB predictor (Radj2=0.632, the root-mean-squared error of estimated AGB was 13.3 Mg ha-1 (or 37.7%), resulting from cross-validation), rather than other combinations of the above cited independent variables. Results indicated that using ASTER fraction images in regression models improves the AGB estimation in Mediterranean pine forests. The spatial distribution of the estimated AGB, based on a multiple linear regression model, may be used as baseline information for forest managers in future studies, such as quantifying the regional carbon budget, fuel accumulation or monitoring of management practices.

  6. Arbuscular mycorrhizal colonization, plant chemistry, and aboveground herbivory on Senecio jacobaea

    Science.gov (United States)

    Reidinger, Stefan; Eschen, René; Gange, Alan C.; Finch, Paul; Bezemer, T. Martijn

    2012-01-01

    Arbuscular mycorrhizal fungi (AMF) can affect insect herbivores by changing plant growth and chemistry. However, many factors can influence the symbiotic relationship between plant and fungus, potentially obscuring experimental treatments and ecosystem impacts. In a field experiment, we assessed AMF colonization levels of individual ragwort ( Senecio jacobaea) plants growing in grassland plots that were originally sown with 15 or 4 plant species, or were unsown. We measured the concentrations of carbon, nitrogen and pyrrolizidine alkaloids (PAs), and assessed the presence of aboveground insect herbivores on the sampled plants. Total AMF colonization and colonization by arbuscules was lower in plots sown with 15 species than in plots sown with 4 species and unsown plots. AMF colonization was positively related to the cover of oxeye daisy ( Leucanthemum vulgare) and a positive relationship between colonization by arbuscules and the occurrence of a specialist seed-feeding fly ( Pegohylemyia seneciella) was found. The occurrence of stem-boring, leaf-mining and sap-sucking insects was not affected by AMF colonization. Total PA concentrations were negatively related to colonization levels by vesicles, but did not differ among the sowing treatments. No single factor explained the observed differences in AMF colonization among the sowing treatments or insect herbivore occurrence on S. jacobaea. However, correlations across the treatments suggest that some of the variation was due to the abundance of one plant species, which is known to stimulate AMF colonization of neighbouring plants, while AMF colonization was related to the occurrence of a specialist insect herbivore. Our results thus illustrate that in natural systems, the ecosystem impact of AMF through their influence on the occurrence of specialist insects can be recognised, but they also highlight the confounding effect of neighbouring plant species identity. Hence, our results emphasise the importance of field

  7. Estimating forest and woodland aboveground biomass using active and passive remote sensing

    Science.gov (United States)

    Wu, Zhuoting; Dye, Dennis G.; Vogel, John M.; Middleton, Barry R.

    2016-01-01

    Aboveground biomass was estimated from active and passive remote sensing sources, including airborne lidar and Landsat-8 satellites, in an eastern Arizona (USA) study area comprised of forest and woodland ecosystems. Compared to field measurements, airborne lidar enabled direct estimation of individual tree height with a slope of 0.98 (R2 = 0.98). At the plot-level, lidar-derived height and intensity metrics provided the most robust estimate for aboveground biomass, producing dominant species-based aboveground models with errors ranging from 4 to 14Mg ha –1 across all woodland and forest species. Landsat-8 imagery produced dominant species-based aboveground biomass models with errors ranging from 10 to 28 Mg ha –1. Thus, airborne lidar allowed for estimates for fine-scale aboveground biomass mapping with low uncertainty, while Landsat-8 seems best suited for broader spatial scale products such as a national biomass essential climate variable (ECV) based on land cover types for the United States.

  8. Net aboveground biomass declines of four major forest types with forest ageing and climate change in western Canada's boreal forests.

    Science.gov (United States)

    Chen, Han Y H; Luo, Yong

    2015-10-01

    Biomass change of the world's forests is critical to the global carbon cycle. Despite storing nearly half of global forest carbon, the boreal biome of diverse forest types and ages is a poorly understood component of the carbon cycle. Using data from 871 permanent plots in the western boreal forest of Canada, we examined net annual aboveground biomass change (ΔAGB) of four major forest types between 1958 and 2011. We found that ΔAGB was higher for deciduous broadleaf (DEC) (1.44 Mg ha(-1)  year(-1) , 95% Bayesian confidence interval (CI), 1.22-1.68) and early-successional coniferous forests (ESC) (1.42, CI, 1.30-1.56) than mixed forests (MIX) (0.80, CI, 0.50-1.11) and late-successional coniferous (LSC) forests (0.62, CI, 0.39-0.88). ΔAGB declined with forest age as well as calendar year. After accounting for the effects of forest age, ΔAGB declined by 0.035, 0.021, 0.032 and 0.069 Mg ha(-1)  year(-1) per calendar year in DEC, ESC, MIX and LSC forests, respectively. The ΔAGB declines resulted from increased tree mortality and reduced growth in all forest types except DEC, in which a large biomass loss from mortality was accompanied with a small increase in growth. With every degree of annual temperature increase, ΔAGB decreased by 1.00, 0.20, 0.55 and 1.07 Mg ha(-1)  year(-1) in DEC, ESC, MIX and LSC forests, respectively. With every cm decrease of annual climatic moisture availability, ΔAGB decreased 0.030, 0.045 and 0.17 Mg ha(-1)  year(-1) in ESC, MIX and LSC forests, but changed little in DEC forests. Our results suggest that persistent warming and decreasing water availability have profound negative effects on forest biomass in the boreal forests of western Canada. Furthermore, our results indicate that forest responses to climate change are strongly dependent on forest composition with late-successional coniferous forests being most vulnerable to climate changes in terms of aboveground biomass. © 2015 John Wiley & Sons Ltd.

  9. Spatial effects of aboveground biomass on soil ecological parameters and trace gas fluxes in a savannah ecosystem of Mount Kilimanjaro

    Science.gov (United States)

    Becker, Joscha; Gütlein, Adrian; Sierra Cornejo, Natalia; Kiese, Ralf; Hertel, Dietrich; Kuzyakov, Yakov

    2015-04-01

    The savannah biome is a hotspot for biodiversity and wildlife conservation in Africa and recently got in the focus of research on carbon sequestration. Savannah ecosystems are under strong pressure from climate and land-use change, especially around populous areas like the Mt. Kilimanjaro region. Savannah vegetation in this area consists of grassland with isolated trees and is therefore characterized by high spatial variation of canopy cover, aboveground biomass and root structure. Canopy structure is known to affect microclimate, throughfall and evapotranspiration and thereby controls soil moisture conditions. Consequently, the canopy structure is a major regulator for soil ecological parameters and soil-atmospheric trace gas exchange (CO2, N2O, CH4) in water limited environments. The spatial distribution of these parameters and the connection between above and belowground processes are important to understand and predict ecosystem changes and estimate its vulnerability. Our objective was to determine trends and changes of soil parameters and relate their spatial variability to the vegetation structure. We chose three trees from each of the two most dominant species (Acacia nilotica and Balanites aegyptiaca) in our research area. For each tree, we selected transects with nine sampling points of the same relative distances to the stem. Distances were calculated in relation to the crown radius. At these each sampling point a soil core was taken and separated in 0-10 cm and 10-30 cm depth. We measured soil carbon (C) and nitrogen (N) storage, microbial biomass carbon C and N, soil respiration as well as root biomass and -density, soil temperature and soil water content. Each tree was characterized by crown spread, leaf area index and basal area. Preliminary results show that C and N stocks decreased about 50% with depth independently of distance to the tree. Soil water content under the tree crown increased with depth while it decreased under grass cover. Microbial

  10. The relationship between species richness and aboveground biomass in a primary Pinus kesiya forest of Yunnan, southwestern China.

    Science.gov (United States)

    Li, Shuaifeng; Lang, Xuedong; Liu, Wande; Ou, Guanglong; Xu, Hui; Su, Jianrong

    2018-01-01

    The relationship between biodiversity and biomass is an essential element of the natural ecosystem functioning. Our research aims at assessing the effects of species richness on the aboveground biomass and the ecological driver of this relationship in a primary Pinus kesiya forest. We sampled 112 plots of the primary P. kesiya forests in Yunnan Province. The general linear model and the structural equation model were used to estimate relative effects of multivariate factors among aboveground biomass, species richness and the other explanatory variables, including climate moisture index, soil nutrient regime and stand age. We found a positive linear regression relationship between the species richness and aboveground biomass using ordinary least squares regressions. The species richness and soil nutrient regime had no direct significant effect on aboveground biomass. However, the climate moisture index and stand age had direct effects on aboveground biomass. The climate moisture index could be a better link to mediate the relationship between species richness and aboveground biomass. The species richness affected aboveground biomass which was mediated by the climate moisture index. Stand age had direct and indirect effects on aboveground biomass through the climate moisture index. Our results revealed that climate moisture index had a positive feedback in the relationship between species richness and aboveground biomass, which played an important role in a link between biodiversity maintenance and ecosystem functioning. Meanwhile, climate moisture index not only affected positively on aboveground biomass, but also indirectly through species richness. The information would be helpful in understanding the biodiversity-aboveground biomass relationship of a primary P. kesiya forest and for forest management.

  11. Antidepressants and Weight Gain

    Science.gov (United States)

    ... 2015;37:46. Blumenthal SR, et al. An electronic health records study of long-term weight gain following antidepressant ... your agreement to the Terms and Conditions and Privacy Policy linked below. Terms and Conditions Privacy Policy ...

  12. Weight gain - unintentional

    Science.gov (United States)

    ... diabetes Hormone changes or medical problems can also cause unintentional weight gain. This may be due to: Cushing syndrome Underactive thyroid, or low thyroid (hypothyroidism) Polycystic ovary syndrome Menopause Pregnancy Bloating, or swelling ...

  13. Combining Multi-Source Remotely Sensed Data and a Process-Based Model for Forest Aboveground Biomass Updating.

    Science.gov (United States)

    Lu, Xiaoman; Zheng, Guang; Miller, Colton; Alvarado, Ernesto

    2017-09-08

    Monitoring and understanding the spatio-temporal variations of forest aboveground biomass (AGB) is a key basis to quantitatively assess the carbon sequestration capacity of a forest ecosystem. To map and update forest AGB in the Greater Khingan Mountains (GKM) of China, this work proposes a physical-based approach. Based on the baseline forest AGB from Landsat Enhanced Thematic Mapper Plus (ETM+) images in 2008, we dynamically updated the annual forest AGB from 2009 to 2012 by adding the annual AGB increment (ABI) obtained from the simulated daily and annual net primary productivity (NPP) using the Boreal Ecosystem Productivity Simulator (BEPS) model. The 2012 result was validated by both field- and aerial laser scanning (ALS)-based AGBs. The predicted forest AGB for 2012 estimated from the process-based model can explain 31% ( n = 35, p forest AGBs, respectively. However, due to the saturation of optical remote sensing-based spectral signals and contribution of understory vegetation, the BEPS-based AGB tended to underestimate/overestimate the AGB for dense/sparse forests. Generally, our results showed that the remotely sensed forest AGB estimates could serve as the initial carbon pool to parameterize the process-based model for NPP simulation, and the combination of the baseline forest AGB and BEPS model could effectively update the spatiotemporal distribution of forest AGB.

  14. Quantifying Changes in Total and Pyrogenic Carbon Stocks Across Fire Severity Gradients Using Active Wildfire Incidents

    Directory of Open Access Journals (Sweden)

    Jessica Miesel

    2018-05-01

    Full Text Available Positive feedbacks between wildfire emissions and climate are expected to increase in strength in the future; however, fires not only release carbon (C from terrestrial to atmospheric pools, they also produce pyrogenic C (PyC which contributes to longer-term C stability. Our objective was to quantify wildfire impacts on total C and PyC stocks in California mixed-conifer forest, and to investigate patterns in C and PyC stocks and changes across gradients of fire severity, using metrics derived from remote sensing and field observations. Our unique study accessed active wildfires to establish and measure plots within days before and after fire, prior to substantial erosion. We measured pre- and post-fire aboveground forest structure and woody fuels to calculate aboveground biomass, C and PyC, and collected forest floor and 0–5 cm mineral soil samples. Immediate tree mortality increased with severity, but overstory C loss was minimal and limited primarily to foliage. Fire released 85% of understory and herbaceous C (comprising < 1.0% of total ecosystem C. The greatest C losses occurred from downed wood and forest floor pools (19.3 ± 5.1 Mg ha−1 and 25.9 ± 3.2 Mg ha−1, respectively. Tree bark and downed wood contributed the greatest PyC gains (1.5 ± 0.3 Mg ha−1 and 1.9 ± 0.8 Mg ha−1, respectively, and PyC in tree bark showed non-significant positive trends with increasing severity. Overall PyC losses of 1.9 ± 0.3 Mg ha−1 and 0.5 ± 0.1 Mg ha−1 occurred from forest floor and 0–5 cm mineral soil, with no clear patterns across severity. Fire resulted in a net ecosystem PyC gain (1.0 ± 1.0 Mg ha−1 across aboveground and belowground components of these forests, and there were no differences among severity levels. Carbon emissions represented only 21.6% of total forest C; however, extensive conversion of C from live to dead pools will contribute to large downed wood C pools susceptible to release in a subsequent fire, indicating

  15. Aboveground and belowground biomass allocation in native Prosopis caldenia Burkart secondaries woodlands in the semi-arid Argentinean pampas

    International Nuclear Information System (INIS)

    Risio, Lucia; Herrero, Celia; Bogino, Stella M.; Bravo, Felipe

    2014-01-01

    The woodlands in the south-west of the Argentinean pampas are dominated by Prosopis Caldenia Burkart (calden). The current deforestation rate of this woodlands is 0.82% per year. Different compensation initiatives have begun that recognize the role of forests as environmental service providers. The financial incentives they offer make it necessary to quantify the amount of carbon stored in the forest biomass. A model for estimating calden biomass was developed. Thirty-eight trees were selected, felled and divided into sections. An equation system was fitted using joint generalized regression to ensure the additivity property. A weighted regression was used to avoid heteroscedasticity. In these woodlands fire is the main disturbance and it can modify tree allometry, due this all models included the area of the base of the stem and tree height as independent variables since it indirectly collects this variability. Total biomass and the stem fraction had the highest R2 A dj. values (0.75), while branches with a diameter less than 7 cm had the lowest (0.58). Tree biomass was also analyzed by partitioning into the basic fractions of stem, crown, roots, and the root/shoot ratio. Biomass allocation was greatest in the crown fraction and the mean root/shoot ratio was 0.58. The carbon stock of the caldenales considering only calden tree biomass is 20.2 Mg ha −1 . While the overall carbon balance of the region is negative (deforestation and biomass burning, the remnant forested area has increased their calden density and in an indirect way his carbon sequestration capacity could also be increased. - Highlights: • A model for estimating aboveground and belowground Prosopis caldenia biomass was developed. • Biomass allocation into the tree and the root/shoot ratio were analyzed. • The equation systems presented had made it possible to more accurately estimate the biomass stored in calden woodlands

  16. Models for estimation of carbon sequestered by Cupressus ...

    African Journals Online (AJOL)

    This study compared models for estimating carbon sequestered aboveground in Cupressus lusitanica plantation stands at Wondo Genet College of Forestry and Natural Resources, Ethiopia. Relationships of carbon storage with tree component and stand age were also investigated. Thirty trees of three different ages (5, ...

  17. Terrestrial biological carbon sequestration: science for enhancement and implementation

    Science.gov (United States)

    Wilfred M. Post; James E. Amonette; Richard Birdsey; Charles T. Jr. Garten; R. Cesar Izaurralde; Philip Jardine; Julie Jastrow; Rattan Lal; Gregg. Marland

    2009-01-01

    The purpose of this chapter is to review terrestrial biological carbon sequestration and evaluate the potential carbon storage capacity if present and new techniques are more aggressively utilized. Photosynthetic CO2 capture from the atmosphere and storage of the C in aboveground and belowground biomass and in soil organic and inorganic forms can...

  18. Local above-ground persistence of vascular plants : Life-history trade-offs and environmental constraints

    NARCIS (Netherlands)

    Ozinga, Wim A.; Hennekens, Stephan M.; Schaminee, Joop H. J.; Smits, Nina A. C.; Bekker, Renee M.; Roemermann, Christine; Klimes, Leos; Bakker, Jan P.; van Groenendael, Jan M.

    Questions: 1. Which plant traits and habitat characteristics best explain local above-ground persistence of vascular plant species and 2. Is there a trade-off between local above-ground persistence and the ability for seed dispersal and below-ground persistence in the soil seed bank? Locations: 845

  19. Above-ground biomass investments and light interception of tropical forest trees and lianas early in succession

    NARCIS (Netherlands)

    Selaya, N.G.; Anten, N.P.R.; Oomen, R.J.; Matthies, M.; Werger, M.J.A.

    2007-01-01

    Background and Aims Crown structure and above-ground biomass investment was studied in relation to light interception of trees and lianas growing in a 6-month-old regenerating forest. Methods The vertical distribution of total above-ground biomass, height, diameter, stem density, leaf angles and

  20. Airborne laser scanner-assisted estimation of aboveground biomass change in a temperate oak-pine forest

    Science.gov (United States)

    Nicholas S. Skowronski; Kenneth L. Clark; Michael Gallagher; Richard A. Birdsey; John L. Hom

    2014-01-01

    We estimated aboveground tree biomass and change in aboveground tree biomass using repeated airborne laser scanner (ALS) acquisitions and temporally coincident ground observations of forest biomass, for a relatively undisturbed period (2004-2007; ∇07-04), a contrasting period of disturbance (2007-2009; ∇09-07...

  1. Effects of above-ground plant species composition and diversity on the diversity of soil-borne microorganisms

    NARCIS (Netherlands)

    Kowalchuk, G.A.; Buma, D.S; De Boer, W.; Klinkhamer, P.G.L.; Van Veen, J.A.

    2002-01-01

    A coupling of above-ground plant diversity and below-ground microbial diversity has been implied in studies dedicated to assessing the role of macrophyte diversity on the stability, resilience, and functioning of ecosystems. Indeed, above-ground plant communities have long been assumed to drive

  2. Carbonization

    Energy Technology Data Exchange (ETDEWEB)

    Hennebutte, H G; Goutal, E

    1921-07-04

    Materials such as coal, peat, or schist are subjected to a rising temperature in successive stages in apparatus in which the distillation products are withdrawn at each stage. For example in a three-stage process, the acid products of the first or low-temperature stage are fixed in a suitable reagent, the basic products from a second or higher-temperature stage are absorbed in an acid reagent, hydrocarbons being retained by solvents, while the third are subjected to a pyrogenation process carried out in a closed vessel. Wherein the material is subjected in stages to a rising temperature, the gasified products being withdrawn at each stage, and are prevented as far as possible from mixing with the carbonized products.

  3. Receiver gain function: the actual NMR receiver gain

    OpenAIRE

    Mo, Huaping; Harwood, John S.; Raftery, Daniel

    2010-01-01

    The observed NMR signal size depends on the receiver gain parameter. We propose a receiver gain function to characterize how much the raw FID is amplified by the receiver as a function of the receiver gain setting. Although the receiver is linear for a fixed gain setting, the actual gain of the receiver may differ from what the gain setting suggests. Nevertheless, for a given receiver, we demonstrate that the receiver gain function can be calibrated. Such a calibration enables accurate compar...

  4. Satellite passive microwaves for monitoring deforestation and drought-induced carbon losses in sub-Saharan Africa

    Science.gov (United States)

    Brandt, M.; Wigneron, J. P.; Chave, J.; Tagesson, T.; Penuelas, J.; Ciais, P.; Rasmussen, K.; Tian, F.; Mbow, C.; Al-Yaari, A.; Rodriguez-Fernandez, N.; Zhang, W.; Kerr, Y. H.; Tucker, C. J.; Mialon, A.; Verger, A.; Fensholt, R.

    2017-12-01

    The African continent is facing one of the driest periods in the past three decades and continuing deforestation. These disturbances threaten vegetation carbon (C) stocks and highlight the need for an operational tool for monitoring carbon stock dynamics. Knowledge of the amount, distribution, and turnover of carbon in African vegetation is crucial for understanding the effects of human pressure and climate change, but the shortcomings of optical and radar satellite products and the lack of systematic field inventories have led to considerable uncertainty in documenting patterns and dynamics of carbon stocks, in particular for drylands. Static carbon maps have been developed, but the temporal dynamics of carbon stocks cannot be derived from the benchmark maps, impeding timely, repeated, and reliable carbon assessments. The Soil Moisture and Ocean Salinity (SMOS) mission launched in 2009 was the first passive microwave-based satellite system operating at L-band (1.4 GHz) frequency. The low frequencies allow the satellite to sense deep within the canopy layer with less influence by the green non-woody plant components. The vegetation optical depth (VOD) derived from SMOS, henceforth L-VOD, is thus less sensitive to saturation effects, marking an important step forward in the monitoring of carbon as a natural resource. In this study, we apply for the first time L-VOD to quantify the inter-annual dynamics of aboveground carbon stocks for the period 2010-2016. We use this new technique to document patterns of carbon gains and losses in sub-Saharan Africa with a focus of dryland response to recent dry years. Results show that drylands lost carbon at a rate of -0.06 Pg C y-1 associated with drying trends, while humid areas lost only -0.02 Pg C y-1. These trends reflect a high inter-annual variability with a very wet (2011) and a very dry year (2016) associated with carbon gains and losses respectively. This study demonstrates, first, the operational applicability of L

  5. Below- and above-ground effects of deadwood and termites in plantation forests

    Science.gov (United States)

    Michael D. Ulyshen; Richard Shefferson; Scott Horn; Melanie K. Taylor; Bryana Bush; Cavell Brownie; Sebastian Seibold; Michael S. Strickland

    2017-01-01

    Deadwood is an important legacy structure in managed forests, providing continuity in shelter and resource availability for many organisms and acting as a vehicle by which nutrients can be passed from one stand to the next following a harvest. Despite existing at the interface between below- and above-ground systems, however, much remains unknown about the role woody...

  6. Relationship between aboveground biomass and multiple measures of biodiversity in subtropical forest of Puerto Rico

    Science.gov (United States)

    Heather D. Vance-Chalcraft; Michael R. Willig; Stephen B. Cox; Ariel E. Lugo; Frederick N. Scatena

    2010-01-01

    Anthropogenic activities have accelerated the rate of global loss of biodiversity, making it more important than ever to understand the structure of biodiversity hotspots. One current focus is the relationship between species richness and aboveground biomass (AGB) in a variety of ecosystems. Nonetheless, species diversity, evenness, rarity, or dominance represent other...

  7. Effects of precipitation changes on aboveground net primary production and soil respiration in a switchgrass field

    Science.gov (United States)

    This study attempted to test whether switchgrass aboveground net primary production (ANPP) responds to precipitation (PPT) changes in a double asymmetry pattern as framed by Knapp et al. (2016), and whether it is held true for other ecosystem processes such as soil respiration (SR). Data were colle...

  8. Predicting aboveground forest biomass with topographic variables in human-impacted tropical dry forest landscapes

    NARCIS (Netherlands)

    Salinas-Melgoza, Miguel A.; Skutsch, Margaret; Lovett, Jon C.

    2018-01-01

    Topographic variables such as slope and elevation partially explain spatial variations in aboveground biomass (AGB) within landscapes. Human activities that impact vegetation, such as cattle grazing and shifting cultivation, often follow topographic features and also play a key role in determining

  9. Environmental and biotic controls over aboveground biomass throughout a tropical rainforest

    Science.gov (United States)

    G.P. Asner; R.F. Hughes; T.A. Varga; D.E. Knapp; T. Kennedy-Bowdoin

    2009-01-01

    The environmental and biotic factors affecting spatial variation in canopy three-dimensional (3-D) structure and aboveground tree biomass (AGB) are poorly understood in tropical rain forests. We combined field measurements and airborne light detection and ranging (lidar) to quantify 3-D structure and AGB across a 5,016 ha rain forest reserve on the...

  10. Aboveground biomass and nutrient accumulation 20 years after clear-cutting a southern Appalachian watershed

    Science.gov (United States)

    Katherine J. Elliott; Lindsay R. Boring; Wayne T. Swank

    2002-01-01

    In 1975, we initiated a long-term interdisciplinary study of forest watershed ecosystem response to clear- cutting and cable logging in watershed 7 at the Coweeta Hydrologic Laboratory in the southern Appalachian Mountains of North Carolina. This paper describes ~20 years of change in species composition, aboveground biomass, leaf area index (LAI),...

  11. Above-ground biomass of mangrove species. I. Analysis of models

    Science.gov (United States)

    Soares, Mário Luiz Gomes; Schaeffer-Novelli, Yara

    2005-10-01

    This study analyzes the above-ground biomass of Rhizophora mangle and Laguncularia racemosa located in the mangroves of Bertioga (SP) and Guaratiba (RJ), Southeast Brazil. Its purpose is to determine the best regression model to estimate the total above-ground biomass and compartment (leaves, reproductive parts, twigs, branches, trunk and prop roots) biomass, indirectly. To do this, we used structural measurements such as height, diameter at breast-height (DBH), and crown area. A combination of regression types with several compositions of independent variables generated 2.272 models that were later tested. Subsequent analysis of the models indicated that the biomass of reproductive parts, branches, and prop roots yielded great variability, probably because of environmental factors and seasonality (in the case of reproductive parts). It also indicated the superiority of multiple regression to estimate above-ground biomass as it allows researchers to consider several aspects that affect above-ground biomass, specially the influence of environmental factors. This fact has been attested to the models that estimated the biomass of crown compartments.

  12. Final Harvest of Above-Ground Biomass and Allometric Analysis of the Aspen FACE Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Mark E. Kubiske

    2013-04-15

    The Aspen FACE experiment, located at the US Forest Service Harshaw Research Facility in Oneida County, Wisconsin, exposes the intact canopies of model trembling aspen forests to increased concentrations of atmospheric CO2 and O3. The first full year of treatments was 1998 and final year of elevated CO2 and O3 treatments is scheduled for 2009. This proposal is to conduct an intensive, analytical harvest of the above-ground parts of 24 trees from each of the 12, 30 m diameter treatment plots (total of 288 trees) during June, July & August 2009. This above-ground harvest will be carefully coordinated with the below-ground harvest proposed by D.F. Karnosky et al. (2008 proposal to DOE). We propose to dissect harvested trees according to annual height growth increment and organ (main stem, branch orders, and leaves) for calculation of above-ground biomass production and allometric comparisons among aspen clones, species, and treatments. Additionally, we will collect fine root samples for DNA fingerprinting to quantify biomass production of individual aspen clones. This work will produce a thorough characterization of above-ground tree and stand growth and allocation above ground, and, in conjunction with the below ground harvest, total tree and stand biomass production, allocation, and allometry.

  13. Loss of aboveground forest biomass and landscape biomass variability in Missouri, US

    Science.gov (United States)

    Brice B. Hanberry; Hong S. He; Stephen R. Shifley

    2016-01-01

    Disturbance regimes and forests have changed over time in the eastern United States. We examined effects of historical disturbance (circa 1813 to 1850) compared to current disturbance (circa 2004 to 2008) on aboveground, live tree biomass (for trees with diameters ≥13 cm) and landscape variation of biomass in forests of the Ozarks and Plains landscapes in Missouri, USA...

  14. Estimation of Aboveground Biomass Using Manual Stereo Viewing of Digital Aerial Photographs in Tropical Seasonal Forest

    Directory of Open Access Journals (Sweden)

    Katsuto Shimizu

    2014-11-01

    Full Text Available The objectives of this study are to: (1 evaluate accuracy of tree height measurements of manual stereo viewing on a computer display using digital aerial photographs compared with airborne LiDAR height measurements; and (2 develop an empirical model to estimate stand-level aboveground biomass with variables derived from manual stereo viewing on the computer display in a Cambodian tropical seasonal forest. We evaluate observation error of tree height measured from the manual stereo viewing, based on field measurements. RMSEs of tree height measurement with manual stereo viewing and LiDAR were 1.96 m and 1.72 m, respectively. Then, stand-level aboveground biomass is regressed against tree height indices derived from the manual stereo viewing. We determined the best model to estimate aboveground biomass in terms of the Akaike’s information criterion. This was a model of mean tree height of the tallest five trees in each plot (R2 = 0.78; RMSE = 58.18 Mg/ha. In conclusion, manual stereo viewing on the computer display can measure tree height accurately and is useful to estimate aboveground stand biomass.

  15. Root biomass in cereals, catch crops and weeds can be reliably estimated without considering aboveground biomass

    DEFF Research Database (Denmark)

    Hu, Teng; Sørensen, Peter; Wahlström, Ellen Margrethe

    2018-01-01

    and management factors may affect this allometric relationship making such estimates uncertain and biased. Therefore, we aimed to explore how root biomass for typical cereal crops, catch crops and weeds could most reliably be estimated. Published and unpublished data on aboveground and root biomass (corrected...

  16. Aboveground biomass subdivisions in woody species of the savanna ecosystem project study area, Nylsvley

    CSIR Research Space (South Africa)

    Rutherford, MC

    1979-01-01

    Full Text Available Aboveground peak season biomass is given for 11 woody species in each of five belt transects under study. Mean aerial biomass for all species was 16 273 kg ha, made up of 14 937 kg ha wood, 236 kg ha current season's twigs and 1 100 kg ha leaves...

  17. Light Use Efficiency of Aboveground Biomass Production of Norway Spruce Stands

    Czech Academy of Sciences Publication Activity Database

    Bellan, Michal; Marková, I.; Zaika, A.; Krejza, Jan

    2017-01-01

    Roč. 65, č. 1 (2017), s. 9-16 ISSN 1211-8516 R&D Projects: GA TA ČR TA02010945 Institutional support: RVO:67179843 Keywords : absorbed photosynthetically active radiation * aboveground biomass increment * allometric relation Subject RIV: GC - Agronomy OBOR OECD: Agronomy, plant breeding and plant protection

  18. Standing crop and aboveground biomass partitioning of a dwarf mangrove forest in Taylor River Slough, Florida

    Science.gov (United States)

    Coronado-Molina, C.; Day, J.W.; Reyes, E.; Perez, B.C.

    2004-01-01

    The structure and standing crop biomass of a dwarf mangrove forest, located in the salinity transition zone ofTaylor River Slough in the Everglades National Park, were studied. Although the four mangrove species reported for Florida occurred at the study site, dwarf Rhizophora mangle trees dominated the forest. The structural characteristics of the mangrove forest were relatively simple: tree height varied from 0.9 to 1.2 meters, and tree density ranged from 7062 to 23 778 stems haa??1. An allometric relationship was developed to estimate leaf, branch, prop root, and total aboveground biomass of dwarf Rhizophora mangle trees. Total aboveground biomass and their components were best estimated as a power function of the crown area times number of prop roots as an independent variable (Y = B ?? Xa??0.5083). The allometric equation for each tree component was highly significant (pRhizophora mangle contributed 85% of total standing crop biomass. Conocarpus erectus, Laguncularia racemosa, and Avicennia germinans contributed the remaining biomass. Average aboveground biomass allocation was 69% for prop roots, 25% for stem and branches, and 6% for leaves. This aboveground biomass partitioning pattern, which gives a major role to prop roots that have the potential to produce an extensive root system, may be an important biological strategy in response to low phosphorus availability and relatively reduced soils that characterize mangrove forests in South Florida.

  19. Aboveground vertebrate and invertebrate herbivore impacts on net N mineralization in subalpine grasslands

    Science.gov (United States)

    Anita C. Risch; Martin Schutz; Martijn L. Vandegehuchte; Wim H. van der Putten; Henk Duyts; Ursina Raschein; Dariusz J. Gwiazdowicz; Matt D. Busse; Deborah S. Page-Dumroese; Stephan Zimmerman

    2015-01-01

    Aboveground herbivores have strong effects on grassland nitrogen (N) cycling. They can accelerate or slow down soil net N mineralization depending on ecosystem productivity and grazing intensity. Yet, most studies only consider either ungulates or invertebrate herbivores, but not the combined effect of several functionally different vertebrate and invertebrate...

  20. Plant responses to variable timing of aboveground clipping and belowground herbivory depend on plant age

    NARCIS (Netherlands)

    Wang, Minggang; Bezemer, T. Martijn; van der Putten, W.H.; Brinkman, Pella; Biere, Arjen

    2017-01-01

    Aims Plants use different types of responses such as tolerance and induced defense to mitigate the effects of herbivores. The direction and magnitude of both these plant responses can vary with plant age. However, most studies have focused on aboveground herbivory, whereas important feeding occurs

  1. Satellite detection of land-use change and effects on regional forest aboveground biomass estimates

    Science.gov (United States)

    Daolan Zheng; Linda S. Heath; Mark J. Ducey

    2008-01-01

    We used remote-sensing-driven models to detect land-cover change effects on forest aboveground biomass (AGB) density (Mg·ha−1, dry weight) and total AGB (Tg) in Minnesota, Wisconsin, and Michigan USA, between the years 1992-2001, and conducted an evaluation of the approach. Inputs included remotely-sensed 1992 reflectance data...

  2. Mechanisms and ecological implications of plant-mediated interactions between belowground and aboveground insect herbivores

    NARCIS (Netherlands)

    Papadopoulou, G.V.; Dam, N.M. van

    2017-01-01

    Plant-mediated interactions between belowground (BG) and aboveground (AG) herbivores have received increasing interest recently. However, the molecular mechanisms underlying ecological consequences of BG–AG interactions are not fully clear yet. Herbivore-induced plant defenses are complex and

  3. Receiver Gain Modulation Circuit

    Science.gov (United States)

    Jones, Hollis; Racette, Paul; Walker, David; Gu, Dazhen

    2011-01-01

    A receiver gain modulation circuit (RGMC) was developed that modulates the power gain of the output of a radiometer receiver with a test signal. As the radiometer receiver switches between calibration noise references, the test signal is mixed with the calibrated noise and thus produces an ensemble set of measurements from which ensemble statistical analysis can be used to extract statistical information about the test signal. The RGMC is an enabling technology of the ensemble detector. As a key component for achieving ensemble detection and analysis, the RGMC has broad aeronautical and space applications. The RGMC can be used to test and develop new calibration algorithms, for example, to detect gain anomalies, and/or correct for slow drifts that affect climate-quality measurements over an accelerated time scale. A generalized approach to analyzing radiometer system designs yields a mathematical treatment of noise reference measurements in calibration algorithms. By treating the measurements from the different noise references as ensemble samples of the receiver state, i.e. receiver gain, a quantitative description of the non-stationary properties of the underlying receiver fluctuations can be derived. Excellent agreement has been obtained between model calculations and radiometric measurements. The mathematical formulation is equivalent to modulating the gain of a stable receiver with an externally generated signal and is the basis for ensemble detection and analysis (EDA). The concept of generating ensemble data sets using an ensemble detector is similar to the ensemble data sets generated as part of ensemble empirical mode decomposition (EEMD) with exception of a key distinguishing factor. EEMD adds noise to the signal under study whereas EDA mixes the signal with calibrated noise. It is mixing with calibrated noise that permits the measurement of temporal-functional variability of uncertainty in the underlying process. The RGMC permits the evaluation of EDA by

  4. Effect of land use change on the carbon cycle in Amazon soils

    Science.gov (United States)

    Trumbore, Susan E.; Davidson, Eric A.

    1994-01-01

    The overall goal of this study was to provide a quantitative understanding of the cycling of carbon in the soils associated with deep-rooting Amazon forests. In particular, we wished to apply the understanding gained by answering two questions: (1) what changes will accompany the major land use change in this region, the conversion of forest to pasture? and (2) what is the role of carbon stored deeper than one meter in depth in these soils? To construct carbon budgets for pasture and forest soils we combined the following: measurements of carbon stocks in above-ground vegetation, root biomass, detritus, and soil organic matter; rates of carbon inputs to soil and detrital layers using litterfall collection and sequential coring to estimate fine root turnover; C-14 analyses of fractionated SOM and soil CO2 to estimate residence times; C-13 analyses to estimate C inputs to pasture soils from C-4 grasses; soil pCO2, volumetric water content, and radon gradients to estimate CO2 production as a function of soil depth; soil respiration to estimate total C outputs; and a model of soil C dynamics that defines SOM fractions cycling on annual, decadal, and millennial time scales.

  5. Prescribed fire effects on field-derived and simulated forest carbon stocks over time

    Science.gov (United States)

    Nicole M. Vaillant; Alicia L. Reiner; Erin K. Noonan-Wright

    2013-01-01

    To better understand the impact of prescribed fire on carbon stocks, we quantified aboveground and belowground carbon stocks within five pools (live trees and coarse roots, dead trees and coarse roots, live understory vegetation, down woody debris, and litter and duff) and potential carbon emissions from a simulated wildfire before and up to 8 years after prescribed...

  6. Grassland Aboveground Biomass in Inner Mongolia: Dynamics (2001-2016) and Driving force

    Science.gov (United States)

    Li, F.; Zeng, Y.; Chen, J.; Wu, B.

    2017-12-01

    Plant biomass is the most critical measure of carbon stored in an ecosystem, yet it remains imprecisely modeled for many terrestrial biomes. This lack of modeling capacity for biomass and its change through time and space has impeded scientists from making headway concerning issues in the geographic and social sciences. Satellite remote sensing techniques excel at detecting changes in the Earth's surface; however, accurate estimates of biomass for the heterogeneous biome landscapes based on remote sensing techniques are few and far between, which has led to many repetitive studies. Here, we argued that our ability to assess biomass in a heterogeneous landscape using satellite remote sensing techniques would be effectively enhanced through a stratification of landscapes, i.e homogenizing landscapes. Specifically, above-ground biomass (AGB) for an extended heterogeneous grassland biome over the entirety of Inner Mongolia during the past 16 years (2001-2016) was explored using remote sensing time series data from the Moderate Resolution Imaging Spectroradiometer (MODIS). Massive and extensive in-situ measurement AGB data and pure vegetation index (PVI) models, developed from normal remote sensing vegetation indices such as the normalized difference vegetation index (NDVI) and the enhanced vegetation index (EVI), were highlighted in the accomplishment of this study. Taking into full consideration the landscape heterogeneity for the grassland biome over Inner Mongolia, we achieved a series of AGB models with high R2 (>0.85) and low RMSE ( 20.85 g/m2). The total average amount of fresh AGB for the entirety of Inner Mongolia grasslands over the past 16 years was estimated as 87 Tg with an inter-annual standard deviation of 9 Tg. Overall, the grassland AGB for Inner Mongolia increased sporadically. We found that the dynamics of AGB in the grassland biome of Inner Mongolia were substantially dominated by variation in precipitation despite the accommodation of a huge

  7. Cadmium uptake in above-ground parts of lettuce (Lactuca sativa L.).

    Science.gov (United States)

    Tang, Xiwang; Pang, Yan; Ji, Puhui; Gao, Pengcheng; Nguyen, Thanh Hung; Tong, Yan'an

    2016-03-01

    Because of its high Cd uptake and translocation, lettuce is often used in Cd contamination studies. However, there is a lack of information on Cd accumulation in the above-ground parts of lettuce during the entire growing season. In this study, a field experiment was carried out in a Cd-contaminated area. Above-ground lettuce parts were sampled, and the Cd content was measured using a flame atomic absorption spectrophotometer (AAS). The results showed that the Cd concentration in the above-ground parts of lettuce increased from 2.70 to 3.62mgkg(-1) during the seedling stage, but decreased from 3.62 to 2.40mgkg(-1) during organogenesis and from 2.40 to 1.64mgkg(-1) during bolting. The mean Cd concentration during the seedling stage was significantly higher than that during organogenesis (a=0.05) and bolting (a=0.01). The Cd accumulation in the above-ground parts of an individual lettuce plant could be described by a sigmoidal curve. Cadmium uptake during organogenesis was highest (80% of the total), whereas that during bolting was only 4.34%. This research further reveals that for Rome lettuce: (1) the highest Cd content of above-ground parts occurred at the end of the seedling phase; (2) the best harvest time with respect to Cd phytoaccumulation is at the end of the organogenesis stage; and (3) the organogenesis stage is the most suitable time to enhance phytoaccumulation efficiency by adjusting the root:shoot ratio. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Deer browsing delays succession by altering aboveground vegetation and belowground seed banks.

    Directory of Open Access Journals (Sweden)

    Antonio DiTommaso

    Full Text Available Soil seed bank composition is important to the recovery of natural and semi-natural areas from disturbance and serves as a safeguard against environmental catastrophe. White-tailed deer (Odocoileus virginianus populations have increased dramatically in eastern North America over the past century and can have strong impacts on aboveground vegetation, but their impacts on seed bank dynamics are less known. To document the long-term effects of deer browsing on plant successional dynamics, we studied the impacts of deer on both aboveground vegetation and seed bank composition in plant communities following agricultural abandonment. In 2005, we established six 15 × 15 m fenced enclosures and paired open plots in recently followed agricultural fields near Ithaca, NY, USA. In late October of each of six years (2005-2010, we collected soil from each plot and conducted seed germination cycles in a greenhouse to document seed bank composition. These data were compared to measurements of aboveground plant cover (2005-2008 and tree density (2005-2012. The impacts of deer browsing on aboveground vegetation were severe and immediate, resulting in significantly more bare soil, reduced plant biomass, reduced recruitment of woody species, and relatively fewer native species. These impacts persisted throughout the experiment. The impacts of browsing were even stronger on seed bank dynamics. Browsing resulted in significantly decreased overall species richness (but higher diversity, reduced seed bank abundance, relatively more short-lived species (annuals and biennials, and fewer native species. Both seed bank richness and the relative abundance of annuals/biennials were mirrored in the aboveground vegetation. Thus, deer browsing has long-term and potentially reinforcing impacts on secondary succession, slowing succession by selectively consuming native perennials and woody species and favoring the persistence of short-lived, introduced species that continually

  9. Plant genetic variation mediates an indirect ecological effect between belowground earthworms and aboveground aphids.

    Science.gov (United States)

    Singh, Akanksha; Braun, Julia; Decker, Emilia; Hans, Sarah; Wagner, Agnes; Weisser, Wolfgang W; Zytynska, Sharon E

    2014-10-21

    Interactions between aboveground and belowground terrestrial communities are often mediated by plants, with soil organisms interacting via the roots and aboveground organisms via the shoots and leaves. Many studies now show that plant genetics can drive changes in the structure of both above and belowground communities; however, the role of plant genetic variation in mediating aboveground-belowground interactions is still unclear. We used an earthworm-plant-aphid model system with two aphid species (Aphis fabae and Acyrthosiphon pisum) to test the effect of host-plant (Vicia faba) genetic variation on the indirect interaction between the belowground earthworms (Eisenia veneta) on the aboveground aphid populations. Our data shows that host-plant variety mediated an indirect ecological effect of earthworms on generalist black bean aphids (A. fabae), with earthworms increasing aphid growth rate in three plant varieties but decreasing it in another variety. We found no effect of earthworms on the second aphid species, the pea aphid (A. pisum), and no effect of competition between the aphid species. Plant biomass was increased when earthworms were present, and decreased when A. pisum was feeding on the plant (mediated by plant variety). Although A. fabae aphids were influenced by the plants and worms, they did not, in turn, alter plant biomass. Previous work has shown inconsistent effects of earthworms on aphids, but we suggest these differences could be explained by plant genetic variation and variation among aphid species. This study demonstrates that the outcome of belowground-aboveground interactions can be mediated by genetic variation in the host-plant, but depends on the identity of the species involved.

  10. Photomultiplier gain stabilisation

    International Nuclear Information System (INIS)

    Le Baud, P.; Sautiez, B.

    1958-07-01

    By the control and adjustment of magnetic deflection applied to the electron beam of a photomultiplier it has proved possible to flatten the gain curve, forming plateaux at levels dependent upon the voltage at intake. It should be possible to add this simple device to most photomultipliers on the market today. (author) [fr

  11. Increased Air Temperature during Simulated Autumn Conditions Does Not Increase Photosynthetic Carbon Gain But Affects the Dissipation of Excess Energy in Seedlings of the Evergreen Conifer Jack Pine1[OA

    Science.gov (United States)

    Busch, Florian; Hüner, Norman P.A.; Ensminger, Ingo

    2007-01-01

    the abundance of thylakoid membrane proteins compared to the summer condition. We conclude that photoperiod control of dormancy in Jack pine appears to negate any potential for an increased carbon gain associated with higher temperatures during the autumn season. PMID:17259287

  12. Learn and gain

    CERN Document Server

    Al-Alami, Suhair Eyad Jamal

    2013-01-01

    Initiating the slogan ""love it, live it"", Learn and Gain includes eight short stories, chosen to illustrate various modes of narration, as well as to provoke reflection and discussion on a range of issues. All texts utilized here illustrate how great writers can, with their insight and gift for words, help us to see the world we live in, in new probing and exciting ways. What characterises the book, the author believes, is the integration of the skills of literary competence, communicative c...

  13. Influence of an Ice Storm on Aboveground Biomass of Subtropical Evergreen Broadleaf Forest in Lechang, Nanling Mountains of Southern China

    Directory of Open Access Journals (Sweden)

    Fang Zhang

    2012-01-01

    Full Text Available This study focuses on the influence of the 2008 ice storm in China and subsequent forest rehabilitation dynamics up until 2011. All seven plots studied exhibited significant damage, with the total number of damaged trees varying between 63 and 92%. In addition, most trees suffered stem bending in 2008 and the extent of damage varied with tree diameter at breast high (DBH. Relationships between loss of biomass as dead trees and stand characteristics were analyzed by multiple stepwise regression. The results showed that the decrease in biomass (Y could be related to altitude (X1, slope (X2, and aboveground biomass (AGB in 2008 (X5 according to the following formula: Y=−0.02456X1+0.2815X5−1.480X2+51.23. After 2 to 3 years, tree numbers had declined in all seven plots. The mean increase in AGB (4.9 t ha−1 for six of the plots was less than the biomass loss as dead trees (9.4 t ha−1 over the 3 year periods. This corresponds to a release of CO2 to the atmosphere for each plot. Therefore, the forests of Lechang in the Nanling Montains have probably acted as a carbon source to the atmosphere for a short period after the 2008 ice storm.

  14. Community-weighted mean of leaf traits and divergence of wood traits predict aboveground biomass in secondary subtropical forests.

    Science.gov (United States)

    Ali, Arshad; Yan, En-Rong; Chang, Scott X; Cheng, Jun-Yang; Liu, Xiang-Yu

    2017-01-01

    Subtropical forests are globally important in providing ecological goods and services, but it is not clear whether functional diversity and composition can predict aboveground biomass in such forests. We hypothesized that high aboveground biomass is associated with high functional divergence (FDvar, i.e., niche complementarity) and community-weighted mean (CWM, i.e., mass ratio; communities dominated by a single plant strategy) of trait values. Structural equation modeling was employed to determine the direct and indirect effects of stand age and the residual effects of CWM and FDvar on aboveground biomass across 31 plots in secondary forests in subtropical China. The CWM model accounted for 78, 20, 6 and 2% of the variation in aboveground biomass, nitrogen concentration in young leaf, plant height and specific leaf area of young leaf, respectively. The FDvar model explained 74, 13, 7 and 0% of the variation in aboveground biomass, plant height, twig wood density and nitrogen concentration in young leaf, respectively. The variation in aboveground biomass, CWM of leaf nitrogen concentration and specific leaf area, and FDvar of plant height, twig wood density and nitrogen concentration in young leaf explained by the joint model was 86, 20, 13, 7, 2 and 0%, respectively. Stand age had a strong positive direct effect but low indirect positive effects on aboveground biomass. Aboveground biomass was negatively related to CWM of nitrogen concentration in young leaf, but positively related to CWM of specific leaf area of young leaf and plant height, and FDvar of plant height, twig wood density and nitrogen concentration in young leaf. Leaf and wood economics spectra are decoupled in regulating the functionality of forests, communities with diverse species but high nitrogen conservative and light acquisitive strategies result in high aboveground biomass, and hence, supporting both the mass ratio and niche complementarity hypotheses in secondary subtropical forests

  15. Individual tree size inequality enhances aboveground biomass in homegarden agroforestry systems in the dry zone of Sri Lanka.

    Science.gov (United States)

    Ali, Arshad; Mattsson, Eskil

    2017-01-01

    Individual tree size variation, which is generally quantified by variances in tree diameter at breast height (DBH) and height in isolation or conjunction, plays a central role in ecosystem functioning in both controlled and natural environments, including forests. However, none of the studies have been conducted in homegarden agroforestry systems. In this study, aboveground biomass, stand quality, cation exchange capacity (CEC), DBH variation, and species diversity were determined across 45 homegardens in the dry zone of Sri Lanka. We employed structural equation modeling (SEM) to test for the direct and indirect effects of stand quality and CEC, via tree size inequality and species diversity, on aboveground biomass. The SEM accounted for 26, 8, and 1% of the variation in aboveground biomass, species diversity and DBH variation, respectively. DBH variation had the strongest positive direct effect on aboveground biomass (β=0.49), followed by the non-significant direct effect of species diversity (β=0.17), stand quality (β=0.17) and CEC (β=-0.05). There were non-significant direct effects of CEC and stand quality on DBH variation and species diversity. Stand quality and CEC had also non-significant indirect effects, via DBH variation and species diversity, on aboveground biomass. Our study revealed that aboveground biomass substantially increased with individual tree size variation only, which supports the niche complementarity mechanism. However, aboveground biomass was not considerably increased with species diversity, stand quality and soil fertility, which might be attributable to the adaptation of certain productive species to the local site conditions. Stand structure shaped by few productive species or independent of species diversity is a main determinant for the variation in aboveground biomass in the studied homegardens. Maintaining stand structure through management practices could be an effective approach for enhancing aboveground biomass in these dry

  16. Aboveground Deadwood Deposition Supports Development of Soil Yeasts

    Directory of Open Access Journals (Sweden)

    Thorsten Wehde

    2012-12-01

    Full Text Available Unicellular saprobic fungi (yeasts inhabit soils worldwide. Although yeast species typically occupy defined areas on the biome scale, their distribution patterns within a single type of vegetation, such as forests, are more complex. In order to understand factors that shape soil yeast communities, soils collected underneath decaying wood logs and under forest litter were analyzed. We isolated and identified molecularly a total of 25 yeast species, including three new species. Occurrence and distribution of yeasts isolated from these soils provide new insights into ecology and niche specialization of several soil-borne species. Although abundance of typical soil yeast species varied among experimental plots, the analysis of species abundance and community composition revealed a strong influence of wood log deposition and leakage of organic carbon. Unlike soils underneath logs, yeast communities in adjacent areas harbored a considerable number of transient (phylloplane-related yeasts reaching 30% of the total yeast quantity. We showed that distinguishing autochthonous community members and species transient in soils is essential to estimate appropriate effects of environmental factors on soil fungi. Furthermore, a better understanding of species niches is crucial for analyses of culture-independent data, and may hint to the discovery of unifying patterns of microbial species distribution.

  17. Lianas reduce carbon accumulation and storage in tropical forests.

    Science.gov (United States)

    van der Heijden, Geertje M F; Powers, Jennifer S; Schnitzer, Stefan A

    2015-10-27

    Tropical forests store vast quantities of carbon, account for one-third of the carbon fixed by photosynthesis, and are a major sink in the global carbon cycle. Recent evidence suggests that competition between lianas (woody vines) and trees may reduce forest-wide carbon uptake; however, estimates of the impact of lianas on carbon dynamics of tropical forests are crucially lacking. Here we used a large-scale liana removal experiment and found that, at 3 y after liana removal, lianas reduced net above-ground carbon uptake (growth and recruitment minus mortality) by ∼76% per year, mostly by reducing tree growth. The loss of carbon uptake due to liana-induced mortality was four times greater in the control plots in which lianas were present, but high variation among plots prevented a significant difference among the treatments. Lianas altered how aboveground carbon was stored. In forests where lianas were present, the partitioning of forest aboveground net primary production was dominated by leaves (53.2%, compared with 39.2% in liana-free forests) at the expense of woody stems (from 28.9%, compared with 43.9%), resulting in a more rapid return of fixed carbon to the atmosphere. After 3 y of experimental liana removal, our results clearly demonstrate large differences in carbon cycling between forests with and without lianas. Combined with the recently reported increases in liana abundance, these results indicate that lianas are an important and increasing agent of change in the carbon dynamics of tropical forests.

  18. Long-term simulations of forest management impacts on carbon storage from loblolly pine plantations in the Southern U.S.

    Science.gov (United States)

    Huei-Jin Wang; Philip J. Radtke; Stephen P. Prisley

    2012-01-01

    Accounting for forest components in carbon accounting systems may be insufficient when substantial amounts of sequestered carbon are harvested and converted to wood products in use and in landfill. The potential of forest offset – in-woods aboveground carbon storage, carbon stored in harvested wood, and energy offset by burning harvested wood – from loblolly pine...

  19. Gains from quota trade

    DEFF Research Database (Denmark)

    Andersen, Jesper Levring; Bogetoft, Peter

    2007-01-01

    We provide a framework for evaluating potential effects of introducing tradable quotas to a sector. The effects depend on the economies of scale and scope of the production technology, and on firms' ability and willingness to learn best practice methods (catching up) and to change their input...... and output composition (mix). To illustrate our approach, data from the Danish fishery are used to calculate the potential gains from introducing individually transferable fishing quotas. Data envelopment analysis is used to model the production technology. We find that pure reallocation is as important...

  20. Gaining Relational Competitive Advantages

    DEFF Research Database (Denmark)

    Hu, Yimei; Zhang, Si; Li, Jizhen

    2015-01-01

    Establishing strategic technological partnerships (STPs) with foreign partners is an increasingly studied topic within the innovation management literature. Partnering firms can jointly create sources of relational competitive advantage. Chinese firms often lack research and development (R......&D) capabilities but are increasingly becoming preferred technological partners for transnational corporations. We investigate an STP between a Scandinavian and a Chinese firm and try to explore how to gain relational competitive advantage by focusing on its two essential stages: relational rent generation...... and appropriation. Based on an explorative case study, we develop a conceptual framework that consists of process, organizational alliance factors, and coordination modes that we propose lead to relational competitive advantage....

  1. [Aboveground biomass of Tamarix on piedmont plain of Tianshan Mountains south slope].

    Science.gov (United States)

    Zhao, Zhenyong; Wang, Ranghui; Zhang, Huizhi; Wang, Lei

    2006-09-01

    Based on the geo-morphological and hydro-geological characteristics, the piedmont plain of Tianshan Mountains south slope was classified into 4 geo-morphological belts, i.e., flood erosion belt, groundwater spill belt, delta belt, and the joining belt of piedmont plain and Tarim floodplain. A field investigation on the Tamarix shrub in this region showed that there was a significant difference in its aboveground biomass among the four belts, ranged from 1428.53 kg x hm(-2) at groundwater spill belt to 111.18 kg x hm(-2) at the joining belt of piedmont plain and Tarim floodplain. The main reason for such a big difference might be the different density of Tamarix shrub on different belts. Both the Tamarix aboveground biomass and the topsoil's salinity were decreased with increasing groundwater level. Groundwater level was the main factor limiting Tamarix growth, while soil salinity was not.

  2. Above-ground biomass equations for Pinus radiata D. Don in Asturias

    Directory of Open Access Journals (Sweden)

    E. Canga

    2013-12-01

    Full Text Available Aim of the study: The aim of this study was to develop a model for above-ground biomass estimation for Pinus radiata D. Don in Asturias.Area of study: Asturias (NE of Spain.Material and methods: Different models were fitted for the different above-ground components and weighted regression was used to correct heteroscedasticity. Finally, all the models were refitted simultaneously by use of Nonlinear Seemingly Unrelated Regressions (NSUR to ensure the additivity of biomass equations.Research highlights: A system of four biomass equations (wood, bark, crown and total biomass was develop, such that the sum of the estimations of the three biomass components is equal to the estimate of total biomass. Total and stem biomass equations explained more than 92% of observed variability, while crown and bark biomass equations explained 77% and 89% respectively.Keywords: radiata pine; plantations; biomass.

  3. Aboveground Biomass Estimation Using Reconstructed Feature of Airborne Discrete-Return LIDAR by Auto-Encoder Neural Network

    Science.gov (United States)

    Li, T.; Wang, Z.; Peng, J.

    2018-04-01

    Aboveground biomass (AGB) estimation is critical for quantifying carbon stocks and essential for evaluating carbon cycle. In recent years, airborne LiDAR shows its great ability for highly-precision AGB estimation. Most of the researches estimate AGB by the feature metrics extracted from the canopy height distribution of the point cloud which calculated based on precise digital terrain model (DTM). However, if forest canopy density is high, the probability of the LiDAR signal penetrating the canopy is lower, resulting in ground points is not enough to establish DTM. Then the distribution of forest canopy height is imprecise and some critical feature metrics which have a strong correlation with biomass such as percentiles, maximums, means and standard deviations of canopy point cloud can hardly be extracted correctly. In order to address this issue, we propose a strategy of first reconstructing LiDAR feature metrics through Auto-Encoder neural network and then using the reconstructed feature metrics to estimate AGB. To assess the prediction ability of the reconstructed feature metrics, both original and reconstructed feature metrics were regressed against field-observed AGB using the multiple stepwise regression (MS) and the partial least squares regression (PLS) respectively. The results showed that the estimation model using reconstructed feature metrics improved R2 by 5.44 %, 18.09 %, decreased RMSE value by 10.06 %, 22.13 % and reduced RMSEcv by 10.00 %, 21.70 % for AGB, respectively. Therefore, reconstructing LiDAR point feature metrics has potential for addressing AGB estimation challenge in dense canopy area.

  4. Intermediate herbivory intensity of an aboveground pest promotes soil labile resources and microbial biomass via modifying rice growth

    NARCIS (Netherlands)

    Huang, J.; Liu, M.; Chen, X.; Chen, J.; Chen, F.; Li, H.; Hu, F.

    2013-01-01

    The importance of aboveground herbivores for modifying belowground ecosystems has prompted numerous studies; however, studies can be biased by context dependent conditions which lead to extremely inconsistent results. So far, the impacts of herbivory inte

  5. Allometric Equations for Aboveground and Belowground Biomass Estimations in an Evergreen Forest in Vietnam.

    Science.gov (United States)

    Nam, Vu Thanh; van Kuijk, Marijke; Anten, Niels P R

    2016-01-01

    Allometric regression models are widely used to estimate tropical forest biomass, but balancing model accuracy with efficiency of implementation remains a major challenge. In addition, while numerous models exist for aboveground mass, very few exist for roots. We developed allometric equations for aboveground biomass (AGB) and root biomass (RB) based on 300 (of 45 species) and 40 (of 25 species) sample trees respectively, in an evergreen forest in Vietnam. The biomass estimations from these local models were compared to regional and pan-tropical models. For AGB we also compared local models that distinguish functional types to an aggregated model, to assess the degree of specificity needed in local models. Besides diameter at breast height (DBH) and tree height (H), wood density (WD) was found to be an important parameter in AGB models. Existing pan-tropical models resulted in up to 27% higher estimates of AGB, and overestimated RB by nearly 150%, indicating the greater accuracy of local models at the plot level. Our functional group aggregated local model which combined data for all species, was as accurate in estimating AGB as functional type specific models, indicating that a local aggregated model is the best choice for predicting plot level AGB in tropical forests. Finally our study presents the first allometric biomass models for aboveground and root biomass in forests in Vietnam.

  6. An assessment of underground and aboveground steam system failures in the SRS waste tank farms

    International Nuclear Information System (INIS)

    Hsu, T.C.; Shurrab, M.S.; Wiersma, B.J.

    1997-01-01

    Underground steam system failures in waste tank farms at the Savannah River Site (SRS) increased significantly in the 3--4 year period prior to 1995. The primary safety issues created by the failures were the formation of sub-surface voids in soil and the loss of steam jet transfer and waste evaporation capability, and the loss of heating and ventilation to the tanks. The average annual cost for excavation and repair of the underground steam system was estimated to be several million dollars. These factors prompted engineering personnel to re-consider long-term solutions to the problem. The primary cause of these failures was the inadequate thermal insulation utilized for steam lines associated with older tanks. The failure mechanisms were either pitting or localized general corrosion on the exterior of the pipe beneath the thermal insulation. The most realistic and practical solution is to replace the underground lines by installing aboveground steam systems, although this option will incur significant initial capital costs. Steam system components, installed aboveground in other areas of the tank farms have experienced few failures, while in continuous use. As a result, piecewise installation of temporary aboveground steam systems have been implemented in F-area whenever opportunities, i.e., failures, present themselves

  7. Stimulation of the Salicylic Acid Pathway Aboveground Recruits Entomopathogenic Nematodes Belowground.

    Directory of Open Access Journals (Sweden)

    Camila Cramer Filgueiras

    Full Text Available Plant defense pathways play a critical role in mediating tritrophic interactions between plants, herbivores, and natural enemies. While the impact of plant defense pathway stimulation on natural enemies has been extensively explored aboveground, belowground ramifications of plant defense pathway stimulation are equally important in regulating subterranean pests and still require more attention. Here we investigate the effect of aboveground stimulation of the salicylic acid pathway through foliar application of the elicitor methyl salicylate on belowground recruitment of the entomopathogenic nematode, Steinernema diaprepesi. Also, we implicate a specific root-derived volatile that attracts S. diaprepesi belowground following aboveground plant stimulation by an elicitor. In four-choice olfactometer assays, citrus plants treated with foliar applications of methyl salicylate recruited S. diaprepesi in the absence of weevil feeding as compared with negative controls. Additionally, analysis of root volatile profiles of citrus plants receiving foliar application of methyl salicylate revealed production of d-limonene, which was absent in negative controls. The entomopathogenic nematode S. diaprepesi was recruited to d-limonene in two-choice olfactometer trials. These results reinforce the critical role of plant defense pathways in mediating tritrophic interactions, suggest a broad role for plant defense pathway signaling belowground, and hint at sophisticated plant responses to pest complexes.

  8. Allometric Equations for Aboveground and Belowground Biomass Estimations in an Evergreen Forest in Vietnam.

    Directory of Open Access Journals (Sweden)

    Vu Thanh Nam

    Full Text Available Allometric regression models are widely used to estimate tropical forest biomass, but balancing model accuracy with efficiency of implementation remains a major challenge. In addition, while numerous models exist for aboveground mass, very few exist for roots. We developed allometric equations for aboveground biomass (AGB and root biomass (RB based on 300 (of 45 species and 40 (of 25 species sample trees respectively, in an evergreen forest in Vietnam. The biomass estimations from these local models were compared to regional and pan-tropical models. For AGB we also compared local models that distinguish functional types to an aggregated model, to assess the degree of specificity needed in local models. Besides diameter at breast height (DBH and tree height (H, wood density (WD was found to be an important parameter in AGB models. Existing pan-tropical models resulted in up to 27% higher estimates of AGB, and overestimated RB by nearly 150%, indicating the greater accuracy of local models at the plot level. Our functional group aggregated local model which combined data for all species, was as accurate in estimating AGB as functional type specific models, indicating that a local aggregated model is the best choice for predicting plot level AGB in tropical forests. Finally our study presents the first allometric biomass models for aboveground and root biomass in forests in Vietnam.

  9. Modeling Aboveground Biomass in Hulunber Grassland Ecosystem by Using Unmanned Aerial Vehicle Discrete Lidar.

    Science.gov (United States)

    Wang, Dongliang; Xin, Xiaoping; Shao, Quanqin; Brolly, Matthew; Zhu, Zhiliang; Chen, Jin

    2017-01-19

    Accurate canopy structure datasets, including canopy height and fractional cover, are required to monitor aboveground biomass as well as to provide validation data for satellite remote sensing products. In this study, the ability of an unmanned aerial vehicle (UAV) discrete light detection and ranging (lidar) was investigated for modeling both the canopy height and fractional cover in Hulunber grassland ecosystem. The extracted mean canopy height, maximum canopy height, and fractional cover were used to estimate the aboveground biomass. The influences of flight height on lidar estimates were also analyzed. The main findings are: (1) the lidar-derived mean canopy height is the most reasonable predictor of aboveground biomass ( R ² = 0.340, root-mean-square error (RMSE) = 81.89 g·m -2 , and relative error of 14.1%). The improvement of multiple regressions to the R ² and RMSE values is unobvious when adding fractional cover in the regression since the correlation between mean canopy height and fractional cover is high; (2) Flight height has a pronounced effect on the derived fractional cover and details of the lidar data, but the effect is insignificant on the derived canopy height when the flight height is within the range (lidar returns.

  10. Stimulation of the Salicylic Acid Pathway Aboveground Recruits Entomopathogenic Nematodes Belowground

    Science.gov (United States)

    Filgueiras, Camila Cramer; Willett, Denis S.; Junior, Alcides Moino; Pareja, Martin; Borai, Fahiem El; Dickson, Donald W.; Stelinski, Lukasz L.; Duncan, Larry W.

    2016-01-01

    Plant defense pathways play a critical role in mediating tritrophic interactions between plants, herbivores, and natural enemies. While the impact of plant defense pathway stimulation on natural enemies has been extensively explored aboveground, belowground ramifications of plant defense pathway stimulation are equally important in regulating subterranean pests and still require more attention. Here we investigate the effect of aboveground stimulation of the salicylic acid pathway through foliar application of the elicitor methyl salicylate on belowground recruitment of the entomopathogenic nematode, Steinernema diaprepesi. Also, we implicate a specific root-derived volatile that attracts S. diaprepesi belowground following aboveground plant stimulation by an elicitor. In four-choice olfactometer assays, citrus plants treated with foliar applications of methyl salicylate recruited S. diaprepesi in the absence of weevil feeding as compared with negative controls. Additionally, analysis of root volatile profiles of citrus plants receiving foliar application of methyl salicylate revealed production of d-limonene, which was absent in negative controls. The entomopathogenic nematode S. diaprepesi was recruited to d-limonene in two-choice olfactometer trials. These results reinforce the critical role of plant defense pathways in mediating tritrophic interactions, suggest a broad role for plant defense pathway signaling belowground, and hint at sophisticated plant responses to pest complexes. PMID:27136916

  11. Degraded tropical rain forests possess valuable carbon storage opportunities in a complex, forested landscape.

    Science.gov (United States)

    Alamgir, Mohammed; Campbell, Mason J; Turton, Stephen M; Pert, Petina L; Edwards, Will; Laurance, William F

    2016-07-20

    Tropical forests are major contributors to the terrestrial global carbon pool, but this pool is being reduced via deforestation and forest degradation. Relatively few studies have assessed carbon storage in degraded tropical forests. We sampled 37,000 m(2) of intact rainforest, degraded rainforest and sclerophyll forest across the greater Wet Tropics bioregion of northeast Australia. We compared aboveground biomass and carbon storage of the three forest types, and the effects of forest structural attributes and environmental factors that influence carbon storage. Some degraded forests were found to store much less aboveground carbon than intact rainforests, whereas others sites had similar carbon storage to primary forest. Sclerophyll forests had lower carbon storage, comparable to the most heavily degraded rainforests. Our findings indicate that under certain situations, degraded forest may store as much carbon as intact rainforests. Strategic rehabilitation of degraded forests could enhance regional carbon storage and have positive benefits for tropical biodiversity.

  12. Towards ground-truthing of spaceborne estimates of above-ground biomass and leaf area index in tropical rain forests

    Science.gov (United States)

    Köhler, P.; Huth, A.

    2010-05-01

    The canopy height of forests is a key variable which can be obtained using air- or spaceborne remote sensing techniques such as radar interferometry or lidar. If new allometric relationships between canopy height and the biomass stored in the vegetation can be established this would offer the possibility for a global monitoring of the above-ground carbon content on land. In the absence of adequate field data we use simulation results of a tropical rain forest growth model to propose what degree of information might be generated from canopy height and thus to enable ground-truthing of potential future satellite observations. We here analyse the correlation between canopy height in a tropical rain forest with other structural characteristics, such as above-ground biomass (AGB) (and thus carbon content of vegetation) and leaf area index (LAI). The process-based forest growth model FORMIND2.0 was applied to simulate (a) undisturbed forest growth and (b) a wide range of possible disturbance regimes typically for local tree logging conditions for a tropical rain forest site on Borneo (Sabah, Malaysia) in South-East Asia. It is found that for undisturbed forest and a variety of disturbed forests situations AGB can be expressed as a power-law function of canopy height h (AGB=a·hb) with an r2~60% for a spatial resolution of 20 m×20 m (0.04 ha, also called plot size). The regression is becoming significant better for the hectare wide analysis of the disturbed forest sites (r2=91%). There seems to exist no functional dependency between LAI and canopy height, but there is also a linear correlation (r2~60%) between AGB and the area fraction in which the canopy is highly disturbed. A reasonable agreement of our results with observations is obtained from a comparison of the simulations with permanent sampling plot data from the same region and with the large-scale forest inventory in Lambir. We conclude that the spaceborne remote sensing techniques have the potential to

  13. THE Eucalyptus sp. AGE PLANTATIONS INFLUENCING THE CARBON STOCKS

    Directory of Open Access Journals (Sweden)

    Charlote Wink

    2013-06-01

    Full Text Available http://dx.doi.org/10.5902/198050989279The tree growth and biomass accumulation, as well as the maintenance of forest residue at the soil surface can act in the removal of carbon from the atmosphere through the cycling process of plant material. The objective was to study the influence of Eucalyptus sp. Plantations with 20, 44 and 240 months of age on the variation of carbon in soil and biomass. The carbon in the soil depth was determined by CHNS auto-analyzer and carbon in the vegetation was determined by the biomass in each forest, considering a factor of 0.45 of the dry mass. We determined the density and particle size distribution of soil. For the comparison between plantations, there was analysis of variance and comparison of means of carbon in vegetation and soil, considering the 5% level of probability. The carbon content and stock in the soil were low, indicating that a natural feature of the category of Paleuldt, or the growth of eucalyptus forests, replacing the field native vegetation did not aggregate a significant increase in the carbon. Although, there was a significant increase carbon in aboveground biomass. It includes forest biomass and litter. So, despite the values ​​of carbon stocks are low, it identified a greater average total in the soil compared to the stock aboveground. Furthermore, this increase aboveground (tree and litter compartments can be considered significant between the eucalyptus plantations of different ages.

  14. Linking carbon and water limitations to drought-induced mortality of Pinus flexilis seedlings

    Science.gov (United States)

    Reinhardt, Keith; Germino, Matthew J.; Kueppers, Lara M.; Domec, Jean-Christophe; Mitton, Jeffry

    2015-01-01

    Survival of tree seedlings at high elevations has been shown to be limited by thermal constraints on carbon balance, but it is unknown if carbon relations also limit seedling survival at lower elevations, where water relations may be more important. We measured and modeled carbon fluxes and water relations in first-year Pinus flexilis seedlings in garden plots just beyond the warm edge of their natural range, and compared these with dry-mass gain and survival across two summers. We hypothesized that mortality in these seedlings would be associated with declines in water relations, more so than with carbon-balance limitations. Rather than gradual declines in survivorship across growing seasons, we observed sharp, large-scale mortality episodes that occurred once volumetric soil-moisture content dropped below 10%. By this point, seedling water potentials had decreased below −5 MPa, seedling hydraulic conductivity had decreased by 90% and seedling hydraulic resistance had increased by >900%. Additionally, non-structural carbohydrates accumulated in aboveground tissues at the end of both summers, suggesting impairments in phloem-transport from needles to roots. This resulted in low carbohydrate concentrations in roots, which likely impaired root growth and water uptake at the time of critically low soil moisture. While photosynthesis and respiration on a leaf area basis remained high until critical hydraulic thresholds were exceeded, modeled seedling gross primary productivity declined steadily throughout the summers. At the time of mortality, modeled productivity was insufficient to support seedling biomass-gain rates, metabolism and secondary costs. Thus the large-scale mortality events that we observed near the end of each summer were most directly linked with acute, episodic declines in plant hydraulic function that were linked with important changes in whole-seedling carbon relations.

  15. Linking carbon and water relations to drought-induced mortality in Pinus flexilis seedlings.

    Science.gov (United States)

    Reinhardt, Keith; Germino, Matthew J; Kueppers, Lara M; Domec, Jean-Christophe; Mitton, Jeffry

    2015-07-01

    Survival of tree seedlings at high elevations has been shown to be limited by thermal constraints on carbon balance, but it is unknown if carbon relations also limit seedling survival at lower elevations, where water relations may be more important. We measured and modeled carbon fluxes and water relations in first-year Pinus flexilis seedlings in garden plots just beyond the warm edge of their natural range, and compared these with dry-mass gain and survival across two summers. We hypothesized that mortality in these seedlings would be associated with declines in water relations, more so than with carbon-balance limitations. Rather than gradual declines in survivorship across growing seasons, we observed sharp, large-scale mortality episodes that occurred once volumetric soil-moisture content dropped below 10%. By this point, seedling water potentials had decreased below -5 MPa, seedling hydraulic conductivity had decreased by 90% and seedling hydraulic resistance had increased by >900%. Additionally, non-structural carbohydrates accumulated in aboveground tissues at the end of both summers, suggesting impairments in phloem-transport from needles to roots. This resulted in low carbohydrate concentrations in roots, which likely impaired root growth and water uptake at the time of critically low soil moisture. While photosynthesis and respiration on a leaf area basis remained high until critical hydraulic thresholds were exceeded, modeled seedling gross primary productivity declined steadily throughout the summers. At the time of mortality, modeled productivity was insufficient to support seedling biomass-gain rates, metabolism and secondary costs. Thus the large-scale mortality events that we observed near the end of each summer were most directly linked with acute, episodic declines in plant hydraulic function that were linked with important changes in whole-seedling carbon relations. © The Author 2015. Published by Oxford University Press. All rights reserved

  16. Acting to gain information

    Science.gov (United States)

    Rosenchein, Stanley J.; Burns, J. Brian; Chapman, David; Kaelbling, Leslie P.; Kahn, Philip; Nishihara, H. Keith; Turk, Matthew

    1993-01-01

    This report is concerned with agents that act to gain information. In previous work, we developed agent models combining qualitative modeling with real-time control. That work, however, focused primarily on actions that affect physical states of the environment. The current study extends that work by explicitly considering problems of active information-gathering and by exploring specialized aspects of information-gathering in computational perception, learning, and language. In our theoretical investigations, we analyzed agents into their perceptual and action components and identified these with elements of a state-machine model of control. The mathematical properties of each was developed in isolation and interactions were then studied. We considered the complexity dimension and the uncertainty dimension and related these to intelligent-agent design issues. We also explored active information gathering in visual processing. Working within the active vision paradigm, we developed a concept of 'minimal meaningful measurements' suitable for demand-driven vision. We then developed and tested an architecture for ongoing recognition and interpretation of visual information. In the area of information gathering through learning, we explored techniques for coping with combinatorial complexity. We also explored information gathering through explicit linguistic action by considering the nature of conversational rules, coordination, and situated communication behavior.

  17. Climate seasonality limits leaf carbon assimilation and wood productivity in tropical forests

    Science.gov (United States)

    Fabien H. Wagner; Bruno Herault; Damien Bonal; Clement Stahl; Liana O. Anderson; Timothy R. Baker; Gabriel Sebastian Becker; Hans Beeckman; Danilo Boanerges Souza; Paulo Cesar Botosso; David M. J. S. Bowman; Achim Brauning; Benjamin Brede; Foster Irving Brown; Jesus Julio Camarero; Plinio Barbosa Camargo; Fernanda C. G. Cardoso; Fabricio Alvim Carvalho; Wendeson Castro; Rubens Koloski Chagas; Jerome Chave; Emmanuel N. Chidumayo; Deborah A. Clark; Flavia Regina Capellotto Costa; Camille Couralet; Paulo Henrique da Silva Mauricio; Helmut Dalitz; Vinicius Resende de Castro; Jacanan Eloisa de Freitas Milani; Edilson Consuelo de Oliveira; Luciano de Souza Arruda; Jean-Louis Devineau; David M. Drew; Oliver Dunisch; Giselda Durigan; Elisha Elifuraha; Marcio Fedele; Ligia Ferreira Fedele; Afonso Figueiredo Filho; Cesar Augusto Guimaraes Finger; Augusto Cesar Franco; Joao Lima Freitas Junior; Franklin Galvao; Aster Gebrekirstos; Robert Gliniars; Paulo Mauricio Lima de Alencastro Graca; Anthony D. Griffiths; James Grogan; Kaiyu Guan; Jurgen Homeier; Maria Raquel Kanieski; Lip Khoon Kho; Jennifer Koenig; Sintia Valerio Kohler; Julia Krepkowski; Jose Pires Lemos-Filho; Diana Lieberman; Milton Eugene Lieberman; Claudio Sergio Lisi; Tomaz Longhi Santos; Jose Luis Lopez Ayala; Eduardo Eijji Maeda; Yadvinder Malhi; Vivian R. B. Maria; Marcia C. M. Marques; Renato Marques; Hector Maza Chamba; Lawrence Mbwambo; Karina Liana Lisboa Melgaco; Hooz Angela Mendivelso; Brett P. Murphy; Joseph O' Brien; Steven F. Oberbauer; Naoki Okada; Raphael Pelissier; Lynda D. Prior; Fidel Alejandro Roig; Michael Ross; Davi Rodrigo Rossatto; Vivien Rossi; Lucy Rowland; Ervan Rutishauser; Hellen Santana; Mark Schulze; Diogo Selhorst; Williamar Rodrigues Silva; Marcos Silveira; Susanne Spannl; Michael D. Swaine; Jose Julio Toledo; Marcos Miranda Toledo; Marisol Toledo; Takeshi Toma; Mario Tomazello Filho; Juan Ignacio Valdez Hernandez; Jan Verbesselt; Simone Aparecida Vieira; Gregoire Vincent; Carolina Volkmer de Castilho; Franziska Volland; Martin Worbes; Magda Lea Bolzan Zanon; Luiz E. O. C. Aragao

    2016-01-01

    The seasonal climate drivers of the carbon cycle in tropical forests remain poorly known, although these forests account for more carbon assimilation and storage than any other terrestrial ecosystem. Based on a unique combination of seasonal pan-tropical data sets from 89 experimental sites (68 include aboveground wood productivity measurements and 35 litter...

  18. Tropical secondary forests regenerating after shifting cultivation in the Philippines uplands are important carbon sinks.

    Science.gov (United States)

    Mukul, Sharif A; Herbohn, John; Firn, Jennifer

    2016-03-08

    In the tropics, shifting cultivation has long been attributed to large scale forest degradation, and remains a major source of uncertainty in forest carbon accounting. In the Philippines, shifting cultivation, locally known as kaingin, is a major land-use in upland areas. We measured the distribution and recovery of aboveground biomass carbon along a fallow gradient in post-kaingin secondary forests in an upland area in the Philippines. We found significantly higher carbon in the aboveground total biomass and living woody biomass in old-growth forest, while coarse dead wood biomass carbon was higher in the new fallow sites. For young through to the oldest fallow secondary forests, there was a progressive recovery of biomass carbon evident. Multivariate analysis indicates patch size as an influential factor in explaining the variation in biomass carbon recovery in secondary forests after shifting cultivation. Our study indicates secondary forests after shifting cultivation are substantial carbon sinks and that this capacity to store carbon increases with abandonment age. Large trees contribute most to aboveground biomass. A better understanding of the relative contribution of different biomass sources in aboveground total forest biomass, however, is necessary to fully capture the value of such landscapes from forest management, restoration and conservation perspectives.

  19. High-resolution forest carbon stocks and emissions in the Amazon

    Science.gov (United States)

    G. P. Asner; George V. N. Powell; Joseph Mascaro; David E. Knapp; John K. Clark; James Jacobson; Ty Kennedy-Bowdoin; Aravindh Balaji; Guayana Paez-Acosta; Eloy Victoria; Laura Secada; Michael Valqui; R. Flint. Hughes

    2010-01-01

    Efforts to mitigate climate change through the Reduced Emissions from Deforestation and Degradation (REDD) depend on mapping and monitoring of tropical forest carbon stocks and emissions over large geographic areas. With a new integrated use of satellite imaging, airborne light detection and ranging, and field plots, we mapped aboveground carbon stocks and emissions at...

  20. A Spatio-Temporal Based Estimation of Sequestered Carbon in the ...

    African Journals Online (AJOL)

    Michael

    2015-06-01

    Jun 1, 2015 ... reduction in carbon emissions due to deforestation and forest ... global initiatives to reduce global warming, and the management of ... using a process-based equilibrium terrestrial. *Manuscript ..... aboveground biomass limits modeled for African lowland ... replacement of vegetation biomass carbon from.

  1. Carbon sequestration resulting from bottomland hardwood afforestation in the Lower Mississippi Alluvial Valley

    Science.gov (United States)

    Bertrand F. Nero; Richard P. Maiers; Janet C. Dewey; Andrew J. Londo

    2010-01-01

    Increasing abandonment of marginal agricultural lands in the Lower Mississippi Alluvial Valley (LMAV) and rising global atmospheric carbon dioxide (CO2) levels create a need for better options of achieving rapid afforestation and enhancing both below and aboveground carbon sequestration. This study examines the responses of six mixtures of bottomland hardwood species...

  2. Where did the US forest biomass/carbon go?

    Science.gov (United States)

    Christopher William. Woodall

    2012-01-01

    In Apr. 2012, with the submission of the 1990-2010 US Greenhouse Gas (GHG) Inventory to the United Nations Framework Convention on Climate Change (UNFCCC), the official estimates of aboveground live tree carbon stocks within managed forests of the United States will drop by approximately 14%, compared with last year's inventory. It does not stop there, dead wood...

  3. Temperate forest dynamics and carbon storage: A 26-year case ...

    African Journals Online (AJOL)

    Overall, these results suggest that the forest is in a post-disturbance recovery phase, although favourable climatic conditions over the last three decades may also have had an influence on AGB accumulation. Keywords: aboveground biomass, carbon sequestration, forest conservation, long-term monitoring, succession ...

  4. Leading Gainful Employment Metric Reporting

    Science.gov (United States)

    Powers, Kristina; MacPherson, Derek

    2016-01-01

    This chapter will address the importance of intercampus involvement in reporting of gainful employment student-level data that will be used in the calculation of gainful employment metrics by the U.S. Department of Education. The authors will discuss why building relationships within the institution is critical for effective gainful employment…

  5. Detection of large above-ground biomass variability in lowland forest ecosystems by airborne LiDAR

    Directory of Open Access Journals (Sweden)

    J. Jubanski

    2013-06-01

    Full Text Available Quantification of tropical forest above-ground biomass (AGB over large areas as input for Reduced Emissions from Deforestation and forest Degradation (REDD+ projects and climate change models is challenging. This is the first study which attempts to estimate AGB and its variability across large areas of tropical lowland forests in Central Kalimantan (Indonesia through correlating airborne light detection and ranging (LiDAR to forest inventory data. Two LiDAR height metrics were analysed, and regression models could be improved through the use of LiDAR point densities as input (R2 = 0.88; n = 52. Surveying with a LiDAR point density per square metre of about 4 resulted in the best cost / benefit ratio. We estimated AGB for 600 km of LiDAR tracks and showed that there exists a considerable variability of up to 140% within the same forest type due to varying environmental conditions. Impact from logging operations and the associated AGB losses dating back more than 10 yr could be assessed by LiDAR but not by multispectral satellite imagery. Comparison with a Landsat classification for a 1 million ha study area where AGB values were based on site-specific field inventory data, regional literature estimates, and default values by the Intergovernmental Panel on Climate Change (IPCC showed an overestimation of 43%, 102%, and 137%, respectively. The results show that AGB overestimation may lead to wrong greenhouse gas (GHG emission estimates due to deforestation in climate models. For REDD+ projects this leads to inaccurate carbon stock estimates and consequently to significantly wrong REDD+ based compensation payments.

  6. Environmental Metabarcoding Reveals Contrasting Belowground and Aboveground Fungal Communities from Poplar at a Hg Phytomanagement Site.

    Science.gov (United States)

    Durand, Alexis; Maillard, François; Foulon, Julie; Gweon, Hyun S; Valot, Benoit; Chalot, Michel

    2017-11-01

    Characterization of microbial communities in stressful conditions at a field level is rather scarce, especially when considering fungal communities from aboveground habitats. We aimed at characterizing fungal communities from different poplar habitats at a Hg-contaminated phytomanagement site by using Illumina-based sequencing, network analysis approach, and direct isolation of Hg-resistant fungal strains. The highest diversity estimated by the Shannon index was found for soil communities, which was negatively affected by soil Hg concentration. Among the significant correlations between soil operational taxonomic units (OTUs) in the co-occurrence network, 80% were negatively correlated revealing dominance of a pattern of mutual exclusion. The fungal communities associated with Populus roots mostly consisted of OTUs from the symbiotic guild, such as members of the Thelephoraceae, thus explaining the lowest diversity found for root communities. Additionally, root communities showed the highest network connectivity index, while rarely detected OTUs from the Glomeromycetes may have a central role in the root network. Unexpectedly high richness and diversity were found for aboveground habitats, compared to the root habitat. The aboveground habitats were dominated by yeasts from the Lalaria, Davidiella, and Bensingtonia genera, not detected in belowground habitats. Leaf and stem habitats were characterized by few dominant OTUs such as those from the Dothideomycete class producing mutual exclusion with other OTUs. Aureobasidium pullulans, one of the dominating OTUs, was further isolated from the leaf habitat, in addition to Nakazawaea populi species, which were found to be Hg resistant. Altogether, these findings will provide an improved point of reference for microbial research on inoculation-based programs of tailings dumps.

  7. MS-Based Metabolite Profiling of Aboveground and Root Components of Zingiber mioga and Officinale.

    Science.gov (United States)

    Han, Ji Soo; Lee, Sunmin; Kim, Hyang Yeon; Lee, Choong Hwan

    2015-09-03

    Zingiber species are members of the Zingiberaceae family, and are widely used for medicinal and food purposes. In this study aboveground and root parts of Zingiber mioga and Zingiber officinale were subjected to metabolite profiling by ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF-MS) and gas chromatography time-of-flight mass spectrometry (GC-TOF-MS) in order to characterize them by species and parts and also to measure bioactivities. Both primary and secondary metabolites showed clear discrimination in the PCA score plot and PLS-DA by species and parts. Tetrahydrocurcumin, diarylheptanoid, 8-gingerol, and 8-paradol were discriminating metabolites between Z. mioga and Z. officinale that were present in different quantities. Eleven flavonoids, six amino acids, six organic acids, four fatty acids, and gingerenone A were higher in the aboveground parts than the root parts. Antioxidant activities were measured and were highest in the root part of Z. officinale. The relatively high contents of tetrahydrocurcumin, diarylheptanoid, and galanganol C in the root part of Z. officinale showed highly positive correlation with bioactivities based on correlation assay. On the basis of these results, we can suggest different usages of structurally different parts of Zingiber species as food plants.

  8. MS-Based Metabolite Profiling of Aboveground and Root Components of Zingiber mioga and Officinale

    Directory of Open Access Journals (Sweden)

    Ji Soo Han

    2015-09-01

    Full Text Available Zingiber species are members of the Zingiberaceae family, and are widely used for medicinal and food purposes. In this study aboveground and root parts of Zingiber mioga and Zingiber officinale were subjected to metabolite profiling by ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF-MS and gas chromatography time-of-flight mass spectrometry (GC-TOF-MS in order to characterize them by species and parts and also to measure bioactivities. Both primary and secondary metabolites showed clear discrimination in the PCA score plot and PLS-DA by species and parts. Tetrahydrocurcumin, diarylheptanoid, 8-gingerol, and 8-paradol were discriminating metabolites between Z. mioga and Z. officinale that were present in different quantities. Eleven flavonoids, six amino acids, six organic acids, four fatty acids, and gingerenone A were higher in the aboveground parts than the root parts. Antioxidant activities were measured and were highest in the root part of Z. officinale. The relatively high contents of tetrahydrocurcumin, diarylheptanoid, and galanganol C in the root part of Z. officinale showed highly positive correlation with bioactivities based on correlation assay. On the basis of these results, we can suggest different usages of structurally different parts of Zingiber species as food plants.

  9. Results for the Aboveground Configuration of the Boiling Water Reactor Dry Cask Simulator

    Energy Technology Data Exchange (ETDEWEB)

    Durbin, Samuel G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lindgren, Eric R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-09-30

    The thermal performance of commercial nuclear spent fuel dry storage casks is evaluated through detailed numerical analysis. These modeling efforts are completed by the vendor to demonstrate performance and regulatory compliance. The calculations are then independently verified by the Nuclear Regulatory Commission (NRC). Carefully measured data sets generated from testing of full-sized casks or smaller cask analogs are widely recognized as vital for validating these models. Recent advances in dry storage cask designs have significantly increased the maximum thermal load allowed in a cask, in part by increasing the efficiency of internal conduction pathways, and also by increasing the internal convection through greater canister helium pressure. These same canistered cask systems rely on ventilation between the canister and the overpack to convect heat away from the canister to the environment for both above- and below-ground configurations. While several testing programs have been previously conducted, these earlier validation attempts did not capture the effects of elevated helium pressures or accurately portray the external convection of above-ground and below-ground canistered dry cask systems. The purpose of the current investigation was to produce data sets that can be used to test the validity of the assumptions associated with the calculations used to determine steady-state cladding temperatures in modern dry casks that utilize elevated helium pressure in the sealed canister in an above-ground configuration.

  10. Estimating mangrove aboveground biomass from airborne LiDAR data: a case study from the Zambezi River delta

    Science.gov (United States)

    Fatoyinbo, Temilola; Feliciano, Emanuelle A.; Lagomasino, David; Kuk Lee, Seung; Trettin, Carl

    2018-02-01

    Mangroves are ecologically and economically important forested wetlands with the highest carbon (C) density of all terrestrial ecosystems. Because of their exceptionally large C stocks and importance as a coastal buffer, their protection and restoration has been proposed as an effective mitigation strategy for climate change. The inclusion of mangroves in mitigation strategies requires the quantification of C stocks (both above and belowground) and changes to accurately calculate emissions and sequestration. A growing number of countries are becoming interested in using mitigation initiatives, such as REDD+ (reducing emissions from deforestation and forest degradation), in these unique coastal forests. However, it is not yet clear how methods to measure C traditionally used for other ecosystems can be modified to estimate biomass in mangroves with the precision and accuracy needed for these initiatives. Airborne Lidar (ALS) data has often been proposed as the most accurate way for larger scale assessments but the application of ALS for coastal wetlands is scarce, primarily due to a lack of contemporaneous ALS and field measurements. Here, we evaluated the variability in field and Lidar-based estimates of aboveground biomass (AGB) through the combination of different local and regional allometric models and standardized height metrics that are comparable across spatial resolutions and sensor types, the end result being a simplified approach for accurately estimating mangrove AGB at large scales and determining the uncertainty by combining multiple allometric models. We then quantified wall-to-wall AGB stocks of a tall mangrove forest in the Zambezi Delta, Mozambique. Our results indicate that the Lidar H100 height metric correlates well with AGB estimates, with R 2 between 0.80 and 0.88 and RMSE of 33% or less. When comparing Lidar H100 AGB derived from three allometric models, mean AGB values range from 192 Mg ha-1 up to 252 Mg ha-1. We suggest the best model

  11. Operational gain : measuring the capture of genetic gain ...

    African Journals Online (AJOL)

    The concept of operational gain is more than the weighted average of the genetic quality of planted hectares, and encompasses tree breeding efficiencies, propagation efficiencies, matching of species and genotype to site, plant use efficiency and early measures of stand density and growth. To test the operational gain ...

  12. Measuring and modeling carbon stock change estimates for US forests and uncertainties from apparent inter-annual variability

    Science.gov (United States)

    James E. Smith; Linda S. Heath

    2015-01-01

    Our approach is based on a collection of models that convert or augment the USDA Forest Inventory and Analysis program survey data to estimate all forest carbon component stocks, including live and standing dead tree aboveground and belowground biomass, forest floor (litter), down deadwood, and soil organic carbon, for each inventory plot. The data, which include...

  13. High Gain Advanced GPS Receiver

    National Research Council Canada - National Science Library

    Brown, Alison; Zhang, Gengsheng

    2006-01-01

    NAVSYS High Gain Advanced GPS Receiver (HAGR) uses a digital beam-steering antenna array to enable up to eight GPS satellites to be tracked, each with up to 10 dBi of additional antenna gain over a conventional receiver solution...

  14. Drivers of aboveground wood production in a lowland tropical forest of West Africa: teasing apart the roles of tree density, tree diversity, soil phosphorus, and historical logging.

    Science.gov (United States)

    Jucker, Tommaso; Sanchez, Aida Cuni; Lindsell, Jeremy A; Allen, Harriet D; Amable, Gabriel S; Coomes, David A

    2016-06-01

    Tropical forests currently play a key role in regulating the terrestrial carbon cycle and abating climate change by storing carbon in wood. However, there remains considerable uncertainty as to whether tropical forests will continue to act as carbon sinks in the face of increased pressure from expanding human activities. Consequently, understanding what drives productivity in tropical forests is critical. We used permanent forest plot data from the Gola Rainforest National Park (Sierra Leone) - one of the largest tracts of intact tropical moist forest in West Africa - to explore how (1) stand basal area and tree diversity, (2) past disturbance associated with past logging, and (3) underlying soil nutrient gradients interact to determine rates of aboveground wood production (AWP). We started by statistically modeling the diameter growth of individual trees and used these models to estimate AWP for 142 permanent forest plots. We then used structural equation modeling to explore the direct and indirect pathways which shape rates of AWP. Across the plot network, stand basal area emerged as the strongest determinant of AWP, with densely packed stands exhibiting the fastest rates of AWP. In addition to stand packing density, both tree diversity and soil phosphorus content were also positively related to productivity. By contrast, historical logging activities negatively impacted AWP through the removal of large trees, which contributed disproportionately to productivity. Understanding what determines variation in wood production across tropical forest landscapes requires accounting for multiple interacting drivers - with stand structure, tree diversity, and soil nutrients all playing a key role. Importantly, our results also indicate that logging activities can have a long-lasting impact on a forest's ability to sequester and store carbon, emphasizing the importance of safeguarding old-growth tropical forests.

  15. Continuous monitoring of a mountain snowpack in the Austrian Alps by above-ground neutron sensing

    Science.gov (United States)

    Schattan, Paul; Baroni, Gabriele; Oswald, Sascha E.; Schöber, Johannes; Fey, Christine; Francke, Till; Huttenlau, Matthias; Achleitner, Stefan

    2017-04-01

    In alpine catchments the knowledge of the spatially and temporally heterogeneous dynamics of snow accumulation and depletion is crucial for modelling and managing water resources. While snow covered area can be retrieved operationally from remote sensing data, continuous measurements of other snow state variables like snow depth (SD) or snow water equivalent (SWE) remain challenging. Existing methods of retrieving both variables in alpine terrain face severe issues like a lack of spatial representativeness, labour-intensity or discontinuity in time. Recently, promising new measurement techniques combining a larger support with low maintenance cost like above-ground gamma-ray scintillators, GPS interferometric reflectometry or above-ground cosmic-ray neutron sensors (CRNS) have been suggested. While CRNS has proven its potential for monitoring soil moisture in a wide range of environments and applications, the empirical knowledge of using CRNS for snowpack monitoring is still very limited and restricted to shallow snowpacks with rather uniform evolution. The characteristics of an above-ground cosmic-ray neutron sensor (CRNS) were therefore evaluated for monitoring a mountain snowpack in the Austrian Alps (Kaunertal, Tyrol) during three winter seasons. The measurement campaign included a number of measurements during the period from 03/2014 to 06/2016: (i) neutron count measurements by CRNS, (ii) continuous point-scale SD and SWE measurements from an automatic weather station and (iii) 17 Terrestrial Laser Scanning (TLS) with simultaneous SD and SWE surveys. The highest accumulation in terms of SWE was found in 04/2014 with 600 mm. Neutron counts were compared to all available snow data. While previous studies suggested a signal saturation at around 100 mm of SWE, no complete signal saturation was found. A strong non-linear relation was found for both SD and SWE with best fits for spatially distributed TLS based snow data. Initially slightly different shapes were

  16. Results for the Aboveground Configuration of the Boiling Water Reactor Dry Cask Simulator

    Energy Technology Data Exchange (ETDEWEB)

    Durbin, Samuel G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Nuclear Fuel Cycle Technologies; Lindgren, Eric Richard [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Nuclear Fuel Cycle Technologies

    2016-09-01

    The thermal performance of commercial nuclear spent fuel dry storage casks are evaluated through detailed numerical analysis. These modeling efforts are completed by the vendor to demonstrate performance and regulatory compliance. The calculations are then independently verified by the Nuclear Regulatory Commission (NRC). Carefully measured data sets generated from testing of full sized casks or smaller cask analogs are widely recognized as vital for validating these models. Recent advances in dry storage cask designs have significantly increased the maximum thermal load allowed in a cask in part by increasing the efficiency of internal conduction pathways and also by increasing the internal convection through greater canister helium pressure. These same canistered cask systems rely on ventilation between the canister and the overpack to convect heat away from the canister to the environment for both above and belowground configurations. While several testing programs have been previously conducted, these earlier validation attempts did not capture the effects of elevated helium pressures or accurately portray the external convection of aboveground and belowground canistered dry cask systems. The purpose of the current investigation was to produce data sets that can be used to test the validity of the assumptions associated with the calculations used to determine steady-state cladding temperatures in modern dry casks that utilize elevated helium pressure in the sealed canister in an aboveground configuration. An existing electrically heated but otherwise prototypic BWR Incoloy-clad test assembly was deployed inside of a representative storage basket and cylindrical pressure vessel that represents a vertical canister system. The symmetric single assembly geometry with well-controlled boundary conditions simplifies interpretation of results. The arrangement of ducting was used to mimic conditions for an aboveground storage configuration in a vertical, dry cask

  17. A first map of tropical Africa's above-ground biomass derived from satellite imagery

    International Nuclear Information System (INIS)

    Baccini, A; Laporte, N; Goetz, S J; Sun, M; Dong, H

    2008-01-01

    Observations from the moderate resolution imaging spectroradiometer (MODIS) were used in combination with a large data set of field measurements to map woody above-ground biomass (AGB) across tropical Africa. We generated a best-quality cloud-free mosaic of MODIS satellite reflectance observations for the period 2000-2003 and used a regression tree model to predict AGB at 1 km resolution. Results based on a cross-validation approach show that the model explained 82% of the variance in AGB, with a root mean square error of 50.5 Mg ha -1 for a range of biomass between 0 and 454 Mg ha -1 . Analysis of lidar metrics from the Geoscience Laser Altimetry System (GLAS), which are sensitive to vegetation structure, indicate that the model successfully captured the regional distribution of AGB. The results showed a strong positive correlation (R 2 = 0.90) between the GLAS height metrics and predicted AGB.

  18. Estimating Stand Volume and Above-Ground Biomass of Urban Forests Using LiDAR

    Directory of Open Access Journals (Sweden)

    Vincenzo Giannico

    2016-04-01

    Full Text Available Assessing forest stand conditions in urban and peri-urban areas is essential to support ecosystem service planning and management, as most of the ecosystem services provided are a consequence of forest stand characteristics. However, collecting data for assessing forest stand conditions is time consuming and labor intensive. A plausible approach for addressing this issue is to establish a relationship between in situ measurements of stand characteristics and data from airborne laser scanning (LiDAR. In this study we assessed forest stand volume and above-ground biomass (AGB in a broadleaved urban forest, using a combination of LiDAR-derived metrics, which takes the form of a forest allometric model. We tested various methods for extracting proxies of basal area (BA and mean stand height (H from the LiDAR point-cloud distribution and evaluated the performance of different models in estimating forest stand volume and AGB. The best predictors for both models were the scale parameters of the Weibull distribution of all returns (except the first (proxy of BA and the 95th percentile of the distribution of all first returns (proxy of H. The R2 were 0.81 (p < 0.01 for the stand volume model and 0.77 (p < 0.01 for the AGB model with a RMSE of 23.66 m3·ha−1 (23.3% and 19.59 Mg·ha−1 (23.9%, respectively. We found that a combination of two LiDAR-derived variables (i.e., proxy of BA and proxy of H, which take the form of a forest allometric model, can be used to estimate stand volume and above-ground biomass in broadleaved urban forest areas. Our results can be compared to other studies conducted using LiDAR in broadleaved forests with similar methods.

  19. Diversity and aboveground biomass of lianas in the tropical seasonal rain forests of Xishuangbanna, SW China.

    Science.gov (United States)

    Lü, Xiao-Tao; Tang, Jian-Wei; Feng, Zhi-Li; Li, Mai-He

    2009-01-01

    Lianas are important components of tropical forests and have significant impacts on the diversity, structure and dynamics of tropical forests. The present study documented the liana flora in a Chinese tropical region. Species richness, abundance, size-class distribution and spatial patterns of lianas were investigated in three 1-ha plots in tropical seasonal rain forests in Xishuangbanna, SW China. All lianas with > or = 2 cm diameter at breast height (dbh) were measured, tagged and identified. A total of 458 liana stems belonging to 95 species (ranging from 38 to 50 species/ha), 59 genera and 32 families were recorded in the three plots. The most well-represented families were Loganiaceae, Annonceae, Papilionaceae, Apocynaceae and Rhamnaceae. Papilionaceae (14 species recorded) was the most important family in the study forests. The population density, basal area and importance value index (IVI) varied greatly across the three plots. Strychnos cathayensis, Byttneria grandifolia and Bousigonia mekongensis were the dominant species in terms of IVI across the three plots. The mean aboveground biomass of lianas (3 396 kg/ha) accounted for 1.4% of the total community above-ground biomass. The abundance, diversity and biomass of lianas in Xishuangbanna tropical seasonal rain forests are lower than those in tropical moist and wet forests, but higher than those in tropical dry forests. This study provides new data on lianas from a geographical region that has been little-studied. Our findings emphasize that other factors beyond the amount and seasonality of precipitation should be included when considering the liana abundance patterns across scales.

  20. Future rainfall variations reduce abundances of aboveground arthropods in model agroecosystems with different soil types

    Directory of Open Access Journals (Sweden)

    Johann G. Zaller

    2014-10-01

    Full Text Available Climate change scenarios for Central Europe predict less frequent but heavier rainfalls and longer drought periods during the growing season. This is expected to alter arthropods in agroecosystems that are important as biocontrol agents, herbivores or food for predators (e.g. farmland birds. In a lysimeter facility (totally 18 3-m2-plots, we experimentally tested the effects of long-term past vs. prognosticated future rainfall variations (15% increased rainfall per event, 25% more dry days according to regionalized climate change models from the Intergovernmental Panel on Climate Change (IPCC on aboveground arthropods in winter wheat (Triticum aestivum L. cultivated at three different soil types (calcaric phaeozem, calcic chernozem and gleyic phaeozem. Soil types were established 17 years and rainfall treatments one month before arthropod sampling; treatments were fully crossed and replicated three times. Aboveground arthropods were assessed by suction sampling, their mean abundances (± SD differed between April, May and June with 20 ± 3 m-2, 90 ± 35 m-2 and 289 ± 93 individuals m-2, respectively. Averaged across sampling dates, future rainfall reduced the abundance of spiders (Araneae, -47%, cicadas and leafhoppers (Auchenorrhyncha, -39%, beetles (Coleoptera, -52%, ground beetles (Carabidae, -41%, leaf beetles (Chrysomelidae, -64%, spring tails (Collembola, -58%, flies (Diptera, -73% and lacewings (Neuroptera, -73% but increased the abundance of snails (Gastropoda, +69%. Across sampling dates, soil types had no effects on arthropod abundances. Arthropod diversity was neither affected by rainfall nor soil types. Arthropod abundance was positively correlated with weed biomass for almost all taxa; abundance of Hemiptera and of total arthropods was positively correlated with weed density. These detrimental effects of future rainfall varieties on arthropod taxa in wheat fields can potentially alter arthropod-associated agroecosystem services.

  1. Belowground interactions with aboveground consequences: Invasive earthworms and arbuscular mycorrhizal fungi.

    Science.gov (United States)

    Paudel, Shishir; Longcore, Travis; MacDonald, Beau; McCormick, Melissa K; Szlavecz, Katalin; Wilson, Gail W T; Loss, Scot R

    2016-03-01

    A mounting body of research suggests that invasive nonnative earthworms substantially alter microbial communities, including arbuscular mycorrhizal fungi (AMF). These changes to AMF can cascade to affect plant communities and vertebrate populations. Despite these research advances, relatively little is known about (1) the mechanisms behind earthworms' effects on AMF and (2) the factors that determine the outcomes of earthworm-AMF interactions (i.e., whether AMF abundance is increased or decreased and subsequent effects on plants). We predict that AMF-mediated effects of nonnative earthworms on ecosystems are nearly universal because (1) AMF are important components of most terrestrial ecosystems, (2) nonnative earthworms have become established in nearly every type of terrestrial ecosystem, and (3) nonnative earthworms, due to their burrowing and feeding behavior, greatly affect AMF with potentially profound concomitant effects on plant communities. We highlight the multiple direct and indirect effects of nonnative earthworms on plants and review what is currently known about the interaction between earthworms and AMF. We also illustrate how the effects of nonnative earthworms on plant-AMF mutualisms can alter the structure and stability of aboveground plant communities, as well as the vertebrate communities relying on these habitats. Integrative studies that assess the interactive effects of earthworms and AMF can provide new insights into the role that belowground ecosystem engineers play in altering aboveground ecological processes. Understanding these processes may improve our ability to predict the structure of plant and animal communities in earthworm-invaded regions and to develop management strategies that limit the numerous undesired impacts of earthworms.

  2. Effect of nitrogen addition and drought on above-ground biomass of expanding tall grasses Calamagrostis epigejos and Arrhenatherum elatius

    Czech Academy of Sciences Publication Activity Database

    Fiala, Karel; Tůma, Ivan; Holub, Petr

    2011-01-01

    Roč. 66, č. 2 (2011), s. 275-281 ISSN 0006-3088 R&D Projects: GA ČR(CZ) GA526/06/0556 Institutional research plan: CEZ:AV0Z60050516 Keywords : nitrogen * drought * above-ground biomass Subject RIV: EF - Botanics Impact factor: 0.557, year: 2011

  3. Lidar-based estimates of aboveground biomass in the continental US and Mexico using ground, airborne, and satellite observations

    Science.gov (United States)

    Ross Nelson; Hank Margolis; Paul Montesano; Guoqing Sun; Bruce Cook; Larry Corp; Hans-Erik Andersen; Ben deJong; Fernando Paz Pellat; Thaddeus Fickel; Jobriath Kauffman; Stephen Prisley

    2017-01-01

    Existing national forest inventory plots, an airborne lidar scanning (ALS) system, and a space profiling lidar system (ICESat-GLAS) are used to generate circa 2005 estimates of total aboveground dry biomass (AGB) in forest strata, by state, in the continental United States (CONUS) and Mexico. The airborne lidar is used to link ground observations of AGB to space lidar...

  4. [Spatial distribution of Tamarix ramosissima aboveground biomass and water consumption in the lower reaches of Heihe River, Northwest China].

    Science.gov (United States)

    Peng, Shou-Zhang; Zhao, Chuan-Yan; Peng, Huan-Hua; Zheng, Xiang-Lin; Xu, Zhong-Lin

    2010-08-01

    Based on the field observation on the Tamarix ramosissima populations in the lower reaches of Heihe River, the relationship models between the aboveground biomass of T. ramosissima and its morphological features (basal diameter, height, and canopy perimeter) were built. In the mean time, the land use/cover of the study area was classified by the decision tree classification with high resolution image (QuickBird), the distribution of T. ramosissima was extracted from classification map, and the morphological feature (canopy perimeter) of T. ramosissima was calculated with ArcGIS 9.2. On the bases of these, the spatial distribution of T. ramosissima aboveground biomass in the study area was estimated. Finally, the spatial distribution of the water consumption of T. ramosissima in the study area was calculated by the transpiration coefficient (300) and the aboveground biomass. The results showed that the aboveground biomass of T. ramosissima was 69644.7 t, and the biomass per unit area was 0.78 kg x m(-2). Spatially, the habitats along the banks of Heihe River were suitable for T. ramosissima, and thus, this tree species had a high biomass. The total amount of water consumption of T. ramosissima in the study area was 2.1 x 10(7) m3, and the annual mean water consumption of T. ramosissima ranged from 30 mm to 386 mm.

  5. Does biodiversity make a difference? Relationships between species richness, evolutionary diversity, and aboveground live tree biomass across US forests

    Science.gov (United States)

    Kevin M. Potter; Christopher W. Woodall

    2014-01-01

    Biodiversity conveys numerous functional benefits to forested ecosystems, including community stability and resilience. In the context of managing forests for climate change mitigation/adaptation, maximizing and/or maintaining aboveground biomass will require understanding the interactions between tree biodiversity, site productivity, and the stocking of live trees....

  6. Data from: Can above-ground ecosystem services compensate for reduced fertilizer input and soil organic matter in annual crops?

    NARCIS (Netherlands)

    Gils, van S.H.; Putten, van der W.H.; Kleijn, D.

    2016-01-01

    Above-ground and below-ground environmental conditions influence crop yield by pollination, pest pressure, and resource supply. However, little is known about how interactions between these factors contribute to yield. Here, we used oilseed rape Brassica napus to test their effects on crop yield. We

  7. Can above-ground ecosystem services compensate for reduced fertilizer input and soil organic matter in annual crops?

    NARCIS (Netherlands)

    van Gils, Stijn; van der Putten, Wim H; Kleijn, David

    2016-01-01

    1.Above-ground and below-ground environmental conditions influence crop yield by pollination, pest pressure, and resource supply. However, little is known about how interactions between these factors contribute to yield. Here, we used oilseed rape Brassica napus to test their effects on crop

  8. Can above-ground ecosystem services compensate for reduced fertilizer input and soil organic matter in annual crops?

    NARCIS (Netherlands)

    Gils, van S.H.; Putten, van der W.H.; Kleijn, D.

    2016-01-01

    1.Above-ground and below-ground environmental conditions influence crop yield by pollination, pest pressure and resource supply. However, little is known about how interactions between these factors contribute to yield. Here, we used oilseed rape Brassica napus to test their effects on crop

  9. Plants as green as phones: Novel insights into plant-mediated communication between below- and above-ground insects

    NARCIS (Netherlands)

    Soler Gamborena, R.; Harvey, J.A.; Bezemer, T.M.; Stuefer, J.F.

    2008-01-01

    can act as vertical communication channels or ‘green phones’ linking soil-dwelling insects and insects in the aboveground ecosystem. When root-feeding insects attack a plant, the direct defense system of the shoot is activated, leading to an accumulation of phytotoxins in the leaves. The protection

  10. Plants as green phones: Novel insights into plant-mediated communication between below- and above-ground insects.

    Science.gov (United States)

    Soler, Roxina; Harvey, Jeffrey A; Bezemer, T Martijn; Stuefer, Josef F

    2008-08-01

    Plants can act as vertical communication channels or 'green phones' linking soil-dwelling insects and insects in the aboveground ecosystem. When root-feeding insects attack a plant, the direct defense system of the shoot is activated, leading to an accumulation of phytotoxins in the leaves. The protection of the plant shoot elicited by root damage can impair the survival, growth and development of aboveground insect herbivores, thereby creating plant-based functional links between soil-dwelling insects and insects that develop in the aboveground ecosystem. The interactions between spatially separated insects below- and aboveground are not restricted to root and foliar plant-feeding insects, but can be extended to higher trophic levels such as insect parasitoids. Here we discuss some implications of plants acting as communication channels or 'green phones' between root and foliar-feeding insects and their parasitoids, focusing on recent findings that plants attacked by root-feeding insects are significantly less attractive for the parasitoids of foliar-feeding insects.

  11. Polarimetric SAR Interferometry based modeling for tree height and aboveground biomass retrieval in a tropical deciduous forest

    Science.gov (United States)

    Kumar, Shashi; Khati, Unmesh G.; Chandola, Shreya; Agrawal, Shefali; Kushwaha, Satya P. S.

    2017-08-01

    The regulation of the carbon cycle is a critical ecosystem service provided by forests globally. It is, therefore, necessary to have robust techniques for speedy assessment of forest biophysical parameters at the landscape level. It is arduous and time taking to monitor the status of vast forest landscapes using traditional field methods. Remote sensing and GIS techniques are efficient tools that can monitor the health of forests regularly. Biomass estimation is a key parameter in the assessment of forest health. Polarimetric SAR (PolSAR) remote sensing has already shown its potential for forest biophysical parameter retrieval. The current research work focuses on the retrieval of forest biophysical parameters of tropical deciduous forest, using fully polarimetric spaceborne C-band data with Polarimetric SAR Interferometry (PolInSAR) techniques. PolSAR based Interferometric Water Cloud Model (IWCM) has been used to estimate aboveground biomass (AGB). Input parameters to the IWCM have been extracted from the decomposition modeling of SAR data as well as PolInSAR coherence estimation. The technique of forest tree height retrieval utilized PolInSAR coherence based modeling approach. Two techniques - Coherence Amplitude Inversion (CAI) and Three Stage Inversion (TSI) - for forest height estimation are discussed, compared and validated. These techniques allow estimation of forest stand height and true ground topography. The accuracy of the forest height estimated is assessed using ground-based measurements. PolInSAR based forest height models showed enervation in the identification of forest vegetation and as a result height values were obtained in river channels and plain areas. Overestimation in forest height was also noticed at several patches of the forest. To overcome this problem, coherence and backscatter based threshold technique is introduced for forest area identification and accurate height estimation in non-forested regions. IWCM based modeling for forest

  12. Developmental gains in visuospatial memory predict gains in mathematics achievement.

    Science.gov (United States)

    Li, Yaoran; Geary, David C

    2013-01-01

    Visuospatial competencies are related to performance in mathematical domains in adulthood, but are not consistently related to mathematics achievement in children. We confirmed the latter for first graders and demonstrated that children who show above average first-to-fifth grade gains in visuospatial memory have an advantage over other children in mathematics. The study involved the assessment of the mathematics and reading achievement of 177 children in kindergarten to fifth grade, inclusive, and their working memory capacity and processing speed in first and fifth grade. Intelligence was assessed in first grade and their second to fourth grade teachers reported on their in-class attentive behavior. Developmental gains in visuospatial memory span (d = 2.4) were larger than gains in the capacity of the central executive (d = 1.6) that in turn were larger than gains in phonological memory span (d = 1.1). First to fifth grade gains in visuospatial memory and in speed of numeral processing predicted end of fifth grade mathematics achievement, as did first grade central executive scores, intelligence, and in-class attentive behavior. The results suggest there are important individual differences in the rate of growth of visuospatial memory during childhood and that these differences become increasingly important for mathematics learning.

  13. Developmental gains in visuospatial memory predict gains in mathematics achievement.

    Directory of Open Access Journals (Sweden)

    Yaoran Li

    Full Text Available Visuospatial competencies are related to performance in mathematical domains in adulthood, but are not consistently related to mathematics achievement in children. We confirmed the latter for first graders and demonstrated that children who show above average first-to-fifth grade gains in visuospatial memory have an advantage over other children in mathematics. The study involved the assessment of the mathematics and reading achievement of 177 children in kindergarten to fifth grade, inclusive, and their working memory capacity and processing speed in first and fifth grade. Intelligence was assessed in first grade and their second to fourth grade teachers reported on their in-class attentive behavior. Developmental gains in visuospatial memory span (d = 2.4 were larger than gains in the capacity of the central executive (d = 1.6 that in turn were larger than gains in phonological memory span (d = 1.1. First to fifth grade gains in visuospatial memory and in speed of numeral processing predicted end of fifth grade mathematics achievement, as did first grade central executive scores, intelligence, and in-class attentive behavior. The results suggest there are important individual differences in the rate of growth of visuospatial memory during childhood and that these differences become increasingly important for mathematics learning.

  14. Developmental Gains in Visuospatial Memory Predict Gains in Mathematics Achievement

    Science.gov (United States)

    Li, Yaoran; Geary, David C.

    2013-01-01

    Visuospatial competencies are related to performance in mathematical domains in adulthood, but are not consistently related to mathematics achievement in children. We confirmed the latter for first graders and demonstrated that children who show above average first-to-fifth grade gains in visuospatial memory have an advantage over other children in mathematics. The study involved the assessment of the mathematics and reading achievement of 177 children in kindergarten to fifth grade, inclusive, and their working memory capacity and processing speed in first and fifth grade. Intelligence was assessed in first grade and their second to fourth grade teachers reported on their in-class attentive behavior. Developmental gains in visuospatial memory span (d = 2.4) were larger than gains in the capacity of the central executive (d = 1.6) that in turn were larger than gains in phonological memory span (d = 1.1). First to fifth grade gains in visuospatial memory and in speed of numeral processing predicted end of fifth grade mathematics achievement, as did first grade central executive scores, intelligence, and in-class attentive behavior. The results suggest there are important individual differences in the rate of growth of visuospatial memory during childhood and that these differences become increasingly important for mathematics learning. PMID:23936154

  15. Lidar-derived estimate and uncertainty of carbon sink in successional phases of woody encroachment

    Science.gov (United States)

    Sankey, Temuulen; Shrestha, Rupesh; Sankey, Joel B.; Hardegree, Stuart; Strand, Eva

    2013-07-01

    encroachment is a globally occurring phenomenon that contributes to the global carbon sink. The magnitude of this contribution needs to be estimated at regional and local scales to address uncertainties present in the global- and continental-scale estimates, and guide regional policy and management in balancing restoration activities, including removal of woody plants, with greenhouse gas mitigation goals. The objective of this study was to estimate carbon stored in various successional phases of woody encroachment. Using lidar measurements of individual trees, we present high-resolution estimates of aboveground carbon storage in juniper woodlands. Segmentation analysis of lidar point cloud data identified a total of 60,628 juniper tree crowns across four watersheds. Tree heights, canopy cover, and density derived from lidar were strongly correlated with field measurements of 2613 juniper stems measured in 85 plots (30 × 30 m). Aboveground total biomass of individual trees was estimated using a regression model with lidar-derived height and crown area as predictors (Adj. R2 = 0.76, p < 0.001, RMSE = 0.58 kg). The predicted mean aboveground woody carbon storage for the study area was 677 g/m2. Uncertainty in carbon storage estimates was examined with a Monte Carlo approach that addressed major error sources. Ranges predicted with uncertainty analysis in the mean, individual tree, aboveground woody C, and associated standard deviation were 0.35 - 143.6 kg and 0.5 - 1.25 kg, respectively. Later successional phases of woody encroachment had, on average, twice the aboveground carbon relative to earlier phases. Woody encroachment might be more successfully managed and balanced with carbon storage goals by identifying priority areas in earlier phases of encroachment where intensive treatments are most effective.

  16. Simulating boreal forest carbon dynamics after stand-replacing fire disturbance: insights from a global process-based vegetation model

    Science.gov (United States)

    Yue, C.; Ciais, P.; Luyssaert, S.; Cadule, P.; Harden, J.; Randerson, J.; Bellassen, V.; Wang, T.; Piao, S.L.; Poulter, B.; Viovy, N.

    2013-01-01

    Stand-replacing fires are the dominant fire type in North American boreal forests. They leave a historical legacy of a mosaic landscape of different aged forest cohorts. This forest age dynamics must be included in vegetation models to accurately quantify the role of fire in the historical and current regional forest carbon balance. The present study adapted the global process-based vegetation model ORCHIDEE to simulate the CO2 emissions from boreal forest fire and the subsequent recovery after a stand-replacing fire; the model represents postfire new cohort establishment, forest stand structure and the self-thinning process. Simulation results are evaluated against observations of three clusters of postfire forest chronosequences in Canada and Alaska. The variables evaluated include: fire carbon emissions, CO2 fluxes (gross primary production, total ecosystem respiration and net ecosystem exchange), leaf area index, and biometric measurements (aboveground biomass carbon, forest floor carbon, woody debris carbon, stand individual density, stand basal area, and mean diameter at breast height). When forced by local climate and the atmospheric CO2 history at each chronosequence site, the model simulations generally match the observed CO2 fluxes and carbon stock data well, with model-measurement mean square root of deviation comparable with the measurement accuracy (for CO2 flux ~100 g C m−2 yr−1, for biomass carbon ~1000 g C m−2 and for soil carbon ~2000 g C m−2). We find that the current postfire forest carbon sink at the evaluation sites, as observed by chronosequence methods, is mainly due to a combination of historical CO2 increase and forest succession. Climate change and variability during this period offsets some of these expected carbon gains. The negative impacts of climate were a likely consequence of increasing water stress caused by significant temperature increases that were not matched by concurrent increases in precipitation. Our simulation

  17. Structural, physiognomic and above-ground biomass variation in savanna–forest transition zones on three continents – how different are co-occurring savanna and forest formations?

    Directory of Open Access Journals (Sweden)

    E. M. Veenendaal

    2015-05-01

    Full Text Available Through interpretations of remote-sensing data and/or theoretical propositions, the idea that forest and savanna represent "alternative stable states" is gaining increasing acceptance. Filling an observational gap, we present detailed stratified floristic and structural analyses for forest and savanna stands located mostly within zones of transition (where both vegetation types occur in close proximity in Africa, South America and Australia. Woody plant leaf area index variation was related to tree canopy cover in a similar way for both savanna and forest with substantial overlap between the two vegetation types. As total woody plant canopy cover increased, so did the relative contribution of middle and lower strata of woody vegetation. Herbaceous layer cover declined as woody cover increased. This pattern of understorey grasses and herbs progressively replaced by shrubs as the canopy closes over was found for both savanna and forests and on all continents. Thus, once subordinate woody canopy layers are taken into account, a less marked transition in woody plant cover across the savanna–forest-species discontinuum is observed compared to that inferred when trees of a basal diameter > 0.1 m are considered in isolation. This is especially the case for shrub-dominated savannas and in taller savannas approaching canopy closure. An increased contribution of forest species to the total subordinate cover is also observed as savanna stand canopy closure occurs. Despite similarities in canopy-cover characteristics, woody vegetation in Africa and Australia attained greater heights and stored a greater amount of above-ground biomass than in South America. Up to three times as much above-ground biomass is stored in forests compared to savannas under equivalent climatic conditions. Savanna–forest transition zones were also found to typically occur at higher precipitation regimes for South America than for Africa. Nevertheless, consistent across all three

  18. Comparison of modeling approaches for carbon partitioning: Impact on estimates of global net primary production and equilibrium biomass of woody vegetation from MODIS GPP

    Science.gov (United States)

    Takeshi Ise; Creighton M. Litton; Christian P. Giardina; Akihiko Ito

    2010-01-01

    Partitioning of gross primary production (GPP) to aboveground versus belowground, to growth versus respiration, and to short versus long�]lived tissues exerts a strong influence on ecosystem structure and function, with potentially large implications for the global carbon budget. A recent meta-analysis of forest ecosystems suggests that carbon partitioning...

  19. Evaluating Generic Pantropical Allometric Models for the Estimation of Above-Ground Biomass in the Teak Plantations of Southern Western Ghats, India

    Directory of Open Access Journals (Sweden)

    S. Sandeep

    2015-09-01

    Full Text Available The use of suitable tree biomass allometric equations is crucial for making precise and non- destructive estimation of carbon storage and biomass energy values. The aim of this research was to evaluate the accuracy of the most commonly used pantropical allometric models and site-specific models to estimate the above-ground biomass (AGB in different aged teak plantations of Southern Western Ghats of India. For this purpose, the AGB data measured for 70 trees with diameter >10 cm from different aged teak plantations in Kerala part of Southern Western Ghats following destructive procedure was used. The results show that site specific models based on a single predictor variable diameter at breast height (dbh, though simple, may grossly increase the uncertainty across sites. Hence, a generic model encompassing dbh, height and wood specific gravity with sufficient calibration taking into account different forest types is advised for the tropical forest systems. The study also suggests that the commonly used pantropical models should be evaluated for different ecosystems prior to their application at national or regional scales.

  20. Allometric Models to Predict Aboveground Woody Biomass of Black Locust (Robinia pseudoacacia L. in Short Rotation Coppice in Previous Mining and Agricultural Areas in Germany

    Directory of Open Access Journals (Sweden)

    Christin Carl

    2017-09-01

    Full Text Available Black locust is a drought-resistant tree species with high biomass productivity during juvenility; it is able to thrive on wastelands, such as former brown coal fields and dry agricultural areas. However, research conducted on this species in such areas is limited. This paper aims to provide a basis for predicting tree woody biomass for black locust based on tree, competition, and site variables at 14 sites in northeast Germany that were previously utilized for mining or agriculture. The study areas, which are located in an area covering 320 km × 280 km, are characterized by a variety of climatic and soil conditions. Influential variables, including tree parameters, competition, and climatic parameters were considered. Allometric biomass models were employed. The findings show that the most important parameters are tree and competition variables. Different former land utilizations, such as mining or agriculture, as well as growth by cores or stumps, significantly influenced aboveground woody biomass production. The new biomass models developed as part of this study can be applied to calculate woody biomass production and carbon sequestration of Robinia pseudoacacia L. in short rotation coppices in previous mining and agricultural areas.

  1. Lidar remote sensing of above-ground biomass in three biomes.

    Science.gov (United States)

    Michael A. Lefsky; Warren B. Cohen; David J. Harding; Geoffrey G. Parkers; Steven A. Acker; S. Thomas. Gower

    2002-01-01

    Estimation of the amount of carbon stored in forests is a key challenge for understanding the global carbon cycle, one which remote sensing is expected to help address. However, estimation of carbon storage in moderate to high biomass forests is difficult for conventional optical and radar sensors. Lidar (light detection and ranging) instruments measure the vertical...

  2. Coarse woody debris carbon storage across a mean annual temperature gradient in tropical montane wet forest

    Science.gov (United States)

    Darcey K. Iwashita; Creighton M. Litton; Christian P. Giardina

    2013-01-01

    Coarse woody debris (CWD; defined here as fallen and standing dead trees and tree ferns) is a critical structural and functional component of forest ecosystems that typically comprises a large proportion of total aboveground carbon (C) storage. However, CWD estimates for the tropics are uncommon, and little is known about how C storage in CWD will respond to climate...

  3. Quantifying Fire's Impacts on Total and Pyrogenic Carbon Stocks in Mixed-Conifer Forests: Results from Pre- and Post-Fire Measurements in Active Wildfire Incidents

    Science.gov (United States)

    Miesel, J. R.; Reiner, A. L.; Ewell, C. M.; Sanderman, J.; Maestrini, B.; Adkins, J.

    2016-12-01

    Widespread US fire suppression policy has contributed to an accumulation of vegetation in many western forests relative to historic conditions, and these changes can exacerbate wildfire severity and carbon (C) emissions. Serious concern exists about positive feedbacks between wildfire emissions and global climate; however, fires not only release C from terrestrial to atmospheric pools, they also create "black" or pyrogenic C (PyC) which contributes to longer-term C stability. Our objective was to quantify wildfire impacts on aboveground and belowground total C and PyC stocks in California mixed-conifer forests. We worked with incident management teams to access five active wildfires to establish and measure plots within days before and after fire. We measured pre- and post-fire aboveground forest structure and woody fuels to calculate aboveground biomass, biomass C, and PyC, and we collected pre- and post-fire forest floor and 0-5 cm mineral soil samples to measure belowground C and PyC stocks. Our preliminary results show that fire had minimal impact on the number of trees per hectare, whereas C losses from the tree layer occurred via consumption of foliage, and PyC gain occurred in tree bark. Fire released 54% to 100% of surface fuel C. In the forest floor layer, we observed 33 to 100% C loss, whereas changes in PyC stocks ranged from 100% loss to 186% gain relative to pre-fire samples. In general, fire had minimal to no impact on 0-5 cm mineral soil C. We will present relationships between total C, PyC and post-fire C and N dynamics in one of the five wildfire sites. Our data are unique because they represent nearly immediate pre- and post-fire measurements in major wildfires in a widespread western U.S. forest type. This research advances understanding of the role of fire on forest C fluxes and C sequestration potential as PyC.

  4. Trade-offs between carbon stocks and timber recovery in tropical forests are mediated by logging intensity.

    Science.gov (United States)

    Roopsind, Anand; Caughlin, T Trevor; van der Hout, Peter; Arets, Eric; Putz, Francis E

    2018-03-30

    Forest degradation accounts for ~ 70% of total carbon losses from tropical forests. Substantial emissions are from selective logging, a land-use activity that decreases forest carbon density. To maintain carbon values in selectively logged forests, climate change mitigation policies and government agencies promote the adoption of reduced-impact logging (RIL) practices. However, whether RIL will maintain both carbon and timber values in managed tropical forests over time remains uncertain. In this study, we quantify the recovery of timber stocks and aboveground carbon at an experimental site where forests were subjected to different intensities of RIL (4 trees ha -1 , 8 trees ha -1 , and 16 trees ha -1 ). Our census data spans 20 years post-logging and 17 years after the liberation of future crop trees from competition in a tropical forest on the Guiana Shield, a globally important forest carbon reservoir. We model recovery of timber and carbon with a breakpoint regression that allowed us to capture elevated tree mortality immediately after logging. Recovery rates of timber and carbon were governed by the presence of residual trees (i.e., trees that persisted through the first harvest). The liberation treatment stimulated faster recovery of timber albeit at a carbon cost. Model results suggest a threshold logging intensity beyond which forests managed for timber and carbon derive few benefits from RIL, with recruitment and residual growth not sufficient to offset losses. Inclusion of the breakpoint at which carbon and timber gains outpaced post-logging mortality led to high predictive accuracy, including out-of-sample R 2 values >90%, and enabled inference on demographic changes post-logging. Our modeling framework is broadly applicable to studies that aim to quantify impacts of logging on forest recovery. Overall, we demonstrate that initial mortality drives variation in recovery rates, that the second harvest depends on old growth wood, and that timber

  5. Carbon sequestration potential of second-growth forest regeneration in the Latin American tropics.

    Science.gov (United States)

    Chazdon, Robin L; Broadbent, Eben N; Rozendaal, Danaë M A; Bongers, Frans; Zambrano, Angélica María Almeyda; Aide, T Mitchell; Balvanera, Patricia; Becknell, Justin M; Boukili, Vanessa; Brancalion, Pedro H S; Craven, Dylan; Almeida-Cortez, Jarcilene S; Cabral, George A L; de Jong, Ben; Denslow, Julie S; Dent, Daisy H; DeWalt, Saara J; Dupuy, Juan M; Durán, Sandra M; Espírito-Santo, Mario M; Fandino, María C; César, Ricardo G; Hall, Jefferson S; Hernández-Stefanoni, José Luis; Jakovac, Catarina C; Junqueira, André B; Kennard, Deborah; Letcher, Susan G; Lohbeck, Madelon; Martínez-Ramos, Miguel; Massoca, Paulo; Meave, Jorge A; Mesquita, Rita; Mora, Francisco; Muñoz, Rodrigo; Muscarella, Robert; Nunes, Yule R F; Ochoa-Gaona, Susana; Orihuela-Belmonte, Edith; Peña-Claros, Marielos; Pérez-García, Eduardo A; Piotto, Daniel; Powers, Jennifer S; Rodríguez-Velazquez, Jorge; Romero-Pérez, Isabel Eunice; Ruíz, Jorge; Saldarriaga, Juan G; Sanchez-Azofeifa, Arturo; Schwartz, Naomi B; Steininger, Marc K; Swenson, Nathan G; Uriarte, Maria; van Breugel, Michiel; van der Wal, Hans; Veloso, Maria D M; Vester, Hans; Vieira, Ima Celia G; Bentos, Tony Vizcarra; Williamson, G Bruce; Poorter, Lourens

    2016-05-01

    Regrowth of tropical secondary forests following complete or nearly complete removal of forest vegetation actively stores carbon in aboveground biomass, partially counterbalancing carbon emissions from deforestation, forest degradation, burning of fossil fuels, and other anthropogenic sources. We estimate the age and spatial extent of lowland second-growth forests in the Latin American tropics and model their potential aboveground carbon accumulation over four decades. Our model shows that, in 2008, second-growth forests (1 to 60 years old) covered 2.4 million km(2) of land (28.1% of the total study area). Over 40 years, these lands can potentially accumulate a total aboveground carbon stock of 8.48 Pg C (petagrams of carbon) in aboveground biomass via low-cost natural regeneration or assisted regeneration, corresponding to a total CO2 sequestration of 31.09 Pg CO2. This total is equivalent to carbon emissions from fossil fuel use and industrial processes in all of Latin America and the Caribbean from 1993 to 2014. Ten countries account for 95% of this carbon storage potential, led by Brazil, Colombia, Mexico, and Venezuela. We model future land-use scenarios to guide national carbon mitigation policies. Permitting natural regeneration on 40% of lowland pastures potentially stores an additional 2.0 Pg C over 40 years. Our study provides information and maps to guide national-level forest-based carbon mitigation plans on the basis of estimated rates of natural regeneration and pasture abandonment. Coupled with avoided deforestation and sustainable forest management, natural regeneration of second-growth forests provides a low-cost mechanism that yields a high carbon sequestration potential with multiple benefits for biodiversity and ecosystem services.

  6. Carbon sequestration potential of second-growth forest regeneration in the Latin American tropics

    Science.gov (United States)

    Chazdon, Robin L.; Broadbent, Eben N.; Rozendaal, Danaë M. A.; Bongers, Frans; Zambrano, Angélica María Almeyda; Aide, T. Mitchell; Balvanera, Patricia; Becknell, Justin M.; Boukili, Vanessa; Brancalion, Pedro H. S.; Craven, Dylan; Almeida-Cortez, Jarcilene S.; Cabral, George A. L.; de Jong, Ben; Denslow, Julie S.; Dent, Daisy H.; DeWalt, Saara J.; Dupuy, Juan M.; Durán, Sandra M.; Espírito-Santo, Mario M.; Fandino, María C.; César, Ricardo G.; Hall, Jefferson S.; Hernández-Stefanoni, José Luis; Jakovac, Catarina C.; Junqueira, André B.; Kennard, Deborah; Letcher, Susan G.; Lohbeck, Madelon; Martínez-Ramos, Miguel; Massoca, Paulo; Meave, Jorge A.; Mesquita, Rita; Mora, Francisco; Muñoz, Rodrigo; Muscarella, Robert; Nunes, Yule R. F.; Ochoa-Gaona, Susana; Orihuela-Belmonte, Edith; Peña-Claros, Marielos; Pérez-García, Eduardo A.; Piotto, Daniel; Powers, Jennifer S.; Rodríguez-Velazquez, Jorge; Romero-Pérez, Isabel Eunice; Ruíz, Jorge; Saldarriaga, Juan G.; Sanchez-Azofeifa, Arturo; Schwartz, Naomi B.; Steininger, Marc K.; Swenson, Nathan G.; Uriarte, Maria; van Breugel, Michiel; van der Wal, Hans; Veloso, Maria D. M.; Vester, Hans; Vieira, Ima Celia G.; Bentos, Tony Vizcarra; Williamson, G. Bruce; Poorter, Lourens

    2016-01-01

    Regrowth of tropical secondary forests following complete or nearly complete removal of forest vegetation actively stores carbon in aboveground biomass, partially counterbalancing carbon emissions from deforestation, forest degradation, burning of fossil fuels, and other anthropogenic sources. We estimate the age and spatial extent of lowland second-growth forests in the Latin American tropics and model their potential aboveground carbon accumulation over four decades. Our model shows that, in 2008, second-growth forests (1 to 60 years old) covered 2.4 million km2 of land (28.1% of the total study area). Over 40 years, these lands can potentially accumulate a total aboveground carbon stock of 8.48 Pg C (petagrams of carbon) in aboveground biomass via low-cost natural regeneration or assisted regeneration, corresponding to a total CO2 sequestration of 31.09 Pg CO2. This total is equivalent to carbon emissions from fossil fuel use and industrial processes in all of Latin America and the Caribbean from 1993 to 2014. Ten countries account for 95% of this carbon storage potential, led by Brazil, Colombia, Mexico, and Venezuela. We model future land-use scenarios to guide national carbon mitigation policies. Permitting natural regeneration on 40% of lowland pastures potentially stores an additional 2.0 Pg C over 40 years. Our study provides information and maps to guide national-level forest-based carbon mitigation plans on the basis of estimated rates of natural regeneration and pasture abandonment. Coupled with avoided deforestation and sustainable forest management, natural regeneration of second-growth forests provides a low-cost mechanism that yields a high carbon sequestration potential with multiple benefits for biodiversity and ecosystem services. PMID:27386528

  7. Dependence of wheat and rice respiration on tissue nitrogen and the corresponding net carbon fixation efficiency under different rates of nitrogen application

    Science.gov (United States)

    Sun, Wenjuan; Huang, Yao; Chen, Shutao; Zou, Jianwen; Zheng, Xunhua

    2007-02-01

    To quantitatively address the role of tissue N in crop respiration under various agricultural practices, and to consequently evaluate the impact of synthetic fertilizer N application on biomass production and respiration, and hence net carbon fixation efficiency ( E ncf), pot and field experiments were carried out for an annual rotation of a rice-wheat cropping system from 2001 to 2003. The treatments of the pot experiments included fertilizer N application, sowing date and planting density. Different rates of N application were tested in the field experiments. Static opaque chambers were used for sampling the gas. The respiration as CO2 emission was detected by a gas chromatograph. A successive biomass clipping method was employed to determine the crop autotrophic respiration coefficient ( R a). Results from the pot experiments revealed a linear relationship between R a and tissue N content as R a = 4.74N-1.45 ( R 2 = 0.85, P < 0.001). Measurements and calculations from the field experiments indicated that fertilizer N application promoted not only biomass production but also increased the respiration of crops. A further investigation showed that the increase of carbon loss in terms of respiration owing to fertilizer N application exceeded that of net carbon gain in terms of aboveground biomass when fertilizer N was applied over a certain rate. Consequently, the E ncf declined as the N application rate increased.

  8. Developmental Gains in Visuospatial Memory Predict Gains in Mathematics Achievement

    OpenAIRE

    Li, Yaoran; Geary, David C.

    2013-01-01

    Visuospatial competencies are related to performance in mathematical domains in adulthood, but are not consistently related to mathematics achievement in children. We confirmed the latter for first graders and demonstrated that children who show above average first-to-fifth grade gains in visuospatial memory have an advantage over other children in mathematics. The study involved the assessment of the mathematics and reading achievement of 177 children in kindergarten to fifth grade, inclusiv...

  9. Wired to the roots: impact of root-beneficial microbe interactions on aboveground plant physiology and protection.

    Science.gov (United States)

    Kumar, Amutha Sampath; Bais, Harsh P

    2012-12-01

    Often, plant-pathogenic microbe interactions are discussed in a host-microbe two-component system, however very little is known about how the diversity of rhizospheric microbes that associate with plants affect host performance against pathogens. There are various studies, which specially direct the importance of induced systemic defense (ISR) response in plants interacting with beneficial rhizobacteria, yet we don't know how rhizobacterial associations modulate plant physiology. In here, we highlight the many dimensions within which plant roots associate with beneficial microbes by regulating aboveground physiology. We review approaches to study the causes and consequences of plant root association with beneficial microbes on aboveground plant-pathogen interactions. The review provides the foundations for future investigations into the impact of the root beneficial microbial associations on plant performance and innate defense responses.

  10. 40K/137Cs discrimination ratios to the aboveground organs of tropical plants

    International Nuclear Information System (INIS)

    Sanches, N.; Anjos, R.M.; Mosquera, B.

    2008-01-01

    In the present work, the accumulation of caesium and potassium in aboveground plant parts was studied in order to improve the understanding on the behaviour of monovalent cations in several compartments of tropical plants. We present the results for activity concentrations of 137 Cs and 40 K, measured by gamma spectrometry, from five tropical plant species: guava (Psidium guajava), mango (Mangifera indica), papaya (Carica papaya), banana (Musa paradisiaca), and manioc (Manihot esculenta). Caesium and potassium have shown a high level of mobility within the plants, exhibiting the highest values of concentration in the growing parts (fruits, leaves, twigs, and barks) of the woody fruit and large herbaceous shrub (such as manioc) species. In contrast, the banana and papaya plants exhibited the lowest levels of 137 Cs and 40 K in their growing parts. However, a significant correlation between activity concentrations of 137 Cs and 40 K was observed in these tropical plants. The 40 K/ 137 Cs discrimination ratios were approximately equal to unity in different compartments of each individual plant, suggesting the possibility of using caesium to predict the behaviour of potassium in several tropical species

  11. {sup 40}K/{sup 137}Cs discrimination ratios to the aboveground organs of tropical plants

    Energy Technology Data Exchange (ETDEWEB)

    Sanches, N. [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n, Gragoata, Niteroi, CEP 24210-346, RJ (Brazil); Anjos, R.M. [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n, Gragoata, Niteroi, CEP 24210-346, RJ (Brazil)], E-mail: meigikos@if.uff.br; Mosquera, B. [Instituto de Fisica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n, Gragoata, Niteroi, CEP 24210-346, RJ (Brazil)

    2008-07-15

    In the present work, the accumulation of caesium and potassium in aboveground plant parts was studied in order to improve the understanding on the behaviour of monovalent cations in several compartments of tropical plants. We present the results for activity concentrations of {sup 137}Cs and {sup 40}K, measured by gamma spectrometry, from five tropical plant species: guava (Psidium guajava), mango (Mangifera indica), papaya (Carica papaya), banana (Musa paradisiaca), and manioc (Manihot esculenta). Caesium and potassium have shown a high level of mobility within the plants, exhibiting the highest values of concentration in the growing parts (fruits, leaves, twigs, and barks) of the woody fruit and large herbaceous shrub (such as manioc) species. In contrast, the banana and papaya plants exhibited the lowest levels of {sup 137}Cs and {sup 40}K in their growing parts. However, a significant correlation between activity concentrations of {sup 137}Cs and {sup 40}K was observed in these tropical plants. The {sup 40}K/{sup 137}Cs discrimination ratios were approximately equal to unity in different compartments of each individual plant, suggesting the possibility of using caesium to predict the behaviour of potassium in several tropical species.

  12. Remediation and recycling of oil-contaminated soil beneath a large above-ground storage tank

    International Nuclear Information System (INIS)

    Wallace, G.

    1994-01-01

    While retrofitting a large 30-year-old, above-ground petroleum storage tank, Southern California Edison Company (SCE) discovered that soil beneath the fixed-roof, single-bottom tank was contaminated with 40,000 gallons of number-sign 6 fuel oil. The steel tank was left in place during the excavation and remediation of the contaminated soil to retain the operating permit. The resulting 2,000 tons of contaminated aggregate was recycled to make asphalt concrete for paving the tank basin and the remaining 5,600 tons of oily soil was thermally treated on site for use as engineered fill at another location. This successful operation provided an economical cleanup solution for a common leakage problem of single-lined tanks and eliminated the long-term liability of Class 1 landfill disposal. As a pro-active environmental effort, this paper shares SCE's site assessment procedure, reveals the engineering method developed to stabilize the tank, discusses the soil treatment technologies used, describes the problems encountered and lessons learned during the cleanup, discloses the costs of the operation, and offers guidelines and recommendations for similar tank remediation. This paper does not describe the work or costs for removing or replacing the tank bottom

  13. Successful range-expanding plants experience less above-ground and below-ground enemy impact.

    Science.gov (United States)

    Engelkes, Tim; Morriën, Elly; Verhoeven, Koen J F; Bezemer, T Martijn; Biere, Arjen; Harvey, Jeffrey A; McIntyre, Lauren M; Tamis, Wil L M; van der Putten, Wim H

    2008-12-18

    Many species are currently moving to higher latitudes and altitudes. However, little is known about the factors that influence the future performance of range-expanding species in their new habitats. Here we show that range-expanding plant species from a riverine area were better defended against shoot and root enemies than were related native plant species growing in the same area. We grew fifteen plant species with and without non-coevolved polyphagous locusts and cosmopolitan, polyphagous aphids. Contrary to our expectations, the locusts performed more poorly on the range-expanding plant species than on the congeneric native plant species, whereas the aphids showed no difference. The shoot herbivores reduced the biomass of the native plants more than they did that of the congeneric range expanders. Also, the range-expanding plants developed fewer pathogenic effects in their root-zone soil than did the related native species. Current predictions forecast biodiversity loss due to limitations in the ability of species to adjust to climate warming conditions in their range. Our results strongly suggest that the plants that shift ranges towards higher latitudes and altitudes may include potential invaders, as the successful range expanders may experience less control by above-ground or below-ground enemies than the natives.

  14. Do soil organisms affect aboveground litter decomposition in the semiarid Patagonian steppe, Argentina?

    Science.gov (United States)

    Araujo, Patricia I; Yahdjian, Laura; Austin, Amy T

    2012-01-01

    Surface litter decomposition in arid and semiarid ecosystems is often faster than predicted by climatic parameters such as annual precipitation or evapotranspiration, or based on standard indices of litter quality such as lignin or nitrogen concentrations. Abiotic photodegradation has been demonstrated to be an important factor controlling aboveground litter decomposition in aridland ecosystems, but soil fauna, particularly macrofauna such as termites and ants, have also been identified as key players affecting litter mass loss in warm deserts. Our objective was to quantify the importance of soil organisms on surface litter decomposition in the Patagonian steppe in the absence of photodegradative effects, to establish the relative importance of soil organisms on rates of mass loss and nitrogen release. We estimated the relative contribution of soil fauna and microbes to litter decomposition of a dominant grass using litterboxes with variable mesh sizes that excluded groups of soil fauna based on size class (10, 2, and 0.01 mm), which were placed beneath shrub canopies. We also employed chemical repellents (naphthalene and fungicide). The exclusion of macro- and mesofauna had no effect on litter mass loss over 3 years (P = 0.36), as litter decomposition was similar in all soil fauna exclusions and naphthalene-treated litter. In contrast, reduction of fungal activity significantly inhibited litter decomposition (P soil fauna have been mentioned as a key control of litter decomposition in warm deserts, biogeographic legacies and temperature limitation may constrain the importance of these organisms in temperate aridlands, particularly in the southern hemisphere.

  15. Taxonomic and Functional Responses of Soil Microbial Communities to Annual Removal of Aboveground Plant Biomass

    Science.gov (United States)

    Guo, Xue; Zhou, Xishu; Hale, Lauren; Yuan, Mengting; Feng, Jiajie; Ning, Daliang; Shi, Zhou; Qin, Yujia; Liu, Feifei; Wu, Liyou; He, Zhili; Van Nostrand, Joy D.; Liu, Xueduan; Luo, Yiqi; Tiedje, James M.; Zhou, Jizhong

    2018-01-01

    Clipping, removal of aboveground plant biomass, is an important issue in grassland ecology. However, few studies have focused on the effect of clipping on belowground microbial communities. Using integrated metagenomic technologies, we examined the taxonomic and functional responses of soil microbial communities to annual clipping (2010–2014) in a grassland ecosystem of the Great Plains of North America. Our results indicated that clipping significantly (P microbial respiration rates. Annual temporal variation within the microbial communities was much greater than the significant changes introduced by clipping, but cumulative effects of clipping were still observed in the long-term scale. The abundances of some bacterial and fungal lineages including Actinobacteria and Bacteroidetes were significantly (P microbial communities were significantly correlated with soil respiration and plant productivity. Intriguingly, clipping effects on microbial function may be highly regulated by precipitation at the interannual scale. Altogether, our results illustrated the potential of soil microbial communities for increased soil organic matter decomposition under clipping land-use practices. PMID:29904372

  16. Sparse Density, Leaf-Off Airborne Laser Scanning Data in Aboveground Biomass Component Prediction

    Directory of Open Access Journals (Sweden)

    Ville Kankare

    2015-05-01

    Full Text Available The demand for cost-efficient forest aboveground biomass (AGB prediction methods is growing worldwide. The National Land Survey of Finland (NLS began collecting airborne laser scanning (ALS data throughout Finland in 2008 to provide a new high-detailed terrain elevation model. Similar data sets are being collected in an increasing number of countries worldwide. These data sets offer great potential in forest mapping related applications. The objectives of our study were (i to evaluate the AGB component prediction accuracy at a resolution of 300 m2 using sparse density, leaf-off ALS data (collected by NLS derived metrics as predictor variables; (ii to compare prediction accuracies with existing large-scale forest mapping techniques (Multi-source National Forest Inventory, MS-NFI based on Landsat TM satellite imagery; and (iii to evaluate the accuracy and effect of canopy height model (CHM derived metrics on AGB component prediction when ALS data were acquired with multiple sensors and varying scanning parameters. Results showed that ALS point metrics can be used to predict component AGBs with an accuracy of 29.7%–48.3%. AGB prediction accuracy was slightly improved using CHM-derived metrics but CHM metrics had a more clear effect on the estimated bias. Compared to the MS-NFI, the prediction accuracy was considerably higher, which was caused by differences in the remote sensing data utilized.

  17. Aboveground dry biomass partitioning and nitrogen accumulation in early maturing soybean ‘Merlin’

    Directory of Open Access Journals (Sweden)

    Tadeusz Zając

    2017-12-01

    Full Text Available The aim of the study was to determine the biomass and nitrogen accumulation in early maturing soybean plants experiencing contrasting weather conditions. Soybean (Glycine max is a species of agricultural crop plant that is widely described in scientific publications. During 2014–2016, a field experiment with early maturing soybean ‘Merlin’ was carried out at Grodziec Śląski, Poland (49°48'01" N, 18°52'04" E. Results showed that the morphological traits of the plants, the yield of individual plants, and the soybean crop were all closely related to the climatic conditions. A high amount of precipitation stimulated seed development, resulting in a high production potential. The harvest index calculated for soybean ‘Merlin’ was high and exceeded 0.5 g g−1. The nitrogen content of the aboveground biomass increased during ontogenesis. The maximum yield of dry matter was noted at the green maturity phase, which subsequently decreased at the full maturity phase because of the loss of the leaf fraction. The variation in the effectiveness of nitrogen accumulation in seeds between 2015 and 2016 was 30%. The nitrogen harvest index values were high in each year of the experiment and exceeded 0.92 g−1. For the production of 1 ton of seeds with an adequate amount of soybean straw, plants needed, on average, 68 kg of nitrogen.

  18. 40K/137Cs discrimination ratios to the aboveground organs of tropical plants.

    Science.gov (United States)

    Sanches, N; Anjos, R M; Mosquera, B

    2008-07-01

    In the present work, the accumulation of caesium and potassium in aboveground plant parts was studied in order to improve the understanding on the behaviour of monovalent cations in several compartments of tropical plants. We present the results for activity concentrations of (137)Cs and (40)K, measured by gamma spectrometry, from five tropical plant species: guava (Psidium guajava), mango (Mangifera indica), papaya (Carica papaya), banana (Musa paradisíaca), and manioc (Manihot esculenta). Caesium and potassium have shown a high level of mobility within the plants, exhibiting the highest values of concentration in the growing parts (fruits, leaves, twigs, and barks) of the woody fruit and large herbaceous shrub (such as manioc) species. In contrast, the banana and papaya plants exhibited the lowest levels of (137)Cs and (40)K in their growing parts. However, a significant correlation between activity concentrations of (137)Cs and (40)K was observed in these tropical plants. The (40)K/(137)Cs discrimination ratios were approximately equal to unity in different compartments of each individual plant, suggesting the possibility of using caesium to predict the behaviour of potassium in several tropical species.

  19. Plant genotypes affect aboveground and belowground herbivore interactions by changing chemical defense.

    Science.gov (United States)

    Li, Xiaoqiong; Guo, Wenfeng; Siemann, Evan; Wen, Yuanguang; Huang, Wei; Ding, Jianqing

    2016-12-01

    Spatially separated aboveground (AG) and belowground (BG) herbivores are closely linked through shared host plants, and both patterns of AG-BG interactions and plant responses may vary among plant genotypes. We subjected invasive (USA) and native (China) genotypes of tallow tree (Triadica sebifera) to herbivory by the AG specialist leaf-rolling weevil Heterapoderopsis bicallosicollis and/or the root-feeding larvae of flea beetle Bikasha collaris. We measured leaf damage and leaves rolled by weevils, quantified beetle survival, and analyzed flavonoid and tannin concentrations in leaves and roots. AG and BG herbivores formed negative feedbacks on both native and invasive genotypes. Leaf damage by weevils and the number of beetle larvae emerging as adults were higher on invasive genotypes. Beetles reduced weevil damage and weevils reduced beetle larval emergence more strongly for invasive genotypes. Invasive genotypes had lower leaf and root tannins than native genotypes. BG beetles decreased leaf tannins of native genotypes but increased root tannins of invasive genotypes. AG herbivory increased root flavonoids of invasive genotypes while BG herbivory decreased leaf flavonoids. Invasive genotypes had lower AG and BG herbivore resistance, and negative AG-BG herbivore feedbacks were much stronger for invasive genotypes. Lower tannin concentrations explained overall better AG and BG herbivore performances on invasive genotypes. However, changes in tannins and flavonoids affected AG and BG herbivores differently. These results suggest that divergent selection on chemical production in invasive plants may be critical in regulating herbivore performances and novel AG and BG herbivore communities in new environments.

  20. Dryland wheat domestication changed the development of aboveground architecture for a well-structured canopy.

    Directory of Open Access Journals (Sweden)

    Pu-Fang Li

    Full Text Available We examined three different-ploidy wheat species to elucidate the development of aboveground architecture and its domesticated mechanism under environment-controlled field conditions. Architecture parameters including leaf, stem, spike and canopy morphology were measured together with biomass allocation, leaf net photosynthetic rate and instantaneous water use efficiency (WUE(i. Canopy biomass density was decreased from diploid to tetraploid wheat, but increased to maximum in hexaploid wheat. Population yield in hexaploid wheat was higher than in diploid wheat, but the population fitness and individual competition ability was higher in diploid wheats. Plant architecture was modified from a compact type in diploid wheats to an incompact type in tetraploid wheats, and then to a more compact type of hexaploid wheats. Biomass accumulation, population yield, harvest index and the seed to leaf ratio increased from diploid to tetraploid and hexaploid, associated with heavier specific internode weight and greater canopy biomass density in hexaploid and tetraploid than in diploid wheat. Leaf photosynthetic rate and WUEi were decreased from diploid to tetraploid and increased from tetraploid to hexaploid due to more compact leaf type in hexaploid and diploid than in tetraploid. Grain yield formation and WUEi were closely associated with spatial stance of leaves and stems. We conclude that the ideotype of dryland wheats could be based on spatial reconstruction of leaf type and further exertion of leaf photosynthetic rate.

  1. Genetic basis of aboveground productivity in two native Populus species and their hybrids.

    Science.gov (United States)

    Lojewski, Nathan R; Fischer, Dylan G; Bailey, Joseph K; Schweitzer, Jennifer A; Whitham, Thomas G; Hart, Stephen C

    2009-09-01

    Demonstration of genetic control over riparian tree productivity has major implications for responses of riparian systems to shifting environmental conditions and effects of genetics on ecosystems in general. We used field studies and common gardens, applying both molecular and quantitative techniques, to compare plot-level tree aboveground net primary productivity (ANPP(tree)) and individual tree growth rate constants in relation to plant genetic identity in two naturally occurring Populus tree species and their hybrids. In field comparisons of four cross types (Populus fremontii S. Wats., Populus angustifolia James, F(1) hybrids and backcross hybrids) across 11 natural stands, productivity was greatest for P. fremontii trees, followed by hybrids and lowest in P. angustifolia. A similar pattern was observed in four common gardens across a 290 m elevation and 100 km environmental gradient. Despite a doubling in productivity across the common gardens, the relative differences among the cross types remained constant. Using clonal replicates in a common garden, we found ANPP(tree) to be a heritable plant trait (i.e., broad-sense heritability), such that plant genetic factors explained between 38% and 82% of the variation in ANPP(tree). Furthermore, analysis of the genetic composition among individual tree genotypes using restriction fragment length polymorphism molecular markers showed that genetically similar trees also exhibited similar ANPP(tree). These findings indicate strong genetic contributions to natural variation in ANPP with important ecological implications.

  2. A combined method for analysis of the acoustic emission signals from aboveground storage tank bottom

    Energy Technology Data Exchange (ETDEWEB)

    Yewei Kang; Mingchun Ling; Min Xiong; Yi Sun; Dongjie Tan [PetroChina Pipeline R and D Center, Langfang (China)

    2009-07-01

    In the late 1980s acoustic emission (AE) technology was first used to assess the corrosion of aboveground storage tank (AST) bottoms. From then on, it attracts great attention because it can do in-service inspection. Recognizing and eliminating noise is still the main challenge due to the small size of the signals in the presence of potential process noise when the AE signals are processed. In this paper a method combining pattern recognition with traditional AE parametric analysis is introduced to assess the corrosion of AST bottom. First, the AE signals are clustered in different clusters by a clustering method based on the distances of AE signal features. The reasonable cluster is selected for next analysis step. Second, a statistical method is used to evaluate the activities of AE on which the final evaluation report is based. Practical inspection is done on a large oil storage tank in the Chongqing distribution station of Lanzhou- Chengdu-Chongqing product oil pipeline of PetroChina Pipeline Company. The analytical result indicates that the combined method is reliable and feasible. (author)

  3. Aboveground endophyte affects root volatile emission and host plant selection of a belowground insect.

    Science.gov (United States)

    Rostás, Michael; Cripps, Michael G; Silcock, Patrick

    2015-02-01

    Plants emit specific blends of volatile organic compounds (VOCs) that serve as multitrophic, multifunctional signals. Fungi colonizing aboveground (AG) or belowground (BG) plant structures can modify VOC patterns, thereby altering the information content for AG insects. Whether AG microbes affect the emission of root volatiles and thus influence soil insect behaviour is unknown. The endophytic fungus Neotyphodium uncinatum colonizes the aerial parts of the grass hybrid Festuca pratensis × Lolium perenne and is responsible for the presence of insect-toxic loline alkaloids in shoots and roots. We investigated whether endophyte symbiosis had an effect on the volatile emission of grass roots and if the root herbivore Costelytra zealandica was able to recognize endophyte-infected plants by olfaction. In BG olfactometer assays, larvae of C. zealandica were more strongly attracted to roots of uninfected than endophyte-harbouring grasses. Combined gas chromatography-mass spectrometry and proton transfer reaction-mass spectrometry revealed that endophyte-infected roots emitted less VOCs and more CO2. Our results demonstrate that symbiotic fungi in plants may influence soil insect distribution by changing their behaviour towards root volatiles. The well-known defensive mutualism between grasses and Neotyphodium endophytes could thus go beyond bioactive alkaloids and also confer protection by being chemically less apparent for soil herbivores.

  4. Aboveground roofed design for the disposal of low-level radioactive waste in Maine

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, J.A. [Univ. of Maine, Orono, ME (United States)

    1993-03-01

    The conceptual designs proposed in this report resulted from a study for the Maine Low-level Radioactive Waste Authority to develop conceptual designs for a safe and reliable disposal facility for Maine`s low-level radioactive waste (LLW). Freezing temperatures, heavy rainfall, high groundwater tables, and very complex and shallow glaciated soils found in Maine place severe constraints on the design. The fundamental idea behind the study was to consider Maine`s climatic and geological conditions at the beginning of conceptual design rather than starting with a design for another location and adapting it for Maine`s conditions. The conceptual designs recommended are entirely above ground and consist of an inner vault designed to provide shielding and protection against inadvertent intrusion and an outer building to protect the inner vault from water. The air dry conditions within the outer building should lead to almost indefinite service life for the concrete inner vault and the waste containers. This concept differs sharply from the usual aboveground vault in its reliance on at least two independent, but more or less conventional, roofing systems for primary and secondary protection against leakage of radioisotopes from the facility. Features include disposal of waste in air dry environment, waste loading and visual inspection by remote-controlled overhead cranes, and reliance on engineered soils for tertiary protection against release of radioactive materials.

  5. Changes in composition, structure and aboveground biomass over seventy-six years (1930-2006) in the Black Rock Forest, Hudson Highlands, southeastern New York State.

    Science.gov (United States)

    Schuster, W S F; Griffin, K L; Roth, H; Turnbull, M H; Whitehead, D; Tissue, D T

    2008-04-01

    We sought to quantify changes in tree species composition, forest structure and aboveground forest biomass (AGB) over 76 years (1930-2006) in the deciduous Black Rock Forest in southeastern New York, USA. We used data from periodic forest inventories, published floras and a set of eight long-term plots, along with species-specific allometric equations to estimate AGB and carbon content. Between the early 1930s and 2000, three species were extirpated from the forest (American elm (Ulmus americana L.), paper birch (Betula papyrifera Marsh.) and black spruce (Picea mariana (nigra) (Mill.) BSP)) and seven species invaded the forest (non-natives tree-of-heaven (Ailanthus altissima (Mill.) Swingle) and white poplar (Populus alba L.) and native, generally southerly distributed, southern catalpa (Catalpa bignonioides Walt.), cockspur hawthorn (Crataegus crus-galli L.), red mulberry (Morus rubra L.), eastern cottonwood (Populus deltoides Bartr.) and slippery elm (Ulmus rubra Muhl.)). Forest canopy was dominated by red oak and chestnut oak, but the understory tree community changed substantially from mixed oak-maple to red maple-black birch. Density decreased from an average of 1500 to 735 trees ha(-1), whereas basal area doubled from less than 15 m(2) ha(-1) to almost 30 m(2) ha(-1) by 2000. Forest-wide mean AGB from inventory data increased from about 71 Mg ha(-1) in 1930 to about 145 Mg ha(-1) in 1985, and mean AGB on the long-term plots increased from 75 Mg ha(-1) in 1936 to 218 Mg ha(-1) in 1998. Over 76 years, red oak (Quercus rubra L.) canopy trees stored carbon at about twice the rate of similar-sized canopy trees of other species. However, there has been a significant loss of live tree biomass as a result of canopy tree mortality since 1999. Important constraints on long-term biomass increment have included insect outbreaks and droughts.

  6. Structure, Aboveground Biomass, and Soil Characterization of Avicennia marina in Eastern Mangrove Lagoon National Park, Abu Dhabi

    Science.gov (United States)

    Alsumaiti, Tareefa Saad Sultan

    Mangrove forests are national treasures of the United Arab Emirates (UAE) and other arid countries with limited forested areas. Mangroves form a crucial part of the coastal ecosystem and provide numerous benefits to society, economy, and especially the environment. Mangrove trees, specifically Avicennia marina, are studied in their native habitat in order to characterize their population structure, aboveground biomass, and soil properties. This study focused on Eastern Mangrove Lagoon National Park in Abu Dhabi, which was the first mangrove protected area to be designated in UAE. In situ measurements were collected to estimate Avicennia marina status, mortality rate (%), height (m), crown spread (m), stem number, diameter at breast height (cm), basal area (m), and aboveground biomass (t ha-1 ). Small-footprint aerial light detection and ranging (LIDAR) data acquired by UAE were processed to characterize mangrove canopy height and aboveground biomass density. This included extraction of LIDAR-derived height percentile statistics, segmentation of the forest into structurally homogenous units, and development of regression relationships between in situ reference and remote sensing data using a machine learning approach. An in situ soil survey was conducted to examine the soils' physical and chemical properties, fertility status, and organic matter. The data of soil survey were used to create soil maps to evaluate key characteristics of soils, and their influence on Avicennia marina in Eastern Mangrove Lagoon National Park. The results of this study provide new insights into Avicennia marina canopy population, structure, aboveground biomass, and soil properties in Abu Dhabi, as data in such arid environments is lacking. This valuable information can help in managing and preserving this unique ecosystem.

  7. Aboveground tree biomass in a recovering tropical sal (Shorea robusta Gaertn. f.) forest of Eastern Ghats, India

    Energy Technology Data Exchange (ETDEWEB)

    Behera, Soumit K.; Misra, Malaya K. [Ecology and Floristic Laboratory, Department of Botany, Berhampur University, Berhampur 760 007, Orissa (India)

    2006-06-15

    Aboveground biomass of individual tree species by component and total biomass per unit area for four different stages of a recovering tropical dry deciduous forest stands, dominated by sal (Shorea robusta Gaertn. f.) of the Eastern Ghats, India were investigated during 2001-2002. Different periods of recovering (2, 4, 6, and 10-year) forest stands (84{sup o}13'E, 20{sup o}29'N) were selected in the Kandhamal district of Orissa, India and sample trees of all species were harvested. Tree species diversity was 23, 23, 21 and 22 in 2, 4, 6, and 10-year recovering stands, respectively. Species-wise Ixora pavetta showed the highest biomass in 2 and 4-year stands while Shorea robusta in 6 and 10-year stands. Component-wise, in all species, bole-wood contribution ranged between 22.6% and 60.9%. Aboveground tree biomass, in all the stands, was dominated by Shorea robusta, which ranged between 12.68 and 231.91Mgha{sup -1}. Total aboveground tree biomass was 30.12, 49.21, 107.54 and 261.08Mgha{sup -1} in 2, 4, 6 and 10-year stands, respectively. (author)

  8. Rapid Turnover and Minimal Accretion of Mineral Soil Carbon During 60-Years of Pine Forest Growth on Previously Cultivated Land

    Science.gov (United States)

    Richter, D., Jr.; Mobley, M. L.; Billings, S. A.; Markewitz, D.

    2016-12-01

    At the Calhoun Long-Term Soil-Ecosystem field experiment (1957-present), reforestation of previously cultivated land over fifty years nearly doubled soil organic carbon (SOC) in surface soils (0 to 7.5-cm) but these gains were offset by significant SOC losses in subsoils (35 to 60-cm). Nearly all of the accretions in surface soils amounted to gains in light fraction SOC, whereas losses at depth were associated with silt and clay-sized particles. These changes are documented in the Calhoun Long-Term Soil-Ecosystem (LTSE) study that resampled soil from 16 plots about every five years and archived all soil samples from four soil layers within the upper 60-cm of mineral soil. We combined soil bulk density, density fractionation, stable isotopes, and radioisotopes to explore changes in SOC and soil organic nitrogen (SON) associated with five decades of the growth of a loblolly pine secondary forest. Isotopic signatures showed relatively large accumulations of contemporary forest-derived carbon in surface soils, and no accumulation of forest-derived carbon in subsoils. We interpret results to indicate that land-use change from cotton fields to secondary pine forests drove soil biogeochemical and hydrological changes that enhanced root and microbial activity and SOM decomposition in subsoils. As pine stands matured and are now transitioning to mixed pines and hardwoods, demands on soil organic matter for nutrients to support aboveground growth has eased due to pine mortality, and bulk SOM and SON and their isotopes in subsoils have stabilized. We anticipate major changes in the next fifty years as 1957 pine trees transition to hardwoods. This study emphasizes the importance of long-term experiments and deep soil measurements when characterizing SOC and SON responses to land use change. There is a remarkable paucity of E long-term soil data deeper than 30 cm.

  9. Disentangling the effects of species diversity, and intraspecific and interspecific tree size variation on aboveground biomass in dry zone homegarden agroforestry systems.

    Science.gov (United States)

    Ali, Arshad; Mattsson, Eskil

    2017-11-15

    The biodiversity - aboveground biomass relationship has been intensively studied in recent decades. However, no consensus has been arrived to consider the interplay of species diversity, and intraspecific and interspecific tree size variation in driving aboveground biomass, after accounting for the effects of plot size heterogeneity, soil fertility and stand quality in natural forest including agroforests. We tested the full, partial and no mediations effects of species diversity, and intraspecific and interspecific tree size variation on aboveground biomass by employing structural equation models (SEMs) using data from 45 homegarden agroforestry systems in Sri Lanka. The full mediation effect of either species diversity or intraspecific and interspecific tree size variation was rejected, while the partial and no mediation effects were accepted. In the no mediation SEM, homegarden size had the strongest negative direct effect (β=-0.49) on aboveground biomass (R 2 =0.65), followed by strong positive direct effect of intraspecific tree size variation (β=0.32), species diversity (β=0.29) and interspecific tree size variation (β=0.28). Soil fertility had a negative direct effect on interspecific tree size variation (β=-0.31). Stand quality had a significant positive total effect on aboveground biomass (β=0.28), but homegarden size had a significant negative total effect (β=-0.62), while soil fertility had a non-significant total effect on aboveground biomass. Similar to the no mediation SEM, the partial mediation SEMs had explained almost similar variation in aboveground biomass because species diversity, and intraspecific and interspecific tree size variation had non-significant indirect effects on aboveground biomass via each other. Our results strongly suggest that a multilayered tree canopy structure, due to high intraspecific and interspecific tree size variation, increases light capture and efficient utilization of resources among component species, and

  10. Taking Stock of Circumboreal Forest Carbon With Ground Measurements, Airborne and Spaceborne LiDAR

    Science.gov (United States)

    Neigh, Christopher S. R.; Nelson, Ross F.; Ranson, K. Jon; Margolis, Hank A.; Montesano, Paul M.; Sun, Guoqing; Kharuk, Viacheslav; Naesset, Erik; Wulder, Michael A.; Andersen, Hans-Erik

    2013-01-01

    The boreal forest accounts for one-third of global forests, but remains largely inaccessible to ground-based measurements and monitoring. It contains large quantities of carbon in its vegetation and soils, and research suggests that it will be subject to increasingly severe climate-driven disturbance. We employ a suite of ground-, airborne- and space-based measurement techniques to derive the first satellite LiDAR-based estimates of aboveground carbon for the entire circumboreal forest biome. Incorporating these inventory techniques with uncertainty analysis, we estimate total aboveground carbon of 38 +/- 3.1 Pg. This boreal forest carbon is mostly concentrated from 50 to 55degN in eastern Canada and from 55 to 60degN in eastern Eurasia. Both of these regions are expected to warm >3 C by 2100, and monitoring the effects of warming on these stocks is important to understanding its future carbon balance. Our maps establish a baseline for future quantification of circumboreal carbon and the described technique should provide a robust method for future monitoring of the spatial and temporal changes of the aboveground carbon content.

  11. Optomechanical transistor with mechanical gain

    Science.gov (United States)

    Zhang, X. Z.; Tian, Lin; Li, Yong

    2018-04-01

    We study an optomechanical transistor, where an input field can be transferred and amplified unidirectionally in a cyclic three-mode optomechanical system. In this system, the mechanical resonator is coupled simultaneously to two cavity modes. We show that it only requires a finite mechanical gain to achieve the nonreciprocal amplification. Here the nonreciprocity is caused by the phase difference between the linearized optomechanical couplings that breaks the time-reversal symmetry of this system. The amplification arises from the mechanical gain, which provides an effective phonon bath that pumps the mechanical mode coherently. This effect is analogous to the stimulated emission of atoms, where the probe field can be amplified when its frequency is in resonance with that of the anti-Stokes transition. We show that by choosing optimal parameters, this optomechanical transistor can reach perfect unidirectionality accompanied with strong amplification. In addition, the presence of the mechanical gain can result in ultralong delay in the phase of the probe field, which provides an alternative to controlling light transport in optomechanical systems.

  12. Assessment of weather-associated causes of red spruce winter injury and consequences to aboveground carbon sequestration

    Science.gov (United States)

    Paul G. Schaberg; Brynne E. Lazarus; Gary J. Hawley; Joshua M. Halman; Catherine H. Borer; Christopher F. Hansen

    2011-01-01

    Despite considerable study, it remains uncertain what environmental factors contribute to red spruce (Picea rubens Sarg.) foliar winter injury and how much this injury influences tree C stores. We used a long-term record of winter injury in a plantation in New Hampshire and conducted stepwise linear regression analyses with local weather and regional...

  13. Thinning and site quality influence aboveground tree carbon stocks in yellow-poplar forests of the southern Appalachians.

    Science.gov (United States)

    Tara Keyser

    2010-01-01

    Little information exists regarding the effects of intermediate stand management activities (e.g., thinning) on C storage. This lack of information has created uncertainty regarding trade-offs between the benefits observed following thinning and C storage. Using long-term growth data, this study examines the effect of thinning on C storage while controlling for the...

  14. Towards ground-truthing of spaceborne estimates of above-ground life biomass and leaf area index in tropical rain forests

    Directory of Open Access Journals (Sweden)

    P. Köhler

    2010-08-01

    Full Text Available The canopy height h of forests is a key variable which can be obtained using air- or spaceborne remote sensing techniques such as radar interferometry or LIDAR. If new allometric relationships between canopy height and the biomass stored in the vegetation can be established this would offer the possibility for a global monitoring of the above-ground carbon content on land. In the absence of adequate field data we use simulation results of a tropical rain forest growth model to propose what degree of information might be generated from canopy height and thus to enable ground-truthing of potential future satellite observations. We here analyse the correlation between canopy height in a tropical rain forest with other structural characteristics, such as above-ground life biomass (AGB (and thus carbon content of vegetation and leaf area index (LAI and identify how correlation and uncertainty vary for two different spatial scales. The process-based forest growth model FORMIND2.0 was applied to simulate (a undisturbed forest growth and (b a wide range of possible disturbance regimes typically for local tree logging conditions for a tropical rain forest site on Borneo (Sabah, Malaysia in South-East Asia. In both undisturbed and disturbed forests AGB can be expressed as a power-law function of canopy height h (AGB = a · hb with an r2 ~ 60% if data are analysed in a spatial resolution of 20 m × 20 m (0.04 ha, also called plot size. The correlation coefficient of the regression is becoming significant better in the disturbed forest sites (r2 = 91% if data are analysed hectare wide. There seems to exist no functional dependency between LAI and canopy height, but there is also a linear correlation (r2 ~ 60% between AGB and the area fraction of gaps in which the canopy is highly disturbed. A reasonable agreement of our results with observations is obtained from a

  15. Towards ground-truthing of spaceborne estimates of above-ground life biomass and leaf area index in tropical rain forests

    Science.gov (United States)

    Köhler, P.; Huth, A.

    2010-08-01

    The canopy height h of forests is a key variable which can be obtained using air- or spaceborne remote sensing techniques such as radar interferometry or LIDAR. If new allometric relationships between canopy height and the biomass stored in the vegetation can be established this would offer the possibility for a global monitoring of the above-ground carbon content on land. In the absence of adequate field data we use simulation results of a tropical rain forest growth model to propose what degree of information might be generated from canopy height and thus to enable ground-truthing of potential future satellite observations. We here analyse the correlation between canopy height in a tropical rain forest with other structural characteristics, such as above-ground life biomass (AGB) (and thus carbon content of vegetation) and leaf area index (LAI) and identify how correlation and uncertainty vary for two different spatial scales. The process-based forest growth model FORMIND2.0 was applied to simulate (a) undisturbed forest growth and (b) a wide range of possible disturbance regimes typically for local tree logging conditions for a tropical rain forest site on Borneo (Sabah, Malaysia) in South-East Asia. In both undisturbed and disturbed forests AGB can be expressed as a power-law function of canopy height h (AGB = a · hb) with an r2 ~ 60% if data are analysed in a spatial resolution of 20 m × 20 m (0.04 ha, also called plot size). The correlation coefficient of the regression is becoming significant better in the disturbed forest sites (r2 = 91%) if data are analysed hectare wide. There seems to exist no functional dependency between LAI and canopy height, but there is also a linear correlation (r2 ~ 60%) between AGB and the area fraction of gaps in which the canopy is highly disturbed. A reasonable agreement of our results with observations is obtained from a comparison of the simulations with permanent sampling plot (PSP) data from the same region and with the

  16. Aboveground and belowground arthropods experience different relative influences of stochastic versus deterministic community assembly processes following disturbance

    Directory of Open Access Journals (Sweden)

    Scott Ferrenberg

    2016-10-01

    Full Text Available Background Understanding patterns of biodiversity is a longstanding challenge in ecology. Similar to other biotic groups, arthropod community structure can be shaped by deterministic and stochastic processes, with limited understanding of what moderates the relative influence of these processes. Disturbances have been noted to alter the relative influence of deterministic and stochastic processes on community assembly in various study systems, implicating ecological disturbances as a potential moderator of these forces. Methods Using a disturbance gradient along a 5-year chronosequence of insect-induced tree mortality in a subalpine forest of the southern Rocky Mountains, Colorado, USA, we examined changes in community structure and relative influences of deterministic and stochastic processes in the assembly of aboveground (surface and litter-active species and belowground (species active in organic and mineral soil layers arthropod communities. Arthropods were sampled for all years of the chronosequence via pitfall traps (aboveground community and modified Winkler funnels (belowground community and sorted to morphospecies. Community structure of both communities were assessed via comparisons of morphospecies abundance, diversity, and composition. Assembly processes were inferred from a mixture of linear models and matrix correlations testing for community associations with environmental properties, and from null-deviation models comparing observed vs. expected levels of species turnover (Beta diversity among samples. Results Tree mortality altered community structure in both aboveground and belowground arthropod communities, but null models suggested that aboveground communities experienced greater relative influences of deterministic processes, while the relative influence of stochastic processes increased for belowground communities. Additionally, Mantel tests and linear regression models revealed significant associations between the

  17. Aboveground and belowground arthropods experience different relative influences of stochastic versus deterministic community assembly processes following disturbance

    Science.gov (United States)

    Martinez, Alexander S.; Faist, Akasha M.

    2016-01-01

    Background Understanding patterns of biodiversity is a longstanding challenge in ecology. Similar to other biotic groups, arthropod community structure can be shaped by deterministic and stochastic processes, with limited understanding of what moderates the relative influence of these processes. Disturbances have been noted to alter the relative influence of deterministic and stochastic processes on community assembly in various study systems, implicating ecological disturbances as a potential moderator of these forces. Methods Using a disturbance gradient along a 5-year chronosequence of insect-induced tree mortality in a subalpine forest of the southern Rocky Mountains, Colorado, USA, we examined changes in community structure and relative influences of deterministic and stochastic processes in the assembly of aboveground (surface and litter-active species) and belowground (species active in organic and mineral soil layers) arthropod communities. Arthropods were sampled for all years of the chronosequence via pitfall traps (aboveground community) and modified Winkler funnels (belowground community) and sorted to morphospecies. Community structure of both communities were assessed via comparisons of morphospecies abundance, diversity, and composition. Assembly processes were inferred from a mixture of linear models and matrix correlations testing for community associations with environmental properties, and from null-deviation models comparing observed vs. expected levels of species turnover (Beta diversity) among samples. Results Tree mortality altered community structure in both aboveground and belowground arthropod communities, but null models suggested that aboveground communities experienced greater relative influences of deterministic processes, while the relative influence of stochastic processes increased for belowground communities. Additionally, Mantel tests and linear regression models revealed significant associations between the aboveground arthropod

  18. ULC/ORD-C80.1 : the standard for aboveground non-metallic tanks for fuel oil

    Energy Technology Data Exchange (ETDEWEB)

    Nikolic, G. [Underwriters' Lab. of Canada, Toronto, ON (Canada)

    2001-09-01

    As a rule, flammable and combustible liquids were stored in aboveground tanks made of steel. Non-metallic materials are now being used for a new generation of aboveground tanks. Corrosion is a problem faced by most tank owners in many parts of Canada. Saltwater mist, sand blasting and bacteria growth formed in the condensation water at the bottom of the tank in the Maritimes affects an aboveground tank installed outdoors and close to the seashore. European non-metallic aboveground tanks for fuel oil first arrived on the North American market, and are now followed by designs from Canada. Requirements for these tanks were developed and tested by the Underwriters' Laboratories of Canada (ULC). It is a not-for-profit, independent organization accredited by the Standards Council of Canada to perform safety, certification, testing, quality registration, and standards development. The minimum criteria for non-metallic aboveground tank construction are contained in the ULC/ORD-C80.1 document. They can be constructed of fiber-reinforced plastic (FRP), single or double wall, or they can be double wall tanks consisting of primary plastic tanks within metallic secondary containment. Other tanks are made of the blow molded high-density polyethylene. To simulate an in-house installation, fire tests were performed where a tank filled with fuel was exposed to pool fire for 30 minutes. A successful test meant the tank had not ruptured nor leaked during and after the test. Testers had to observe that any collapse occurred above the liquid level, and that violent explosion of any part of the tank or its content did not occur. The design requirements were evaluated by performing an analysis of the temperature chart: maximum vapour temperature inside the tank was 358 Celsius, while the liquid reached a maximum temperature of 91 Celsius and the outside temperature reached 600 Celsius. Primary tank pressure did not exceed 17 kilo Pascal. Building simulation of venting installation

  19. Analysis of Carbon Storage and Its Contributing Factors—A Case Study in the Loess Plateau (China

    Directory of Open Access Journals (Sweden)

    Gaohuan Liu

    2018-06-01

    Full Text Available The Chinese Loess Plateau is an ecologically fragile and sensitive area. The carbon storage dynamics in this region and the contributions from land use/land cover change (LUCC and carbon density from 2000 to 2010 were analyzed in this paper. Normalized difference vegetation index (NDVI, biomass and soil carbon data in 2000 were used for regression analysis of biomass and soil carbon, and an inversion analysis was used to estimate biomass and soil carbon in 2005 and 2010. Quadrat data, including aboveground biomass and soil organic carbon, were used to calibrate the model output. Carbon storage and sequestration were calculated by the InVEST toolset with four carbon pools, including aboveground biomass, belowground biomass, dead wood and soil carbon. The results showed that carbon storage increased steadily from 2000 to 2010, increasing by 0.260 billion tons, and that woodland area increased and arable land decreased; the overall trend in land cover improved, but the improvement was not pronounced. Carbon storage in the Loess Plateau was correlated with geographical factors. We found that when assuming a constant carbon density, carbon storage decreased, accounting for −1% of the carbon storage dynamics. When assuming no land conversion, carbon storage increased, accounting for 101% of the carbon storage dynamics.

  20. Radiation cooling and gain calculation for C VI 182 A line in C/Se plasma

    International Nuclear Information System (INIS)

    Nam, C.H.; Valeo, E.; Suckewer, S.; Feldman, U.

    1986-04-01

    A model is developed which is capable of describing the evolution of gain resulting from both rapid radiative and expansion cooling of a recombining, freely expanding plasma. It is demonstrated for the particular case of a carbon/selenium plasma that the cooling rate which leads to optimal gain can be achieved by adjusting the admixture of an efficiently radiating material (selenium) in the gain medium (carbon). Comparison is made to a recent observation of gain in a recent NRL/Rochester experiment with carbon/selenium plasma for the n = 3 → 2 transition in C VI occurring at 182 A. The predicted maximum gain is approx.10 cm -1 , as compared to observation of 2 to 3 cm -1

  1. A disconnect between O horizon and mineral soil carbon - Implications for soil C sequestration

    Science.gov (United States)

    Garten, Charles T., Jr.

    2009-03-01

    Changing inputs of carbon to soil is one means of potentially increasing carbon sequestration in soils for the purpose of mitigating projected increases in atmospheric CO 2 concentrations. The effect of manipulations of aboveground carbon input on soil carbon storage was tested in a temperate, deciduous forest in east Tennessee, USA. A 4.5-year experiment included exclusion of aboveground litterfall and supplemental litter additions (three times ambient) in an upland and a valley that differed in soil nitrogen availability. The estimated decomposition rate of the carbon stock in the O horizon was greater in the valley than in the upland due to higher litter quality (i.e., lower C/N ratios). Short-term litter exclusion or addition had no effect on carbon stock in the mineral soil, measured to a depth of 30 cm, or the partitioning of carbon in the mineral soil between particulate- and mineral-associated organic matter. A two-compartment model was used to interpret results from the field experiments. Field data and a sensitivity analysis of the model were consistent with little carbon transfer between the O horizon and the mineral soil. Increasing aboveground carbon input does not appear to be an effective means of promoting carbon sequestration in forest soil at the location of the present study because a disconnect exists in carbon dynamics between O horizon and mineral soil. Factors that directly increase inputs to belowground soil carbon, via roots, or reduce decomposition rates of organic matter are more likely to benefit efforts to increase carbon sequestration in forests where carbon dynamics in the O horizon are uncoupled from the mineral soil.

  2. Carbon dynamics in an Imperata grassland in Northeast India

    Directory of Open Access Journals (Sweden)

    Amrabati Thokchom

    2016-01-01

    Full Text Available Carbon stocks and soil CO2 flux were assessed in an Imperata cylindrica grassland of Manipur, Northeast India. Carbon stocks in the vegetative components were estimated to be 11.17 t C/ha and soil organic carbon stocks were 55.94 t C/ha to a depth of 30 cm. The rates of carbon accumulation in above-ground and below-ground biomass were estimated to be 11.85 t C/ha/yr and 11.71 t C/ha/yr, respectively. Annual soil CO2 flux was evaluated as 6.95 t C/ha and was highly influenced by soil moisture, soil temperature and soil organic carbon as well as by C stocks in above-ground biomass. Our study on the carbon budget of the grassland ecosystem revealed that annually 23.56 t C/ha was captured by the vegetation through photosynthesis, and 6.95 t C/ha was returned to the atmosphere through roots and microbial respiration, with a net balance of 16.61 t C/ha/yr being retained in the grassland ecosystem. Thus the present Imperata grassland exhibited a high capacity to remove atmospheric CO2 and to induce high C stocks in the soil provided it is protected from burning and overgrazing.Keywords: Above-ground biomass, below-ground biomass, carbon stocks, carbon storage, net primary productivity, soil CO2 flux.DOI: 10.17138/TGFT(419-28  

  3. Diversity and aboveground biomass of lianas in the tropical seasonal rain forests of Xishuangbanna, SW China

    Directory of Open Access Journals (Sweden)

    Xiao-Tao Lü

    2009-06-01

    Full Text Available Lianas are important components of tropical forests and have significant impacts on the diversity, structure and dynamics of tropical forests. The present study documented the liana flora in a Chinese tropical region. Species richness, abundance, size-class distribution and spatial patterns of lianas were investigated in three 1-ha plots in tropical seasonal rain forests in Xishuangbanna, SW China. All lianas with = 2 cm diameter at breast height (dbh were measured, tagged and identified. A total of 458 liana stems belonging to 95 species (ranging from 38 to 50 species/ha, 59 genera and 32 families were recorded in the three plots. The most well-represented families were Loganiaceae, Annonceae, Papilionaceae, Apocynaceae and Rhamnaceae. Papilionaceae (14 species recorded was the most important family in the study forests. The population density, basal area and importance value index (IVI varied greatly across the three plots. Strychnos cathayensis, Byttneria grandifolia and Bousigonia mekongensis were the dominant species in terms of IVI across the three plots. The mean aboveground biomass of lianas (3 396 kg/ha accounted for 1.4% of the total community aboveground biomass. The abundance, diversity and biomass of lianas in Xishuangbanna tropical seasonal rain forests are lower than those in tropical moist and wet forests, but higher than those in tropical dry forests. This study provides new data on lianas from a geographical region that has been little-studied. Our findings emphasize that other factors beyond the amount and seasonality of precipitation should be included when considering the liana abundance patterns across scales. Rev. Biol. Trop. 57 (1-2: 211-222. Epub 2009 June 30.Las lianas son componentes importantes de los bosques tropicales y tienen importantes impactos en la diversidad, la estructura y la dinámica de los bosques tropicales. El presente estudio documenta la flora de lianas en una región tropical estacional china. La

  4. Reducing Uncertainty in Mapping of Mangrove Aboveground Biomass Using Airborne Discrete Return Lidar Data

    Directory of Open Access Journals (Sweden)

    Francisca Rocha de Souza Pereira

    2018-04-01

    Full Text Available Remote sensing techniques offer useful tools for estimating forest biomass to large extent, thereby contributing to the monitoring of land use and landcover dynamics and the effectiveness of environmental policies. The main goal of this study was to investigate the potential use of discrete return light detection and ranging (lidar data to produce accurate aboveground biomass (AGB maps of mangrove forests. AGB was estimated in 34 small plots scatted over a 50 km2 mangrove forest in Rio de Janeiro, Brazil. Plot AGB was computed using either species-specific or non-species-specific allometric models. A total of 26 descriptive lidar metrics were extracted from the normalized height of the lidar point cloud data, and various model forms (random forest and partial least squares regression with backward selection of predictors (Auto-PLS were tested to predict the recorded AGB. The models developed using species-specific allometric models were distinctly more accurate (R2(calibration = 0.89, R2(validation = 0.80, root-mean-square error (RMSE, calibration = 11.20 t·ha−1, and RMSE(validation = 14.80 t·ha−1. The use of non-species-specific allometric models yielded large errors on a landscape scale (+14% or −18% bias depending on the allometry considered, indicating that using poor quality training data not only results in low precision but inaccuracy at all scales. It was concluded that under suitable sampling pattern and provided that accurate field data are used, discrete return lidar can accurately estimate and map the AGB in mangrove forests. Conversely this study underlines the potential bias affecting the estimates of AGB in other forested landscapes where only non-species-specific allometric equations are available.

  5. Tundra plant above-ground biomass and shrub dominance mapped across the North Slope of Alaska

    Science.gov (United States)

    Berner, Logan T.; Jantz, Patrick; Tape, Ken D.; Goetz, Scott J.

    2018-03-01

    Arctic tundra is becoming greener and shrubbier due to recent warming. This is impacting climate feedbacks and wildlife, yet the spatial distribution of plant biomass in tundra ecosystems is uncertain. In this study, we mapped plant and shrub above-ground biomass (AGB; kg m-2) and shrub dominance (%; shrub AGB/plant AGB) across the North Slope of Alaska by linking biomass harvests at 28 field sites with 30 m resolution Landsat satellite imagery. We first developed regression models (p plant AGB (r 2 = 0.79) and shrub AGB (r 2 = 0.82) based on the normalized difference vegetation index (NDVI) derived from imagery acquired by Landsat 5 and 7. We then predicted regional plant and shrub AGB by combining these regression models with a regional Landsat NDVI mosaic built from 1721 summer scenes acquired between 2007 and 2016. Our approach employed a Monte Carlo uncertainty analysis that propagated sampling and sensor calibration errors. We estimated that plant AGB averaged 0.74 (0.60, 0.88) kg m-2 (95% CI) and totaled 112 (91, 135) Tg across the region, with shrub AGB accounting for ~43% of regional plant AGB. The new maps capture landscape variation in plant AGB visible in high resolution satellite and aerial imagery, notably shrubby riparian corridors. Modeled shrub AGB was strongly correlated with field measurements of shrub canopy height at 25 sites (rs  = 0.88) and with a regional map of shrub cover (rs  = 0.76). Modeled plant AGB and shrub dominance were higher in shrub tundra than graminoid tundra and increased between areas with the coldest and warmest summer air temperatures, underscoring the fact that future warming has the potential to greatly increase plant AGB and shrub dominance in this region. These new biomass maps provide a unique source of ecological information for a region undergoing rapid environmental change.

  6. Optimal Atmospheric Correction for Above-Ground Forest Biomass Estimation with the ETM+ Remote Sensor.

    Science.gov (United States)

    Nguyen, Hieu Cong; Jung, Jaehoon; Lee, Jungbin; Choi, Sung-Uk; Hong, Suk-Young; Heo, Joon

    2015-07-31

    The reflectance of the Earth's surface is significantly influenced by atmospheric conditions such as water vapor content and aerosols. Particularly, the absorption and scattering effects become stronger when the target features are non-bright objects, such as in aqueous or vegetated areas. For any remote-sensing approach, atmospheric correction is thus required to minimize those effects and to convert digital number (DN) values to surface reflectance. The main aim of this study was to test the three most popular atmospheric correction models, namely (1) Dark Object Subtraction (DOS); (2) Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes (FLAASH) and (3) the Second Simulation of Satellite Signal in the Solar Spectrum (6S) and compare them with Top of Atmospheric (TOA) reflectance. By using the k-Nearest Neighbor (kNN) algorithm, a series of experiments were conducted for above-ground forest biomass (AGB) estimations of the Gongju and Sejong region of South Korea, in order to check the effectiveness of atmospheric correction methods for Landsat ETM+. Overall, in the forest biomass estimation, the 6S model showed the bestRMSE's, followed by FLAASH, DOS and TOA. In addition, a significant improvement of RMSE by 6S was found with images when the study site had higher total water vapor and temperature levels. Moreover, we also tested the sensitivity of the atmospheric correction methods to each of the Landsat ETM+ bands. The results confirmed that 6S dominates the other methods, especially in the infrared wavelengths covering the pivotal bands for forest applications. Finally, we suggest that the 6S model, integrating water vapor and aerosol optical depth derived from MODIS products, is better suited for AGB estimation based on optical remote-sensing data, especially when using satellite images acquired in the summer during full canopy development.

  7. Mapping aboveground woody biomass using forest inventory, remote sensing and geostatistical techniques.

    Science.gov (United States)

    Yadav, Bechu K V; Nandy, S

    2015-05-01

    Mapping forest biomass is fundamental for estimating CO₂ emissions, and planning and monitoring of forests and ecosystem productivity. The present study attempted to map aboveground woody biomass (AGWB) integrating forest inventory, remote sensing and geostatistical techniques, viz., direct radiometric relationships (DRR), k-nearest neighbours (k-NN) and cokriging (CoK) and to evaluate their accuracy. A part of the Timli Forest Range of Kalsi Soil and Water Conservation Division, Uttarakhand, India was selected for the present study. Stratified random sampling was used to collect biophysical data from 36 sample plots of 0.1 ha (31.62 m × 31.62 m) size. Species-specific volumetric equations were used for calculating volume and multiplied by specific gravity to get biomass. Three forest-type density classes, viz. 10-40, 40-70 and >70% of Shorea robusta forest and four non-forest classes were delineated using on-screen visual interpretation of IRS P6 LISS-III data of December 2012. The volume in different strata of forest-type density ranged from 189.84 to 484.36 m(3) ha(-1). The total growing stock of the forest was found to be 2,024,652.88 m(3). The AGWB ranged from 143 to 421 Mgha(-1). Spectral bands and vegetation indices were used as independent variables and biomass as dependent variable for DRR, k-NN and CoK. After validation and comparison, k-NN method of Mahalanobis distance (root mean square error (RMSE) = 42.25 Mgha(-1)) was found to be the best method followed by fuzzy distance and Euclidean distance with RMSE of 44.23 and 45.13 Mgha(-1) respectively. DRR was found to be the least accurate method with RMSE of 67.17 Mgha(-1). The study highlighted the potential of integrating of forest inventory, remote sensing and geostatistical techniques for forest biomass mapping.

  8. Estimating above-ground biomass on mountain meadows and pastures through remote sensing

    Science.gov (United States)

    Barrachina, M.; Cristóbal, J.; Tulla, A. F.

    2015-06-01

    Extensive stock-breeding systems developed in mountain areas like the Pyrenees are crucial for local farming economies and depend largely on above-ground biomass (AGB) in the form of grass produced on meadows and pastureland. In this study, a multiple linear regression analysis technique based on in-situ biomass collection and vegetation and wetness indices derived from Landsat-5 TM data is successfully applied in a mountainous Pyrenees area to model AGB. Temporal thoroughness of the data is ensured by using a large series of images. Results of on-site AGB collection show the importance for AGB models to capture the high interannual and intraseasonal variability that results from both meteorological conditions and farming practices. AGB models yield best results at midsummer and end of summer before mowing operations by farmers, with a mean R2, RMSE and PE for 2008 and 2009 midsummer of 0.76, 95 g m-2 and 27%, respectively; and with a mean R2, RMSE and PE for 2008 and 2009 end of summer of 0.74, 128 g m-2 and 36%, respectively. Although vegetation indices are a priori more related with biomass production, wetness indices play an important role in modeling AGB, being statistically selected more frequently (more than 50%) than other traditional vegetation indexes (around 27%) such as NDVI. This suggests that middle infrared bands are crucial descriptors of AGB. The methodology applied in this work compares favorably with other works in the literature, yielding better results than those works in mountain areas, owing to the ability of the proposed methodology to capture natural and anthropogenic variations in AGB which are the key to increasing AGB modeling accuracy.

  9. Aboveground Net Primary Productivity in a Riparian Wetland Following Restoration of Hydrology

    Directory of Open Access Journals (Sweden)

    Melissa Koontz

    2016-02-01

    Full Text Available This research presents the initial results of the effects of hydrological restoration on forested wetlands in the Mississippi alluvial plain near Memphis, Tennessee. Measurements were carried out in a secondary channel, the Loosahatchie Chute, in which rock dikes were constructed in the 1960s to keep most flow in the main navigation channel. In 2008–2009, the dikes were notched to allow more flow into the secondary channel. Study sites were established based on relative distance downstream of the notched dikes. Additionally, a reference site was established north of the Loosahatchie Chute where the dikes remained unnotched. We compared various components of vegetation composition and productivity at sites in the riparian wetlands for two years. Salix nigra had the highest Importance Value at every site. Species with minor Importance Values were Celtis laevigata, Acer rubrum, and Plantanus occidentalis. Productivity increased more following the introduction of river water in affected sites compared to the reference. Aboveground net primary productivity was highest at the reference site (2926 ± 458.1 g·m−2·year−1, the intact site; however, there were greater increase at the sites in the Loosahatchie Chute, where measurements ranged from 1197.7 ± 160.0 g m−2·year−1·to 2874.2 ± 794.0 g·m−2·year−1. The site furthest from the notching was the most affected. Pulsed inputs into these wetlands may enhance forested wetland productivity. Continued monitoring will quantify impacts of restored channel hydrology along the Mississippi River.

  10. Aboveground Net Primary Productivity in a Riparian Wetland Following Restoration of Hydrology.

    Science.gov (United States)

    Koontz, Melissa; Lundberg, Christopher; Lane, Robert; Day, John; Pezeshki, Reza

    2016-02-04

    This research presents the initial results of the effects of hydrological restoration on forested wetlands in the Mississippi alluvial plain near Memphis, Tennessee. Measurements were carried out in a secondary channel, the Loosahatchie Chute, in which rock dikes were constructed in the 1960s to keep most flow in the main navigation channel. In 2008-2009, the dikes were notched to allow more flow into the secondary channel. Study sites were established based on relative distance downstream of the notched dikes. Additionally, a reference site was established north of the Loosahatchie Chute where the dikes remained unnotched. We compared various components of vegetation composition and productivity at sites in the riparian wetlands for two years. Salix nigra had the highest Importance Value at every site. Species with minor Importance Values were Celtis laevigata, Acer rubrum, and Plantanus occidentalis. Productivity increased more following the introduction of river water in affected sites compared to the reference. Aboveground net primary productivity was highest at the reference site (2926 ± 458.1 g·m(-2)·year(-1)), the intact site; however, there were greater increase at the sites in the Loosahatchie Chute, where measurements ranged from 1197.7 ± 160.0 g m(-2)·year(-1)·to 2874.2 ± 794.0 g·m(-2)·year(-1). The site furthest from the notching was the most affected. Pulsed inputs into these wetlands may enhance forested wetland productivity. Continued monitoring will quantify impacts of restored channel hydrology along the Mississippi River.

  11. The carbon-sequestration potential of a global afforestation program

    International Nuclear Information System (INIS)

    Nilsson, S.; Schopfhauser, W.

    1995-01-01

    The authors analyzed the changes in the carbon cycle that could be achieved with a global large-scale afforestation program that is economically, politically and technically feasible. They estimated that of the areas regarded as suitable for large-scale plantations, only about 345 million ha would actually be available for plantations and agroforestry for the sole purpose of sequestering carbon. The maximum annual rate of carbon fixation (1.48 Gt/yr) would only be achieved 60 years after the establishment of the plantation - 1.14 Gt by above-ground biomass and 0.34 Gt by below-ground biomass. Over the periods from 1995 to 2095, a total of 104 Gt of carbon would be sequestered. This is substantially lower than the amount of carbon required to offset current carbon emissions (3.8 Gt/yr) in order to stabilize the carbon content of the atmosphere. 108 refs., 1 fig., 14 tabs

  12. Exploring the Role of Plant Genetics to Enhance Soil Carbon Sequestration in Hybrid Poplar Plantations

    Science.gov (United States)

    Wullschleger, S. D.; Garten, C. T.; Classen, A. T.

    2008-12-01

    Atmospheric CO2 concentrations have increased in recent decades and are projected to increase even further during the coming century. These projections have prompted scientists and policy-makers to consider how plants and soils can be used to stabilize CO2 concentrations. Although storing carbon in terrestrial ecosystems represents an attractive near-term option for mitigating rising atmospheric CO2 concentrations, enhancing the sequestration potential of managed systems will require advancements in understanding the fundamental mechanisms that control rates of carbon transfer and turnover in plants and soils. To address this challenge, a mathematical model was constructed to evaluate how changes in particular plant traits and management practices could affect soil carbon storage beneath hybrid poplar (Populus) plantations. The model was built from four sub-models that describe aboveground biomass, root biomass, soil carbon dynamics, and soil nitrogen transformations for trees growing throughout a user-defined rotation. Simulations could be run over one or multiple rotations. A sensitivity analysis of the model indicated changes in soil carbon storage were affected by variables that could be linked to hybrid poplar traits like rates of aboveground production, partitioning of carbon to coarse and fine roots, and rates of root decomposition. A higher ratio of belowground to aboveground production was especially important and correlated directly with increased soil carbon storage. Faster decomposition rates for coarse and fine dead roots resulted in a greater loss of carbon to the atmosphere as CO2 and less residual organic carbon for transfer to the fast soil carbon pool. Hence, changes in root chemistry that prolonged dead root decomposition rates, a trait that is under potential genetic control, were predicted to increase soil carbon storage via higher soil carbon inputs. Nitrogen limitation of both aboveground biomass production and soil carbon sequestration was

  13. Modeling Coupled Landscape Evolution and Soil Organic Carbon Dynamics in Intensively Management Landscapes

    Science.gov (United States)

    Yan, Q.; Kumar, P.

    2017-12-01

    Soil is the largest reservoir of carbon in the biosphere but in agricultural areas it is going through rapid erosion due disturbance arising from crop harvest, tillage, and tile drainage. Identifying whether the production of soil organic carbon (SOC) from the crops can compensate for the loss due to erosion is critical to ensure our food security and adapt to climate change. In the U.S. Midwest where large areas of land are intensively managed for agriculture practices, predicting soil quantity and quality are critical for maintaining crop yield and other Critical Zone services. This work focuses on modeling the coupled landscape evolutions soil organic carbon dynamics in agricultural fields. It couples landscape evolution, surface water runoff, organic matter transformation, and soil moisture dynamics to understand organic carbon gain and loss due to natural forcing and farming practices, such as fertilizer application and tillage. A distinctive feature of the model is the coupling of surface ad subsurface processes that predicts both surficial changes and transport along with the vertical transport and dynamics. Our results show that landscape evolution and farming practices play dominant roles in soil organic carbon (SOC) dynamics both above- and below-ground. Contrary to the common assumption that a vertical profile of SOC concentration decreases exponentially with depth, we find that in many situations SOC concentration below-ground could be higher than that at the surface. Tillage plays a complex role in organic matter dynamics. On one hand, tillage would accelerate the erosion rate, on the other hand, it would improve carbon storage by burying surface SOC into below ground. Our model consistently reproduces the observed above- and below-ground patterns of SOC in the field sites of Intensively Managed Landscapes Critical Zone Observatory (IMLCZO). This model bridges the gaps between the landscape evolution, below- and above-ground hydrologic cycle, and

  14. GAIN Technology Workshops Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    Braase, Lori Ann [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-08-01

    National and global demand for nuclear energy is increasing and United States (U.S.) global leadership is eroding. There is a sense of urgency with respect to the deployment of the innovative nuclear energy technologies. The Gateway for Accelerated Innovation in Nuclear (GAIN) initiative is based on the simultaneous achievement of three strategic goals. The first is maintaining global technology leadership within the U.S. Department of Energy (DOE). The second is enabling global industrial leadership for nuclear vendors and suppliers. The third is focused on utility optimization of nuclear energy within the clean energy portfolio. An effective public-private partnership is required to achieve these goals. DOEs recognizes the recent sense of urgency new developers and investors have in getting their concepts to market. They know that time to market for nuclear technology takes too long and the facilities needed to conduct the necessary research, development and demonstration (RD&D) activities are very expensive to develop and maintain. Early technologies, in the lower technology readiness levels (TRL) need materials testing, analysis, modeling, code development, etc., most of which currently exists in the DOE national laboratory system. However, mature technologies typically need large component testing and demonstration facilities, which are expensive and long-lead efforts. By understanding the needs of advanced nuclear technology developers, GAIN will connect DOE national laboratory capabilities (e.g., facilities, expertise, materials, and data) with industry RD&D needs. In addition, GAIN is working with the Nuclear Regulatory Commission (NRC) to streamline processes and increase understanding of the licensing requirements for advanced reactors.

  15. GAIN Technology Workshops Summary Report

    International Nuclear Information System (INIS)

    Braase, Lori Ann

    2016-01-01

    National and global demand for nuclear energy is increasing and United States (U.S.) global leadership is eroding. There is a sense of urgency with respect to the deployment of the innovative nuclear energy technologies. The Gateway for Accelerated Innovation in Nuclear (GAIN) initiative is based on the simultaneous achievement of three strategic goals. The first is maintaining global technology leadership within the U.S. Department of Energy (DOE). The second is enabling global industrial leadership for nuclear vendors and suppliers. The third is focused on utility optimization of nuclear energy within the clean energy portfolio. An effective public-private partnership is required to achieve these goals. DOEs recognizes the recent sense of urgency new developers and investors have in getting their concepts to market. They know that time to market for nuclear technology takes too long and the facilities needed to conduct the necessary research, development and demonstration (RD&D) activities are very expensive to develop and maintain. Early technologies, in the lower technology readiness levels (TRL) need materials testing, analysis, modeling, code development, etc., most of which currently exists in the DOE national laboratory system. However, mature technologies typically need large component testing and demonstration facilities, which are expensive and long-lead efforts. By understanding the needs of advanced nuclear technology developers, GAIN will connect DOE national laboratory capabilities (e.g., facilities, expertise, materials, and data) with industry RD&D needs. In addition, GAIN is working with the Nuclear Regulatory Commission (NRC) to streamline processes and increase understanding of the licensing requirements for advanced reactors.

  16. Commutated automatic gain control system

    Science.gov (United States)

    Yost, S. R.

    1982-01-01

    A commutated automatic gain control (AGC) system was designed and built for a prototype Loran C receiver. The receiver uses a microcomputer to control a memory aided phase-locked loop (MAPLL). The microcomputer also controls the input/output, latitude/longitude conversion, and the recently added AGC system. The circuit designed for the AGC is described, and bench and flight test results are presented. The AGC circuit described actually samples starting at a point 40 microseconds after a zero crossing determined by the software lock pulse ultimately generated by a 30 microsecond delay and add network in the receiver front end envelope detector.

  17. [Fast food promotes weight gain].

    Science.gov (United States)

    Stender, Steen; Dyerberg, Jørn; Astrup, Arne V

    2007-05-07

    The total amounts of fat in a fast food menu consisting of French fries and fried Chicken Nuggets from McDonald's and KFC, respectively, bought in 35 different countries vary from 41 to 71 gram. In most countries the menu contained unacceptably high amounts of industrially-produced trans fat which contributes to an increased risk of ischaemic heart disease, weight gain, abdominal fat accumulation and type 2 diabetes. The quality of the ingredients in fast food ought to be better and the size of the portions smaller and less energy-dense so that frequent fast food meals do not increase the risk of obesity and diseases among customers.

  18. Soil carbon and nitrogen content and stabilization in mid-rotation, intensively managed sweetgum and loblolly stands

    Science.gov (United States)

    Kurt H. Johnsen; Lisa J. Samuelson; Felipe G. Sanchez; Bob Eaton

    2013-01-01

    Intensive forestry has resulted in considerable increases in aboveground stand productivity including foliar and belowground biomass which are the primary sources of soil organic matter. Soil organic matter is important for the maintenance of soil physical, chemical and biological quality. Additionally, sequestering carbon (C) in soils may provide a means of mitigating...

  19. Can Beta Blockers Cause Weight Gain?

    Science.gov (United States)

    ... cause weight gain? Can beta blockers cause weight gain? Answers from Sheldon G. Sheps, M.D. Yes. Weight gain can occur as a side effect of some ... and metoprolol (Lopressor, Toprol-XL). The average weight gain is about 2.6 pounds (about 1.2 ...

  20. A gain-coefficient switched Alexandrite laser

    International Nuclear Information System (INIS)

    Lee, Chris J; Van der Slot, Peter J M; Boller, Klaus-J

    2013-01-01

    We report on a gain-coefficient switched Alexandrite laser. An electro-optic modulator is used to switch between high and low gain states by making use of the polarization dependent gain of Alexandrite. In gain-coefficient switched mode, the laser produces 85 ns pulses with a pulse energy of 240 mJ at a repetition rate of 5 Hz.

  1. Model Effects on GLAS-Based Regional Estimates of Forest Biomass and Carbon

    Science.gov (United States)

    Nelson, Ross

    2008-01-01

    ICESat/GLAS waveform data are used to estimate biomass and carbon on a 1.27 million sq km study area. the Province of Quebec, Canada, below treeline. The same input data sets and sampling design are used in conjunction with four different predictive models to estimate total aboveground dry forest biomass and forest carbon. The four models include nonstratified and stratified versions of a multiple linear model where either biomass or (square root of) biomass serves as the dependent variable. The use of different models in Quebec introduces differences in Provincial biomass estimates of up to 0.35 Gt (range 4.942+/-0.28 Gt to 5.29+/-0.36 Gt). The results suggest that if different predictive models are used to estimate regional carbon stocks in different epochs, e.g., y2005, y2015, one might mistakenly infer an apparent aboveground carbon "change" of, in this case, 0.18 Gt, or approximately 7% of the aboveground carbon in Quebec, due solely to the use of different predictive models. These findings argue for model consistency in future, LiDAR-based carbon monitoring programs. Regional biomass estimates from the four GLAS models are compared to ground estimates derived from an extensive network of 16,814 ground plots located in southern Quebec. Stratified models proved to be more accurate and precise than either of the two nonstratified models tested.

  2. Estimating the potential gains from mergers

    DEFF Research Database (Denmark)

    Bogetoft, Peter; Wang, Dexiang

    2005-01-01

    We introduce simple production economic models to estimate the potential gains from mergers. We decompose the gains into technical ef¿ciency, size (scale) and harmony (mix) gains, and we discuss alternative ways to capture these gains. We propose to approximate the production processes using...... the non-parametric. Data Envelopment Analysis (DEA) approach, and we use the resulting operational approach to estimate the potential gains from merging agricultural extension of¿ces in Denmark....

  3. The role of above-ground competition and nitrogen vs. phosphorus enrichment in seedling survival of common European plant species of semi-natural grasslands.

    Directory of Open Access Journals (Sweden)

    Tobias Ceulemans

    Full Text Available Anthropogenic activities have severely altered fluxes of nitrogen and phosphorus in ecosystems worldwide. In grasslands, subsequent negative effects are commonly attributed to competitive exclusion of plant species following increased above-ground biomass production. However, some studies have shown that this does not fully account for nutrient enrichment effects, questioning whether lowering competition by reducing grassland productivity through mowing or herbivory can mitigate the environmental impact of nutrient pollution. Furthermore, few studies so far discriminate between nitrogen and phosphorus pollution. We performed a full factorial experiment in greenhouse mesocosms combining nitrogen and phosphorus addition with two clipping regimes designed to relax above-ground competition. Next, we studied the survival and growth of seedlings of eight common European grassland species and found that five out of eight species showed higher survival under the clipping regime with the lowest above-ground competition. Phosphorus addition negatively affected seven plant species and nitrogen addition negatively affected four plant species. Importantly, the negative effects of nutrient addition and higher above-ground competition were independent of each other for all but one species. Our results suggest that at any given level of soil nutrients, relaxation of above-ground competition allows for higher seedling survival in grasslands. At the same time, even at low levels of above-ground competition, nutrient enrichment negatively affects survival as compared to nutrient-poor conditions. Therefore, although maintaining low above-ground competition appears essential for species' recruitment, for instance through mowing or herbivory, these management efforts are likely to be insufficient and we conclude that environmental policies aimed to reduce both excess nitrogen and particularly phosphorus inputs are also necessary.

  4. Development of a data driven process-based model for remote sensing of terrestrial ecosystem productivity, evapotranspiration, and above-ground biomass

    Science.gov (United States)

    El Masri, Bassil

    2011-12-01

    Modeling terrestrial ecosystem functions and structure has been a subject of increasing interest because of the importance of the terrestrial carbon cycle in global carbon budget and climate change. In this study, satellite data were used to estimate gross primary production (GPP), evapotranspiration (ET) for two deciduous forests: Morgan Monroe State forest (MMSF) in Indiana and Harvard forest in Massachusetts. Also, above-ground biomass (AGB) was estimated for the MMSF and the Howland forest (mixed forest) in Maine. Surface reflectance and temperature, vegetation indices, soil moisture, tree height and canopy area derived from the Moderate Resolution Imagining Spectroradiometer (MODIS), the Advanced Microwave Scanning Radiometer (AMRS-E), LIDAR, and aerial imagery respectively, were used for this purpose. These variables along with others derived from remotely sensed data were used as inputs variables to process-based models which estimated GPP and ET and to a regression model which estimated AGB. The process-based models were BIOME-BGC and the Penman-Monteith equation. Measured values for the carbon and water fluxes obtained from the Eddy covariance flux tower were compared to the modeled GPP and ET. The data driven methods produced good estimation of GPP and ET with an average root mean square error (RMSE) of 0.17 molC/m2 and 0.40 mm/day, respectively for the MMSF and the Harvard forest. In addition, allometric data for the MMSF were used to develop the regression model relating AGB with stem volume. The performance of the AGB regression model was compared to site measurements using remotely sensed data for the MMSF and the Howland forest where the model AGB RMSE ranged between 2.92--3.30 Kg C/m2. Sensitivity analysis revealed that improvement in maintenance respiration estimation and remotely sensed maximum photosynthetic activity as well as accurate estimate of canopy resistance will result in improved GPP and ET predictions. Moreover, AGB estimates were

  5. Quaternion-Based Texture Analysis of Multiband Satellite Images: Application to the Estimation of Aboveground Biomass in the East Region of Cameroon.

    Science.gov (United States)

    Djiongo Kenfack, Cedrigue Boris; Monga, Olivier; Mpong, Serge Moto; Ndoundam, René

    2018-03-01

    Within the last decade, several approaches using quaternion numbers to handle and model multiband images in a holistic manner were introduced. The quaternion Fourier transform can be efficiently used to model texture in multidimensional data such as color images. For practical application, multispectral satellite data appear as a primary source for measuring past trends and monitoring changes in forest carbon stocks. In this work, we propose a texture-color descriptor based on the quaternion Fourier transform to extract relevant information from multiband satellite images. We propose a new multiband image texture model extraction, called FOTO++, in order to address biomass estimation issues. The first stage consists in removing noise from the multispectral data while preserving the edges of canopies. Afterward, color texture descriptors are extracted thanks to a discrete form of the quaternion Fourier transform, and finally the support vector regression method is used to deduce biomass estimation from texture indices. Our texture features are modeled using a vector composed with the radial spectrum coming from the amplitude of the quaternion Fourier transform. We conduct several experiments in order to study the sensitivity of our model to acquisition parameters. We also assess its performance both on synthetic images and on real multispectral images of Cameroonian forest. The results show that our model is more robust to acquisition parameters than the classical Fourier Texture Ordination model (FOTO). Our scheme is also more accurate for aboveground biomass estimation. We stress that a similar methodology could be implemented using quaternion wavelets. These results highlight the potential of the quaternion-based approach to study multispectral satellite images.

  6. Variation in stem mortality rates determines patterns of above-ground biomass in Amazonian forests: implications for dynamic global vegetation models.

    Science.gov (United States)

    Johnson, Michelle O; Galbraith, David; Gloor, Manuel; De Deurwaerder, Hannes; Guimberteau, Matthieu; Rammig, Anja; Thonicke, Kirsten; Verbeeck, Hans; von Randow, Celso; Monteagudo, Abel; Phillips, Oliver L; Brienen, Roel J W; Feldpausch, Ted R; Lopez Gonzalez, Gabriela; Fauset, Sophie; Quesada, Carlos A; Christoffersen, Bradley; Ciais, Philippe; Sampaio, Gilvan; Kruijt, Bart; Meir, Patrick; Moorcroft, Paul; Zhang, Ke; Alvarez-Davila, Esteban; Alves de Oliveira, Atila; Amaral, Ieda; Andrade, Ana; Aragao, Luiz E O C; Araujo-Murakami, Alejandro; Arets, Eric J M M; Arroyo, Luzmila; Aymard, Gerardo A; Baraloto, Christopher; Barroso, Jocely; Bonal, Damien; Boot, Rene; Camargo, Jose; Chave, Jerome; Cogollo, Alvaro; Cornejo Valverde, Fernando; Lola da Costa, Antonio C; Di Fiore, Anthony; Ferreira, Leandro; Higuchi, Niro; Honorio, Euridice N; Killeen, Tim J; Laurance, Susan G; Laurance, William F; Licona, Juan; Lovejoy, Thomas; Malhi, Yadvinder; Marimon, Bia; Marimon, Ben Hur; Matos, Darley C L; Mendoza, Casimiro; Neill, David A; Pardo, Guido; Peña-Claros, Marielos; Pitman, Nigel C A; Poorter, Lourens; Prieto, Adriana; Ramirez-Angulo, Hirma; Roopsind, Anand; Rudas, Agustin; Salomao, Rafael P; Silveira, Marcos; Stropp, Juliana; Ter Steege, Hans; Terborgh, John; Thomas, Raquel; Toledo, Marisol; Torres-Lezama, Armando; van der Heijden, Geertje M F; Vasquez, Rodolfo; Guimarães Vieira, Ima Cèlia; Vilanova, Emilio; Vos, Vincent A; Baker, Timothy R

    2016-12-01

    Understanding the processes that determine above-ground biomass (AGB) in Amazonian forests is important for predicting the sensitivity of these ecosystems to environmental change and for designing and evaluating dynamic global vegetation models (DGVMs). AGB is determined by inputs from woody productivity [woody net primary productivity (NPP)] and the rate at which carbon is lost through tree mortality. Here, we test whether two direct metrics of tree mortality (the absolute rate of woody biomass loss and the rate of stem mortality) and/or woody NPP, control variation in AGB among 167 plots in intact forest across Amazonia. We then compare these relationships and the observed variation in AGB and woody NPP with the predictions of four DGVMs. The observations show that stem mortality rates, rather than absolute rates of woody biomass loss, are the most important predictor of AGB, which is consistent with the importance of stand size structure for determining spatial variation in AGB. The relationship between stem mortality rates and AGB varies among different regions of Amazonia, indicating that variation in wood density and height/diameter relationships also influences AGB. In contrast to previous findings, we find that woody NPP is not correlated with stem mortality rates and is weakly positively correlated with AGB. Across the four models, basin-wide average AGB is similar to the mean of the observations. However, the models consistently overestimate woody NPP and poorly represent the spatial patterns of both AGB and woody NPP estimated using plot data. In marked contrast to the observations, DGVMs typically show strong positive relationships between woody NPP and AGB. Resolving these differences will require incorporating forest size structure, mechanistic models of stem mortality and variation in functional composition in DGVMs. © 2016 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

  7. Assessment of Above-Ground Biomass of Borneo Forests through a New Data-Fusion Approach Combining Two Pan-Tropical Biomass Maps

    Directory of Open Access Journals (Sweden)

    Andreas Langner

    2015-08-01

    Full Text Available This study investigates how two existing pan-tropical above-ground biomass (AGB maps (Saatchi 2011, Baccini 2012 can be combined to derive forest ecosystem specific carbon estimates. Several data-fusion models which combine these AGB maps according to their local correlations with independent datasets such as the spectral bands of SPOT VEGETATION imagery are analyzed. Indeed these spectral bands convey information about vegetation type and structure which can be related to biomass values. Our study area is the island of Borneo. The data-fusion models are evaluated against a reference AGB map available for two forest concessions in Sabah. The highest accuracy was achieved by a model which combines the AGB maps according to the mean of the local correlation coefficients calculated over different kernel sizes. Combining the resulting AGB map with a new Borneo land cover map (whose overall accuracy has been estimated at 86.5% leads to average AGB estimates of 279.8 t/ha and 233.1 t/ha for forests and degraded forests respectively. Lowland dipterocarp and mangrove forests have the highest and lowest AGB values (305.8 t/ha and 136.5 t/ha respectively. The AGB of all natural forests amounts to 10.8 Gt mainly stemming from lowland dipterocarp (66.4%, upper dipterocarp (10.9% and peat swamp forests (10.2%. Degraded forests account for another 2.1 Gt of AGB. One main advantage of our approach is that, once the best fitting data-fusion model is selected, no further AGB reference dataset is required for implementing the data-fusion process. Furthermore, the local harmonization of AGB datasets leads to more spatially precise maps. This approach can easily be extended to other areas in Southeast Asia which are dominated by lowland dipterocarp forest, and can be repeated when newer or more accurate AGB maps become available.

  8. Determining aboveground biomass of the forest successional chronosequence in a test-site of Brazilian Amazon through X- and L-band data analysis

    Science.gov (United States)

    Santos, João. R.; Silva, Camila V. d. J.; Galvão, Lênio S.; Treuhaft, Robert; Mura, José C.; Madsen, Soren; Gonçalves, Fábio G.; Keller, Michael M.

    2014-08-01

    Secondary succession is an important process in the Amazonian region with implications for the global carbon cycle and for the sustainable regional agricultural and pasture activities. In order to better discriminate the secondary succession and to characterize and estimate the aboveground biomass (AGB), backscatter and interferometric SAR data generally have been analyzed through empirical-based statistical modeling. The objective of this study is to verify the capability of the full polarimetric PALSAR/ALOS (L-band) attributes, when combined with the interferometric (InSAR) coherence from the TanDEM-X (X-band), to improve the AGB estimates of the succession chronosequence located in the Brazilian Tapajós region. In order to perform this study, we carried out multivariate regression using radar attributes and biophysical parameters acquired during a field inventory. A previous floristic-structural analysis was performed to establish the chronosequence in three stages: initial vegetation regrowth, intermediate, and advanced regrowth. The relationship between PALSAR data and AGB was significant (p<0.001) and results suggested that the "volumetric scattering" (Pv) and "anisotropy" (A) attributes were important to explain the biomass content of the successional chronosequence (R2adjusted = 0.67; RMSE = 32.29 Mg.ha-1). By adding the TanDEM-derived interferometric coherence (Υi) into the regression modeling, better results were obtained (R2adjusted = 0.75; RMSE = 28.78Mg.ha-1). When we used both the L- and X-band attributes, the stock density prediction improved to 10.8 % for the secondary succession stands.

  9. Effects of elevated temperature and CO2 on aboveground-belowground systems: a case study with plants, their mutualistic bacteria and root / shoot herbivores

    Directory of Open Access Journals (Sweden)

    James Michael William Ryalls

    2013-11-01

    Full Text Available Interactions between above- and belowground herbivores have been prominent in the field of aboveground-belowground ecology from the outset, although little is known about how climate change affects these organisms when they share the same plant. Additionally, the interactive effects of multiple factors associated with climate change such as elevated temperature (eT and elevated atmospheric carbon dioxide (eCO2 are untested. We investigated how eT and eCO2 affected larval development of the lucerne weevil (Sitona discoideus and colonisation by the pea aphid (Acyrthosiphon pisum, on three cultivars of a common host plant, lucerne (Medicago sativa. Sitona discoideus larvae feed on root nodules housing N2-fixing rhizobial bacteria, allowing us to test the effects of eT and eCO2 on three trophic levels. Moreover, we assessed the influence of these factors on plant growth. eT increased plant growth rate initially (6, 8 and 10 weeks after sowing, with cultivar ‘Sequel’ achieving the greatest height. Inoculation with aphids, however, reduced plant growth at week 14. eT severely reduced root nodulation by 43%, whereas eCO2 promoted nodulation by 56%, but only at ambient temperatures. Weevil presence increased net root biomass and nodulation, by 31 and 45%, respectively, showing an overcompensatory plant growth response. Effects of eT and eCO2 on root nodulation were mirrored by weevil larval development; eT and eCO2 reduced and increased larval development, respectively. Contrary to expectations, aphid colonisation was unaffected by eT or eCO2, but there was a near-significant 10% reduction in colonisation rates on plants with weevils present belowground. The contrasting effects of eT and eCO2 on weevils potentially occurred through changes in root nodulation patterns.

  10. Estimating the Above-Ground Biomass in Miombo Savanna Woodlands (Mozambique, East Africa Using L-Band Synthetic Aperture Radar Data

    Directory of Open Access Journals (Sweden)

    Maria J. Vasconcelos

    2013-03-01

    Full Text Available The quantification of forest above-ground biomass (AGB is important for such broader applications as decision making, forest management, carbon (C stock change assessment and scientific applications, such as C cycle modeling. However, there is a great uncertainty related to the estimation of forest AGB, especially in the tropics. The main goal of this study was to test a combination of field data and Advanced Land Observing Satellite (ALOS Phased Array L-band Synthetic Aperture Radar (PALSAR backscatter intensity data to reduce the uncertainty in the estimation of forest AGB in the Miombo savanna woodlands of Mozambique (East Africa. A machine learning algorithm, based on bagging stochastic gradient boosting (BagSGB, was used to model forest AGB as a function of ALOS PALSAR Fine Beam Dual (FBD backscatter intensity metrics. The application of this method resulted in a coefficient of correlation (R between observed and predicted (10-fold cross-validation forest AGB values of 0.95 and a root mean square error of 5.03 Mg·ha−1. However, as a consequence of using bootstrap samples in combination with a cross validation procedure, some bias may have been introduced, and the reported cross validation statistics could be overoptimistic. Therefore and as a consequence of the BagSGB model, a measure of prediction variability (coefficient of variation on a pixel-by-pixel basis was also produced, with values ranging from 10 to 119% (mean = 25% across the study area. It provides additional and complementary information regarding the spatial distribution of the error resulting from the application of the fitted model to new observations.

  11. Heritability of gestational weight gain

    DEFF Research Database (Denmark)

    Andersson, Elina Scheers; Silventoinen, Karri; Tynelius, Per

    2015-01-01

    Gestational weight gain (GWG) is a complex trait involving intrauterine environmental, maternal environmental, and genetic factors. However, the extent to which these factors contribute to the total variation in GWG is unclear. We therefore examined the genetic and environmental influences...... on the variation in GWG in the first and second pregnancy in monozygotic (MZ) and dizygotic (DZ) twin mother-pairs. Further, we explored if any co-variance existed between factors influencing the variation in GWG of the mothers’ first and second pregnancies. By using Swedish nationwide record-linkage data, we...... identified 694 twin mother-pairs with complete data on their first pregnancy and 465 twin mother-pairs with complete data on their second pregnancy during 1982–2010. For a subanalysis, 143 twin mother-pairs had complete data on two consecutive pregnancies during the study period. We used structural equation...

  12. Unidirectional high gain brake stop

    Science.gov (United States)

    Lang, David J. (Inventor)

    1987-01-01

    This invention relates to a unidirectional high gain brake arrangement that includes in combination a shaft mounted for rotation within a housing. The shaft is rotatable in either direction. A brake is selectively releasably coupled to the housing and to the shaft. The brake has a first member. An intermittent motion device is respectively coupled through the first member to the housing and through a one-way clutch to the shaft. The brake also has a second member that is mechanically coupled to the first brake member and to the housing. The intermittent motion device causes the brake to be activated by movement imparted to the first brake member after a preset number of revolutions of the shaft in one direction. The brake is released by rotation of the shaft in an opposite direction whereby torque transmitted through the one-way clutch to the first brake member is removed.

  13. Boesmanland gains from nuclear wastes

    International Nuclear Information System (INIS)

    Smit, I.

    1984-01-01

    It is being claimed that the geobotany of the Boesmanland will gain from the use of the farm Vaalputs for radioactive waste disposal from the Koeberg nuclear power station. Only 1 km 2 of the 10 000 ha that was bought for the purpose will be used for the disposal of low-level radioactive wastes and 2 m 3 to 3 m 3 per year will be used for the storage of high-level radioactive wastes. The rest of the area, Nucor plans to develop as a nature reserve, restoring the natural botany and ecology. Before Vaalputs was selected as site for radioactive waste disposal, a regional analysis was done. According to this there is more or less 500 people staying within a radius of 25km from the farm. Geological surveys showed no mineral deposits of economic value. During the past 100 million years the area was also free from seismic activity

  14. Carbon Standards and Carbon Labelling: An Emerging Trade Concern

    OpenAIRE

    Nitya Nanda; Rajan Sudesh Ratna

    2010-01-01

    The current debate on climate change and its linkages to trade is rapidly gaining global attention. Thus it is reasonable to expect that the focus on carbon leakage and border tax adjustment will only intensify in the future. Carbon leakage is said to happen when production of carbon intensive products migrates from countries which have measures to reduce emissions to countries where there are no such measures. Therefore, border tax adjustment is suggested when carbon intensive products are i...

  15. Aboveground biomass mapping of African forest mosaics using canopy texture analysis: toward a regional approach.

    Science.gov (United States)

    Bastin, Jean-François; Barbier, Nicolas; Couteron, Pierre; Adams, Benoît; Shapiro, Aurélie; Bogaert, Jan; De Cannière, Charles

    In the context of the reduction of greenhouse gas emissions caused by deforestation and forest degradation (the REDD+ program), optical very high resolution (VHR) satellite images provide an opportunity to characterize forest canopy structure and to quantify aboveground biomass (AGB) at less expense than methods based on airborne remote sensing data. Among the methods for processing these VHR images, Fourier textural ordination (FOTO) presents a good method to detect forest canopy structural heterogeneity and therefore to predict AGB variations. Notably, the method does not saturate at intermediate AGB values as do pixelwise processing of available space borne optical and radar signals. However, a regional-scale application requires overcoming two difficulties: (1) instrumental effects due to variations in sun–scene–sensor geometry or sensor-specific responses that preclude the use of wide arrays of images acquired under heterogeneous conditions and (2) forest structural diversity including monodominant or open canopy forests, which are of particular importance in Central Africa. In this study, we demonstrate the feasibility of a rigorous regional study of canopy texture by harmonizing FOTO indices of images acquired from two different sensors (Geoeye-1 and QuickBird-2) and different sun–scene–sensor geometries and by calibrating a piecewise biomass inversion model using 26 inventory plots (1 ha) sampled across very heterogeneous forest types. A good agreement was found between observed and predicted AGB (residual standard error [RSE] = 15%; R2 = 0.85; P biomass map (100-m pixels) was produced for a 400-km2 area, and predictions obtained from both imagery sources were consistent with each other (r = 0.86; slope = 1.03; intercept = 12.01 Mg/ha). These results highlight the horizontal structure of forest canopy as a powerful descriptor of the entire forest stand structure and heterogeneity. In particular, we show that quantitative metrics resulting from such

  16. Lidar aboveground vegetation biomass estimates in shrublands: Prediction, uncertainties and application to coarser scales

    Science.gov (United States)

    Li, Aihua; Dhakal, Shital; Glenn, Nancy F.; Spaete, Luke P.; Shinneman, Douglas; Pilliod, David S.; Arkle, Robert; McIlroy, Susan

    2017-01-01

    Our study objectives were to model the aboveground biomass in a xeric shrub-steppe landscape with airborne light detection and ranging (Lidar) and explore the uncertainty associated with the models we created. We incorporated vegetation vertical structure information obtained from Lidar with ground-measured biomass data, allowing us to scale shrub biomass from small field sites (1 m subplots and 1 ha plots) to a larger landscape. A series of airborne Lidar-derived vegetation metrics were trained and linked with the field-measured biomass in Random Forests (RF) regression models. A Stepwise Multiple Regression (SMR) model was also explored as a comparison. Our results demonstrated that the important predictors from Lidar-derived metrics had a strong correlation with field-measured biomass in the RF regression models with a pseudo R2 of 0.76 and RMSE of 125 g/m2 for shrub biomass and a pseudo R2 of 0.74 and RMSE of 141 g/m2 for total biomass, and a weak correlation with field-measured herbaceous biomass. The SMR results were similar but slightly better than RF, explaining 77–79% of the variance, with RMSE ranging from 120 to 129 g/m2 for shrub and total biomass, respectively. We further explored the computational efficiency and relative accuracies of using point cloud and raster Lidar metrics at different resolutions (1 m to 1 ha). Metrics derived from the Lidar point cloud processing led to improved biomass estimates at nearly all resolutions in comparison to raster-derived Lidar metrics. Only at 1 m were the results from the point cloud and raster products nearly equivalent. The best Lidar prediction models of biomass at the plot-level (1 ha) were achieved when Lidar metrics were derived from an average of fine resolution (1 m) metrics to minimize boundary effects and to smooth variability. Overall, both RF and SMR methods explained more than 74% of the variance in biomass, with the most important Lidar variables being associated with vegetation structure

  17. Impacts of Storm Surge Mitigation Strategies on Aboveground Storage Tank Chemical Spill Transport

    Science.gov (United States)

    Do, C.; Bass, B. J.; Bernier, C.; Samii, A.; Dawson, C.; Bedient, P. B.

    2017-12-01

    The Houston Ship Channel (HSC), located in the hurricane-prone Houston-Galveston region of the upper Texas Coast, is one of the busiest waterways in the United States and is home to one of the largest petrochemical complexes in the world. Due to the proximity of the HSC to Galveston Bay and the Gulf of Mexico, chemical spills resulting from storm surge damage to aboveground storage tanks (ASTs) pose serious threats to the environment, residential communities, and national/international markets whose activities in the HSC generate billions of dollars annually. In an effort to develop a comprehensive storm surge mitigation strategy for Galveston Bay and its constituents, Rice University's Severe Storm Prediction, Education, and Evacuation from Disasters Center proposed two structural storm surge mitigation concepts, the Mid Bay Structure (MBS) and the Lower Bay Structure (LBS) as components of the Houston-Galveston Area Protection System (H-GAPS) project. The MBS consists of levees along the HSC and a navigational gate across the channel, and the LBS consists of a navigation gate and environmental gates across Bolivar Road. The impacts of these two barrier systems on the fate of AST chemical spills in the HSC have previously been unknown. This study applies the coupled 2D SWAN+ADCIRC model to simulate hurricane storm surge circulation within the Gulf of Mexico and Galveston Bay due to a synthetic storm which results in approximately 250-year surge levels in Galveston Bay. The SWAN+ADCIRC model is run using high-resolution computational meshes that incorporate the MBS and LBS scenarios, separately. The resulting wind and water velocities are then fed into a Lagrangian particle transport model to simulate the spill trajectories of the ASTs most likely to fail during the 250-year proxy storm. Results from this study illustrate how each storm surge mitigation strategy impacts the transport of chemical spills (modeled as Lagrangian particles) during storm surge as

  18. Gain attenuation of gated framing camera

    International Nuclear Information System (INIS)

    Xiao Shali; Liu Shenye; Cao Zhurong; Li Hang; Zhang Haiying; Yuan Zheng; Wang Liwei

    2009-01-01

    The theoretic model of framing camera's gain attenuation is analyzed. The exponential attenuation curve of the gain along the pulse propagation time is simulated. An experiment to measure the coefficient of gain attenuation based on the gain attenuation theory is designed. Experiment result shows that the gain follows an exponential attenuation rule with a quotient of 0.0249 nm -1 , the attenuation coefficient of the pulse is 0.00356 mm -1 . The loss of the pulse propagation along the MCP stripline is the leading reason of gain attenuation. But in the figure of a single stripline, the gain dose not follow the rule of exponential attenuation completely, instead, there is a gain increase at the stripline bottom. That is caused by the reflection of the pulse. The reflectance is about 24.2%. Combining the experiment and theory, which design of the stripline MCP can improved the gain attenuation. (authors)

  19. [Soil seed bank and its correlations with aboveground vegetation and environmental factors in water level fluctuating zone of Danjiangkou Reservoir, Central China].

    Science.gov (United States)

    Liu, Rui-Xue; Zhan, Juan; Shi, Zhi-Hua; Chen, Long-qing

    2013-03-01

    Taking the water level fluctuating zone of the Danjiangkou Reservoir as a case, and by the method of hierarchical cluster analysis, the soil seed banks at 37 sampling plots within the areas of 140-145 m elevation were divided into 6 groups, and the species composition, density, and diversity of the soil seed banks among the groups were compared. The differences between the soil seed banks and the aboveground vegetations were analyzed by S0rensen similarity coefficient, and the correlations among the soil seed banks, aboveground vegetations, and environmental factors were explored by principal component analysis (PCA) and multivariable regression analysis. At the same altitudes of the water level fluctuating zone, the species composition of the soil seed banks had obvious heterogeneity, and the density and diversity indices of the soil seed banks among different groups were great. The similarity coefficient between the soil seed banks and aboveground vegetations was low, and the species number in the soil seed banks was obviously lesser than that in the aboveground vegetations. The density of the soil seed banks was highly positively correlated with the aboveground vegetations coverage and species number and the soil texture, but highly negatively correlated with the soil water-holding capacity and soil porosity.

  20. Urban tree effects on soil organic carbon.

    Directory of Open Access Journals (Sweden)

    Jill L Edmondson

    Full Text Available Urban trees sequester carbon into biomass and provide many ecosystem service benefits aboveground leading to worldwide tree planting schemes. Since soils hold ∼75% of ecosystem organic carbon, understanding the effect of urban trees on soil organic carbon (SOC and soil properties that underpin belowground ecosystem services is vital. We use an observational study to investigate effects of three important tree genera and mixed-species woodlands on soil properties (to 1 m depth compared to adjacent urban grasslands. Aboveground biomass and belowground ecosystem service provision by urban trees are found not to be directly coupled. Indeed, SOC enhancement relative to urban grasslands is genus-specific being highest under Fraxinus excelsior and Acer spp., but similar to grasslands under Quercus robur and mixed woodland. Tree cover type does not influence soil bulk density or C∶N ratio, properties which indicate the ability of soils to provide regulating ecosystem services such as nutrient cycling and flood mitigation. The trends observed in this study suggest that genus selection is important to maximise long-term SOC storage under urban trees, but emerging threats from genus-specific pathogens must also be considered.

  1. Estimating terrestrial aboveground biomass estimation using lidar remote sensing: a meta-analysis

    Science.gov (United States)

    Zolkos, S. G.; Goetz, S. J.; Dubayah, R.

    2012-12-01

    Estimating biomass of terrestrial vegetation is a rapidly expanding research area, but also a subject of tremendous interest for reducing carbon emissions associated with deforestation and forest degradation (REDD). The accuracy of biomass estimates is important in the context carbon markets emerging under REDD, since areas with more accurate estimates command higher prices, but also for characterizing uncertainty in estimates of carbon cycling and the global carbon budget. There is particular interest in mapping biomass so that carbon stocks and stock changes can be monitored consistently across a range of scales - from relatively small projects (tens of hectares) to national or continental scales - but also so that other benefits of forest conservation can be factored into decision making (e.g. biodiversity and habitat corridors). We conducted an analysis of reported biomass accuracy estimates from more than 60 refereed articles using different remote sensing platforms (aircraft and satellite) and sensor types (optical, radar, lidar), with a particular focus on lidar since those papers reported the greatest efficacy (lowest errors) when used in the a synergistic manner with other coincident multi-sensor measurements. We show systematic differences in accuracy between different types of lidar systems flown on different platforms but, perhaps more importantly, differences between forest types (biomes) and plot sizes used for field calibration and assessment. We discuss these findings in relation to monitoring, reporting and verification under REDD, and also in the context of more systematic assessment of factors that influence accuracy and error estimation.

  2. Greenhouse gas emissions and carbon sequestration by agroforestry systems in southeastern Brazil.

    Science.gov (United States)

    Torres, Carlos Moreira Miquelino Eleto; Jacovine, Laércio Antônio Gonçalves; Nolasco de Olivera Neto, Sílvio; Fraisse, Clyde William; Soares, Carlos Pedro Boechat; de Castro Neto, Fernando; Ferreira, Lino Roberto; Zanuncio, José Cola; Lemes, Pedro Guilherme

    2017-12-01

    Agrosilvopastoral and silvopastoral systems can increase carbon sequestration, offset greenhouse gas (GHG) emissions and reduce the carbon footprint generated by animal production. The objective of this study was to estimate GHG emissions, the tree and grass aboveground biomass production and carbon storage in different agrosilvopastoral and silvopastoral systems in southeastern Brazil. The number of trees required to offset these emissions were also estimated. The GHG emissions were calculated based on pre-farm (e.g. agrochemical production, storage, and transportation), and on-farm activities (e.g. fertilization and machinery operation). Aboveground tree grass biomass and carbon storage in all systems was estimated with allometric equations. GHG emissions from the agroforestry systems ranged from 2.81 to 7.98 t CO 2 e ha -1 . Carbon storage in the aboveground trees and grass biomass were 54.6, 11.4, 25.7 and 5.9 t C ha -1 , and 3.3, 3.6, 3.8 and 3.3 t C ha -1 for systems 1, 2, 3 and 4, respectively. The number of trees necessary to offset the emissions ranged from 17 to 44 trees ha -1 , which was lower than the total planted in the systems. Agroforestry systems sequester CO 2 from the atmosphere and can help the GHG emission-reduction policy of the Brazilian government.

  3. Review of High Gain FELs

    International Nuclear Information System (INIS)

    Shintake, Tsumoru

    2007-01-01

    For understanding on basic radiation mechanism of the high-gain FEL based on SASE, the author presents electron-crystal interpretation of FEL radiation. In the electron-crystal, electrons are localized at regularly spaced multi-layers, which represents micro-bunching, whose spacing is equal to the radiation wavelength, and the multi-layers are perpendicular to beam axis, thus, diffracted wave creates Bragg's spots in forward and backward directions. Due to the Doppler's effect, frequency of the back-scattered wave is up-converted, generates forwardly focused X-ray. The Bragg's effect contributes focusing the X-ray beam into a spot, thus peak power becomes extremely higher by factor of typically 107. This is the FEL radiation. As well known, the total numbers of scattered photons in Bragg's spots is equal to the total elastic scattering photons from the atoms contained in the crystal. Therefore, total power in the FEL laser is same as the spontaneous radiation power from the undulator for the same beam parameter. The FEL radiation phenomenon is simple interference effect. In today's presentations, we use the laser pointer, and we frequently experience difficulty in pointing precisely or steadily in one place on the screen, since the laser spot is very small and does not spread. Exactly same to this, X-ray FEL is a highly focused beam, and pointing stability dominates productivity of experiment, thus we need special care on beam stability from linear accelerator

  4. Benefits of tree mixes in carbon plantings

    Science.gov (United States)

    Hulvey, Kristin B.; Hobbs, Richard J.; Standish, Rachel J.; Lindenmayer, David B.; Lach, Lori; Perring, Michael P.

    2013-10-01

    Increasingly governments and the private sector are using planted forests to offset carbon emissions. Few studies, however, examine how tree diversity -- defined here as species richness and/or stand composition -- affects carbon storage in these plantings. Using aboveground tree biomass as a proxy for carbon storage, we used meta-analysis to compare carbon storage in tree mixtures with monoculture plantings. Tree mixes stored at least as much carbon as monocultures consisting of the mixture's most productive species and at times outperformed monoculture plantings. In mixed-species stands, individual species, and in particular nitrogen-fixing trees, increased stand biomass. Further motivations for incorporating tree richness into planted forests include the contribution of diversity to total forest carbon-pool development, carbon-pool stability and the provision of extra ecosystem services. Our findings suggest a two-pronged strategy for designing carbon plantings including: (1) increased tree species richness; and (2) the addition of species that contribute to carbon storage and other target functions.

  5. Carbon stocks in tree biomass and soils of German forests

    Directory of Open Access Journals (Sweden)

    Wellbrock Nicole

    2017-06-01

    Full Text Available Close to one third of Germany is forested. Forests are able to store significant quantities of carbon (C in the biomass and in the soil. Coordinated by the Thünen Institute, the German National Forest Inventory (NFI and the National Forest Soil Inventory (NFSI have generated data to estimate the carbon storage capacity of forests. The second NFI started in 2002 and had been repeated in 2012. The reporting time for the NFSI was 1990 to 2006. Living forest biomass, deadwood, litter and soils up to a depth of 90 cm have stored 2500 t of carbon within the reporting time. Over all 224 t C ha-1 in aboveground and belowground biomass, deadwood and soil are stored in forests. Specifically, 46% stored in above-ground and below-ground biomass, 1% in dead wood and 53% in the organic layer together with soil up to 90 cm. Carbon stocks in mineral soils up to 30 cm mineral soil increase about 0.4 t C ha-1 yr-1 stocks between the inventories while the carbon pool in the organic layers declined slightly. In the living biomass carbon stocks increased about 1.0 t C ha-1 yr-1. In Germany, approximately 58 mill. tonnes of CO2 were sequestered in 2012 (NIR 2017.

  6. Predicting carbon benefits from climate-smart agriculture: High-resolution carbon mapping and uncertainty assessment in El Salvador.

    Science.gov (United States)

    Kearney, Sean Patrick; Coops, Nicholas C; Chan, Kai M A; Fonte, Steven J; Siles, Pablo; Smukler, Sean M

    2017-11-01

    Agroforestry management in smallholder agriculture can provide climate change mitigation and adaptation benefits and has been promoted as 'climate-smart agriculture' (CSA), yet has generally been left out of international and voluntary carbon (C) mitigation agreements. A key reason for this omission is the cost and uncertainty of monitoring C at the farm scale in heterogeneous smallholder landscapes. A largely overlooked alternative is to monitor C at more aggregated scales and develop C contracts with groups of land owners, community organizations or C aggregators working across entire landscapes (e.g., watersheds, communities, municipalities, etc.). In this study we use a 100-km 2 agricultural area in El Salvador to demonstrate how high-spatial resolution optical satellite imagery can be used to map aboveground woody biomass (AGWB) C at the landscape scale with very low uncertainty (95% probability of a deviation of less than 1%). Uncertainty of AGWB-C estimates remained low (agricultural lands in the study area, and that utilizing AGWB-C maps to target denuded areas could increase C gains per unit area by 46%. The potential value of C credits under a plausible adoption scenario would range from $38,270 to $354,000 yr -1 for the study area, or about $13 to $124 ha -1  yr -1 , depending on C prices. Considering farm sizes in smallholder landscapes rarely exceed 1-2 ha, relying solely on direct C payments to farmers may not lead to widespread CSA adoption, especially if farm-scale monitoring is required. Instead, landscape-scale approaches to C contracting, supported by satellite-based monitoring methods such as ours, could be a key strategy to reduce costs and uncertainty of C monitoring in heterogeneous smallholder landscapes, thereby incentivizing more widespread CSA adoption. Copyright © 2017. Published by Elsevier Ltd.

  7. Lidar-derived estimate and uncertainty of carbon sink in successional phases of woody encroachment

    Science.gov (United States)

    Sankey, Temuulen; Shrestha, Rupesh; Sankey, Joel B.; Hardgree, Stuart; Strand, Eva

    2013-01-01

    Woody encroachment is a globally occurring phenomenon that contributes to the global carbon sink. The magnitude of this contribution needs to be estimated at regional and local scales to address uncertainties present in the global- and continental-scale estimates, and guide regional policy and management in balancing restoration activities, including removal of woody plants, with greenhouse gas mitigation goals. The objective of this study was to estimate carbon stored in various successional phases of woody encroachment. Using lidar measurements of individual trees, we present high-resolution estimates of aboveground carbon storage in juniper woodlands. Segmentation analysis of lidar point cloud data identified a total of 60,628 juniper tree crowns across four watersheds. Tree heights, canopy cover, and density derived from lidar were strongly correlated with field measurements of 2613 juniper stems measured in 85 plots (30 × 30 m). Aboveground total biomass of individual trees was estimated using a regression model with lidar-derived height and crown area as predictors (Adj. R2 = 0.76, p 2. Uncertainty in carbon storage estimates was examined with a Monte Carlo approach that addressed major error sources. Ranges predicted with uncertainty analysis in the mean, individual tree, aboveground woody C, and associated standard deviation were 0.35 – 143.6 kg and 0.5 – 1.25 kg, respectively. Later successional phases of woody encroachment had, on average, twice the aboveground carbon relative to earlier phases. Woody encroachment might be more successfully managed and balanced with carbon storage goals by identifying priority areas in earlier phases of encroachment where intensive treatments are most effective.

  8. [Estimating individual tree aboveground biomass of the mid-subtropical forest using airborne LiDAR technology].

    Science.gov (United States)

    Liu, Feng; Tan, Chang; Lei, Pi-Feng

    2014-11-01

    Taking Wugang forest farm in Xuefeng Mountain as the research object, using the airborne light detection and ranging (LiDAR) data under leaf-on condition and field data of concomitant plots, this paper assessed the ability of using LiDAR technology to estimate aboveground biomass of the mid-subtropical forest. A semi-automated individual tree LiDAR cloud point segmentation was obtained by using condition random fields and optimization methods. Spatial structure, waveform characteristics and topography were calculated as LiDAR metrics from the segmented objects. Then statistical models between aboveground biomass from field data and these LiDAR metrics were built. The individual tree recognition rates were 93%, 86% and 60% for coniferous, broadleaf and mixed forests, respectively. The adjusted coefficients of determination (R(2)adj) and the root mean squared errors (RMSE) for the three types of forest were 0.83, 0.81 and 0.74, and 28.22, 29.79 and 32.31 t · hm(-2), respectively. The estimation capability of model based on canopy geometric volume, tree percentile height, slope and waveform characteristics was much better than that of traditional regression model based on tree height. Therefore, LiDAR metrics from individual tree could facilitate better performance in biomass estimation.

  9. SEVERAL PESTA TABLET TRIALS WITH Aspergillus alliaceus Thom & Church FOR EFFECTIVE UNDERGROUND AND ABOVEGROUND Orobanche L. BIOCONTROL

    Directory of Open Access Journals (Sweden)

    Mehmet AYBEKE

    2016-06-01

    Full Text Available The present study was performed in order to determine the efficiency of the fungi Aspergillus alliaceus in fighting broomrape by the pesta-tablet trials under below- and above-ground conditions and to determine the appropriate tablet formulations for both conditions. For this purpose, different tablets were used in different experimental steps and their efficiencies were evaluated. The results showed that the tablets T-1, T-2, T-3, T-5, T-12 and T-13 greatly reduced the amount of broomrape in below-ground conditions, particularly with previous and high amount or crushed-tablet applications before crop-sowing. In above-ground conditions, any tablet formulation or directly sclerotial contacting were very effective in broomrape control and it was determined that close presence to or direct contact with broomrape is essential for successful biocontrol. In conclusion, considering the durability of the fungal agent against harsh environmental conditions and its sclerotial structure, it was deduced that if the fungi could be implemented in a stand-alone or especially integrated with each other, it will provide long-term, high-level broomrape biocontrol, indicating the advantages of A. alliaceus against other alternative fungal agents.

  10. Impact of deforestation and climate on the Amazon Basin's above-ground biomass during 1993-2012.

    Science.gov (United States)

    Exbrayat, Jean-François; Liu, Yi Y; Williams, Mathew

    2017-11-15

    Since the 1960s, large-scale deforestation in the Amazon Basin has contributed to rising global CO 2 concentrations and to climate change. Recent advances in satellite observations enable estimates of gross losses of above-ground biomass (AGB) stocks due to deforestation. However, because of simultaneous regrowth, the net contribution of deforestation emissions to rising atmospheric CO 2 concentrations is poorly quantified. Climate change may also reduce the potential for forest regeneration in previously disturbed regions. Here, we address these points of uncertainty with a machine-learning approach that combines satellite observations of AGB with climate data across the Amazon Basin to reconstruct annual maps of potential AGB during 1993-2012, the above-ground C storage potential of the undisturbed landscape. We derive a 2.2 Pg C loss of AGB over the study period, and, for the regions where these losses occur, we estimate a 0.7 Pg C reduction in potential AGB. Thus, climate change has led to a decline of ~1/3 in the capacity of these disturbed forests to recover and recapture the C lost in disturbances during 1993-2012. Our approach further shows that annual variations in land use change mask the natural relationship between the El Niño/Southern Oscillation and AGB stocks in disturbed regions.

  11. Gain scheduling using the Youla parameterization

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Stoustrup, Jakob

    1999-01-01

    Gain scheduling controllers are considered in this paper. The gain scheduling problem where the scheduling parameter vector cannot be measured directly, but needs to be estimated is considered. An estimation of the scheduling vector has been derived by using the Youla parameterization. The use...... in connection with H_inf gain scheduling controllers....

  12. Determination of the STIS CCD Gain

    Science.gov (United States)

    Riley, Allyssa; Monroe, TalaWanda; Lockwood, Sean

    2016-09-01

    This report summarizes the analysis and absolute gain results of the STIS Cycle 23 special calibration program 14424 that was designed to measure the gain of amplifiers A, C and D at nominal gain settings of 1 and 4 e-/DN. We used the mean-variance technique and the results indicate a mean-variance technique.

  13. Climate change induced range-expanding plants : aboveground and belowground interactions

    NARCIS (Netherlands)

    Morriën, W.E.

    2011-01-01

    Burning of fossil fuels has raised the level of atmospheric carbon dioxide, which contributes to global climate warming. As a result the mean earth surface temperature has increased faster in the past decades than in the previous thousands of years before. This rapid climate warming together

  14. Direct estimation of aboveground forest productivity through hyperspectral remote sensing of canopy nitrogen

    Science.gov (United States)

    Marie-Louise Smith; Scott V. Ollinger; Mary E. Martin; John D. Aber; Richard A. Hallett; Christine L. Goodale

    2002-01-01

    The concentration of nitrogen in foliage has been related to rates of net photosynthesis across a wide range of plant species and functional groups and thus represents a simple and biologically meaningful link between terrestrial cycles of carbon and nitrogen. Although foliar N is used by ecosystem models to predict rates of leaf-level photosynthesis, it has rarely...

  15. Does functional trait diversity predict aboveground biomass and productivity of tropical forests? Testing three alternative hypotheses

    NARCIS (Netherlands)

    Finegan, B.; Pena Claros, M.; Silva de Oliveira, A.; Ascarrunz, N.; Bret-Harte, M.S.; Carreño Rocabado, I.G.; Casanoves, F.; Diaz, S.; Eguiguren Velepucha, P.; Fernandez, F.; Licona, J.C.; Lorenzo, L.; Salgado Negret, B.; Vaz, M.; Poorter, L.

    2014-01-01

    1. Tropical forests are globally important, but it is not clear whether biodiversity enhances carbon storage and sequestration in them. We tested this relationship focusing on components of functional trait biodiversity as predictors. 2. Data are presented for three rain forests in Bolivia, Brazil

  16. Does functional trait diversity predict aboveground biomass and productivity of tropical forests? Testing three alternative hypotheses

    NARCIS (Netherlands)

    Finegan, B.; Peña Claros, M.; Oliviera, de A.; Alarcón, A.; Ascarrunz, N.; Bret-Harte, M.S.; Carreño-Rocabado, G.; Casanoves, F.; Díaz, S.; Eguiguren Velepucha, P.; Fernandez, F.; Licona, J.C.; Lorenzo, L.; Salgado Negret, B.; Vaz, M.; Poorter, L.

    2015-01-01

    Tropical forests are globally important, but it is not clear whether biodiversity enhances carbon storage and sequestration in them. We tested this relationship focusing on components of functional trait biodiversity as predictors. Data are presented for three rain forests in Bolivia, Brazil and

  17. The variable effects of soil nitrogen availability and insect herbivory on aboveground and belowground plant biomass in an old-field ecosystem

    DEFF Research Database (Denmark)

    Blue, Jarrod D.; Souza, Lara; Classen, Aimée T.

    2011-01-01

    in an old-field ecosystem. In 2004, we established 36 experimental plots in which we manipulated soil nitrogen (N) availability and insect abundance in a completely randomized plot design. In 2009, after 6 years of treatments, we measured aboveground biomass and assessed root production at peak growth...... not be limiting primary production in this ecosystem. Insects reduced the aboveground biomass of subdominant plant species and decreased coarse root production. We found no statistical interactions between N availability and insect herbivory for any response variable. Overall, the results of 6 years of nutrient...

  18. The role of remnant trees in carbon sequestration, vegetation structure and tree diversity of early succession regrowing fallows in eastern Sierra Leone

    DEFF Research Database (Denmark)

    Cuni Sanchez, Aida; Lindsell, Jeremy A.

    2017-01-01

    Remnant tree presence affects forest recovery after slash-and-burn agriculture. However, little is known about its effect on above-ground carbon stocks, especially in Africa. We focused our study on Sierra Leone, part of the Upper Guinean forests, an important centre of endemism threatened...

  19. Creating With Carbon

    Science.gov (United States)

    2003-01-01

    A subsidiary of SI Diamond Technology, Inc., Applied Nanotech, of Austin, Texas, is creating a buzz among various technology firms and venture capital groups interested in the company s progressive research on carbon-related field emission devices, including carbon nanotubes, filaments of pure carbon less than one ten-thousandth the width of human hair. Since their discovery in 1991, carbon nanotubes have gained considerable attention due to their unique physical properties. For example, a single perfect carbon nanotube can range from 10 to 100 times stronger than steel, per unit weight. Recent studies also indicate that the nanotubes may be the best heat-conducting material in existence. These properties, combined with the ease of growing thin films or nanotubes by a variety of deposition techniques, make the carbon-based material one of the most desirable for cold field emission cathodes.

  20. Carbon Dynamics in Heathlands in Response to a Changing Climate

    DEFF Research Database (Denmark)

    Nielsen, Pia Lund

    Climate is changing, and more adverse changes are expected in the future. Changes, caused by continuously rising atmospheric concentrations of greenhouse gasses as CO2, will affect ecosystem processes and functions in the future and hence the cycling of carbon. The vaste amount of studies have...... layers showed much slower decomposition than fine root from top layer. Higher roots biomass and allocation of carbon deeper down in the soil profile in response to elevated CO2 combined with the slower decomposition of deep roots could affect future carbon cycling, but soil carbon sequestration depends...... focused on effects of climate change on aboveground biomass, less have been conducted on belowground biomass, and the thesis is one of few studies comprising both above- and belowground biomass and take interactions of climate change factors into account. To follow the fate of carbon in the ecosystem we...

  1. Carbon Stocks across a Fifty Year Chronosequence of Rubber Plantations in Tropical China

    Directory of Open Access Journals (Sweden)

    Chenggang Liu

    2017-06-01

    Full Text Available Transition from forest to rubber (Hevea brasiliensis Muell. Arg. plantation has occurred in tropical China for decades. Rubber has been planted on 1 million ha to provide raw materials to the rubber industry. The role of various-aged rubber plantations in carbon (C sequestration remains unclear. The biomass C accumulation including latex C and C distribution in soil of five different-aged stands (7, 13, 19, 25 and 47 years old were examined. The total biomass C stock (TBC and total net primary productivity (NPPtotal, whether with or without latex C, had a close quadratic relationship with stand age. Regardless of stand age, around 68% of the C was stored in aboveground biomass, and NPPlatex contributed to approximately 18% of C sequestration. Soil organic carbon stock in the 100-cm depth remained relatively stable, but it lost about 16.8 Mg ha−1 with stand age. The total ecosystem C stock (TEC across stands averaged 159.6, 174.4, 229.6, 238.1 and 291.9 Mg ha−1, respectively, of which more than 45% was stored in the soil. However, biomass would become the major C sink rather than soil over a maximal rubber life expectancy. Regression analysis showed that TEC for rubber plantation at 22 years is comparable to a baseline of 230.4 Mg ha−1 for tropical forest in China, and would reach the maximum value at around 54 years. Therefore, rubber plantation can be considered as alternative land use without affecting net forest ecosystem C storage. In addition to the potential C gains, a full set of ecosystem and economic properties have to be quantified in order to assess the trade-offs associated with forest-to-rubber transition.

  2. Aboveground and belowground legacies of native Sami land use on boreal forest in northern Sweden 100 years after abandonment.

    Science.gov (United States)

    Freschet, Grégoire T; Ostlund, Lars; Kichenin, Emilie; Wardle, David A

    2014-04-01

    Human activities that involve land-use change often cause major transformations to community and ecosystem properties both aboveground and belowground, and when land use is abandoned, these modifications can persist for extended periods. However, the mechanisms responsible for rapid recovery vs. long-term maintenance of ecosystem changes following abandonment remain poorly understood. Here, we examined the long-term ecological effects of two remote former settlements, regularly visited for -300 years by reindeer-herding Sami and abandoned -100 years ago, within an old-growth boreal forest that is considered one of the most pristine regions in northern Scandinavia. These human legacies were assessed through measurements of abiotic and biotic soil properties and vegetation characteristics at the settlement sites and at varying distances from them. Low-intensity land use by Sami is characterized by the transfer of organic matter towards the settlements by humans and reindeer herds, compaction of soil through trampling, disappearance of understory vegetation, and selective cutting of pine trees for fuel and construction. As a consequence, we found a shift towards early successional plant species and a threefold increase in soil microbial activity and nutrient availability close to the settlements relative to away from them. These changes in soil fertility and vegetation contributed to 83% greater total vegetation productivity, 35% greater plant biomass, and 23% and 16% greater concentrations of foliar N and P nearer the settlements, leading to a greater quantity and quality of litter inputs. Because decomposer activity was also 40% greater towards the settlements, soil organic matter cycling and nutrient availability were further increased, leading to likely positive feedbacks between the aboveground and belowground components resulting from historic land use. Although not all of the activities typical of Sami have left visible residual traces on the ecosystem after

  3. Deadwood biomass: an underestimated carbon stock in degraded tropical forests?

    Science.gov (United States)

    Pfeifer, Marion; Lefebvre, Veronique; Turner, Edgar; Cusack, Jeremy; Khoo, MinSheng; Chey, Vun K.; Peni, Maria; Ewers, Robert M.

    2015-04-01

    Despite a large increase in the area of selectively logged tropical forest worldwide, the carbon stored in deadwood across a tropical forest degradation gradient at the landscape scale remains poorly documented. Many carbon stock studies have either focused exclusively on live standing biomass or have been carried out in primary forests that are unaffected by logging, despite the fact that coarse woody debris (deadwood with ≥10 cm diameter) can contain significant portions of a forest’s carbon stock. We used a field-based assessment to quantify how the relative contribution of deadwood to total above-ground carbon stock changes across a disturbance gradient, from unlogged old-growth forest to severely degraded twice-logged forest, to oil palm plantation. We measured in 193 vegetation plots (25 × 25 m), equating to a survey area of >12 ha of tropical humid forest located within the Stability of Altered Forest Ecosystems Project area, in Sabah, Malaysia. Our results indicate that significant amounts of carbon are stored in deadwood across forest stands. Live tree carbon storage decreased exponentially with increasing forest degradation 7-10 years after logging while deadwood accounted for >50% of above-ground carbon stocks in salvage-logged forest stands, more than twice the proportion commonly assumed in the literature. This carbon will be released as decomposition proceeds. Given the high rates of deforestation and degradation presently occurring in Southeast Asia, our findings have important implications for the calculation of current carbon stocks and sources as a result of human-modification of tropical forests. Assuming similar patterns are prevalent throughout the tropics, our data may indicate a significant global challenge to calculating global carbon fluxes, as selectively-logged forests now represent more than one third of all standing tropical humid forests worldwide.

  4. Influences of finite gain bandwidth on pulse propagation in parabolic fiber amplifiers with distributed gain profiles

    International Nuclear Information System (INIS)

    Zhao Jia-Sheng; Li Pan; Chen Xiao-Dong; Feng Su-Juan; Mao Qing-He

    2012-01-01

    The evolutions of the pulses propagating in decreasing and increasing gain distributed fiber amplifiers with finite gain bandwidths are investigated by simulations with the nonlinear Schrödinger equation. The results show that the parabolic pulse propagations in both the decreasing and the increasing gain amplifiers are restricted by the finite gain bandwidth. For a given input pulse, by choosing a small initial gain coefficient and gain variation rate, the whole gain for the pulse amplification limited by the gain bandwidth may be higher, which is helpful for the enhancement of the output linearly chirped pulse energy. Compared to the decreasing gain distributed fiber amplifier, the increasing gain distributed amplifier may be more conducive to suppress the pulse spectral broadening and increase the critical amplifier length for achieving a larger output linearly chirped pulse energy

  5. Energy Gaining Windows for Residental Buildings

    DEFF Research Database (Denmark)

    Kragh, Jesper; Laustsen, Jacob Birck; Svendsen, Svend

    2008-01-01

    This paper presents some of the research done during the last 8 years at the Technical University of Denmark developing improved low-energy window solutions. The focus has been on maximizing the net energy gain of windows for residential buildings. The net energy gain of windows is the solar gain...... minus the heat loss integrated over the heating season. It is assumed that in northern cold climates all of the solar gain during the heating season can be utilized for space heating. Problems with overheating in the summer period must be solved with overhang or moveable solar shading devices. Two...... and longer durability of the window. The glazing in these fiber reinforced polyester windows is both unsealed and sealed triple glazing units. To increase the net energy gain slim frame profiles have been developed to increase the glazing area and thereby the solar gain. The challenge when developing slim...

  6. [Effects of different disturbance modes on the morphological characteristics and aboveground biomass of Alhagi sparsifolia in oasis-desert ecotone].

    Science.gov (United States)

    Li, Hai-Feng; Zeng, Fan-Jiang; Gui, Dong-Wei; An, Gui-Xiang; Liu, Zhen; Zhang, Li-Gang; Liu, Bo

    2012-01-01

    Taking Cele oasis at the southern fringe of Taklimakan Desert as a case, this paper studied the effects of different disturbances (burning in spring, cutting in spring, and cutting in fall) on the morphological characteristics and aboveground biomass of natural vegetation Alhagi sparsifolia in the ecotone of oasis-desert. Burning in spring decreased the A. sparsifolia plant height, crown width, and biomass significantly, being harmful to the regeneration and growth of the vegetation. Cutting in spring decreased the A. sparsifolia plant height, crown width, and biomass but increased the leaf biomass, thorn length, and thorn diameter, whereas cutting in fall decreased the plant height and crown width but increased the ramification amount and biomass of A. sparsifolia. Moderate cutting in fall could benefit the protection of A. sparsifolia at the southern fringe of Taklimakan Desert.

  7. Ecosystem Carbon Stocks of Intertidal Wetlands in Singapore

    Science.gov (United States)

    Phang, V. X. H.; Friess, D.; Chou, L. M.

    2014-12-01

    Mangrove forests and seagrass meadows provide numerous ecosystem services, with huge recent interest in their carbon sequestration and storage value. Mangrove forests and seagrass meadows as well as mudflats and sandbars form a continuum of intertidal wetlands, but studies that consider these spatially-linked habitats as a whole are limited. This paper presents the results of a field-based and remote sensing carbon stock assessment, including the first study of the ecosystem carbon stocks of these adjacent habitats in the tropics. Aboveground, belowground and soil organic carbon pools were quantified at Chek Jawa, an intertidal wetland in Singapore. Total ecosystem carbon stocks averaged 499 Mg C ha-1 in the mangrove forest and 140 Mg C ha-1 in the seagrass meadow. Soil organic carbon dominated the total storage in both habitats. In the adjacent mudflats and sandbars, soil organic carbon averaged 143 and 124 Mg C ha-1 respectively. High amount of carbon stored in soil demonstrate the role of intertidal wetlands in sequestering large amount of carbon in sediments accumulated over millennia. High-resolution remote sensing imagery was used to create spatial models that upscaled field-based carbon measurements to the national scale. Field-based data and spatial modeling of ecosystem carbon stocks to the entire island through remote sensing provides a large-scale and holistic carbon stock value, important for the understanding and management of these threatened intertidal ecosystems.

  8. Predictive modeling of hazardous waste landfill total above-ground biomass using passive optical and LIDAR remotely sensed data

    Science.gov (United States)

    Hadley, Brian Christopher

    This dissertation assessed remotely sensed data and geospatial modeling technique(s) to map the spatial distribution of total above-ground biomass present on the surface of the Savannah River National Laboratory's (SRNL) Mixed Waste Management Facility (MWMF) hazardous waste landfill. Ordinary least squares (OLS) regression, regression kriging, and tree-structured regression were employed to model the empirical relationship between in-situ measured Bahia (Paspalum notatum Flugge) and Centipede [Eremochloa ophiuroides (Munro) Hack.] grass biomass against an assortment of explanatory variables extracted from fine spatial resolution passive optical and LIDAR remotely sensed data. Explanatory variables included: (1) discrete channels of visible, near-infrared (NIR), and short-wave infrared (SWIR) reflectance, (2) spectral vegetation indices (SVI), (3) spectral mixture analysis (SMA) modeled fractions, (4) narrow-band derivative-based vegetation indices, and (5) LIDAR derived topographic variables (i.e. elevation, slope, and aspect). Results showed that a linear combination of the first- (1DZ_DGVI), second- (2DZ_DGVI), and third-derivative of green vegetation indices (3DZ_DGVI) calculated from hyperspectral data recorded over the 400--960 nm wavelengths of the electromagnetic spectrum explained the largest percentage of statistical variation (R2 = 0.5184) in the total above-ground biomass measurements. In general, the topographic variables did not correlate well with the MWMF biomass data, accounting for less than five percent of the statistical variation. It was concluded that tree-structured regression represented the optimum geospatial modeling technique due to a combination of model performance and efficiency/flexibility factors.

  9. [Aboveground biomass and nutrient distribution patterns of larch plantation in a montane region of eastern Liaoning Province, China].

    Science.gov (United States)

    Yan, Tao; Zhu, Jiao-Jun; Yang, Kai; Yu, Li-Zhong

    2014-10-01

    Larch is the main timber species of forest plantations in North China. Imbalance in nutrient cycling in soil emerged due to single species composition and mono system structure of plantation. Thus it is necessary to grasp its biomass and nutrients allocation for scientific management and nutrient cycling studies of larch plantation. We measured aboveground biomass (stem, branch, bark and leaf) and nutrient concentrations (C, N, P, K, Ca, Mg, Fe, Mn, Cu and Zn), and analyzed the patterns of accumulation and distribution of 19-year-old larch plantation with diameter at breast height of 12. 8 cm, tree height of 15. 3 m, and density of 2308 trees · hm(-2), in a montane region of eastern Liaoning Province, China. The results showed that aboveground biomass values were 70.26 kg and 162.16 t · hm(-2) for the individual tree of larch and the stand, respectively. There was a significant difference between biomass of the organs, and decreased in the order of stem > branch > bark > leaf. Nutrient accumulation was 749.94 g and 1730.86 kg · hm(-2) for the individual tree of larch and the stand, respectively. Nutrient accumulation of stem was significantly higher than that of branch, bark and leaf, whether it was macro-nutrient or micro-nutrient. Averagely, 749.94 g nutrient elements would be removed from the system when a 19-year-old larch tree was harvested. If only the stem part was removed from the system, the removal of nutrient elements could be reduced by 40.7%.

  10. A Comparison of Two Above-Ground Biomass Estimation Techniques Integrating Satellite-Based Remotely Sensed Data and Ground Data for Tropical and Semiarid Forests in Puerto Rico

    Science.gov (United States)

    Two above-ground forest biomass estimation techniques were evaluated for the United States Territory of Puerto Rico using predictor variables acquired from satellite based remotely sensed data and ground data from the U.S. Department of Agriculture Forest Inventory Analysis (FIA)...

  11. Evaluation of drought and UV radiation impacts on above-ground biomass of mountain grassland by spectral reflectance and thermal imaging techniques

    Czech Academy of Sciences Publication Activity Database

    Novotná, Kateřina; Klem, Karel; Holub, Petr; Rapantová, Barbora; Urban, Otmar

    2016-01-01

    Roč. 9, 1-2 (2016), s. 21-30 ISSN 1803-2451 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:67179843 Keywords : above-ground biomass * drought stress * grassland * UV radiation * precipitation * spectral reflectance * thermal imaging Subject RIV: EH - Ecology, Behaviour

  12. Crop resistance traits modify the effects of an aboveground herbivore, brown planthopper, on soil microbial biomass and nematode community via changes to plant performance.

    NARCIS (Netherlands)

    Huang, J.; Liu, M.; Chen, F.; Griffiths, B.S.; Chen, X.; Johnson, S.N.; Hu, F.

    2012-01-01

    Plant-mediated effects of aboveground herbivory on the belowground ecosystem are well documented, but less attention has been paid to agro-ecosystems and in particular how crop cultivars with different traits (i.e. resistance to pests) shape such interactions. A fully factorial experiment was

  13. Luxury consumption of soil nutrients: a possible competitive strategy in above-ground and below-ground biomass allocation and root morphology for slow-growing arctic vegetation?

    NARCIS (Netherlands)

    Wijk, van M.T.; Williams, M.; Gough, L.; Hobbie, S.E.; Shaver, G.R.

    2003-01-01

    1 A field-experiment was used to determine how plant species might retain dominance in an arctic ecosystem receiving added nutrients. We both measured and modelled the above-ground and below-ground biomass allocation and root morphology of non-acidic tussock tundra near Toolik Lake, Alaska, after 4

  14. Effects of water table position and plant functional group on plant community, aboveground production, and peat properties in a peatland mesocosm experiment (PEATcosm)

    Science.gov (United States)

    Lynette R. Potvin; Evan S. Kane; Rodney A. Chimner; Randall K. Kolka; Erik A. Lilleskov

    2015-01-01

    Aims Our objective was to assess the impacts of water table position and plant functional type on peat structure, plant community composition and aboveground plant production. Methods We initiated a full factorial experiment with 2 water table (WT) treatments (high and low) and 3 plant functional groups (PFG: sedge, Ericaceae,...

  15. Estimation of crown biomass of Pinus pinaster stands and shrubland above-ground biomass using forest inventory data, remotely sensed imagery and spatial prediction models

    Science.gov (United States)

    H. Viana; J. Aranha; D. Lopes; Warren B. Cohen

    2012-01-01

    Spatially crown biomass of Pinus pinaster stands and shrubland above-ground biomass (AGB) estimation was carried-out in a region located in Centre-North Portugal, by means of different approaches including forest inventory data, remotely sensed imagery and spatial prediction models. Two cover types (pine stands and shrubland) were inventoried and...

  16. Evaluating Site-Specific and Generic Spatial Models of Aboveground Forest Biomass Based on Landsat Time-Series and LiDAR Strip Samples in the Eastern USA

    Science.gov (United States)

    Ram Deo; Matthew Russell; Grant Domke; Hans-Erik Andersen; Warren Cohen; Christopher Woodall

    2017-01-01

    Large-area assessment of aboveground tree biomass (AGB) to inform regional or national forest monitoring programs can be efficiently carried out by combining remotely sensed data and field sample measurements through a generic statistical model, in contrast to site-specific models. We integrated forest inventory plot data with spatial predictors from Landsat time-...

  17. Influence of grazing on soil seed banks determines the restoration potential of aboveground vegetation in a semi-arid savanna in Ethiopia

    NARCIS (Netherlands)

    Tessema, Z.K.; Boer, de W.F.; Baars, R.M.T.; Prins, H.H.T.

    2012-01-01

    Species composition, number of emerging seedlings, species diversity and functional group of the soil seed banks, and the influence of grazing on the similarity between the soil seed banks and aboveground vegetation, were studied in 2008 and 2009 in a semi-arid savanna of Ethiopia. We tested whether

  18. Refuse dumps from leaf-cutting ant nests reduce the intensity of above-ground competition among neighboring plants in a Patagonian steppe

    Science.gov (United States)

    Farji-Brener, Alejandro G.; Lescano, María Natalia

    2017-11-01

    In arid environments, the high availability of sunlight due to the scarcity of trees suggests that plant competition take place mainly belowground for water and nutrients. However, the occurrence of soil disturbances that increase nutrient availability and thereby promote plant growth may enhance shoot competition between neighboring plants. We conducted a greenhouse experiment to evaluate the influence of the enriched soil patches generated by the leaf-cutting ant, Acromyrmex lobicornis, on the performance of the alien forb Carduus thoermeri (Asteraceae) under different intraspecific competition scenarios. Our results showed that substrate type and competition scenario affected mainly aboveground plant growth. As expected, plants growing without neighbors and in nutrient-rich ant refuse dumps showed more aboveground biomass than plants growing with neighbors and in nutrient-poor steppe soils. However, aboveground competition was more intense in nutrient-poor substrates: plants under shoot and full competition growing in the nutrient-rich ant refuse dumps showed higher biomass than those growing on steppe soils. Belowground biomass was similar among focal plants growing under different substrate type. Our results support the traditional view that increments in resource availability reduce competition intensity. Moreover, the fact that seedlings in this sunny habitat mainly compete aboveground illustrates how limiting factors may be scale-dependent and change in importance as plants grow.

  19. Measurement of Antenna Bore-Sight Gain

    Science.gov (United States)

    Fortinberry, Jarrod; Shumpert, Thomas H.

    2016-01-01

    The absolute or free-field gain of a simple antenna can be approximated using standard antenna theory formulae or for a more accurate prediction, numerical methods may be employed to solve for antenna parameters including gain. Both of these methods will result in relatively reasonable estimates but in practice antenna gain is usually verified and documented via measurements and calibration. In this paper, a relatively simple and low-cost, yet effective means of determining the bore-sight free-field gain of a VHF/UHF antenna is proposed by using the Brewster angle relationship.

  20. Terrestrial Carbon Fluxes from Deforestation in the Brazilian Amazon and Cerrado Regions Predicted from MODIS Satellite Data and Ecosystem Modeling

    Science.gov (United States)

    Klooster, S.; Potter, C.; Genovese, V.

    2008-12-01

    The NASA-CASA (Carnegie Ames Stanford Approach) simulation model based on satellite observations of monthly vegetation cover from the Moderate Resolution Imaging Spectroradiometer (MODIS) was used to estimate tropical forest and savanna (Cerrado) carbon pools for the Brazilian Amazon region over the period 2000-2004. Adjustments for mean age of forest stands were carried out across the region, resulting in a new mapping of aboveground biomass pools based on MODIS satellite data. Yearly maps of newly deforested lands from the Brazilian PRODES (Programa de calculo do desflorestamento da Amazonia ) project were combined with these NASA-CASA biomass predictions to generate seasonal budgets of potential carbon and nitrogen trace gas losses from biomass burning events. Simulations of plant residue and soil carbon decomposition were conducted in the NASA-CASA model during and following deforestation events to track the fate of aboveground biomass pools that were cut and burned each year across the region.

  1. Data for developing allometric models and evaluating carbon stocks of the Zambezi Teak Forests in Zambia.

    Science.gov (United States)

    Ngoma, Justine; Moors, Eddy; Kruijt, Bart; Speer, James H; Vinya, Royd; Chidumayo, Emmanuel N; Leemans, Rik

    2018-04-01

    This paper presents data on carbon stocks of tropical tree species along a rainfall gradient. The data was generated from the Sesheke, Namwala, and Kabompo sites in Zambia. Though above-ground data was generated for all these three sites, we uprooted trees to determine below-ground biomass from the Sesheke site only. The vegetation was assessed in all three sites. The data includes tree diameter at breast height (DBH), total tree height, wood density, wood dry weight and root dry weight for large (≥ 5 cm DBH) and small (importance-value indices of various species for large and small trees are also determined. Below and above-ground carbon stocks of the surveyed tree species are presented per site. This data were used by Ngoma et al. (2018) [1] to develop above and below-ground biomass models and the reader is referred to this study for additional information, interpretation, and reflection on applying this data.

  2. Idaho forest carbon projections from 2017 to 2117 under forest disturbance and climate change scenarios

    Science.gov (United States)

    Hudak, A. T.; Crookston, N.; Kennedy, R. E.; Domke, G. M.; Fekety, P.; Falkowski, M. J.

    2017-12-01

    Commercial off-the-shelf lidar collections associated with tree measures in field plots allow aboveground biomass (AGB) estimation with high confidence. Predictive models developed from such datasets are used operationally to map AGB across lidar project areas. We use a random selection of these pixel-level AGB predictions as training for predicting AGB annually across Idaho and western Montana, primarily from Landsat time series imagery processed through LandTrendr. At both the landscape and regional scales, Random Forests is used for predictive AGB modeling. To project future carbon dynamics, we use Climate-FVS (Forest Vegetation Simulator), the tree growth engine used by foresters to inform forest planning decisions, under either constant or changing climate scenarios. Disturbance data compiled from LandTrendr (Kennedy et al. 2010) using TimeSync (Cohen et al. 2010) in forested lands of Idaho (n=509) and western Montana (n=288) are used to generate probabilities of disturbance (harvest, fire, or insect) by land ownership class (public, private) as well as the magnitude of disturbance. Our verification approach is to aggregate the regional, annual AGB predictions at the county level and compare them to annual county-level AGB summarized independently from systematic, field-based, annual inventories conducted by the US Forest Inventory and Analysis (FIA) Program nationally. This analysis shows that when federal lands are disturbed the magnitude is generally high and when other lands are disturbed the magnitudes are more moderate. The probability of disturbance in corporate lands is higher than in other lands but the magnitudes are generally lower. This is consistent with the much higher prevalence of fire and insects occurring on federal lands, and greater harvest activity on private lands. We found large forest carbon losses in drier southern Idaho, only partially offset by carbon gains in wetter northern Idaho, due to anticipated climate change. Public and

  3. Ecosystem warming does not affect photosynthesis or aboveground autotrophic respiration for boreal black spruce

    Energy Technology Data Exchange (ETDEWEB)

    Bronson, D.R. [Wyoming Univ., Laramie, WY (United States). Dept. of Renewable Resources; Gower, S.T. [Wisconsin Univ., Madison, WI (United States). Dept. of Forest Ecology and Management

    2010-04-15

    Substantial increases in climatic temperatures may cause boreal forests to become a carbon source. An improved understanding of the effect of climatic warming on photosynthesis and autotrophic respiration is needed in order to determine the impact of temperature increases on net carbon balances. This study measured the light-saturated photosynthesis foliage respiration and stem respiration of black spruce in heated and control plots during a 3-year period at a site located in Thompson, Manitoba. Greenhouses and soil-heating cables were used to maintain air and soil temperatures at 5 degrees C above ambient air and soil temperatures. Studies were conducted to determine the influence of soil and air warming; soil-only warming; and greenhouses maintained at ambient temperatures. The study showed that treatment differences for photosynthesis, foliage respiration, and stem respiration were not significant over the 3-year period. Results suggested that black spruce may not have significant changes in photosynthesis or respiration rates in warmer climates. 38 refs., 3 tabs., 4 figs.

  4. Estimation of forest aboveground biomass and uncertainties by integration of field measurements, airborne LiDAR, and SAR and optical satellite data in Mexico.

    Science.gov (United States)

    Urbazaev, Mikhail; Thiel, Christian; Cremer, Felix; Dubayah, Ralph; Migliavacca, Mirco; Reichstein, Markus; Schmullius, Christiane

    2018-02-21

    Information on the spatial distribution of aboveground biomass (AGB) over large areas is needed for understanding and managing processes involved in the carbon cycle and supporting international policies for climate change mitigation and adaption. Furthermore, these products provide important baseline data for the development of sustainable management strategies to local stakeholders. The use of remote sensing data can provide spatially explicit information of AGB from local to global scales. In this study, we mapped national Mexican forest AGB using satellite remote sensing data and a machine learning approach. We modelled AGB using two scenarios: (1) extensive national forest inventory (NFI), and (2) airborne Light Detection and Ranging (LiDAR) as reference data. Finally, we propagated uncertainties from field measurements to LiDAR-derived AGB and to the national wall-to-wall forest AGB map. The estimated AGB maps (NFI- and LiDAR-calibrated) showed similar goodness-of-fit statistics (R 2 , Root Mean Square Error (RMSE)) at three different scales compared to the independent validation data set. We observed different spatial patterns of AGB in tropical dense forests, where no or limited number of NFI data were available, with higher AGB values in the LiDAR-calibrated map. We estimated much higher uncertainties in the AGB maps based on two-stage up-scaling method (i.e., from field measurements to LiDAR and from LiDAR-based estimates to satellite imagery) compared to the traditional field to satellite up-scaling. By removing LiDAR-based AGB pixels with high uncertainties, it was possible to estimate national forest AGB with similar uncertainties as calibrated with NFI data only. Since LiDAR data can be acquired much faster and for much larger areas compared to field inventory data, LiDAR is attractive for repetitive large scale AGB mapping. In this study, we showed that two-stage up-scaling methods for AGB estimation over large areas need to be analyzed and validated

  5. Determining Optimal New Generation Satellite Derived Metrics for Accurate C3 and C4 Grass Species Aboveground Biomass Estimation in South Africa

    Directory of Open Access Journals (Sweden)

    Cletah Shoko

    2018-04-01

    Full Text Available While satellite data has proved to be a powerful tool in estimating C3 and C4 grass species Aboveground Biomass (AGB, finding an appropriate sensor that can accurately characterize the inherent variations remains a challenge. This limitation has hampered the remote sensing community from continuously and precisely monitoring their productivity. This study assessed the potential of a Sentinel 2 MultiSpectral Instrument, Landsat 8 Operational Land Imager, and WorldView-2 sensors, with improved earth imaging characteristics, in estimating C3 and C4 grasses AGB in the Cathedral Peak, South Africa. Overall, all sensors have shown considerable potential in estimating species AGB; with the use of different combinations of the derived spectral bands and vegetation indices producing better accuracies. However, WorldView-2 derived variables yielded better predictive accuracies (R2 ranging between 0.71 and 0.83; RMSEs between 6.92% and 9.84%, followed by Sentinel 2, with R2 between 0.60 and 0.79; and an RMSE 7.66% and 14.66%. Comparatively, Landsat 8 yielded weaker estimates, with R2 ranging between 0.52 and 0.71 and high RMSEs ranging between 9.07% and 19.88%. In addition, spectral bands located within the red edge (e.g., centered at 0.705 and 0.745 µm for Sentinel 2, SWIR, and NIR, as well as the derived indices, were found to be very important in predicting C3 and C4 AGB from the three sensors. The competence of these bands, especially of the free-available Landsat 8 and Sentinel 2 dataset, was also confirmed from the fusion of the datasets. Most importantly, the three sensors managed to capture and show the spatial variations in AGB for the target C3 and C4 grassland area. This work therefore provides a new horizon and a fundamental step towards C3 and C4 grass productivity monitoring for carbon accounting, forage mapping, and modelling the influence of environmental changes on their productivity.

  6. Weight gain following treatment of hyperthyroidism.

    Science.gov (United States)

    Dale, J; Daykin, J; Holder, R; Sheppard, M C; Franklyn, J A

    2001-08-01

    Patients frequently express concern that treating hyperthyroidism will lead to excessive weight gain. This study aimed to determine the extent of, and risk factors for, weight gain in an unselected group of hyperthyroid patients. We investigated 162 consecutive hyperthyroid patients followed for at least 6 months. Height, weight, clinical features, biochemistry and management were recorded at each clinic visit. Documented weight gain was 5.42 +/- 0.46 kg (mean +/- SE) and increase in BMI was 8.49 +/- 0.71%, over a mean 24.2 +/- 1.6 months. Pre-existing obesity, Graves' disease causing hyperthyroidism, weight loss before presentation and length of follow-up each independently predicted weight gain. Patients treated with thionamides or radioiodine gained a similar amount of weight (thionamides, n = 87, 5.16 +/- 0.63 kg vs. radioiodine, n = 62, 4.75 +/- 0.57 kg, P = 0.645), but patients who underwent thyroidectomy (n = 13) gained more weight (10.27 +/- 2.56 kg vs. others, P = 0.007). Development of hypothyroidism (even transiently) was associated with weight gain (never hypothyroid, n = 102, 4.57 +/- 0.52 kg, transiently hypothyroid, n = 29, 5.37 +/- 0.85 kg, on T4, n = 31, 8.06 +/- 1.42 kg, P = 0.014). This difference remained after correcting for length of follow-up. In the whole cohort, weight increased by 3.95 +/- 0.40 kg at 1 year (n = 144) to 9.91 +/- 1.62 kg after 4 years (n = 27) (P = 0.008), representing a mean weight gain of 3.66 +/- 0.44 kg/year. We have demonstrated marked weight gain after treatment of hyperthyroidism. Pre-existing obesity, a diagnosis of Graves' disease and prior weight loss independently predicted weight gain and weight continued to rise with time. Patients who became hypothyroid, despite T4 replacement, gained most weight.

  7. Above-ground biomass production and allometric relations of Eucalyptus globulus Labill. coppice plantations along a chronosequence in the central highlands of Ethiopia

    International Nuclear Information System (INIS)

    Zewdie, Mulugeta; Olsson, Mats; Verwijst, Theo

    2009-01-01

    Eucalyptus plantations are extensively managed for wood production in the central highlands of Ethiopia. Nevertheless, little is known about their biomass (dry matter) production, partitioning and dynamics over time. Data from 10 different Eucalyptus globulus stands, with a plantation age ranging from 11 to 60 years and with a coppice-shoot age ranging from 1 to 9 years were collected and analyzed. Above-ground tree biomass of 7-10 sampled trees per stand was determined destructively. Dry weights of tree components (W c ; leaves, twigs, branches, stembark, and stemwood) and total above-ground biomass (W a ) were estimated as a function of diameter above stump (D), tree height (H) and a combination of these. The best fits were obtained, using combinations of D and H. When only one explanatory variable was used, D performed better than H. Total above-ground biomass was linearly related to coppice-shoot age. In contrast a negative relation was observed between the above-ground biomass production and total plantation age (number of cutting cycles). Total above-ground biomass increased from 11 t ha -1 at a stand age of 1 year to 153 t ha -1 at 9 years. The highest dry weight was allocated to stemwood and decreased in the following order: stemwood > leaves > stembark > twigs > branches. The equations developed in this study to estimate biomass components can be applied to other Eucalyptus plantations under the assumption that the populations being studied are similar with regard to density and tree size to those for which the relationships were developed

  8. Above-ground biomass production and allometric relations of Eucalyptus globulus Labill. coppice plantations along a chronosequence in the central highlands of Ethiopia

    Energy Technology Data Exchange (ETDEWEB)

    Zewdie, Mulugeta; Olsson, Mats; Verwijst, Theo [Swedish University of Agricultural Sciences, Department of Crop Production Ecology, P.O. Box 7043, 75007 Uppsala (Sweden)

    2009-03-15

    Eucalyptus plantations are extensively managed for wood production in the central highlands of Ethiopia. Nevertheless, little is known about their biomass (dry matter) production, partitioning and dynamics over time. Data from 10 different Eucalyptus globulus stands, with a plantation age ranging from 11 to 60 years and with a coppice-shoot age ranging from 1 to 9 years were collected and analyzed. Above-ground tree biomass of 7-10 sampled trees per stand was determined destructively. Dry weights of tree components (W{sub c}; leaves, twigs, branches, stembark, and stemwood) and total above-ground biomass (W{sub a}) were estimated as a function of diameter above stump (D), tree height (H) and a combination of these. The best fits were obtained, using combinations of D and H. When only one explanatory variable was used, D performed better than H. Total above-ground biomass was linearly related to coppice-shoot age. In contrast a negative relation was observed between the above-ground biomass production and total plantation age (number of cutting cycles). Total above-ground biomass increased from 11 t ha{sup -1} at a stand age of 1 year to 153 t ha{sup -1} at 9 years. The highest dry weight was allocated to stemwood and decreased in the following order: stemwood > leaves > stembark > twigs > branches. The equations developed in this study to estimate biomass components can be applied to other Eucalyptus plantations under the assumption that the populations being studied are similar with regard to density and tree size to those for which the relationships were developed. (author)

  9. Gain measurements at 182 /angstrom/ in C VI generated by a Nd/glass laser

    International Nuclear Information System (INIS)

    Kim, D.; Skinner, C.H.; Umesh, G.; Suckewer, S.

    1988-11-01

    We present recent gain measurements in C VI at 182 A for a soft x-ray amplifier produced by a line-focused glass laser(1.053 μm) on a solid carbon target. The maximum gain measured was 8 +- 1 cm/sup /minus/1/ in the recombining plasma column with additional radiation cooling by iron impurities. 10 refs., 3 figs

  10. Interactions between carbon sequestration and shade tree diversity in a smallholder coffee cooperative in El Salvador.

    Science.gov (United States)

    Richards, Meryl Breton; Méndez, V Ernesto

    2014-04-01

    Agroforestry systems have substantial potential to conserve native biodiversity and provide ecosystem services. In particular, agroforestry systems have the potential to conserve native tree diversity and sequester carbon for climate change mitigation. However, little research has been conducted on the temporal stability of species diversity and aboveground carbon stocks in these systems or the relation between species diversity and aboveground carbon sequestration. We measured changes in shade-tree diversity and shade-tree carbon stocks in 14 plots of a 35-ha coffee cooperative over 9 years and analyzed relations between species diversity and carbon sequestration. Carbon sequestration was positively correlated with initial species richness of shade trees. Species diversity of shade trees did not change significantly over the study period, but carbon stocks increased due to tree growth. Our results show a potential for carbon sequestration and long-term biodiversity conservation in smallholder coffee agroforestry systems and illustrate the opportunity for synergies between biodiversity conservation and climate change mitigation. © 2013 Society for Conservation Biology.

  11. Norway spruce fine root dynamics and carbon input into soil in relation to environmental factors

    OpenAIRE

    Leppälammi-Kujansuu, Jaana

    2014-01-01

    Knowledge of the quantity of belowground litter carbon (C) input is scarce but highly valued in C budget calculations. Specifically, the turnover rate of fine roots is considered to be one of the most important parameters in the estimation of changes in soil C stock. In this thesis Norway spruce (Picea abies L. (Karst.)) fine root lifespan and litter production and their responses to nutrient availability and temperature were examined. Aboveground foliage and understory litter C inputs were a...

  12. Maximum gain of Yagi-Uda arrays

    DEFF Research Database (Denmark)

    Bojsen, J.H.; Schjær-Jacobsen, Hans; Nilsson, E.

    1971-01-01

    Numerical optimisation techniques have been used to find the maximum gain of some specific parasitic arrays. The gain of an array of infinitely thin, equispaced dipoles loaded with arbitrary reactances has been optimised. The results show that standard travelling-wave design methods are not optimum....... Yagi–Uda arrays with equal and unequal spacing have also been optimised with experimental verification....

  13. Gain Shift Corrections at Chi-Nu

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Tristan Brooks [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of Massachusetts, Lowell, MA (United States). Dept. of Physics and Applied Physics; Devlin, Matthew James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-30

    Ambient conditions have the potential to cause changes in liquid scintillator detector gain that vary with time and temperature. These gain shifts can lead to poor resolution in both energy as well as pulse shape discrimination. In order to correct for these shifts in the Chi-Nu high energy array, a laser system has been developed for calibration of the pulse height signals.

  14. Nonunity gain minimal-disturbance measurement

    DEFF Research Database (Denmark)

    Sabuncu, Metin; Mišta, L.; Fiurášek, J.

    2007-01-01

    We propose and experimentally demonstrate an optimal nonunity gain Gaussian scheme for partial measurement of an unknown coherent state that causes minimal disturbance of the state. The information gain and the state disturbance are quantified by the noise added to the measurement outcomes...

  15. Efficiency gains, bounds, and risk in finance

    NARCIS (Netherlands)

    Sarisoy, Cisil

    2015-01-01

    This thesis consists of three chapters. The first chapter analyzes efficiency gains in the estimation of expected returns based on asset pricing models and examines the economic implications of such gains in portfolio allocation exercises. The second chapter provides nonparametric efficiency bounds

  16. Evaluating realized genetic gains from tree improvement.

    Science.gov (United States)

    J.B. St. Clair

    1993-01-01

    Tree improvement has become an essential part of the management of forest lands for wood production, and predicting yields and realized gains from forests planted with genetically-improved trees will become increasingly important. This paper discusses concepts of tree improvement and genetic gain important to growth and yield modeling, and reviews previous studies of...

  17. Studies of population inversion and gains for xuv laser development in a recombining plasma column

    International Nuclear Information System (INIS)

    Milchberg, H.M.

    1985-01-01

    An experimental study is presented of population inversions and gains in CO 2 laser produced plasmas in a number of different solid and gas targets, with and without the presence of a magnetic field. Population inversions and gains were measured in hydrogenic carbon, CVI, and in the Li-like sequence CIV, OVI, FVII, and NeVIII. The Li-like species were easily produced in gas targets and, in general, 4d-3d population inversions were seen to increase with a combination of higher target pressure and the presence of an external magnetic field. Ratios of the 4d-3d sublevel populations ranged up to approx.10, for OVI. Inversions in CIV and FVII, in cases where solid targets were used, were less sensitive to the presence of the magnetic field. Gains in the CVI 182.17 A (3-2) line were measured using solid carbon targets, and increased in the presence of a magnetic field. The effect of placing aluminum blades near the target, for plasma cooling and faster recombination, was inconclusive. In general, gains determined by measuring an on-axis enhancement of the 182.17 A line were consistent with absolute measurements of CVI excitation-level populations. Gains of 2-4 cm -1 were measured. Axially oriented carbon-fiber targets were irradiated by the CO 2 laser, and it was found that population inversions and gain resulted only when there was no magnetic field present

  18. Gain control mechanisms in spinal motoneurons

    Directory of Open Access Journals (Sweden)

    Michael David Johnson

    2014-07-01

    Full Text Available Motoneurons provide the only conduit for motor commands to reach muscles. For many years, motoneurons were in fact considered to be little more than passive wires. Systematic studies in the past 25 years however have clearly demonstrated that the intrinsic electrical properties of motoneurons are under strong neuromodulatory control via multiple sources. The discovery of potent neuromodulation from the brainstem and its ability to change the gain of motoneurons shows that the passive view of the motor output stage is no longer tenable. A mechanism for gain control at the motor output stage makes good functional sense considering our capability of generating an enormous range of forces, from very delicate (e.g. putting in a contact lens to highly forceful (emergency reactions. Just as sensory systems need gain control to deal with a wide dynamic range of inputs, so to might motor output need gain control to deal with the wide dynamic range of the normal movement repertoire. Two problems emerge from the potential use of the brainstem monoaminergic projection to motoneurons for gain control. First, the projection is highly diffuse anatomically, so that independent control of the gains of different motor pools is not feasible. In fact, the system is so diffuse that gain for all the motor pools in a limb likely increases in concert. Second, if there is a system that increases gain, probably a system to reduce gain is also needed. In this review, we summarize recent studies that show local inhibitory circuits within the spinal cord, especially reciprocal and recurrent inhibition, have the potential to solve both of these problems as well as constitute another source of gain modulation.

  19. Carbon storage in the seagrass meadows of Gazi Bay, Kenya.

    Directory of Open Access Journals (Sweden)

    Michael N Githaiga

    Full Text Available Vegetated marine habitats are globally important carbon sinks, making a significant contribution towards mitigating climate change, and they provide a wide range of other ecosystem services. However, large gaps in knowledge remain, particularly for seagrass meadows in Africa. The present study estimated biomass and sediment organic carbon (Corg stocks of four dominant seagrass species in Gazi Bay, Kenya. It compared sediment Corg between seagrass areas in vegetated and un-vegetated 'controls', using the naturally patchy occurence of seagrass at this site to test the impacts of seagrass growth on sediment Corg. It also explored relationships between the sediment and above-ground Corg, as well as between the total biomass and above-ground parameters. Sediment Corg was significantly different between species, range: 160.7-233.8 Mg C ha-1 (compared to the global range of 115.3 to 829.2 Mg C ha-1. Vegetated areas in all species had significantly higher sediment Corg compared with un-vegetated controls; the presence of seagrass increased Corg by 4-6 times. Biomass carbon differed significantly between species with means ranging between 4.8-7.1 Mg C ha-1 compared to the global range of 2.5-7.3 Mg C ha-1. To our knowledge, these are among the first results on seagrass sediment Corg to be reported from African seagrass beds; and contribute towards our understanding of the role of seagrass in global carbon dynamics.

  20. Developing a Carbon Monitoring System For Pinyon-juniper Forests and Woodlands

    Science.gov (United States)

    Falkowski, M. J.; Hudak, A. T.; Fekety, P.; Filippelli, S.

    2017-12-01

    Pinyon-juniper (PJ) forests and woodlands are the third largest vegetation type in the United States. They cover over 40 million hectares across the western US, representing 40% of the total forest and woodland area in the Intermountain West. Although the density of carbon stored in these ecosystems is relatively low compared to other forest types, the vast area of short stature forests and woodlands (both nationally and globally) make them critical components of regional, national, and global carbon budgets. The overarching goal of this research is to prototype a carbon monitoring, reporting, and verification (MRV) system for characterizing total aboveground biomass stocks and flux across the PJ vegetation gradient in the western United States. We achieve this by combining in situ forest measurements and novel allometric equations with tree measurements derived from high resolution airborne imagery to map aboveground biomass across 500,000 km2 in the Western US. These high-resolution maps of aboveground biomass are then leveraged as training data to predict biomass flux through time from Landsat time-series data. The results from this research highlight the potential in mapping biomass stocks and flux in open forests and woodlands, and could be easily adopted into an MRV framework.

  1. Changes of Organic Carbon Quantity and Quality in Temperate Forest Soils

    Science.gov (United States)

    Kühnel, Anna; Satwika Lestari, Annisa; Schubert, Alfred; Wiesmeier, Martin; Spörlein, Peter; Schilling, Bernd; Kögel-Knabner, Ingrid

    2017-04-01

    Climate change will have profound impacts on organic matter stocks and thus on the functionality of soils. Soil organic carbon (SOC) content in soil is mainly regulated by the fluxes of organic matter which are highly associated with the aboveground and root litter production and their decompositions into CO2 by soil microorganism. The predicted rising temperatures in Bavaria might lead to an increased decomposition and release of soil carbon into the atmosphere, which would deteriorate a number of important soil functions. Here, we present an assessment of SOC stocks in three temperate forest sites over the last 30 years. Soil to a depth of 30 cm was analysed with density fractionation to evaluate SOC stocks and distribution in different pools. Additionally, tree-aboveground organic carbon (OC) stocks were measured to assess their influence on SOC. SOC stocks decreased between 1988 and 2004 and increased between 2004 and 2016. OC changes of litter + O layer and mineral soil differed. Highest changes of SOC occurred in the light fractions, followed by the mineral fractions. Tree-aboveground biomass, stand composition, and changing climate had an influence on SOC stocks. Precipitation change was correlated with the litter + O layer OC stocks. Further studies on the changes of each SOC fraction and the influence of other edaphic factors are needed to better understand the changes in SOC stocks and quality.

  2. Optimal weight gain in triplet pregnancies.

    Science.gov (United States)

    Johnston, Robert C; Erfani, Hadi; Shamshirsaz, Amir A; Spiel, Melissa; Ravangard, Sam F; Shaman, Majid; Allaf, M Baraa; Shamshirsaz, Alireza A; Haeri, Sina

    2017-08-01

    To identify appropriate weight gain in triplet gestations, which may aid in reducing the risk of perinatal morbidity within this high-risk cohort. This retrospective cohort study evaluated all non-anomalous triplet pregnancies between 23 and 40 weeks' gestation resulting in live births at five tertiary-care medical centers between 1991 and 2011. Subjects were divided by pre-pregnancy BMI into underweight, normal-weight, overweight, and obese groups, and then stratified by low (gain (≥1.5 lbs/week). Primary outcomes included spontaneous preterm birth and preeclampsia. We included 116 mothers and 348 corresponding neonates for final analysis. The incidence of preeclampsia and preterm delivery less than 32 weeks' gestation was 37% and 41%, respectively. The incidence of preeclampsia increased with weight gain per week, but was not statistically different from subjects who gained less weight. We found no statistical correlation between weight gain per week and preterm delivery. We found no association between preeclampsia or preterm delivery and increasing weight gain in triplet pregnancies. The association with increased risk for preeclampsia was predominantly due to BMI effect. Based on the current study, recommendations for optimal weight gain in mothers with triplet gestations could not be defined.

  3. Personality type influence the gestational weight gain.

    Science.gov (United States)

    Franik, Grzegorz; Lipka, Nela; Kopyto, Katarzyna; Kopocińska, Joanna; Owczarek, Aleksander; Sikora, Jerzy; Madej, Paweł; Chudek, Jerzy; Olszanecka-Glinianowicz, Magdalena

    2017-08-01

    Pregnancy is frequently followed by the development of obesity. Aside from psychological factors, hormonal changes influence weight gain in pregnant women. We attempted to assess the potential association between personality type and the extent of gestational weight gain. The study group involved 773 women after term delivery (age 26.3 ± 3.9 years, body mass before pregnancy 61.2 ± 11.1 kg). Weight gain during pregnancy was calculated by using self-reported body mass prior to and during the 38th week of pregnancy. Personality type was assessed using the Polish version of the Framingham Type A Behavior Patterns Questionnaire (adapted by Juczynski). Two hundred forty-six (31.8%) study subjects represented type A personalities, 272 (35.2%) type B and 255 (33.0%) an indirect type. Gestational weight gain was related to the behavior patterns questionnaire score and age. In women gain was higher than in women with type B behavior of the same age. In women >30, the gestational weight gain was larger for type B personalities. Type A personality and increased urgency in younger pregnant women increases the risk of developing obesity during pregnancy in women below 30 years old. A higher level of competitiveness demonstrates a risk factor of excessive weight gain during pregnancy regardless of age.

  4. Controlling gain one photon at a time

    Science.gov (United States)

    Schwartz, Gregory W; Rieke, Fred

    2013-01-01

    Adaptation is a salient property of sensory processing. All adaptational or gain control mechanisms face the challenge of obtaining a reliable estimate of the property of the input to be adapted to and obtaining this estimate sufficiently rapidly to be useful. Here, we explore how the primate retina balances the need to change gain rapidly and reliably when photons arrive rarely at individual rod photoreceptors. We find that the weakest backgrounds that decrease the gain of the retinal output signals are similar to those that increase human behavioral threshold, and identify a novel site of gain control in the retinal circuitry. Thus, surprisingly, the gain of retinal signals begins to decrease essentially as soon as background lights are detectable; under these conditions, gain control does not rely on a highly averaged estimate of the photon count, but instead signals from individual photon absorptions trigger changes in gain. DOI: http://dx.doi.org/10.7554/eLife.00467.001 PMID:23682314

  5. Intrinsic gain modulation and adaptive neural coding.

    Directory of Open Access Journals (Sweden)

    Sungho Hong

    2008-07-01

    Full Text Available In many cases, the computation of a neural system can be reduced to a receptive field, or a set of linear filters, and a thresholding function, or gain curve, which determines the firing probability; this is known as a linear/nonlinear model. In some forms of sensory adaptation, these linear filters and gain curve adjust very rapidly to changes in the variance of a randomly varying driving input. An apparently similar but previously unrelated issue is the observation of gain control by background noise in cortical neurons: the slope of the firing rate versus current (f-I curve changes with the variance of background random input. Here, we show a direct correspondence between these two observations by relating variance-dependent changes in the gain of f-I curves to characteristics of the changing empirical linear/nonlinear model obtained by sampling. In the case that the underlying system is fixed, we derive relationships relating the change of the gain with respect to both mean and variance with the receptive fields derived from reverse correlation on a white noise stimulus. Using two conductance-based model neurons that display distinct gain modulation properties through a simple change in parameters, we show that coding properties of both these models quantitatively satisfy the predicted relationships. Our results describe how both variance-dependent gain modulation and adaptive neural computation result from intrinsic nonlinearity.

  6. ABOVEGROUND BIOMASS DISTRIBUTION OF US EASTERN HARDWOOD FORESTS AND THE USE OF LARGE TREES AS AN INDICATOR OF FOREST DEVELOPMENT

    Science.gov (United States)

    Past clearing and harvesting of the deciduous hardwood forests of eastern USA released large amount of carbon dioxide into the atmosphere, but through recovery and regrowth these forests are now accumulating atmospheric carbon (C). This study examined quantities and distribution ...

  7. Point Information Gain and Multidimensional Data Analysis

    Directory of Open Access Journals (Sweden)

    Renata Rychtáriková

    2016-10-01

    Full Text Available We generalize the point information gain (PIG and derived quantities, i.e., point information gain entropy (PIE and point information gain entropy density (PIED, for the case of the Rényi entropy and simulate the behavior of PIG for typical distributions. We also use these methods for the analysis of multidimensional datasets. We demonstrate the main properties of PIE/PIED spectra for the real data with the examples of several images and discuss further possible utilizations in other fields of data processing.

  8. TCAD simulation of Low Gain Avalanche Detectors

    Science.gov (United States)

    Dalal, Ranjeet; Jain, Geetika; Bhardwaj, Ashutosh; Ranjan, Kirti

    2016-11-01

    In the present work, detailed simulation using Technology Computer Aided Design (TCAD) tool, Silvaco for non-irradiated and irradiated LGAD (Low Gain Avalanche Detector) devices has been carried out. The effects of different design parameters and proton irradiation on LGAD operation are discussed in detail. An already published effective two trap bulk damage model is used to simulate the radiation damage without implementing any acceptor removal term. The TCAD simulation for irradiated LGAD devices produce decreasing gain with increasing fluence, similar to the measurement results. The space charge density and electric field distribution are used to illustrate the possible reasons for the degradation of gain of the irradiated LGAD devices.

  9. TCAD simulation of Low Gain Avalanche Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Dalal, Ranjeet; Jain, Geetika; Bhardwaj, Ashutosh, E-mail: ashutosh.bhardwaj@cern.ch; Ranjan, Kirti

    2016-11-11

    In the present work, detailed simulation using Technology Computer Aided Design (TCAD) tool, Silvaco for non-irradiated and irradiated LGAD (Low Gain Avalanche Detector) devices has been carried out. The effects of different design parameters and proton irradiation on LGAD operation are discussed in detail. An already published effective two trap bulk damage model is used to simulate the radiation damage without implementing any acceptor removal term. The TCAD simulation for irradiated LGAD devices produce decreasing gain with increasing fluence, similar to the measurement results. The space charge density and electric field distribution are used to illustrate the possible reasons for the degradation of gain of the irradiated LGAD devices.

  10. TCAD simulation of Low Gain Avalanche Detectors

    International Nuclear Information System (INIS)

    Dalal, Ranjeet; Jain, Geetika; Bhardwaj, Ashutosh; Ranjan, Kirti

    2016-01-01

    In the present work, detailed simulation using Technology Computer Aided Design (TCAD) tool, Silvaco for non-irradiated and irradiated LGAD (Low Gain Avalanche Detector) devices has been carried out. The effects of different design parameters and proton irradiation on LGAD operation are discussed in detail. An already published effective two trap bulk damage model is used to simulate the radiation damage without implementing any acceptor removal term. The TCAD simulation for irradiated LGAD devices produce decreasing gain with increasing fluence, similar to the measurement results. The space charge density and electric field distribution are used to illustrate the possible reasons for the degradation of gain of the irradiated LGAD devices.

  11. Comparing aboveground biomass predictions for an uneven-aged pine-dominated stand using local, regional, and national models

    Science.gov (United States)

    D.C. Bragg; K.M. McElligott

    2013-01-01

    Sequestration by Arkansas forests removes carbon dioxide from the atmosphere, storing this carbon in biomass that fills a number of critical ecological and socioeconomic functions. We need a better understanding of the contribution of forests to the carbon cycle, including the accurate quantification of tree biomass. Models have long been developed to predict...

  12. Active rc filter permits easy trade-off of amplifier gain and sensitivity to gain

    Science.gov (United States)

    Kerwin, W. J.; Shaffer, C. V.

    1968-01-01

    Passive RC network was designed with zeros of transmission in the right half of the complex frequency plane in the feedback loop of a simple negative-gain amplifier. The proper positioning provides any desired trade-off between amplifier gain and sensitivity to amplifier gain.

  13. MOS current gain cells with electronically variable gain and constant bandwidth

    NARCIS (Netherlands)

    Klumperink, Eric A.M.; Seevinck, Evert

    1989-01-01

    Two MOS current gain cells are proposed that provide linear amplification of currents supplied by several linear MOS V-I converters. The gain is electronically variable by a voltage or a current and can be made insensitive to temperature and IC processing. The gain cells have a constant

  14. Detective quantum efficiency gains compared with speed gains for hypersensitized astronomical plates

    International Nuclear Information System (INIS)

    Kaye, A.L.

    1977-01-01

    It is reasonable to assume that gains in detective quantum efficiency (DQE) are far better criteria for assessing the performance of hypersensitizing techniques than gains in speed. It is shown here that gains in speed can be misleading, for some methods of hypersensitization give plates of increased speed but reduced detective quantum efficiency. (author)

  15. Optical properties of nanowire metamaterials with gain

    DEFF Research Database (Denmark)

    Isidio de Lima, Joaquim Junior; Adam, Jost; Rego, Davi

    2016-01-01

    The transmittance, reflectance and absorption of a nanowire metamaterial with optical gain are numerically simulated and investigated. It is assumed that the metamaterial is represented by aligned silver nanowires embedded into a semiconductor matrix, made of either silicon or gallium phosphide....... The gain in the matrix is modeled by adding a negative imaginary part to the dielectric function of the semiconductor. It is found that the optical coefficients of the metamaterial depend on the gain magnitude in a non-trivial way: they can both increase and decrease with gain depending on the lattice...... constant of the metamaterial. This peculiar behavior is explained by the field redistribution between the lossy metal nanowires and the amplifying matrix material. These findings are significant for a proper design of nanowire metamaterials with low optical losses for diverse applications....

  16. Active Microwave Metamaterials Incorporating Ideal Gain Devices

    Directory of Open Access Journals (Sweden)

    Hao Xin

    2010-12-01

    Full Text Available Incorporation of active devices/media such as transistors for microwave and gain media for optics may be very attractive for enabling desired low loss and broadband metamaterials. Such metamaterials can even have gain which may very well lead to new and exciting physical phenomena. We investigate microwave composite right/left-handed transmission lines (CRLH-TL incorporating ideal gain devices such as constant negative resistance. With realistic lumped element values, we have shown that the negative phase constant of this kind of transmission lines is maintained (i.e., left-handedness kept while gain can be obtained (negative attenuation constant of transmission line simultaneously. Possible implementation and challenging issues of the proposed active CRLH-TL are also discussed.

  17. Transient optical gain in germanium quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Chatterjee, Sangam; Lange, Christoph; Koester, Niko S.; Schaefer, Martin; Kira, Mackillo; Koch, Stephan W. [Faculty of Physics and Materials Sciences Center, Philipps-Universitaet Marburg (Germany); Chrastina, Daniel; Isella, Giovanni; Kaenel, Hans von [CNISM, Como (Italy); L-NESS, Dipartimento di Fisica del Politecnico di Milano, Como (Italy); Sigg, Hans [Laboratory for Micro and Nanotecnology, Paul Scherrer Institut, Villigen PSI (Switzerland)

    2010-07-01

    One of today's most-sought goals in semiconductor technology is the monolithic integration of microelectronics and photonics on Si. Optical gain is, in general, not expected for Si and Ge or its alloys due to the indirect nature of the band gap in this material system. Here, we show that Ge/SiGe QWs show transient optical gain and may thus be used as an optically-pumped amplifier at room temperature. Further, the nonequilibrium effects which govern the relaxation dynamics of the optically injected carrier distributions in this material were observed and analyzed using a microscopic many-body theory. Strong non-equilibrium gain was obtained on a sub-100 fs time scale. Long-lived gain arising from {gamma}-point transitions is overcompensated by a process bearing the character of free carrier absorption.

  18. Carbon and nitrogen balances for six shrublands across Europe

    DEFF Research Database (Denmark)

    Beier, Claus; Emmett, Bridget A.; Tietema, Albert

    2009-01-01

    ,546 g C m−2, and the systems ranged from being net sinks (126 g C m−2 a−1) to being net sources (−536 g C m−2 a−1) of carbon with the largest storage and sink of carbon at wet and cold climatic conditions. The soil carbon store dominates the carbon budget at all sites and in particular at the site...... with a cold and wet climate where soil C constitutes 95% of the total carbon in the ecosystem. Respiration of carbon from the soil organic matter pool dominated the carbon loss at all sites while carbon loss from aboveground litter decomposition appeared less important. Total belowground carbon allocation...... that in the future a climate-driven land cover change between grasslands and shrublands in Europe will likely lead to increased ecosystem C where shrublands are promoted and less where grasses are promoted. However, it also emphasizes that if feedbacks on the global carbon cycle are to be predicted it is critically...

  19. Carbon storage and recycling in short-rotation energy crops

    International Nuclear Information System (INIS)

    Ranney, J.W.; Wright, L.L.; Mitchell, C.P.

    1991-01-01

    Short-rotation energy crops can play a significant role in storing carbon compared to the agricultural land uses they would displace. However, the benefits from these plantations in avoiding further use of fossil fuel and in taking pressure off of native forests for energy uses provides longer term carbon benetfits than the plantation carbon sequestration itself. The fast growth and harvest frequency of plantations tends to limit the amount of above and below-ground carbon storage in them. The primary components of plantation carbon sequestering compared to sustained agricultural practices involve above-ground wood, possible increased soil carbon, litter layer formation, and increased root biomass. On the average, short-rotation plantations in total may increase carbon inventories by about 30 to 40 tonnes per hectare over about a 20- to 56-year period when displacing cropland. This is about doubling in storage over cropland and about one-half the storage in human-impacted forests. The sequestration benefit of wood energy crops over cropland would be negated in about 75 to 100 years by the use of fossil fuels to tend the plantations and handle biomass. Plantation interactions with other land uses and total landscape carbon inventory is important in assessing the relative role plantations play in terrestrial and atmospheric carbon dynamics. It is speculated that plantations, when viewed in this context. could trencrate a global leveling of net carbon emissions for approximately 10 to 20 years

  20. Renyi information gain on quantum key

    International Nuclear Information System (INIS)

    Brandt, Howard E

    2007-01-01

    The concept of maximum Renyi information gain from quantum key is important in eavesdropping and security analyses of quantum key distribution. It is particularly useful in the design optimization of eavesdropping probes. The present work reviews the quantitative measure of Renyi information gain, its optimization, and application to the design of eavesdropping probes in which single-photon probe states become optimally entangled with the signal states on their way between the legitimate transmitter and receiver

  1. Enhanced Gain in Photonic Crystal Amplifiers

    DEFF Research Database (Denmark)

    Ek, Sara; Semenova, Elizaveta; Hansen, Per Lunnemann

    2012-01-01

    We experimentally demonstrate enhanced gain in the slow-light regime of quantum well photonic crystal amplifiers. A strong gain enhancement is observed with the increase of the group refractive index, due to light slow-down. The slow light enhancement is shown in a amplified spontaneous emission....... These results are promising for short and efficient semiconductor optical amplifiers. This effect will also benefit other devices, such as mode locked lasers....

  2. The production of phytolith-occluded carbon in China's forests: implications to biogeochemical carbon sequestration.

    Science.gov (United States)

    Song, Zhaoliang; Liu, Hongyan; Li, Beilei; Yang, Xiaomin

    2013-09-01

    The persistent terrestrial carbon sink regulates long-term climate change, but its size, location, and mechanisms remain uncertain. One of the most promising terrestrial biogeochemical carbon sequestration mechanisms is the occlusion of carbon within phytoliths, the silicified features that deposit within plant tissues. Using phytolith content-biogenic silica content transfer function obtained from our investigation, in combination with published silica content and aboveground net primary productivity (ANPP) data of leaf litter and herb layer in China's forests, we estimated the production of phytolith-occluded carbon (PhytOC) in China's forests. The present annual phytolith carbon sink in China's forests is 1.7 ± 0.4 Tg CO2  yr(-1) , 30% of which is contributed by bamboo because the production flux of PhytOC through tree leaf litter for bamboo is 3-80 times higher than that of other forest types. As a result of national and international bamboo afforestation and reforestation, the potential of phytolith carbon sink for China's forests and world's bamboo can reach 6.8 ± 1.5 and 27.0 ± 6.1 Tg CO2  yr(-1) , respectively. Forest management practices such as bamboo afforestation and reforestation may significantly enhance the long-term terrestrial carbon sink and contribute to mitigation of global climate warming. © 2013 John Wiley & Sons Ltd.

  3. Longevity of contributions to SOC stocks from roots and aboveground plant litter below a Miscanthus plantation

    Science.gov (United States)

    Robertson, Andrew; Smith, Pete; Davies, Christian; Bottoms, Emily; McNamara, Niall

    2013-04-01

    Miscanthus is a lignocellulosic crop that uses the Hatch-Slack (C4) photosynthetic pathway as opposed to most C3 vegetation native to the UK. Miscanthus can be grown for a number of practical end-uses but recently interest has increased in its viability as a bioenergy crop; both providing a renewable source of energy and helping to limit climate change by improving the carbon (C) budgets associated with energy generation. Recent studies have shown that Miscanthus plantations may increase stocks of soil organic carbon (SOC), however the longevity and origin of this 'new' SOC must be assessed. Consequently, we combined an input manipulation experiment with physio-chemical soil fractionation to quantify new SOC and CO2 emissions from Miscanthus roots, decomposing plant litter and soil individually. Further, fractionation of SOC from the top 30 cm gave insight into the longevity of that SOC. In January 2009 twenty-five 2 m2 plots were set up in a three-year old 11 hectare Miscanthus plantation in Lincolnshire, UK; with five replicates of five treatments. These treatments varied plant input to the soil by way of controlled exclusion techniques. Treatments excluded roots only ("No Roots"), surface litter only ("No Litter"), both roots and surface litter ("No Roots or Litter") or had double the litter amount added to the soil surface ("Double Litter"). A fifth treatment was a control with undisturbed roots and an average amount of litter added. Monthly measurements of CO2 emissions were taken at the soil surface from each treatment between March 2009 and March 2013, and soil C from the top 30 cm was monitored in all plots over the same period. Miscanthus-derived SOC was determined using the isotopic discrimination between C4 plant matter and C3 soil, and soil fractionation was then used to establish the longevity of that Miscanthus-derived SOC. Ongoing results for CO2 emissions indicate a strong seasonal variation; litter decomposition forms a large portion of the CO2

  4. Reduced aboveground tree growth associated with higher arbuscular mycorrhizal fungal diversity in tropical forest restoration.

    Science.gov (United States)

    Holste, Ellen K; Holl, Karen D; Zahawi, Rakan A; Kobe, Richard K

    2016-10-01

    Establishing diverse mycorrhizal fungal communities is considered important for forest recovery, yet mycorrhizae may have complex effects on tree growth depending on the composition of fungal species present. In an effort to understand the role of mycorrhizal fungi community in forest restoration in southern Costa Rica, we sampled the arbuscular mycorrhizal fungal (AMF) community across eight sites that were planted with the same species ( Inga edulis, Erythrina poeppigiana, Terminalia amazonia, and Vochysia guatemalensis ) but varied twofold to fourfold in overall tree growth rates. The AMF community was measured in multiple ways: as percent colonization of host tree roots, by DNA isolation of the fungal species associated with the roots, and through spore density, volume, and identity in both the wet and dry seasons. Consistent with prior tropical restoration research, the majority of fungal species belonged to the genus Glomus and genus Acaulospora , accounting for more than half of the species and relative abundance found on trees roots and over 95% of spore density across all sites. Greater AMF diversity correlated with lower soil organic matter, carbon, and nitrogen concentrations and longer durations of prior pasture use across sites. Contrary to previous literature findings, AMF species diversity and spore densities were inversely related to tree growth, which may have arisen from trees facultatively increasing their associations with AMF in lower soil fertility sites. Changes to AMF community composition also may have led to variation in disturbance susceptibility, host tree nutrient acquisition, and tree growth. These results highlight the potential importance of fungal-tree-soil interactions in forest recovery and suggest that fungal community dynamics could have important implications for tree growth in disturbed soils.

  5. FEL gain optimisation and spontaneous radiation

    Energy Technology Data Exchange (ETDEWEB)

    Bali, L.M.; Srivastava, A.; Pandya, T.P. [Lucknow Univ. (India)] [and others

    1995-12-31

    Colson have evaluated FEL gains for small deviations from perfect electron beam injection, with radiation of the same polarisation as that of the wiggler fields. We find that for optimum gain the polarisation of the optical field should be the same as that of the spontaneous emission under these conditions. With a helical wiggler the axial oscillations resulting from small departures from perfect electron beam injection lead to injection dependent unequal amplitudes and phases of the spontaneous radiation in the two transverse directions. Viewed along the axis therefore the spontaneous emission is elliptically polarised. The azimuth of the ellipse varies with the difference of phase of the two transverse components of spontaneous emission but the eccentricity remains the same. With planar wigglers the spontaneous emission viewed in the axial direction is linearly polarised, again with an injection dependent azimuth. For optimum coherent gain of a radiation field its polarisation characteristics must be the same as those of the spontaneous radiation with both types of wiggler. Thus, with a helical wiggler and the data reported earlier, an increase of 10% in the FEL gain at the fundamental frequency and of 11% at the fifth harmonic has been calculated in the small gain per pass limit. Larger enhancements in gain may result from more favourable values of input parameters.

  6. Central gain control in tinnitus and hyperacusis

    Directory of Open Access Journals (Sweden)

    Benjamin D Auerbach

    2014-10-01

    Full Text Available Sensorineural hearing loss induced by noise or ototoxic drug exposure reduces the neural activity transmitted from the cochlea to the central auditory system. Despite a reduced cochlear output, neural activity from more central auditory structures is paradoxically enhanced at suprathreshold intensities. This compensatory increase in the central auditory activity in response to the loss of sensory input is referred to as central gain enhancement. Enhanced central gain is hypothesized to be a potential mechanism that gives rise to hyperacusis and tinnitus, two debilitating auditory perceptual disorders that afflict millions of individuals. This review will examine the evidence for gain enhancement in the central auditory system in response to cochlear damage. Further, it will address the potential cellular and molecular mechanisms underlying this enhancement and discuss the contribution of central gain enhancement to tinnitus and hyperacusis. Current evidence suggests that multiple mechanisms with distinct temporal and spectral profiles are likely to contribute to central gain enhancement. Dissecting the contributions of these different mechanisms at different levels of the central auditory system is essential for elucidating the role of central gain enhancement in tinnitus and hyperacusis and, most importantly, the development of novel treatments for these disorders.

  7. Potential gains from hospital mergers in Denmark.

    Science.gov (United States)

    Kristensen, Troels; Bogetoft, Peter; Pedersen, Kjeld Moeller

    2010-12-01

    The Danish hospital sector faces a major rebuilding program to centralize activity in fewer and larger hospitals. We aim to conduct an efficiency analysis of hospitals and to estimate the potential cost savings from the planned hospital mergers. We use Data Envelopment Analysis (DEA) to estimate a cost frontier. Based on this analysis, we calculate an efficiency score for each hospital and estimate the potential gains from the proposed mergers by comparing individual efficiencies with the efficiency of the combined hospitals. Furthermore, we apply a decomposition algorithm to split merger gains into technical efficiency, size (scale) and harmony (mix) gains. The motivation for this decomposition is that some of the apparent merger gains may actually be available with less than a full-scale merger, e.g., by sharing best practices and reallocating certain resources and tasks. Our results suggest that many hospitals are technically inefficient, and the expected "best practice" hospitals are quite efficient. Also, some mergers do not seem to lower costs. This finding indicates that some merged hospitals become too large and therefore experience diseconomies of scale. Other mergers lead to considerable cost reductions; we find potential gains resulting from learning better practices and the exploitation of economies of scope. To ensure robustness, we conduct a sensitivity analysis using two alternative returns-to-scale assumptions and two alternative estimation approaches. We consistently find potential gains from improving the technical efficiency and the exploitation of economies of scope from mergers.

  8. Can LENR Energy Gains Exceed 1000?

    Science.gov (United States)

    Nagel, David J.

    2011-03-01

    Energy gain is defined as the energy realized from reactions divided by the energy required to produce those reactions. Low Energy Nuclear Reactions (LENR) have already been measured to significantly exceed the energy gain of 10 projected from ITER,possibly 15 years from now. Electrochemical experiments using the Pd-D system have shown energy gains exceeding 10. Gas phase experiments with the Ni-H system were reported to yield energy gains of over 100. Neither of these reports has been adequately verified or reproduced. However, the question in the title still deserves consideration. If, as thought by many, it is possible to trigger nuclear reactions that yield MeV energies with chemical energies of the order of eV, then the most optimistic expectation is that LENR gains could approach one million. Hence, the very tentative answer to the question above is yes. However, if LENR could be initiated with some energy cost, and then continue to ``burn,'' very high energy gains might be realized. Consider a match and a pile of dry logs. The phenomenon termed ``heat after death'' will be examined to see if it might be the initial evidence for nuclear ``burning.''

  9. Central Gain Control in Tinnitus and Hyperacusis

    Science.gov (United States)

    Auerbach, Benjamin D.; Rodrigues, Paulo V.; Salvi, Richard J.

    2014-01-01

    Sensorineural hearing loss induced by noise or ototoxic drug exposure reduces the neural activity transmitted from the cochlea to the central auditory system. Despite a reduced cochlear output, neural activity from more central auditory structures is paradoxically enhanced at suprathreshold intensities. This compensatory increase in the central auditory activity in response to the loss of sensory input is referred to as central gain enhancement. Enhanced central gain is hypothesized to be a potential mechanism that gives rise to hyperacusis and tinnitus, two debilitating auditory perceptual disorders that afflict millions of individuals. This review will examine the evidence for gain enhancement in the central auditory system in response to cochlear damage. Further, it will address the potential cellular and molecular mechanisms underlying this enhancement and discuss the contribution of central gain enhancement to tinnitus and hyperacusis. Current evidence suggests that multiple mechanisms with distinct temporal and spectral profiles are likely to contribute to central gain enhancement. Dissecting the contributions of these different mechanisms at different levels of the central auditory system is essential for elucidating the role of central gain enhancement in tinnitus and hyperacusis and, most importantly, the development of novel treatments for these disorders. PMID:25386157

  10. Mapping Above-Ground Biomass in a Tropical Forest in Cambodia Using Canopy Textures Derived from Google Earth

    Directory of Open Access Journals (Sweden)

    Minerva Singh

    2015-04-01

    Full Text Available This study develops a modelling framework for utilizing very high-resolution (VHR aerial imagery for monitoring stocks of above-ground biomass (AGB in a tropical forest in Southeast Asia. Three different texture-based methods (grey level co-occurrence metric (GLCM, Gabor wavelets and Fourier-based textural ordination (FOTO were used in conjunction with two different machine learning (ML-based regression techniques (support vector regression (SVR and random forest (RF regression. These methods were implemented on both 50-cm resolution Digital Globe data extracted from Google Earth™ (GE and 8-cm commercially obtained VHR imagery. This study further examines the role of forest biophysical parameters, such as ground-measured canopy cover and vertical canopy height, in explaining AGB distribution. Three models were developed using: (i horizontal canopy variables (i.e., canopy cover and texture variables plus vertical canopy height; (ii horizontal variables only; and (iii texture variables only. AGB was variable across the site, ranging from 51.02 Mg/ha to 356.34 Mg/ha. GE-based AGB estimates were comparable to those derived from commercial aerial imagery. The findings demonstrate that novel use of this array of texture-based techniques with GE imagery can help promote the wider use of freely available imagery for low-cost, fine-resolution monitoring of forests parameters at the landscape scale.

  11. Effect of growth regulator Kelpak SL on the formation of aboveground biomass of Festulolium braunii (K. Richt. A. Camus

    Directory of Open Access Journals (Sweden)

    Jacek Sosnowski

    2013-07-01

    Full Text Available A study on the cultivation of Festulolium braunii cv. 'Felopa' was carried out using polyurethane rings with a diameter of 36 cm and a height of 40 cm, which were sunk into the ground to a depth of 30 cm and filled with soil material. In this experiment, Kelpak SL was used as a bioregulator. It consists of natural plant hormones such as auxins (11 mg in dm3 and cytokinins (0.03 mg in dm3. The experimental factors were as follows: A1-control; A2 – 20% solution of the growth regulator; A3 – 40% solution; and A4 – 60% solution. The preparation was applied to all three regrowths in the form of spray, at a rate of 3 cm3 ring-1, at the stem elongation stage. The full period of this experiment was in the years 2010–2011. During this time, detailed investigations were carried out on aboveground biomass yield (g DM ring-1, number of shoots (pcs ring-1, leaf blade length (cm, width of the leaf blade base (mm, leaf greenness index (SPAD. The study showed a significant effect of the growth regulator on the formation of Festulolium braunii biomass. However, its highest effectiveness was observed when the 60% solution was applied.

  12. Spatiotemporal dynamics of grassland aboveground biomass on the Qinghai-Tibet Plateau based on validated MODIS NDVI.

    Science.gov (United States)

    Liu, Shiliang; Cheng, Fangyan; Dong, Shikui; Zhao, Haidi; Hou, Xiaoyun; Wu, Xue

    2017-06-23

    Spatiotemporal dynamics of aboveground biomass (AGB) is a fundamental problem for grassland environmental management on the Qinghai-Tibet Plateau (QTP). Moderate Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) data can feasibly be used to estimate AGB at large scales, and their precise validation is necessary to utilize them effectively. In our study, the clip-harvest method was used at 64 plots in QTP grasslands to obtain actual AGB values, and a handheld hyperspectral spectrometer was used to calculate field-measured NDVI to validate MODIS NDVI. Based on the models between NDVI and AGB, AGB dynamics trends during 2000-2012 were analyzed. The results showed that the AGB in QTP grasslands increased during the study period, with 70% of the grasslands undergoing increases mainly in the Qinghai Province. Also, the meadow showed a larger increasing trend than steppe. Future AGB dynamic trends were also investigated using a combined analysis of the slope values and the Hurst exponent. The results showed high sustainability of AGB dynamics trends after the study period. Predictions indicate 60% of the steppe and meadow grasslands would continue to increase in AGB, while 25% of the grasslands would remain in degradation, with most of them distributing in Tibet.

  13. Nitrogen mediates above-ground effects of ozone but not below-ground effects in a rhizomatous sedge

    International Nuclear Information System (INIS)

    Jones, M.L.M.; Hodges, G.; Mills, G.

    2010-01-01

    Ozone and atmospheric nitrogen are co-occurring pollutants with adverse effects on natural grassland vegetation. Plants of the rhizomatous sedge Carex arenaria were exposed to four ozone regimes representing increasing background concentrations (background-peak): 10-30, 35-55, 60-80 and 85-105 ppb ozone at two nitrogen levels: 12 and 100 kg N ha -1 yr -1 . Ozone increased the number and proportion of senesced leaves, but not overall leaf number. There was a clear nitrogen x ozone interaction with high nitrogen reducing proportional senescence in each treatment and increasing the ozone dose (AOT40) at which enhanced senescence occurred. Ozone reduced total biomass due to significant effects on root biomass. There were no interactive effects on shoot:root ratio. Rhizome tissue N content was increased by both nitrogen and ozone. Results suggest that nitrogen mediates above-ground impacts of ozone but not impacts on below-ground resource translocation. This may lead to complex interactive effects between the two pollutants on natural vegetation. - Nitrogen alters threshold of ozone-induced senescence, but not below-ground resource allocation.

  14. Qualitative and quantitative modifications of root mitochondria during senescence of above-ground parts of Arabidopis thaliana.

    Science.gov (United States)

    Fanello, Diego Darío; Bartoli, Carlos Guillermo; Guiamet, Juan José

    2017-05-01

    This work studied modifications experienced by root mitochondria during whole plant senescence or under light deprivation, using Arabidopsis thaliana plants with YFP tagged to mitochondria. During post-bolting development, root respiratory activity started to decline after aboveground organs (i.e., rosette leaves) had senesced. This suggests that carbohydrate starvation may induce root senescence. Similarly, darkening the whole plant induced a decrease in respiration of roots. This was partially due to a decrease in the number of total mitochondria (YFP-labelled mitochondria) and most probably to a decrease in the quantity of mitochondria with a developed inner membrane potential (ΔΨm, i.e., Mitotracker red- labelled mitochondria). Also, the lower amount of mitochondria with ΔΨm compared to YFP-labelled mitochondria at 10d of whole darkened plant, suggests the presence of mitochondria in a "standby state". The experiments also suggest that small mitochondria made the main contribution to the respiratory activity that was lost during root senescence. Sugar supplementation partially restored the respiration of mitochondria after 10d of whole plant dark treatment. These results suggest that root senescence is triggered by carbohydrate starvation, with loss of ΔΨm mitochondria and changes in mitochondrial size distribution. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Evaluating land use and aboveground biomass dynamics in an oil palm-dominated landscape in Borneo using optical remote sensing

    Science.gov (United States)

    Singh, Minerva; Malhi, Yadvinder; Bhagwat, Shonil

    2014-01-01

    The focus of this study is to assess the efficacy of using optical remote sensing (RS) in evaluating disparities in forest composition and aboveground biomass (AGB). The research was carried out in the East Sabah region, Malaysia, which constitutes a disturbance gradient ranging from pristine old growth forests to forests that have experienced varying levels of disturbances. Additionally, a significant proportion of the area consists of oil palm plantations. In accordance with local laws, riparian forest (RF) zones have been retained within oil palm plantations and other forest types. The RS imagery was used to assess forest stand structure and AGB. Band reflectance, vegetation indicators, and gray-level co-occurrence matrix (GLCM) consistency features were used as predictor variables in regression analysis. Results indicate that the spectral variables were limited in their effectiveness in differentiating between forest types and in calculating biomass. However, GLCM based variables illustrated strong correlations with the forest stand structures as well as with the biomass of the various forest types in the study area. The present study provides new insights into the efficacy of texture examination methods in differentiating between various land-use types (including small, isolated forest zones such as RFs) as well as their AGB stocks.

  16. Diversity and above-ground biomass patterns of vascular flora induced by flooding in the drawdown area of China's Three Gorges Reservoir.

    Directory of Open Access Journals (Sweden)

    Qiang Wang

    Full Text Available Hydrological alternation can dramatically influence riparian environments and shape riparian vegetation zonation. However, it was difficult to predict the status in the drawdown area of the Three Gorges Reservoir (TGR, because the hydrological regime created by the dam involves both short periods of summer flooding and long-term winter impoundment for half a year. In order to examine the effects of hydrological alternation on plant diversity and biomass in the drawdown area of TGR, twelve sites distributed along the length of the drawdown area of TGR were chosen to explore the lateral pattern of plant diversity and above-ground biomass at the ends of growing seasons in 2009 and 2010. We recorded 175 vascular plant species in 2009 and 127 in 2010, indicating that a significant loss of vascular flora in the drawdown area of TGR resulted from the new hydrological regimes. Cynodon dactylon and Cyperus rotundus had high tolerance to short periods of summer flooding and long-term winter flooding. Almost half of the remnant species were annuals. Species richness, Shannon-Wiener Index and above-ground biomass of vegetation exhibited an increasing pattern along the elevation gradient, being greater at higher elevations subjected to lower submergence stress. Plant diversity, above-ground biomass and species distribution were significantly influenced by the duration of submergence relative to elevation in both summer and previous winter. Several million tonnes of vegetation would be accumulated on the drawdown area of TGR in every summer and some adverse environmental problems may be introduced when it was submerged in winter. We conclude that vascular flora biodiversity in the drawdown area of TGR has dramatically declined after the impoundment to full capacity. The new hydrological condition, characterized by long-term winter flooding and short periods of summer flooding, determined vegetation biodiversity and above-ground biomass patterns along the

  17. Optical gain and gain suppression of quantum-well lasers with valence band mixing

    International Nuclear Information System (INIS)

    Ahn, D.; Chuang, S.L.

    1990-01-01

    The effects of valence band mixing on the nonlinear gains of quantum-well lasers are studied theoretically. The authors' analysis is based on the multiband effective-mass theory and the density matrix formalism with intraband relaxation taken into account. The gain and the gain-suppression coefficient of a quantum-well laser are calculated from the complex optical susceptibility obtained by the density matrix formulation with the theoretical dipole moments obtained from the multiband effective-mass theory. The calculated gain spectrum shows that there are remarkable differences (both in peak amplitude and spectral shape) between our model with valence band mixing and the conventional parabolic band model. The shape of the gain spectrum calculated by the authors' model becomes more symmetric due to intraband relaxation together with nonparabolic energy dispersions and is closer to the experimental observations when compared with the conventional method using the parabolic band model and the multiband effective-mass calculation without intraband relaxation. Both give quite asymmetric gain spectra. Optical intensity in the GaAs active region is estimated by solving rate equations for the stationary states with nonlinear gain suppression. The authors calculate the mode gain for the resonant mode including the gain suppression, which results in spectral hole burning of the gain spectrum

  18. Recent Progress in Measuring and Modeling Patterns of Biomass and Soil Carbon Pools Across the Amazon Basin

    Science.gov (United States)

    Potter, Christopher; Malhi, Yadvinder

    2004-01-01

    Ever more detailed representations of above-ground biomass and soil carbon pools have been developed during the LBA project. Environmental controls such as regional climate, land cover history, secondary forest regrowth, and soil fertility are now being taken into account in regional inventory studies. This paper will review the evolution of measurement-extrapolation approaches, remote sensing, and simulation modeling techniques for biomass and soil carbon pools, which together help constrain regional carbon budgets and enhance in our understanding of uncertainty at the regional level.

  19. CONDITIONS FOR CSR MICROBUNCHING GAIN SUPPRESSION

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Cheng Ying [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Douglas, David R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Li, Rui [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Tennant, Christopher D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); di Mitri, Simone [Elettra–Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy

    2016-05-01

    The coherent synchrotron radiation (CSR) of a high brightness electron beam traversing a series of dipoles, such as transport arcs, may result in phase space degradation. On one hand, the CSR can perturb electron transverse motion in dispersive regions along the beamline, causing emittance growth. On the other hand, the CSR effect on the longitudinal beam dynamics could result in microbunching gain enhancement. For transport arcs, several schemes have been proposed* to suppress the CSR-induced emittance growth. Similarly, several scenarios have been introduced** to suppress CSR-induced microbunching gain, which however mostly aim for linac-based machines. In this paper we try to provide sufficient conditions for suppression of CSR-induced microbunching gain along a transport arc, analogous to*. Several example lattices are presented, with the relevant microbunching analyses carried out by our semi-analytical Vlasov solver***. The simulation results show that lattices satisfying the proposed conditions indeed have microbunching gain suppressed. We expect this analysis can shed light on lattice design approach that could suppress the CSR-induced microbunching gain.

  20. Biotic and abiotic controls on the distribution of tropical forest aboveground biomass

    Science.gov (United States)

    Saatchi, S. S.; Schimel, D.; Keller, M. M.; Chambers, J. Q.; Dubayah, R.; Duffy, P.; Yu, Y.; Robinson, C. M.; Chowdhury, D.; Yang, Y.

    2013-12-01

    AUTHOR: Sassan Saatchi1,2, Yan Yang2, Diya Chowdhury2, Yifan Yu2, Chelsea Robinson2, David Schimel1, Paul Duffy3, Michael Keller4, Ralph Dubayah5, Jeffery Chambers6 1. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA 2. Institute of Environment and Sustainability, University of California, Los Angeles, CA, USA 3. Neptune and Company, Inc. Denver, CO, USA 4. International Institute of Tropical Forestry & International Programs, USDA Forest Service, Campinas, Brazil 5. Department of Geography, University of Maryland, College Park, MD, USA 6. Department of Geography, University of California, Berkeley, CA, USA ABSTRACT BODY: In recent years, climate change policies and scientific research created a widespread interest in quantify the carbon stock and changes of global tropical forests extending from forest patches to national and regional scales. Using a combination of inventory data from field plots and forest structure from spaceborne Lidar data, we examine the main controls on the distribution of tropical forest biomass. Here, we concentrate on environmental and landscape variables (precipitation, temperature, topography, and soil), and biotic variables such as functional traits (density of large trees, and wood specific gravity). The analysis is performed using global bioclimatic variables for precipitation and temperature, SRTM data for topographical variables (elevation and ruggedness), and global harmonized soil data for soil type and texture. For biotic variables, we use the GLAS Lidar data to quantify the distribution of large trees, a combined field and remote sensing data for distribution of tree wood specific gravity. The results show that climate variables such as precipitation of dry season can explain the heterogeneity of forest biomass over the landscape but cannot predict the biomass variability significantly and particularly for high biomass forests. Topography such as elevation and ruggedness along with temperature can