An analysis of the decadal variability of Carbon fluxes in three evergreen European forests through modelling

Science.gov (United States)

Delpierre, N.; Dufrêne, E.

2009-04-01

With several sites measuring mass and energy turbulent fluxes for more than ten years, the CarboEurope database appears as a valuable resource for addressing the question of the determinism of the interannual variability of carbon (C) and water balances in forests ecosystems. Apart from major climate-driven anomalies during the anomalous 2003 summer and 2007 spring, little is known about the factors driving interannual variability (IAV) of the C balance in forest ecosystems. We used the CASTANEA process-based model to simulate the C and W fluxes and balances of three European evergreen forests for the 2000-2007 period (FRPue Quercus ilex, 44°N; DETha Picea abies, 51°N; FIHyy Pinus sylvestris, 62°N). The model fairly reproduced the day-to-day variability of measured fluxes, accounting for 70-81%, 77-91% and 59-90% of the daily variance of measured NEP, GPP and TER, respectively. However, the model was challenged in representing the IAV of fluxes integrated on an annual time scale. It reproduced ca. 80% of the interannual variance of measured GPP, but no significant relationship could be established between annual measured and modelled NEP or TER. Accordingly, CASTANEA appeared as a suitable tool for disentangling the influence of climate and biological processes on GPP at mutiple time scales. We show that climate and biological processes relative influences on the modelled GPP vary from year to year in European evergreen forests. Water-stress related and phenological processes (i.e. release of the winter thermal constraint on photosynthesis in evergreens) appear as primary drivers for the particular 2003 and 2007 years, respectively, but the relative influence of other climatic factors widely varies for less remarkable years at all sites. We discuss shortcomings of the method, as related to the influence of compensating errors in the simulated fluxes, and assess the causes of the model poor ability to represent the IAV of the annual sums of NEP and TER.

Protected Areas: Mixed Success in Conserving East Africa’s Evergreen Forests

Science.gov (United States)

Pfeifer, Marion; Burgess, Neil D.; Swetnam, Ruth D.; Platts, Philip J.; Willcock, Simon; Marchant, Robert

2012-01-01

In East Africa, human population growth and demands for natural resources cause forest loss contributing to increased carbon emissions and reduced biodiversity. Protected Areas (PAs) are intended to conserve habitats and species. Variability in PA effectiveness and ‘leakage’ (here defined as displacement of deforestation) may lead to different trends in forest loss within, and adjacent to, existing PAs. Here, we quantify spatial variation in trends of evergreen forest coverage in East Africa between 2001 and 2009, and test for correlations with forest accessibility and environmental drivers. We investigate PA effectiveness at local, landscape and national scales, comparing rates of deforestation within park boundaries with those detected in park buffer zones and in unprotected land more generally. Background forest loss (BFL) was estimated at −9.3% (17,167 km2), but varied between countries (range: −0.9% to −85.7%; note: no BFL in South Sudan). We document high variability in PA effectiveness within and between PA categories. The most successful PAs were National Parks, although only 26 out of 48 parks increased or maintained their forest area (i.e. Effective parks). Forest Reserves (Ineffective parks, i.e. parks that lose forest from within boundaries: 204 out of 337), Nature Reserves (six out of 12) and Game Parks (24 out of 26) were more likely to lose forest cover. Forest loss in buffer zones around PAs exceeded background forest loss, in some areas indicating leakage driven by Effective National Parks. Human pressure, forest accessibility, protection status, distance to fires and long-term annual rainfall were highly significant drivers of forest loss in East Africa. Some of these factors can be addressed by adjusting park management. However, addressing close links between livelihoods, natural capital and poverty remains a fundamental challenge in East Africa’s forest conservation efforts. PMID:22768074

Modeling the early-phase redistribution of radiocesium fallouts in an evergreen coniferous forest after Chernobyl and Fukushima accidents

Energy Technology Data Exchange (ETDEWEB)

Calmon, P.; Gonze, M.-A.; Mourlon, Ch.

2015-10-01

Following the Chernobyl accident, the scientific community gained numerous data on the transfer of radiocesium in European forest ecosystems, including information regarding the short-term redistribution of atmospheric fallout onto forest canopies. In the course of international programs, the French Institute for Radiological Protection and Nuclear Safety (IRSN) developed a forest model, named TREE4 (Transfer of Radionuclides and External Exposure in FORest systems), 15 years ago. Recently published papers on a Japanese evergreen coniferous forest contaminated by Fukushima radiocesium fallout provide interesting and quantitative data on radioactive mass fluxes measured within the forest in the months following the accident. The present study determined whether the approach adopted in the TREE4 model provides satisfactory results for Japanese forests or whether it requires adjustments. This study focused on the interception of airborne radiocesium by forest canopy, and the subsequent transfer to the forest floor through processes such as litterfall, throughfall, and stemflow, in the months following the accident. We demonstrated that TREE4 quite satisfactorily predicted the interception fraction (20%) and the canopy-to-soil transfer (70% of the total deposit in 5 months) in the Tochigi forest. This dynamics was similar to that observed in the Höglwald spruce forest. However, the unexpectedly high contribution of litterfall (31% in 5 months) in the Tochigi forest could not be reproduced in our simulations (2.5%). Possible reasons for this discrepancy are discussed; and sensitivity of the results to uncertainty in deposition conditions was analyzed. - Highlights: • Transfer of radiocesium atmospheric fallout in evergreen forests was modeled. • The model was tested using observations from Chernobyl and Fukushima accidents. • Model predictions of canopy interception and depuration agree with measurements. • Unexpectedly high contribution of litterfall for the

Constructing seasonal LAI trajectory by data-model fusion for global evergreen needle-leaf forests

Science.gov (United States)

Wang, R.; Chen, J.; Mo, G.

2010-12-01

For decades, advancements in optical remote sensors made it possible to produce maps of a biophysical parameter--the Leaf Area Index (LAI), which is critically necessary in regional and global modeling of exchanges of carbon, water, energy and other substances, across large areas in a fast way. Quite a few global LAI products have been generated since 2000, e.g. GLOBCARBON (Deng et al., 2006), MODIS Collection 5 (Shabanov et al., 2007), CYCLOPES (Baret et al., 2007), etc. Albeit these progresses, the basic physics behind the technology restrains it from accurate estimation of LAI in winter, especially for northern high-latitude evergreen needle-leaf forests. Underestimation of winter LAI in these regions has been reported in literature (Yang et al., 2000; Cohen et al., 2003; Tian et al., 2004; Weiss et al., 2007; Pisek et al., 2007), and the distortion is usually attributed to the variations of canopy reflectance caused by understory change (Weiss et al., 2007) as well as by the presence of ice and snow on leaves and ground (Cohen, 2003; Tian et al., 2004). Seasonal changes in leaf pigments can also be another reason for low LAI retrieved in winter. Low conifer LAI values in winter retrieved from remote sensing make them unusable for surface energy budget calculations. To avoid these drawbacks of remote sensing approaches, we attempt to reconstruct the seasonal LAI trajectory through model-data fusion. A 1-degree LAI map of global evergreen needle-leaf forests at 10-day interval is produced based on the carbon allocation principle in trees. With net primary productivity (NPP) calculated by the Boreal Ecosystems Productivity Simulator (BEPS) (Chen et al., 1999), carbon allocated to needles is quantitatively evaluated and then can be further transformed into LAI using the specific leaf area (SLA). A leaf-fall scheme is developed to mimic the carbon loss caused by falling needles throughout the year. The seasonally maximum LAI from remote sensing data for each pixel

Estimation of canopy water interception of a near-tropical montane cloud forest in Taiwan

Science.gov (United States)

Apurva, B.; Huang, C. Y.; Zhang, J.

2017-12-01

Tropical and subtropical montane cloud forests are some of the rarest and least studied ecosystems. Due to the frequent immersion of fog water with high humidity, these zones are major water sources for lowland environments and habitats for many fauna and flora. Their dependence on cloud water leaves them highly susceptible to the effects of climate change. Studies have been conducted to quantify the characteristics of the low altitude clouds such as spatial dynamics, cloud top and base heights, occurrence frequency or immersion duration. In this study, we carried out a field measurement to estimate canopy water interception (CWI), which is directly utilized by the ecosystems. The study site was a 61 ha near-tropical hinoki cypress montane cloud forest plantation in northern Taiwan at 1705 m asl. Leaves of CHOB were clipped, air-dried and attached to trees at three different canopy depths from the top to the base of canopies along a high tower. The samples were weighed before and after the occurrence of a fog event. In addition, a cylinder shaped fog gauge was installed at the ground level next to the tower to assess amount of fog water penetrating the canopy layer. After afternoon fog events with the duration of 60 minutes, we found that there was an apparent trend of decline of CWI from top (mean ± standard deviation = 0.023 g ± 0.0015 g), middle (0.021 g ± 0.0015 g) to the bottom (0.013 g ± 0.0015 g) of the canopies. Since the study site is a coniferous evergreen forest plantation with a relatively homogenous surface through seasons, with the background knowledge of the average leaf area index of 4.4, we estimated that this 61 ha site harvested 28.2 Mg of CWI for a daily fog event. We also found that no clear evidence of CWI was observed below the canopies by referring to bi-weekly records from the cylinder shaded fog gauge. Therefore, we can assume that the majority fog water was intercepted by the hinoki cypress canopy layer. This study demonstrates that a

Retention of available P in acid soils of tropical and subtropical evergreen broad-leaved forests

Institute of Scientific and Technical Information of China (English)

CHEN Jianhui; ZOU Xiaoming; YANG Xiaodong

2007-01-01

Precipitation of mineral phosphate is often recognized as a factor of limiting the availability of P in acidic soils of tropical and subtropical forests.For this paper,we studied the extractable P pools and their transformation rates in soils of a tropical evergreen forest at Xishuangbanna and a subtropical montane wet forest at the Ailao Mountains in order to understand the biogeochemical processes regulating P availability in acidic soils.The two forests differ in forest humus layer;it is deep in the Ailao forest while little is present in the Xishuangbanna forest.The extractable P pools by resin and sodium-bicarbonate decreased when soil organic carbon content was reduced.The lowest levels of extractable P pools occurred in the surface (0-10 era) mineral soils of the Xishuangbanna forest.However,microbial P in the mineral soil of the Xishuangbauna forest was twice that in the Ailao forest.Potential rates of microbial P immobilization were greater than those of organic P mineralization in mineral soils for both forests.We suggest that microbial P immobilization plays an essential role in avoiding mineral P precipitation and retaining available P of plant in tropical acidic soils,whereas both floor mass accumulation and microbial P immobilization function benefit retaining plant available P in subtropical montane wet forests.

Effect of urbanization on the structure and functional traits of remnant subtropical evergreen broad-leaved forests in South China

Science.gov (United States)

Liujing Huang; Hongfeng Chen; Hai Ren; Jun Wang; Qinfeng Guo

2013-01-01

We investigated the effects of major environmental drivers associated with urbanization on species diversity and plant functional traits (PFTs) in the remnant subtropical evergreen broad-leaved forests in Metropolitan Guangzhou (Guangdong, China). Twenty environmental factors including topography, light, and soil properties were used to quantify the effects of...

Mapping the Distribution of Cloud Forests Using MODIS Imagery

Science.gov (United States)

Douglas, M. W.; Mejia, J.; Murillo, J.; Orozco, R.

2007-05-01

Tropical cloud forests - those forests that are frequently immersed in clouds or otherwise very humid, are extremely difficult to map from the ground, and are not easily distinguished in satellite imagery from other forest types, but they have a very different flora and fauna than lowland rainforest. Cloud forests, although found in many parts of the tropics, have a very restricted vertical extent and thus are also restricted horizontally. As a result, they are subject to both human disturbance (coffee growing for example) and the effects of possible climate change. Motivated by a desire to seek meteorological explanations for the distribution of cloud forests, we have begun to map cloudiness using MODIS Terra and Aqua visible imagery. This imagery, at ~1030 LT and 1330 LT, is an approximation for mid-day cloudiness. In tropical regions the amount of mid-day cloudiness strongly controls the shortwave radiation and thus the potential for evaporation (and aridity). We have mapped cloudiness using a simple algorithm that distinguishes between the cloud-free background brightness and the generally more reflective clouds to separate clouds from the underlying background. A major advantage of MODIS imagery over many other sources of satellite imagery is its high spatial resolution (~250m). This, coupled with precisely navigated images, means that detailed maps of cloudiness can be produced. The cloudiness maps can then be related to the underlying topography to further refine the location of the cloud forests. An advantage of this technique is that we are mapping the potential cloud forest, based on cloudiness, rather than the actual cloud forest, which are commonly based on forest estimates from satellite and digital elevation data. We do not derive precipitation, only estimates of daytime cloudiness. Although only a few years of MODIS imagery has been used in our studies, we will show that this is sufficient to describe the climatology of cloudiness with acceptable

Insect herbivores associated with an evergreen tree Goniorrhachis marginata Taub. (Leguminosae: Caesalpinioideae) in a tropical dry forest.

Science.gov (United States)

Silva, J O; Neves, F S

2014-08-01

Goniorrhachis marginata Taub. (Leguminosae: Caesalpinioideae) is a tree species found in Brazilian tropical dry forests that retain their leaves during the dry season. That being, we addressed the following question: i) How do insect diversity (sap-sucking and chewing), leaf herbivory and defensive traits (tannin and leaf sclerophylly) vary on the evergreen tree species G. marginata between seasons? The abundance of sap-sucking insects was higher in the dry season than in the rainy season. However, we did not verify any difference in the species richness and abundance of chewing insects between seasons. Leaf herbivory was higher in the rainy season, whereas leaf sclerophylly was higher in the dry season. However, herbivory was not related to sclerophylly. Insect herbivores likely decrease their folivory activity during the dry season due to life history patterns or changes in behaviour, possibly entering diapause or inactivity during this period. Therefore, G. marginata acts as a likely keystone species, serving as a moist refuge for the insect fauna during the dry season in tropical dry forest, and the presence of this evergreen species is crucial to conservation strategies of this threatened ecosystem.

Growing up with stress - carbon sequestration and allocation dynamics of a broadleaf evergreen forest

Science.gov (United States)

Griebel, Anne; Bennett, Lauren T.; Arndt, Stefan K.

2016-04-01

Evergreen forests have the potential to sequester carbon year-round due to the presence of leaves with a multi-year lifespan. Eucalypt forests occur in warmer climates where temperature and radiation are not imposing a strong seasonality. Thus, unlike deciduous or many coniferous trees, many eucalypts grow opportunistically as conditions allow. As such, many eucalypts do not produce distinct growth rings, which present challenges to the implementation of standard methods and data interpretation approaches for monitoring and explaining carbon allocation dynamics in response to climatic stress. As a consequence, there is a lack of detailed understanding of seasonal growth dynamics of evergreen forests as a whole, and, in particular, of the influence of climatic drivers on carbon allocation to the various biomass pools. We used a multi-instrument approach in a mixed species eucalypt forest to investigate the influence of climatic drivers on the seasonal growth dynamics of a predominantly temperate and moisture-regulated environment in south-eastern Australia. Ecosystem scale observations of net ecosystem exchange (NEE) from a flux tower in the Wombat forest near Melbourne indicated that the ecosystem is a year-round carbon sink, but that intra-annual variations in temperature and moisture along with prolonged heat waves and dry spells resulted in a wide range of annual sums over the past three years (NEE ranging from ~4 to 12 t C ha-1 yr-1). Dendrometers were used to monitor stem increments of the three dominant eucalypt species. Stem expansion was generally opportunistic with the greatest increments under warm but moist conditions (often in spring and autumn), and the strongest indicators of stem growth dynamics being radiation, vapour pressure deficit and a combined heat-moisture index. Differences in the seasonality of stem increments between species were largely due to differences in the canopy position of sampled individuals. The greatest stem increments were

Species and acoustic diversity of bats in a palaeotropical wet evergreen forest in southern India

OpenAIRE

Raghuram, H; Jain, M; Balakrishnan, R

2014-01-01

The Western Ghats of India is among the top 25 biodiversity hotspots in the world. About 43% of the reported 117 bat species in India are found in this region, but few quantitative studies of bat echolocation calls and diversity have been carried out here thus far. A quantitative study of bat diversity was therefore conducted using standard techniques, including mist-netting, acoustical and roost surveys in the wet evergreen forests of Kudremukh National Park in the Western Ghats of Karnataka...

Monitoring phenology of photosynthesis in temperate evergreen and mixed deciduous forests using the normalized difference vegetation index (NDVI) and the photochemical reflectance index (PRI) at leaf and canopy scales

Science.gov (United States)

Wong, C. Y.; Arain, M. A.; Ensminger, I.

2016-12-01

Evergreen conifers in boreal and temperate regions undergo strong seasonal changes in photoperiod and temperatures, which determines their phenology of high photosynthetic activity in the growing season and downregulation during the winter. Monitoring the timing of the transition between summer activity and winter downregulation in evergreens is difficult since this is a largely invisible process, unlike in deciduous trees that have a visible budding and a sequence of leaf unfolding in the spring and leaf abscission in the fall. The light-use efficiency (LUE) model estimates gross primary productivity (GPP) and may be parameterized using remotely sensed vegetation indices. Using spectral reflectance data, we derived the normalized difference vegetation index (NDVI), a measure of leaf "greenness", and the photochemical reflectance index (PRI), a proxy for chlorophyll:carotenoid ratios which is related to photosynthetic activity. To better understand the relationship between these vegetation indices and photosynthetic activity and to contrast this relationship between plant functional types, the phenology of NDVI, PRI and photosynthesis was monitored in an evergreen forest and a mixed deciduous forest at the leaf and canopy scale. Our data indicates that the LUE model can be parameterized by NDVI and PRI to track forest phenology. Differences in the sensitivity of PRI and NDVI will be discussed. These findings have implications to address the phenology of evergreen conifers by using PRI to complement NDVI in the LUE model, potentially improving model productivity estimates in northern hemisphere forests, that are dominated by conifers.

Seed rain, soil seed bank, seed loss and regeneration of Castanopsis fargesii (Fagaceae) in a subtropical evergreen broad-leaved forest

Science.gov (United States)

Xiaojun Du; Qinfeng Guo; Xianming Gao; Keping Na

2007-01-01

Understanding the seed rain and seed loss dynamics in the natural condition has important significance for revealing the natural regeneration mechanisms.We conducted a 3-year field observation on seed rain, seed loss and natural regeneration of Castanopsis fargesii Franch., a dominant tree species in evergreen broad-leaved forests in Dujiangyan,...

Composition and diversity of tree species in transects of location lowland evergreen forest of Ecuador

Directory of Open Access Journals (Sweden)

Jorge Caranqui A.

2015-09-01

Full Text Available The study was conducted in 9 transects 1000m2 of lowland evergreen forest, located in two locations on the coast and one in eastern Ecuador. It was to contribute to knowledge of the diversity and composition of woody plants over 10 cm diameter at breast height (DBH plus infer the state of conservation of forests based on the composition, the number of species, indices diversity and importance value (IV, found in 9 transects of 1000 m² of forest: 156 species, 107 genera and 39 families distributed in 9 transects, in each one the Simpson diversity index is of 0.92 to 0.95, in this case are diversity because all approaches 1. Most were found species aren´t present in all transects, the index value in each transect does not exceed 40%. Grouping transects match three locations exception made to transect 5 and 8 were conducted in disturbed sites, the most transects are intermediate disturbance that their high levels of diversity.

Satellite-Observed Vertical Structures of Clouds over the Amazon Basin

Science.gov (United States)

Wu, M.; Lee, J. E.

2017-12-01

The long wet season of the Amazon basin currently plays a critical role in the terrestrial ecosystem, regulating carbon balance and supporting high biodiversity. It has been argued that the land surface processes are important in maintaining high precipitation; yet, how the land-atmosphere interactions modulate the atmospheric processes are not completely understood. As a first step toward solving this problem, here we examine the vertical structures of clouds and the thermodynamics of the atmosphere over the entire basin at the different time of the year. We combine the vertical distribution of cloud water content from CloudSat, and the atmospheric thermodynamic conditions from the ECMWF ERA-interim reanalysis to compare and contrast the atmospheric condition at different time of the year-the wet, dry, and dry-to-wet transition seasons-and in different regions-ever-wet evergreen broadleaf forests, wet evergreen broadleaf forests with a dry season, and dry wooded grasslands/woodlands-following water stress gradient. In the ever-wet and wet regions, a large amount of cloud ice water is present in the upper atmosphere (above 11km) and convective available potential energy (CAPE) is high during the transition season, supporting the claim that the convective activity is strongest during the transition season. In the dry region, there are more cloud water above 8km over woodlands than over wooded grasslands during the dry and transition seasons, indicating the influence of the land cover. We also classified our data following the large-scale circulation pattern, and the CloudSat data support more deep convective activities in the wet and dry regions when the wind blows from the east during the wet and transition seasons. As a next step, we will focus more on linking the cloud structure to the large-scale circulation and surface processes.

Structure and Regeneration Status of Gedo Dry Evergreen Montane ...

African Journals Online (AJOL)

This study was conducted on Gedo Dry Evergreen Montane Forest in West Shewa Zone of Oromia National Regional State, 182-196 km west of Addis Ababa (Finfinne). The objective of the study was to determine structure and regeneration status of Gedo Forest. All trees and shrubs with Diameter at Breast Height (DBH) ...

Clouds, Wind and the Biogeography of Central American Cloud Forests: Remote Sensing, Atmospheric Modeling, and Walking in the Jungle

Science.gov (United States)

Lawton, R.; Nair, U. S.

2011-12-01

Cloud forests stand at the core of the complex of montane ecosystems that provide the backbone to the multinational Mesoamerican Biological Corridor, which seeks to protect a biodiversity conservation "hotspot" of global significance in an area of rapidly changing land use. Although cloud forests are generally defined by frequent and prolonged immersion in cloud, workers differ in their feelings about "frequent" and "prolonged", and quantitative assessments are rare. Here we focus on the dry season, in which the cloud and mist from orographic cloud plays a critical role in forest water relations, and discuss remote sensing of orographic clouds, and regional and atmospheric modeling at several scales to quantitatively examine the distribution of the atmospheric conditions that characterize cloud forests. Remote sensing using data from GOES reveals diurnal and longer scale patterns in the distribution of dry season orographic clouds in Central America at both regional and local scales. Data from MODIS, used to calculate the base height of orographic cloud banks, reveals not only the geographic distributon of cloud forest sites, but also striking regional variation in the frequency of montane immersion in orographic cloud. At a more local scale, wind is known to have striking effects on forest structure and species distribution in tropical montane ecosystems, both as a general mechanical stress and as the major agent of ecological disturbance. High resolution regional atmospheric modeling using CSU RAMS in the Monteverde cloud forests of Costa Rica provides quantitative information on the spatial distribution of canopy level winds, insight into the spatial structure and local dynamics of cloud forest communities. This information will be useful in not only in local conservation planning and the design of the Mesoamerican Biological Corridor, but also in assessments of the sensitivity of cloud forests to global and regional climate changes.

Changes in structure and composition of evergreen forests on an altitudinal gradient in the Venezuelan Guayana Shield

Directory of Open Access Journals (Sweden)

Lionel Hernández

2012-03-01

Full Text Available There have been several ecological studies in forests of the Guayana Shield, but so far none had examined the changes in structure and composition of evergreen forests with altitude. This study describes and analyzes the structure, species composition and soil characteristics of forest stands at different altitudinal zones in Southeastern Venezuelan Guayana, in order to explain the patterns and the main factors that determine the structure and composition of evergreen forests along the altitudinal gradient. Inventories of 3 948 big (>10cm DBH and 1 328 small (5-10cm DBH woody stems were carried out in eleven plots, ranging from 0.1 to 1.0ha, along a 188km long transect with elevations between 290 and 1 395masl. It has been found that 1 hemiepihytes become more dominant and lianas reduce their dominance with increasing altitude and 2 the forest structure in the study area is size-dependent. Five families and 12 genera represented only 9% of the total number of families and genera, respectively, recorded troughout the gradient, but the two groups of taxa comprised more than 50% of the Importance Value (the sum of the relative density and the relative dominance of all measured stems. Moreover, the results suggest that low species richness seems to be associated with the dominance of one or few species. Stand-level wood density (WD of trees decreased significantly with increasing elevation. WD is an indicator of trees’life history strategy. Its decline suggests a change in the functional composition of the forest with increasing altitude. The Canonical Correspondence Analysis (CCA indicated a distinction of the studied forests on the basis of their altitudinal levels and geographic location, and revealed different ecological responses by the forests, to environmental variables along the altitudinal gradient. The variation in species composition, in terms of basal area among stands, was controlled primarily by elevation and secondarily by rainfall

Quantitative Measures of Immersion in Cloud and the Biogeography of Cloud Forests

Science.gov (United States)

Lawton, R. O.; Nair, U. S.; Ray, D.; Regmi, A.; Pounds, J. A.; Welch, R. M.

2010-01-01

Sites described as tropical montane cloud forests differ greatly, in part because observers tend to differ in their opinion as to what constitutes frequent and prolonged immersion in cloud. This definitional difficulty interferes with hydrologic analyses, assessments of environmental impacts on ecosystems, and biogeographical analyses of cloud forest communities and species. Quantitative measurements of cloud immersion can be obtained on site, but the observations are necessarily spatially limited, although well-placed observers can examine 10 50 km of a mountain range under rainless conditions. Regional analyses, however, require observations at a broader scale. This chapter discusses remote sensing and modeling approaches that can provide quantitative measures of the spatiotemporal patterns of cloud cover and cloud immersion in tropical mountain ranges. These approaches integrate remote sensing tools of various spatial resolutions and frequencies of observation, digital elevation models, regional atmospheric models, and ground-based observations to provide measures of cloud cover, cloud base height, and the intersection of cloud and terrain. This combined approach was applied to the Monteverde region of northern Costa Rica to illustrate how the proportion of time the forest is immersed in cloud may vary spatially and temporally. The observed spatial variation was largely due to patterns of airflow over the mountains. The temporal variation reflected the diurnal rise and fall of the orographic cloud base, which was influenced in turn by synoptic weather conditions, the seasonal movement of the Intertropical Convergence Zone and the north-easterly trade winds. Knowledge of the proportion of the time that sites are immersed in clouds should facilitate ecological comparisons and biogeographical analyses, as well as land use planning and hydrologic assessments in areas where intensive on-site work is not feasible.

[Dynamic Characteristics of Base Cations During Wet Deposition in Evergreen Broad-leaf Forest Ecosystem].

Science.gov (United States)

An, Si-wei; Sun, Tao; Ma, Ming; Wang, Ding-yong

2015-12-01

Based on field tests and laboratory experiments, effects of precipitation, throughfall, litterfall, and groundwater runoff of the ever-green broad-leaf forest on the dynamic characteristics of base cations in Simian Mountain were investigated from September 2012 to August 2013. The results showed that the rainfall of Simian Mountain was apparently acidic, with average pH of 4.90 and maximum pH of 5.14. The soil and canopies could increase pH of precipitation, with soils having the maximum increment, followed by the forest canopy. Forest canopy only had the function of interception on Na⁺. And precipitation could leach out Ca2⁺, Mg2⁺ and K⁺ of the canopies. Moreover, the degradation of litter was probably the main reason for the increase of base cations concentrations in the surface litter water. The litter water leached Ca2⁺, Mg2⁺ and Na⁺ of the forest soil through downward infiltration. The total retention rates of Ca²⁺, Mg²⁺, Na⁺ and K⁺ were 33.82%, -7.06%, 74.36% and 42.87%, respectively. Ca²⁺, Na⁺, K⁺ were found to be reserved in the forest ecosystem, and the highest interception rate was found for Na⁺.

Mapping Distinct Forest Types Improves Overall Forest Identification Based on Multi-Spectral Landsat Imagery for Myanmar’s Tanintharyi Region

Directory of Open Access Journals (Sweden)

Grant Connette

2016-10-01

Full Text Available We investigated the use of multi-spectral Landsat OLI imagery for delineating mangrove, lowland evergreen, upland evergreen and mixed deciduous forest types in Myanmar’s Tanintharyi Region and estimated the extent of degraded forest for each unique forest type. We mapped a total of 16 natural and human land use classes using both a Random Forest algorithm and a multivariate Gaussian model while considering scenarios with all natural forest classes grouped into a single intact or degraded category. Overall, classification accuracy increased for the multivariate Gaussian model with the partitioning of intact and degraded forest into separate forest cover classes but slightly decreased based on the Random Forest classifier. Natural forest cover was estimated to be 80.7% of total area in Tanintharyi. The most prevalent forest types are upland evergreen forest (42.3% of area and lowland evergreen forest (21.6%. However, while just 27.1% of upland evergreen forest was classified as degraded (on the basis of canopy cover <80%, 66.0% of mangrove forest and 47.5% of the region’s biologically-rich lowland evergreen forest were classified as degraded. This information on the current status of Tanintharyi’s unique forest ecosystems and patterns of human land use is critical to effective conservation strategies and land-use planning.

Propagation of Native Tree Species to Restore Subtropical Evergreen Broad-Leaved Forests in SW China

Directory of Open Access Journals (Sweden)

Yang Lu

2016-01-01

Full Text Available Subtropical evergreen broad-leaved forest (EBLF is a widespread vegetation type throughout East Asia that has suffered extensive deforestation and fragmentation. Selection and successful propagation of native tree species are important for improving ecological restoration of these forests. We carried out a series of experiments to study the propagation requirements of indigenous subtropical tree species in Southwest China. Seeds of 21 tree species collected from the natural forest were materials for the experiment. This paper examines the seed germination and seedling growth performance of these species in a nursery environment. Germination percentages ranged from 41% to 96% and were ≥50% for 19 species. The median length of germination time (MLG ranged from 24 days for Padus wilsonii to 144 days for Ilex polyneura. Fifteen species can reach the transplant size (≥15 cm in height within 12 months of seed collection. Nursery-grown seedlings for each species were planted in degraded site. Two years after planting, the seedling survival rate was >50% in 18 species and >80% in 12 species. Based on these results, 17 species were recommended as appropriate species for nursery production in forest restoration projects. Our study contributes additional knowledge regarding the propagation techniques for various native subtropical tree species in nurseries for forest restoration.

Seasonal variations of gas exchange and water relations in deciduous and evergreen trees in monsoonal dry forests of Thailand.

Science.gov (United States)

Ishida, Atsushi; Harayama, Hisanori; Yazaki, Kenichi; Ladpala, Phanumard; Sasrisang, Amornrat; Kaewpakasit, Kanokwan; Panuthai, Samreong; Staporn, Duriya; Maeda, Takahisa; Gamo, Minoru; Diloksumpun, Sapit; Puangchit, Ladawan; Ishizuka, Moriyoshi

2010-08-01

This study compared leaf gas exchange, leaf hydraulic conductance, twig hydraulic conductivity and leaf osmotic potential at full turgor between two drought-deciduous trees, Vitex peduncularis Wall. and Xylia xylocarpa (Roxb.) W. Theob., and two evergreen trees, Hopea ferrea Lanessan and Syzygium cumini (L.) Skeels, at the uppermost canopies in tropical dry forests in Thailand. The aims were to examine (i) whether leaf and twig hydraulic properties differ in relation to leaf phenology and (ii) whether xylem cavitation is a determinant of leaf shedding during the dry season. The variations in almost all hydraulic traits were more dependent on species than on leaf phenology. Evergreen Hopea exhibited the lowest leaf-area-specific twig hydraulic conductivity (leaf-area-specific K(twig)), lamina hydraulic conductance (K(lamina)) and leaf osmotic potential at full turgor (Ψ(o)) among species, whereas evergreen Syzygium exhibited the highest leaf-area-specific K(twig), K(lamina) and Ψ(o). Deciduous Xylia had the highest sapwood-area-specific K(twig), along with the lowest Huber value (sapwood area/leaf area). More negative osmotic Ψ(o) and leaf osmotic adjustment during the dry season were found in deciduous Vitex and evergreen Hopea, accompanied by low sapwood-area-specific K(twig). Regarding seasonal changes in hydraulics, no remarkable decrease in K(lamina) and K(twig) was found during the dry season in any species. Results suggest that leaf shedding during the dry season is not always associated with extensive xylem cavitation.

The potential negative impacts of global climate change on tropical montane cloud forests

Science.gov (United States)

Foster, Pru

2001-10-01

Nearly every aspect of the cloud forest is affected by regular cloud immersion, from the hydrological cycle to the species of plants and animals within the forest. Since the altitude band of cloud formation on tropical mountains is limited, the tropical montane cloud forest occurs in fragmented strips and has been likened to island archipelagoes. This isolation and uniqueness promotes explosive speciation, exceptionally high endemism, and a great sensitivity to climate. Global climate change threatens all ecosystems through temperature and rainfall changes, with a typical estimate for altitude shifts in the climatic optimum for mountain ecotones of hundreds of meters by the time of CO 2 doubling. This alone suggests complete replacement of many of the narrow altitude range cloud forests by lower altitude ecosystems, as well as the expulsion of peak residing cloud forests into extinction. However, the cloud forest will also be affected by other climate changes, in particular changes in cloud formation. A number of global climate models suggest a reduction in low level cloudiness with the coming climate changes, and one site in particular, Monteverde, Costa Rica, appears to already be experiencing a reduction in cloud immersion. The coming climate changes appear very likely to upset the current dynamic equilibrium of the cloud forest. Results will include biodiversity loss, altitude shifts in species' ranges and subsequent community reshuffling, and possibly forest death. Difficulties for cloud forest species to survive in climate-induced migrations include no remaining location with a suitable climate, no pristine location to colonize, migration rates or establishment rates that cannot keep up with climate change rates and new species interactions. We review previous cloud forest species redistributions in the paleo-record in light of the coming changes. The characteristic epiphytes of the cloud forest play an important role in the light, hydrological and nutrient

Estimation of above ground biomass by using multispectral data for Evergreen Forest in Phu Hin Rong Kla National Park, Thailand

International Nuclear Information System (INIS)

Suwanprasit, C.

2010-01-01

Tropical forest is the most important and largest source for stocking CO 2 from the atmosphere which might be one of the main sources of carbon emission, global warming and climate change in recent decades. There are two main objectives of this study. The first one is to establish a relationship between above ground biomass and vegetation indices and the other is to evaluate above ground biomass and carbon sequestration for evergreen forest areas in Phu Hin Rong Kla National park, Thailand. Random sampling design based was applied for calculating the above ground biomass at stand level in the selected area by using Brown and Tsutsumi allometric equations. Landsat 7 ETM+ data in February 2009 was used. Support Vector Machine (SVM) was applied for identifying evergreen forest area. Forty-three of vegetation indices and image transformations were used for finding the best correlation with forest stand biomass. Regression analysis was used to investigate the relationship between the biomass volume at stand level and digital data from the satellite image. TM51 which derived from Tsutsumi allometric equation was the highest correlation with stand biomass. Normalized Difference Vegetation Index (NDVI) was not the best correlation in this study. The best biomass estimation model was from TM51 and ND71 (R2 =0.658). The totals of above ground biomass and carbon sequestration were 112,062,010 ton and 56,031,005 ton respectively. The application of this study would be quite useful for understanding the terrestrial carbon dynamics and global climate change. (author)

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.

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.

Effect of the degree of anthropization in the structure, at three sites fragmented evergreen piedmont forest

Directory of Open Access Journals (Sweden)

Hugo Gabriel Sánchez Villacis

2017-08-01

Full Text Available The Ecuadorian Amazon is recognized worldwide for its extraordinary megadiversity and multiplicity of forest goods and services. However, the inadequate practices of extractive use of non-timber forest products, the clearing of extensive areas of forests for the development of oil activity and the unsustainable use of timber as economic sustenance of communities have led to structural and functional changes In ecosystems. The study was carried out in three sites of a degraded evergreen forest of the eastern Amazon (Mera, Shell and Puyo in order to evaluate the effect of the degree of intervention on the forest structure. A floristic inventory was carried out with 60 plots of 25 x 25 m2 and tree species ≥ 2.5 cm d1.30 and species in natural regeneration phase with h <2 m were measured. We found 35 families, 65 genera, 101 species and 2 298 individuals, with Arecaceae, Fabaceae and Moraceae being the most representative botanical families. The degree of anthropization was highly modified where Mera was the best state of conservation. It was evidenced a low floristic diversity with patterns of alteration in the vertical and horizontal structure, distinguished phytosociologically by two strata in the sites of Shell and Puyo and by three in Mera, indicator of structural changes.

Phosphorus conservation by evergreenness of mountain laurel. [Kalmia latifolia

Energy Technology Data Exchange (ETDEWEB)

Thomas, W A [Oak Ridge National Lab., TN; Grigal, D F

1976-01-01

Field studies and compartmental model analyses demonstrate that the evergreen nature of mountain laurel Kalmia latifolia L. helps conserve phosphorus on infertile sites. The perennial canopy continuously adds P to the forest floor through foliar leaching and year-round leaf fall. Slow mineralization of leaf litter provides a steady addition of available P. The evergreenness of Kalmia allows it to utilize increases in available P, thus keeping it in circulation through biological tissues. Retention of a sufficient P supply in this manner allows the site to respond when changes such as disturbance or succession occur in the system.

Tree Diversity and Structure of Andaman Giant Evergreen Forests, India

Directory of Open Access Journals (Sweden)

M. Rajkumar

2008-12-01

Full Text Available We investigated tree diversity in ‘giant evergreen forest’ of Andaman and Nicobar Islands, which falls within the Indo-Burma hot spot of biodiversity in the world. A one hectare square plot was established in sites Kalapahad (KP and Macarthy Valley (MV of Middle Andamans, in which all trees ≥ 30 cm girth at breast height (gbh were enumerated. Tree diversity totaled 105 species that belonged to 63 genera and 49 families. Site MV harboured ~10% greater species richness than KP. Species diversity indices did not vary much between the two sites. In the two sites, there were 1311 individuals of trees (579 ha-1 in KP and 732 in MV. The stand basal area was nearly equal in both the sites (KP- 45.59 m2 ha-1; MV- 47.93 m2 ha-1. Thirteen tree species (12.38% were strict endemics to Andamans. Ten species recorded are rare to the flora of these islands. The two sites are distinctly dominated by two different plant families; Dipterocarpaceae in KP and Myristicaceae in MV. Most of the species were common to central and lower region of Myanmar and Indian mainland. The forest stand structure exhibited a typical reverse-J shape, but site MV had double the density of stems in the lower tree size class than that of KP. The voluminous dipterocarps contributed more to the total above-ground live biomass. The need to preserve these species- and endemics- rich, fragile island forests, prioritized for biodiversity conservation, is emphasized.

Facilitating the recovery of natural evergreen forests in South Africa via invader plant stands

Directory of Open Access Journals (Sweden)

Coert J. Geldenhuys

2017-11-01

Full Text Available Contrary to general belief, planted and naturalized stands of introduced species facilitate the recovery of natural evergreen forests and their diversity. Forest rehabilitation actions are often performed at great cost: mature forest species are planted, while species with adaptations to recover effectively and quickly after severe disturbance are ignored; or stands are cleared of invasive alien species before native tree species are planted. By contrast, cost-effective commercial plantation forestry systems generally use fast-growing pioneer tree species introduced from other natural forest regions. Such planted tree stands often facilitate the recovery of shade-tolerant native forest species. This paper provides a brief overview of disturbance-recovery processes at landscape level, and how pioneer stands of both native and introduced tree species develop from monocultures to diverse mature forest communities. It uses one example of a study of how natural forest species from small forest patches of 3 ha in total invaded a 90-ha stand of the invasive Black wattle, Acacia mearnsii, over a distance of 3.1 ha at Swellendam near Cape Town, South Africa. The study recorded 329 forest species clusters across the wattle stand: more large clusters closer to and more smaller clusters further away from natural forest patches. The 28 recorded forest species (of potentially 40 species in the surrounding forest patches included 79% tree and 21% shrub species. Colonizing forest species had mostly larger fleshy fruit and softer small seeds, and were dispersed by mostly birds and primate species. Maturing forest trees within developing clusters in the wattle stand became a source for forest regeneration away from the clusters, showing different expansion patterns. Four sets of fenced-unfenced plots in the wattle stand showed the impact of browsing by livestock, antelope, rodents and insects on the successful establishment of regenerating forest species, and the

Why Do Some Evergreen Species Keep Their Leaves for a Second Winter, While Others Lose Them?

Directory of Open Access Journals (Sweden)

Peter J. Grubb

2014-10-01

Full Text Available In subtropical montane semi-moist forest in SW China (SMSF, a large majority of evergreen tree and tall shrub species was found to have only one cohort of old leaves in early spring. In contrast, almost all species of evergreen tree and tall shrub in warm temperate rain forest (WTRF in Japan and sclerophylls in Mediterranean-climate forest (MSF of the Mediterranean Basin have two or more cohorts of old leaves in early spring; they drop their oldest cohort during or soon after leaf outgrowth in spring. Japanese WTRF has no dry season and MSF a dry summer. SMSF has a dry winter. On four evergreen Rhododendron species from SW China with only one cohort of old leaves in spring when in cultivation in Scotland, the majority of leaves in the senescing cohort fell by the end of December. We hypothesize that with dry winters, there is an advantage to dropping older leaves in autumn, because there is a low chance of appreciable positive assimilation in winter and a high chance of desiccation, reducing the resorption of dry mass and mineral nutrients from ageing leaves. Our hypothesis may be extended to cover evergreens at high altitude or high latitude that experience cold soils in winter.

Analyzing cloud base at local and regional scales to understand tropical montane cloud forest vulnerability to climate change

Science.gov (United States)

Ashley E. Van Beusekom; Grizelle Gonzalez; Martha A. Scholl

2017-01-01

The degree to which cloud immersion provides water in addition to rainfall, suppresses transpiration, and sustains tropical montane cloud forests (TMCFs) during rainless periods is not well understood. Climate and land use changes represent a threat to these forests if cloud base altitude rises as a result of regional warming or deforestation. To establish a baseline...

Water cycle observations in forest watersheds of Cambodia

Science.gov (United States)

Shimizu, A.; Tamai, K.; Kabeya, N.; Shimizu, T.; Iida, S. I.

2015-12-01

The Lower Mekong River flows through Cambodia, where forests cover ~60% of the country and are believed to have a marked effect on the water cycle. These tropical seasonal forests in the Cambodian flat lands are very precious in the Indochinese Peninsula as few forests of this type remain. However, few hydrological observations have been conducted in these areas. In Cambodia, deciduous and evergreen forests make up 42% and 33% of the total forest area, respectively. We established experimental watersheds both in deciduous and evergreen forests containing meteorological observation towers in Cambodia and collected various observational data since 2003 (O'Krieng, deciduous forest watershed including a 30-m-high observation tower, 2,245 km2; Stung Chinit, evergreen forest watershed including a 60-m-high observation tower, 3,700 km2 including three small watersheds). The basic data from these sites included various kinds of information related to the composition of vegetation, soil characteristics, etc. Hydrologic data was collected and linked to the above data; the main hydrologic research results follow. The water budget for each watershed was determined using an observational rainfall and runoff dataset. The evapotranspiration rate in an evergreen forest was obtained using various observational methods including the Bowen energy-balance ratio and the bandpass eddy covariance method. The annual evapotranspiration of evergreen forests, estimated using the Bowen energy-balance ratio method and water balance, was about 1100-1200 mm, corresponding to 70-80% of annual rainfall. While considering the importance of the presence of evergreen forest, we conducted sap flow measurements to analyze the transpiration process that maintains water uptake through root systems that reach to depths exceeding 8 m. Characteristics of the evaporation from the forest floor that form an important element of the evaporation system were estimated in both evergreen and deciduous forests.

Vegetation Response and Landscape Dynamics of Indian Summer Monsoon Variations during Holocene: An Eco-Geomorphological Appraisal of Tropical Evergreen Forest Subfossil Logs

Science.gov (United States)

Kumaran, Navnith K. P.; Padmalal, Damodaran; Nair, Madhavan K.; Limaye, Ruta B.; Guleria, Jaswant S.; Srivastava, Rashmi; Shukla, Anumeha

2014-01-01

The high rainfall and low sea level during Early Holocene had a significant impact on the development and sustenance of dense forest and swamp-marsh cover along the southwest coast of India. This heavy rainfall flooded the coastal plains, forest flourishing in the abandoned river channels and other low-lying areas in midland.The coastline and other areas in lowland of southwestern India supply sufficient evidence of tree trunks of wet evergreen forests getting buried during the Holocene period under varying thickness of clay, silty-clay and even in sand sequences. This preserved subfossil log assemblage forms an excellent proxy for eco-geomorphological and palaeoclimate appraisal reported hitherto from Indian subcontinent, and complements the available palynological data. The bulk of the subfossil logs and partially carbonized wood remains have yielded age prior to the Holocene transgression of 6.5 k yrs BP, suggesting therein that flooding due to heavy rainfall drowned the forest cover, even extending to parts of the present shelf. These preserved logs represent a unique palaeoenvironmental database as they contain observable cellular structure. Some of them can even be compared to modern analogues. As these woods belong to the Late Pleistocene and Holocene, they form a valuable source of climate data that alleviates the lack of contemporaneous meteorological records. These palaeoforests along with pollen proxies depict the warmer environment in this region, which is consistent with a Mid Holocene Thermal Maximum often referred to as Holocene Climate Optimum. Thus, the subfossil logs of tropical evergreen forests constitute new indices of Asian palaeomonsoon, while their occurrence and preservation are attributed to eco-geomorphology and hydrological regimes associated with the intensified Asian Summer Monsoon, as recorded elsewhere. PMID:24727672

Seasonal abundance and activity of pill millipedes ( Arthrosphaera magna) in mixed plantation and semi-evergreen forest of southern India

Science.gov (United States)

Ashwini, Krishna M.; Sridhar, Kandikere R.

2006-01-01

Seasonal occurrence and activity of endemic pill millipedes ( Arthrosphaera magna) were examined in organically managed mixed plantation and semi-evergreen forest reserve in southwest India between November 1996 and September 1998. Abundance and biomass of millipedes were highest in both habitats during monsoon season. Soil moisture, conductivity, organic carbon, phosphate, potassium, calcium and magnesium were higher in plantation than in forest. Millipede abundance and biomass were about 12 and 7 times higher in plantation than in forest, respectively ( P 0.05). Millipede abundance and biomass were positively correlated with rainfall ( P = 0.01). Besides rainfall, millipedes in plantation were positively correlated with soil moisture as well as temperature ( P = 0.001). Among the associated fauna with pill millipedes, earthworms rank first followed by soil bugs in both habitats. Since pill millipedes are sensitive to narrow ecological changes, the organic farming strategies followed in mixed plantation and commonly practiced in South India seem not deleterious for the endangered pill millipedes Arthrosphaera and reduce the risk of local extinctions.

Analyzing cloud base at local and regional scales to understand tropical montane cloud forest vulnerability to climate change

Science.gov (United States)

Van Beusekom, Ashley E.; González, Grizelle; Scholl, Martha A.

2017-01-01

The degree to which cloud immersion provides water in addition to rainfall, suppresses transpiration, and sustains tropical montane cloud forests (TMCFs) during rainless periods is not well understood. Climate and land use changes represent a threat to these forests if cloud base altitude rises as a result of regional warming or deforestation. To establish a baseline for quantifying future changes in cloud base, we installed a ceilometer at 100 m altitude in the forest upwind of the TMCF that occupies an altitude range from ∼ 600 m to the peaks at 1100 m in the Luquillo Mountains of eastern Puerto Rico. Airport Automated Surface Observing System (ASOS) ceilometer data, radiosonde data, and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite data were obtained to investigate seasonal cloud base dynamics, altitude of the trade-wind inversion (TWI), and typical cloud thickness for the surrounding Caribbean region. Cloud base is rarely quantified near mountains, so these results represent a first look at seasonal and diurnal cloud base dynamics for the TMCF. From May 2013 to August 2016, cloud base was lowest during the midsummer dry season, and cloud bases were lower than the mountaintops as often in the winter dry season as in the wet seasons. The lowest cloud bases most frequently occurred at higher elevation than 600 m, from 740 to 964 m. The Luquillo forest low cloud base altitudes were higher than six other sites in the Caribbean by ∼ 200–600 m, highlighting the importance of site selection to measure topographic influence on cloud height. Proximity to the oceanic cloud system where shallow cumulus clouds are seasonally invariant in altitude and cover, along with local trade-wind orographic lifting and cloud formation, may explain the dry season low clouds. The results indicate that climate change threats to low-elevation TMCFs are not limited to the dry season; changes in synoptic-scale weather patterns

Interannual variation of carbon fluxes from three contrasting evergreen forests: the role of forest dynamics and climate.

Science.gov (United States)

Sierra, Carlos A; Loescher, Henry W; Harmon, Mark E; Richardson, Andrew D; Hollinger, David Y; Perakis, Steven S

2009-10-01

Interannual variation of carbon fluxes can be attributed to a number of biotic and abiotic controls that operate at different spatial and temporal scales. Type and frequency of disturbance, forest dynamics, and climate regimes are important sources of variability. Assessing the variability of carbon fluxes from these specific sources can enhance the interpretation of past and current observations. Being able to separate the variability caused by forest dynamics from that induced by climate will also give us the ability to determine if the current observed carbon fluxes are within an expected range or whether the ecosystem is undergoing unexpected change. Sources of interannual variation in ecosystem carbon fluxes from three evergreen ecosystems, a tropical, a temperate coniferous, and a boreal forest, were explored using the simulation model STANDCARB. We identified key processes that introduced variation in annual fluxes, but their relative importance differed among the ecosystems studied. In the tropical site, intrinsic forest dynamics contributed approximately 30% of the total variation in annual carbon fluxes. In the temperate and boreal sites, where many forest processes occur over longer temporal scales than those at the tropical site, climate controlled more of the variation among annual fluxes. These results suggest that climate-related variability affects the rates of carbon exchange differently among sites. Simulations in which temperature, precipitation, and radiation varied from year to year (based on historical records of climate variation) had less net carbon stores than simulations in which these variables were held constant (based on historical records of monthly average climate), a result caused by the functional relationship between temperature and respiration. This suggests that, under a more variable temperature regime, large respiratory pulses may become more frequent and high enough to cause a reduction in ecosystem carbon stores. Our results

Interannual variation of carbon fluxes from three contrasting evergreen forests: The role of forest dynamics and climate

Science.gov (United States)

Sierra, C.A.; Loescher, H.W.; Harmon, M.E.; Richardson, A.D.; Hollinger, D.Y.; Perakis, S.S.

2009-01-01

Interannual variation of carbon fluxes can be attributed to a number of biotic and abiotic controls that operate at different spatial and temporal scales. Type and frequency of disturbance, forest dynamics, and climate regimes are important sources of variability. Assessing the variability of carbon fluxes from these specific sources can enhance the interpretation of past and current observations. Being able to separate the variability caused by forest dynamics from that induced by climate will also give us the ability to determine if the current observed carbon fluxes are within an expected range or whether the ecosystem is undergoing unexpected change. Sources of interannual variation in ecosystem carbon fluxes from three evergreen ecosystems, a tropical, a temperate coniferous, and a boreal forest, were explored using the simulation model STANDCARB. We identified key processes that introduced variation in annual fluxes, but their relative importance differed among the ecosystems studied. In the tropical site, intrinsic forest dynamics contributed ?? 30% of the total variation in annual carbon fluxes. In the temperate and boreal sites, where many forest processes occur over longer temporal scales than those at the tropical site, climate controlled more of the variation among annual fluxes. These results suggest that climate-related variability affects the rates of carbon exchange differently among sites. Simulations in which temperature, precipitation, and radiation varied from year to year (based on historical records of climate variation) had less net carbon stores than simulations in which these variables were held constant (based on historical records of monthly average climate), a result caused by the functional relationship between temperature and respiration. This suggests that, under a more variable temperature regime, large respiratory pulses may become more frequent and high enough to cause a reduction in ecosystem carbon stores. Our results also show

Endophytic Fungi of Various Medicinal Plants Collected From Evergreen Forest Baluran National Park and Its Potential as Laboratory Manual for Mycology Course

OpenAIRE

Murdiyah, Siti

2017-01-01

Endophytic fungi found on a variety of medicinal plants may express particular benefit. These fungi provide an alternative to overcome the progressive microbial resistance and as an effort to combat infectious diseases that became one of the leading causes of mortality. The main objective of this study was to isolate endophytic fungi from leaf samples of five medicinal plants species collected from evergreen forests Baluran National Park and its use as laboratory manual for Micology. Research...

Predicting vegetation type through physiological and environmental interactions with leaf traits: evergreen and deciduous forests in an earth system modeling framework.

Science.gov (United States)

Weng, Ensheng; Farrior, Caroline E; Dybzinski, Ray; Pacala, Stephen W

2017-06-01

Earth system models are incorporating plant trait diversity into their land components to better predict vegetation dynamics in a changing climate. However, extant plant trait distributions will not allow extrapolations to novel community assemblages in future climates, which will require a mechanistic understanding of the trade-offs that determine trait diversity. In this study, we show how physiological trade-offs involving leaf mass per unit area (LMA), leaf lifespan, leaf nitrogen, and leaf respiration may explain the distribution patterns of evergreen and deciduous trees in the temperate and boreal zones based on (1) an evolutionary analysis of a simple mathematical model and (2) simulation experiments of an individual-based dynamic vegetation model (i.e., LM3-PPA). The evolutionary analysis shows that these leaf traits set up a trade-off between carbon- and nitrogen-use efficiency at the scale of individual trees and therefore determine competitively dominant leaf strategies. As soil nitrogen availability increases, the dominant leaf strategy switches from one that is high in nitrogen-use efficiency to one that is high in carbon-use efficiency or, equivalently, from high-LMA/long-lived leaves (i.e., evergreen) to low-LMA/short-lived leaves (i.e., deciduous). In a region of intermediate soil nitrogen availability, the dominant leaf strategy may be either deciduous or evergreen depending on the initial conditions of plant trait abundance (i.e., founder controlled) due to feedbacks of leaf traits on soil nitrogen mineralization through litter quality. Simulated successional patterns by LM3-PPA from the leaf physiological trade-offs are consistent with observed successional dynamics of evergreen and deciduous forests at three sites spanning the temperate to boreal zones. © 2016 John Wiley & Sons Ltd.

Islands in the Sky: Ecophysiological Cloud-Vegetation Linkages in Southern Appalachian Mountain Cloud Forests

Science.gov (United States)

Reinhardt, K.; Emanuel, R. E.; Johnson, D. M.

2013-12-01

Mountain cloud forest (MCF) ecosystems are characterized by a high frequency of cloud fog, with vegetation enshrouded in fog. The altitudinal boundaries of cloud-fog zones co-occur with conspicuous, sharp vegetation ecotones between MCF- and non-MCF-vegetation. This suggests linkages between cloud-fog and vegetation physiology and ecosystem functioning. However, very few studies have provided a mechanistic explanation for the sharp changes in vegetation communities, or how (if) cloud-fog and vegetation are linked. We investigated ecophysiological linkages between clouds and trees in Southern Appalachian spruce-fir MCF. These refugial forests occur in only six mountain-top, sky-island populations, and are immersed in clouds on up to 80% of all growing season days. Our fundamental research questions was: How are cloud-fog and cloud-forest trees linked? We measured microclimate and physiology of canopy tree species across a range of sky conditions (cloud immersed, partly cloudy, sunny). Measurements included: 1) sunlight intensity and spectral quality; 2) carbon gain and photosynthetic capacity at leaf (gas exchange) and ecosystem (eddy covariance) scales; and 3) relative limitations to carbon gain (biochemical, stomatal, hydraulic). RESULTS: 1) Midday sunlight intensity ranged from very dark (2500 μmol m-2 s-1), and was highly variable on minute-to-minute timescales whenever clouds were present in the sky. Clouds and cloud-fog increased the proportion of blue-light wavelengths 5-15% compared to sunny conditions, and altered blue:red and red:far red ratios, both of which have been shown to strongly affect stomatal functioning. 2) Cloud-fog resulted in ~50% decreased carbon gain at leaf and ecosystem scales, due to sunlight levels below photosynthetic light-saturation-points. However, greenhouse studies and light-response-curve analyses demonstrated that MCF tree species have low light-compensation points (can photosynthesize even at low light levels), and maximum

Whole-tree distribution and temporal variation of non-structural carbohydrates in broadleaf evergreen trees.

Science.gov (United States)

Smith, Merryn G; Miller, Rebecca E; Arndt, Stefan K; Kasel, Sabine; Bennett, Lauren T

2018-04-01

Non-structural carbohydrates (NSCs) form a fundamental yet poorly quantified carbon pool in trees. Studies of NSC seasonality in forest trees have seldom measured whole-tree NSC stocks and allocation among organs, and are not representative of all tree functional types. Non-structural carbohydrate research has primarily focussed on broadleaf deciduous and coniferous evergreen trees with distinct growing seasons, while broadleaf evergreen trees remain under-studied despite their different growth phenology. We measured whole-tree NSC allocation and temporal variation in Eucalyptus obliqua L'Hér., a broadleaf evergreen tree species typically occurring in mixed-age temperate forests, which has year-round growth and the capacity to resprout after fire. Our overarching objective was to improve the empirical basis for understanding the functional importance of NSC allocation and stock changes at the tree- and organ-level in this tree functional type. Starch was the principal storage carbohydrate and was primarily stored in the stem and roots of young (14-year-old) trees rather than the lignotuber, which did not appear to be a specialized starch storage organ. Whole-tree NSC stocks were depleted during spring and summer due to significant decreases in starch mass in the roots and stem, seemingly to support root and crown growth but potentially exacerbated by water stress in summer. Seasonality of stem NSCs differed between young and mature trees, and was not synchronized with stem basal area increments in mature trees. Our results suggest that the relative magnitude of seasonal NSC stock changes could vary with tree growth stage, and that the main drivers of NSC fluctuations in broadleaf evergreen trees in temperate biomes could be periodic disturbances such as summer drought and fire, rather than growth phenology. These results have implications for understanding post-fire tree recovery via resprouting, and for incorporating NSC pools into carbon models of mixed

Phylogenetic Structure of Tree Species across Different Life Stages from Seedlings to Canopy Trees in a Subtropical Evergreen Broad-Leaved Forest.

Science.gov (United States)

Jin, Yi; Qian, Hong; Yu, Mingjian

2015-01-01

Investigating patterns of phylogenetic structure across different life stages of tree species in forests is crucial to understanding forest community assembly, and investigating forest gap influence on the phylogenetic structure of forest regeneration is necessary for understanding forest community assembly. Here, we examine the phylogenetic structure of tree species across life stages from seedlings to canopy trees, as well as forest gap influence on the phylogenetic structure of forest regeneration in a forest of the subtropical region in China. We investigate changes in phylogenetic relatedness (measured as NRI) of tree species from seedlings, saplings, treelets to canopy trees; we compare the phylogenetic turnover (measured as βNRI) between canopy trees and seedlings in forest understory with that between canopy trees and seedlings in forest gaps. We found that phylogenetic relatedness generally increases from seedlings through saplings and treelets up to canopy trees, and that phylogenetic relatedness does not differ between seedlings in forest understory and those in forest gaps, but phylogenetic turnover between canopy trees and seedlings in forest understory is lower than that between canopy trees and seedlings in forest gaps. We conclude that tree species tend to be more closely related from seedling to canopy layers, and that forest gaps alter the seedling phylogenetic turnover of the studied forest. It is likely that the increasing trend of phylogenetic clustering as tree stem size increases observed in this subtropical forest is primarily driven by abiotic filtering processes, which select a set of closely related evergreen broad-leaved tree species whose regeneration has adapted to the closed canopy environments of the subtropical forest developed under the regional monsoon climate.

[Biomass allometric equations of nine common tree species in an evergreen broadleaved forest of subtropical China].

Science.gov (United States)

Zuo, Shu-di; Ren, Yin; Weng, Xian; Ding, Hong-feng; Luo, Yun-jian

2015-02-01

Biomass allometric equation (BAE) considered as a simple and reliable method in the estimation of forest biomass and carbon was used widely. In China, numerous studies focused on the BAEs for coniferous forest and pure broadleaved forest, and generalized BAEs were frequently used to estimate the biomass and carbon of mixed broadleaved forest, although they could induce large uncertainty in the estimates. In this study, we developed the species-specific and generalized BAEs using biomass measurement for 9 common broadleaved trees (Castanopsis fargesii, C. lamontii, C. tibetana, Lithocarpus glaber, Sloanea sinensis, Daphniphyllum oldhami, Alniphyllum fortunei, Manglietia yuyuanensis, and Engelhardtia fenzlii) of subtropical evergreen broadleaved forest, and compared differences in species-specific and generalized BAEs. The results showed that D (diameter at breast height) was a better independent variable in estimating the biomass of branch, leaf, root, aboveground section and total tree than a combined variable (D2 H) of D and H (tree height) , but D2H was better than D in estimating stem biomass. R2 (coefficient of determination) values of BAEs for 6 species decreased when adding H as the second independent variable into D- only BAEs, where R2 value for S. sinensis decreased by 5.6%. Compared with generalized D- and D2H-based BAEs, standard errors of estimate (SEE) of BAEs for 8 tree species decreased, and similar decreasing trend was observed for different components, where SEEs of the branch decreased by 13.0% and 20.3%. Therefore, the biomass carbon storage and its dynamic estimates were influenced largely by tree species and model types. In order to improve the accuracy of the estimates of biomass and carbon, we should consider the differences in tree species and model types.

Presence of understory shrubs constrains carbon gain in sunflecks by advance-regeneration seedlings: evidence from Quercus Rubra seedling grouwing in understory forest patches with or without evergreen shrubs present

Science.gov (United States)

E.T. Nilsen; T.T. Lei; S.W. Semones

2009-01-01

We investigated whether dynamic photosynthesis of understory Quercus rubra L. (Fagaceae) seedlings can acclimate to the altered pattern of sunflecks in forest patches with Rhododendron maximum L. (Ericaceae), an understory evergreen shrub. Maximum photosynthesis (A) and total CO2 accumulated during lightflecks was greatest for 400-s lightflecks, intermediate for 150-s...

Lidar observed seasonal variation of vertical canopy structure in the Amazon evergreen forests

Science.gov (United States)

Tang, H.; Dubayah, R.

2017-12-01

Both light and water are important environmental factors governing tree growth. Responses of tropical forests to their changes are complicated and can vary substantially across different spatial and temporal scales. Of particular interest is the dry-season greening-up of Amazon forests, a phenomenon undergoing considerable debates whether it is real or a "light illusion" caused by artifacts of passive optical remote sensing techniques. Here we analyze seasonal dynamic patterns of vertical canopy structure in the Amazon forests using lidar observations from NASA's Ice, Cloud, and and land Elevation Satellite (ICESat). We found that the net greening of canopy layer coincides with the wet-to-dry transition period, and its net browning occurs mostly at the late dry season. The understory also shows a seasonal cycle, but with an opposite variation to canopy and minimal correlation to seasonal variations in rainfall or radiation. Our results further suggest a potential interaction between canopy layers in the light regime that can optimize the growth of Amazon forests during the dry season. This light regime variability that exists in both spatial and temporal domains can better reveal the dry-season greening-up phenomenon, which appears less obvious when treating the Amazon forests as a whole.

Community composition and cellulase activity of cellulolytic bacteria from forest soils planted with broad-leaved deciduous and evergreen trees.

Science.gov (United States)

Yang, Jiang-Ke; Zhang, Jing-Jing; Yu, Heng-Yu; Cheng, Jian-Wen; Miao, Li-Hong

2014-02-01

Cellulolytic bacteria in forest soil provide carbon sources to improve the soil fertility and sustain the nutrient balance of the forest ecological system through the decomposition of cellulosic remains. These bacteria can also be utilized for the biological conversion of biomass into renewable biofuels. In this study, the community compositions and activities of cellulolytic bacteria in the soils of forests planted with broad-leaved deciduous (Chang Qing Garden, CQG) and broad-leaved evergreen (Forest Park, FP) trees in Wuhan, China were resolved through restriction fragment length polymorphism (RFLP) and sequencing analysis of the 16S rRNA gene. All of the isolates exhibited 35 RFLP fingerprint patterns and were clustered into six groups at a similarity level of 50 %. The phylogeny analysis based on the 16S rRNA gene sequence revealed that these RFLP groups could be clustered into three phylogenetic groups and further divided into six subgroups at a higher resolution. Group I consists of isolates from Bacillus cereus, Bacillus subtilis complex (I-A) and from Paenibacillus amylolyticus-related complex (I-B) and exhibited the highest cellulase activity among all of the cellulolytic bacteria isolates. Cluster II consists of isolates belonging to Microbacterium testaceum (II-A), Chryseobacterium indoltheticum (II-B), and Flavobacterium pectinovorum and the related complex (II-C). Cluster III consists of isolates belonging to Pseudomonas putida-related species. The community shift with respect to the plant species and the soil properties was evidenced by the phylogenetic composition of the communities. Groups I-A and I-B, which account for 36.0 % of the cellulolytic communities in the CQG site, are the dominant groups (88.4 %) in the FP site. Alternatively, the ratio of the bacteria belonging to group III (P. putida-related isolates) shifted from 28.0 % in CQG to 4.0 % in FP. The soil nutrient analysis revealed that the CQG site planted with deciduous broad

The leaf size-twig size spectrum in evergreen broadleaved forest of ...

African Journals Online (AJOL)

Compared to deciduous broad-leaved species, the evergreen broad-leaved species were smaller in total leaf area for a given cross-sectional area or stem mass. This suggests that the species would support less leaf area at a given twig cross-sectional area with increasing environmental stress. And the life form can modify ...

A Variable Impacts Measurement in Random Forest for Mobile Cloud Computing

Directory of Open Access Journals (Sweden)

Jae-Hee Hur

2017-01-01

Full Text Available Recently, the importance of mobile cloud computing has increased. Mobile devices can collect personal data from various sensors within a shorter period of time and sensor-based data consists of valuable information from users. Advanced computation power and data analysis technology based on cloud computing provide an opportunity to classify massive sensor data into given labels. Random forest algorithm is known as black box model which is hardly able to interpret the hidden process inside. In this paper, we propose a method that analyzes the variable impact in random forest algorithm to clarify which variable affects classification accuracy the most. We apply Shapley Value with random forest to analyze the variable impact. Under the assumption that every variable cooperates as players in the cooperative game situation, Shapley Value fairly distributes the payoff of variables. Our proposed method calculates the relative contributions of the variables within its classification process. In this paper, we analyze the influence of variables and list the priority of variables that affect classification accuracy result. Our proposed method proves its suitability for data interpretation in black box model like a random forest so that the algorithm is applicable in mobile cloud computing environment.

Life in the clouds: are tropical montane cloud forests responding to changes in climate?

Science.gov (United States)

Hu, Jia; Riveros-Iregui, Diego A

2016-04-01

The humid tropics represent only one example of the many places worldwide where anthropogenic disturbance and climate change are quickly affecting the feedbacks between water and trees. In this article, we address the need for a more long-term perspective on the effects of climate change on tropical montane cloud forests (TMCF) in order to fully assess the combined vulnerability and long-term response of tropical trees to changes in precipitation regimes, including cloud immersion. We first review the ecophysiological benefits that cloud water interception offers to trees in TMCF and then examine current climatological evidence that suggests changes in cloud base height and impending changes in cloud immersion for TMCF. Finally, we propose an experimental approach to examine the long-term dynamics of tropical trees in TMCF in response to environmental conditions on decade-to-century time scales. This information is important to assess the vulnerability and long-term response of TMCF to changes in cloud cover and fog frequency and duration.

Effect of Severe Winter Cold on the Photosynthetic Potentials of Three Co-occurring Evergreen Woody Species in a Mediterranean Forest, Catalonia (Spain)

Science.gov (United States)

Sperlich, Dominik; Gracia, Carlos; Peñuelas, Josep; Sabaté, Santi

2013-04-01

Evergreen tree species in the Mediterranean region have to cope with a wide range of environmental stress conditions from summer drought to winter cold. The winter period can lead to photoinhibition due to a combination of high solar irradiances and chilling temperatures which can reduce the light saturation point. However, Mediterranean winter mildness can lead periodically to favourable environmental conditions above the threshold for positive carbon balance benefitting evergreen woody species in contrast to winter deciduous species. The advantage of being able to photosynthesis all year round with a significant fraction in the winter month is compensating for the lower photosynthetic potentials during spring and summer in comparison to deciduous species. In this work, we investigated the physiological behaviour of three evergreen tree species (Quercus ilex, Pinus halepensis, Arbutus undeo) co-occurring in a natural and mature Mediterranean forest after a period of mild winter conditions and their response to a sudden period of intense cold weather. Therefore, we examined in each period the photosynthetic potentials by estimating the maximum carboxylation rate (Vcmax) and the maximum electron transport rate (Jmax) through gas exchange measurements. The results indicate that all species exhibited extraordinary high photosynthetic potentials during the first period of measurement as a response to the mild conditions. However, the sudden cold period affected negatively the photosynthetic potentials of Quercus ilex and A. unedo with reduction ranging between 37 to 45 %, whereas they were observed to be only insignificantly reduced in Pinus halepensis. Our results can be explained by previous classifications into photoinhibition-avoiding (P. halpensis) and photoinhibition-tolerant (Q. ilex, A. undeo) species on the basis of their susceptibility to dynamic photoinhibition (Martinez Ferri 2000). Photoinhibition tolerant species are characterised with a more dynamic

Accuracy of LiDAR-based tree height estimation and crown recognition in a subtropical evergreen broad-leaved forest in Okinawa, Japan

Directory of Open Access Journals (Sweden)

Azita Ahmad Zawawi

2015-04-01

Full Text Available Aim of study: To present an approach for estimating tree heights, stand density and crown patches using LiDAR data in a subtropical broad-leaved forest. Area of study: The study was conducted within the Yambaru subtropical evergreen broad-leaved forest, Okinawa main island, Japan. Materials and methods: A digital canopy height model (CHM was extracted from the LiDAR data for tree height estimation and a watershed segmentation method was applied for the individual crown delineation. Dominant tree canopy layers were estimated using multi-scale filtering and local maxima detection. The LiDAR estimation results were then compared to the ground inventory data and a high resolution orthophoto image for accuracy assessment. Main results: A Wilcoxon matched pair test suggests that LiDAR data is highly capable of estimating tree height in a subtropical forest (z = 4.0, p = 0.345, but has limitation to detect small understory trees and a single tree delineation. The results show that there is a statistically significant different type of crown detection from LiDAR data over forest inventory (z = 0, p = 0.043. We also found that LiDAR computation results underestimated the stand density and overestimated the crown size. Research highlights: Most studies involving crown detection and tree height estimation have focused on the analysis of plantations, boreal forests and temperate forests, and less was conducted on tropical and/or subtropical forests. Our study tested the capability of LiDAR as an effective application for analyzing a highly dense forest

Distribution patterns of the subtropical evergreen broad-leaved forests of southwestern China, as compared with those of the eastern Chinese subtropical regions

Directory of Open Access Journals (Sweden)

Tang, C. Q.

2015-12-01

Full Text Available This paper analyzes the geographic distribution patterns of the subtropical evergreen broad-leaved forests of southwestern China, and compares with other subtropical regions in the east of China in terms of forest types, pertinent species, and spatial distribution along latitudinal, longitudinal and altitudinal gradients. In general, for both the western and the eastern subtropical regions, the evergreen broad-leaved forests are dominated by species of Castanopsis, Lithocarpus, Cyclobalanopsis (Fagaceae, Machilus, Cinnamomum (Lauraceae, Schima (Theaceae, Manglietia, and Michelia, (Magnoliaceae, while in southwestern China there are more diverse forest types including semi-humid, monsoon, mid-montane moist and humid evergreen broad-leaved forests, but only monsoon and humid forests in the east. The Yunnan area has more varied species of Lithocarpus or Cyclobalanopsis or Castanopsis as dominants than does eastern China, where the chief dominant genus is Castanopsis. The upper limits of the evergreen broad-leaved forests are mainly 2400–2800 m in western Yunnan and western Sichuan, much higher than in eastern China (600–1500, but 2500 m in Taiwan. Also discussed are the environmental effects on plant diversity of the evergreen broad-leaved forest ecosystems exemplified by Yunnan and Taiwan.En este trabajo se analiza los patrones de distribución geográfica de los bosques subtropicales perennifolios de hoja ancha del suroeste de china, y se comparan con los de otras regiones subtropicales del este de China en términos de tipología de bosque, especies relevantes, y distribución espacial a lo largo de un gradiente latitudinal, longitudinal y altitudinal. De manera general, los bosques perennifolios de hoja ancha de la regiones subtropicales tanto orientales como occidentales presentan dominancia de especies de Castanopsis, Lithocarpus, Cyclobalanopsis (Fagaceae, Machilus, Cinnamomum (Lauraceae, Schima (Theaceae, Manglietia y Michelia

Impact of a drier Early-Mid-Holocene climate upon Amazonian forests.

Science.gov (United States)

Mayle, Francis E; Power, Mitchell J

2008-05-27

This paper uses a palaeoecological approach to examine the impact of drier climatic conditions of the Early-Mid-Holocene (ca 8000-4000 years ago) upon Amazonia's forests and their fire regimes. Palaeovegetation (pollen data) and palaeofire (charcoal) records are synthesized from 20 sites within the present tropical forest biome, and the underlying causes of any emergent patterns or changes are explored by reference to independent palaeoclimate data and present-day patterns of precipitation, forest cover and fire activity across Amazonia. During the Early-Mid-Holocene, Andean cloud forest taxa were replaced by lowland tree taxa as the cloud base rose while lowland ecotonal areas, which are presently covered by evergreen rainforest, were instead dominated by savannahs and/or semi-deciduous dry forests. Elsewhere in the Amazon Basin there is considerable spatial and temporal variation in patterns of vegetation disturbance and fire, which probably reflects the complex heterogeneous patterns in precipitation and seasonality across the basin, and the interactions between climate change, drought- and fire susceptibility of the forests, and Palaeo-Indian land use. Our analysis shows that the forest biome in most parts of Amazonia appears to have been remarkably resilient to climatic conditions significantly drier than those of today, despite widespread evidence of forest burning. Only in ecotonal areas is there evidence of biome replacement in the Holocene. From this palaeoecological perspective, we argue against the Amazon forest 'dieback' scenario simulated for the future.

Water use efficiency in a primary subtropical evergreen forest in Southwest China.

Science.gov (United States)

Song, Qing-Hai; Fei, Xue-Hai; Zhang, Yi-Ping; Sha, Li-Qing; Liu, Yun-Tong; Zhou, Wen-Jun; Wu, Chuan-Sheng; Lu, Zhi-Yun; Luo, Kang; Gao, Jin-Bo; Liu, Yu-Hong

2017-02-20

We calculated water use efficiency (WUE) using measures of gross primary production (GPP) and evapotranspiration (ET) from five years of continuous eddy covariance measurements (2009-2013) obtained over a primary subtropical evergreen broadleaved forest in southwestern China. Annual mean WUE exhibited a decreasing trend from 2009 to 2013, varying from ~2.28 to 2.68 g C kg H 2 O -1 . The multiyear average WUE was 2.48 ± 0.17 (mean ± standard deviation) g C kg H 2 O -1 . WUE increased greatly in the driest year (2009), due to a larger decline in ET than in GPP. At the diurnal scale, WUE in the wet season reached 5.1 g C kg H 2 O -1 in the early morning and 4.6 g C kg H 2 O -1 in the evening. WUE in the dry season reached 3.1 g C kg H 2 O -1 in the early morning and 2.7 g C kg H 2 O -1 in the evening. During the leaf emergence stage, the variation of WUE could be suitably explained by water-related variables (relative humidity (RH), soil water content at 100 cm (SWC_100)), solar radiation and the green index (Sgreen). These results revealed large variation in WUE at different time scales, highlighting the importance of individual site characteristics.

[Early responses of soil fauna in three typical forests of south subtropical China to simulated N deposition addition].

Science.gov (United States)

Xu, Guolian; Mo, Jiangming; Zhou, Guoyi

2005-07-01

In this paper, simulated N deposition addition (0, 50, 100 and 150 kg x hm(-2) x yr(-1)) by spreading water or NH4NO3 was conducted to study the early responses of soil fauna in three typical native forests (monsoon evergreen broadleaf forest, pine forest, and broadleaf-pine mixed forest) of subtropical China. The results showed that in monsoon evergreen broadleaf forest, N deposition addition had an obviously negative effect on the three indexes for soil fauna, but in pine forest, the positive effect was significant (P soil fauna community could reach the level in mixed forest, even that in monsoon evergreen broadleaf forest at sometime. The responses in mixed forest were not obvious. In monsoon evergreen broadleaf forest, the negative effects were significant (P soil fauna groups. The results obtained might imply the N saturation-response mechanisms of forest ecosystems in subtropical China, and the conclusions from this study were also consisted with some related researches.

The influence of canopy-layer composition on understory plant diversity in southern temperate forests

Directory of Open Access Journals (Sweden)

Luciana Mestre

2017-05-01

Full Text Available Background Understory plants represents the largest component of biodiversity in most forest ecosystems and plays a key role in forest functioning. Despite their importance, the influence of overstory-layer composition on understory plant diversity is relatively poorly understood within deciduous-evergreen broadleaved mixed forests. The aim of this work was to evaluate how tree overstory-layer composition influences on understory-layer diversity in three forest types (monospecific deciduous Nothofagus pumilio (Np, monospecific evergreen Nothofagus betuloides (Nb, and mixed N. pumilio-N. betuloides (M forests, comparing also between two geographical locations (coast and mountain to estimate differences at landscape level. Results We recorded 46 plant species: 4 ferns, 12 monocots, and 30 dicots. Canopy-layer composition influences the herb-layer structure and diversity in two different ways: while mixed forests have greater similarity to evergreen forests in the understory structural features, deciduous and mixed were similar in terms of the specific composition of plant assemblage. Deciduous pure stands were the most diverse, meanwhile evergreen stands were least diverse. Lack of exclusive species of mixed forest could represent a transition where evergreen and deciduous communities meet and integrate. Moreover, landscape has a major influence on the structure, diversity and richness of understory vegetation of pure and mixed forests likely associated to the magnitude and frequency of natural disturbances, where mountain forest not only had highest herb-layer diversity but also more exclusive species. Conclusions Our study suggests that mixed Nothofagus forest supports coexistence of both pure deciduous and pure evergreen understory plant species and different assemblages in coastal and mountain sites. Maintaining the mixture of canopy patch types within mixed stands will be important for conserving the natural patterns of understory plant

Estimating seasonal variations in cloud droplet number concentration over the boreal forest from satellite observations

NARCIS (Netherlands)

Janssen, R.; Ganzeveld, L.N.; Kabat, P.; Kulmala, M.; Nieminen, T.; Roebeling, R.A.

2011-01-01

Seasonal variations in cloud droplet number concentration (NCD) in low-level stratiform clouds over the boreal forest are estimated from MODIS observations of cloud optical and microphysical properties, using a sub-adiabatic cloud model to interpret vertical profiles of cloud properties. An

Influences of evergreen gymnosperm and deciduous angiosperm tree species on the functioning of temperate and boreal forests

DEFF Research Database (Denmark)

Augusto, Laurent; De Schrijver, An; Vesterdal, Lars

2015-01-01

It has been recognized for a long time that the overstorey composition of a forest partly determines its biological and physical-chemical functioning. Here, we review evidence of the influence of evergreen gymnosperm (EG) tree species and deciduous angiosperm (DA) tree species on the water balance...... present the current state of the art, define knowledge gaps, and briefly discuss how selection of tree species can be used to mitigate pollution or enhance accumulation of stable organic carbon in the soil. The presence of EGs generally induces a lower rate of precipitation input into the soil than DAs......, resulting in drier soil conditions and lower water discharge. Soil temperature is generally not different, or slightly lower, under an EG canopy compared to a DA canopy. Chemical properties, such as soil pH, can also be significantly modified by taxonomic groups of tree species. Biomass production...

Changes in forest structure and composition after fire in tropical montane cloud forests near the Andean treeline

NARCIS (Netherlands)

Oliveras Menor, I.; Malhi, Y.; Salinas, N.; Huaman, V.; Urquiaga-Flores, E.; Kala-Mamani, J.; Quintano-Loaiza, J.A.; Cuba-Torres, I.; Lizarraga-Morales, N.; Roman-Cuesta, R.M.

2014-01-01

Background: In tropical montane cloud forests (TMCFs) fires can be a frequent source of disturbance near the treeline. Aims: To identify how forest structure and tree species composition change in response to fire and to identify fire-tolerant species, and determine which traits or characteristics

Population dynamics of the epiphytic bromeliad Tillandsia butzii in cloud forest

Science.gov (United States)

Toledo-Aceves, Tarin; Hernández-Apolinar, Mariana

2016-02-01

Epiphytes are a major component of tropical montane cloud forests. Over-exploitation and forest loss and degradation affect remnant populations. In this study, we analysed the population dynamics of the epiphytic bromeliad Tillandsia butzii over a 2-y period in a tropical montane cloud forest fragment in southern Mexico. Matrix analysis revealed that the T. butzii population is likely to be stable at the study site. On average the λ value did not differ significantly from unity: λ (95% confidence interval) = 0.978 (0.936-1.001). λ was highly influenced by stasis, to a lesser extent by growth and only slightly by fecundity. Overall, adult plant stasis and phalanx growth habit played a fundamental role in population maintenance. T. butzii tolerance to xeric conditions may contribute to population stability in the studied region.

Acceleration and novelty: community restoration speeds recovery and transforms species composition in Andean cloud forest.

Science.gov (United States)

Wilson, Sarah Jane; Rhemtulla, Jeanine M

2016-01-01

Community-based tropical forest restoration projects, often promoted as a win-win solution for local communities and the environment, have increased dramatically in number in the past decade. Many such projects are underway in Andean cloud forests, which, given their extremely high biodiversity and history of extensive clearing, are understudied. This study investigates the efficacy of community-based tree-planting projects to accelerate cloud forest recovery, as compared to unassisted natural regeneration. This study takes place in northwest Andean Ecuador, where the majority of the original, highly diverse cloud forests have been cleared, in five communities that initiated tree-planting projects to restore forests in 2003. In 2011, we identified tree species along transects in planted forests (n = 5), naturally regenerating forests (n = 5), and primary forests (n = 5). We also surveyed 120 households about their restoration methods, tree preferences, and forest uses. We found that tree diversity was higher in planted than in unplanted secondary forest, but both were less diverse than primary forests. Ordination analysis showed that all three forests had distinct species compositions, although planted forests shared more species with primary forests than did unplanted forests. Planted forests also contained more animal-dispersed species in both the planted canopy and in the unplanted, regenerating understory than unplanted forests, and contained the highest proportion of species with use value for local people. While restoring forest increased biodiversity and accelerated forest recovery, restored forests may also represent novel ecosystems that are distinct from the region's previous ecosystems and, given their usefulness to people, are likely to be more common in the future.

Introducing two Random Forest based methods for cloud detection in remote sensing images

Science.gov (United States)

Ghasemian, Nafiseh; Akhoondzadeh, Mehdi

2018-07-01

Cloud detection is a necessary phase in satellite images processing to retrieve the atmospheric and lithospheric parameters. Currently, some cloud detection methods based on Random Forest (RF) model have been proposed but they do not consider both spectral and textural characteristics of the image. Furthermore, they have not been tested in the presence of snow/ice. In this paper, we introduce two RF based algorithms, Feature Level Fusion Random Forest (FLFRF) and Decision Level Fusion Random Forest (DLFRF) to incorporate visible, infrared (IR) and thermal spectral and textural features (FLFRF) including Gray Level Co-occurrence Matrix (GLCM) and Robust Extended Local Binary Pattern (RELBP_CI) or visible, IR and thermal classifiers (DLFRF) for highly accurate cloud detection on remote sensing images. FLFRF first fuses visible, IR and thermal features. Thereafter, it uses the RF model to classify pixels to cloud, snow/ice and background or thick cloud, thin cloud and background. DLFRF considers visible, IR and thermal features (both spectral and textural) separately and inserts each set of features to RF model. Then, it holds vote matrix of each run of the model. Finally, it fuses the classifiers using the majority vote method. To demonstrate the effectiveness of the proposed algorithms, 10 Terra MODIS and 15 Landsat 8 OLI/TIRS images with different spatial resolutions are used in this paper. Quantitative analyses are based on manually selected ground truth data. Results show that after adding RELBP_CI to input feature set cloud detection accuracy improves. Also, the average cloud kappa values of FLFRF and DLFRF on MODIS images (1 and 0.99) are higher than other machine learning methods, Linear Discriminate Analysis (LDA), Classification And Regression Tree (CART), K Nearest Neighbor (KNN) and Support Vector Machine (SVM) (0.96). The average snow/ice kappa values of FLFRF and DLFRF on MODIS images (1 and 0.85) are higher than other traditional methods. The

[Biogeographic regionalization of the mammals of tropical evergreen forests in Mesoamerica].

Science.gov (United States)

Olguin-Monroy, Hector C; Gutiérrez-Blando, Cirene; Rios-Muñoz, César A; León-Paniagua, Livia; Navarro-Sigüenza, Adolfo G

2013-06-01

Mesoamerica is a biologically complex zone that expands from Southern Mexico to extreme Northern Colombia. The biogeographical patterns and relationships of the mammalian fauna associated to the Mesoamerican Tropical Evergreen Forest (MTEF) are poorly understood, in spite of the wide distribution of this kind of habitat in the region. We compiled a complete georeferenced database of mammalian species distributed in the MTEF of specimens from museum collections and scientific literature. This database was used to create potential distribution maps through the use of environmental niche models (ENMs) by using the Genetic Algorithm for Rule-Set Production (GARP) using 22 climatic and topographic layers. Each map was used as a representation of the geographic distribution of the species and all available maps were summed to obtain general patterns of species richness in the region. Also, the maps were used to construct a presence-absence matrix in a grid of squares of 0.5 degrees of side, that was analyzed in a Parsimony Analysis of Endemicity (PAE), which resulted in a hypothesis of the biogeographic scheme in the region. We compiled a total of 41 527 records of 233 species of mammals associated to the MTEF. The maximum concentration of species richness (104-138 species) is located in the areas around the Isthmus of Tehuantepec, Northeastern Chiapas-Western Guatemala, Western Honduras, Central Nicaragua to Northwestern Costa Rica and Western Panama. The proposed regionalization indicates that mammalian faunas associated to these forests are composed of two main groups that are divided by the Isthmus of Tehuantepec in Oaxaca in: a) a Northern group that includes Sierra Madre of Chiapas-Guatemala and Yucatan Peninsula; and b) an austral group, that contains the Pacific slope of Chiapas towards the South including Central America. Some individual phylogenetic studies of mammal species in the region support the relationships between the areas of endemism proposed, which

[Effects of simulated nitrogen deposition on soil microbial biomass carbon and nitrogen in natural evergreen broad-leaved forest in the Rainy Area of West China].

Science.gov (United States)

Zhou, Shi Xing; Zou, Cheng; Xiao, Yong Xiang; Xiang, Yuan Bin; Han, Bo Han; Tang, Jian Dong; Luo, Chao; Huang, Cong de

2017-01-01

To understand the effects of increasing nitrogen deposition on soil microbial biomass carbon (MBC) and nitrogen(MBN), an in situ experiment was conducted in a natural evergreen broad-leaved forest in Ya'an City, Sichuan Province. Four levels of nitrogen deposition were set: i.e., control (CK, 0 g N·m -2 ·a -1 ), low nitrogen (L, 5 g N·m -2 ·a -1 ), medium nitrogen (M, 15 g N·m -2 ·a -1 ), and high nitrogen (H, 30 g N·m -2 ·a -1 ). The results indicated that nitrogen deposition significantly decreased MBC and MBN in the 0-10 cm soil layer, and as N de-position increased, the inhibition effect was enhanced. L and M treatments had no significant effect on MBC and MBN in the 10-20 cm soil layer, while H treatment significantly reduced. The influence of N deposition on MBC and MBN was weakened with the increase of soil depth. MBC and MBN had obvious seasonal dynamic, which were highest in autumn and lowest in summer both in the 0-10 and 10-20 cm soil layers. The fluctuation ranges of soil microbial biomass C/N were respectively 10.58-11.19 and 9.62-12.20 in the 0-10 cm and 10-20 cm soil layers, which indicated that the fungi hold advantage in the soil microbial community in this natural evergreen broad-leaved forest.

Vegetation-zonation patterns across a temperate mountain cloud forest ecotone are not explained by variation in hydraulic functioning or water relations.

Science.gov (United States)

Berry, Z Carter; Johnson, Daniel M; Reinhardt, Keith

2015-09-01

Many studies have demonstrated linkages between the occurrence of fog and ecophysiological functioning in cloud forests, but few have investigated hydraulic functioning as a determining factor that explains sharp changes in vegetation. The objective of this study was to compare the plant water status during cloud-immersed and non-immersed conditions and hydraulic vulnerability in branches and roots of species across a temperate, mountain fog ecotone. Because cloud forests are often dark, cool and very moist, we expected cloud forest species to have less drought-tolerant characteristics (i.e., lower Pe and P50-the pressures required to induce a 12 and 50% loss in hydraulic conductivity, respectively) relative to non-cloud forest species in adjacent (lower elevation) forests. Additionally, due to the ability of cloud forest species to absorb cloud-fog water, we predicted greater improvements in hydraulic functioning during fog in cloud forest species relative to non-cloud forest species. Across the cloud forest ecotone, most species measured were very resistant to losses in conductivity with branch P50 values from -4.5 to -6.0 MPa, hydraulic safety margins (Ψmin - P50) >1.5 MPa and low calculated hydraulic conductivity losses. Roots had greater vulnerabilities, with P50 values ranging from -1.4 to -2.5 MPa, leading to greater predicted losses in conductivity (∼20%). Calculated values suggested strong losses of midday leaf hydraulic conductance in three of the four species, supporting the hydraulic segmentation hypothesis. In both cloud forest and hardwood species, Ψs were greater on foggy days than sunny days, demonstrating the importance of fog periods to plant water balance across fog regimes. Thus, frequent fog did not result in systemic changes in hydraulic functioning or vulnerability to embolism across our temperate cloud forest ecotone. Finally, roots functioned with lower hydraulic conductivity than branches, suggesting that they may serve as more

Historical reconstruction of climatic and elevation preferences and the evolution of cloud forest-adapted tree ferns in Mesoamerica

OpenAIRE

Sosa, Victoria; Ornelas, Juan Francisco; Ram?rez-Barahona, Santiago; G?ndara, Etelvina

2016-01-01

Background Cloud forests, characterized by a persistent, frequent or seasonal low-level cloud cover and fragmented distribution, are one of the most threatened habitats, especially in the Neotropics. Tree ferns are among the most conspicuous elements in these forests, and ferns are restricted to regions in which minimum temperatures rarely drop below freezing and rainfall is high and evenly distributed around the year. Current phylogeographic data suggest that some of the cloud forest-adapted...

Do evergreen and deciduous trees have different effects on net N mineralization in soil?

Science.gov (United States)

Mueller, Kevin E; Hobbie, Sarah E; Oleksyn, Jacek; Reich, Peter B; Eissenstat, David M

2012-06-01

Evergreen and deciduous plants are widely expected to have different impacts on soil nitrogen (N) availability because of differences in leaf litter chemistry and ensuing effects on net N mineralization (N(min)). We evaluated this hypothesis by compiling published data on net N(min) rates beneath co-occurring stands of evergreen and deciduous trees. The compiled data included 35 sets of co-occurring stands in temperate and boreal forests. Evergreen and deciduous stands did not have consistently divergent effects on net N(min) rates; net N(min) beneath deciduous trees was higher when comparing natural stands (19 contrasts), but equivalent to evergreens in plantations (16 contrasts). We also compared net N(min) rates beneath pairs of co-occurring genera. Most pairs of genera did not differ consistently, i.e., tree species from one genus had higher net N(min) at some sites and lower net N(min) at other sites. Moreover, several common deciduous genera (Acer, Betula, Populus) and deciduous Quercus spp. did not typically have higher net N(min) rates than common evergreen genera (Pinus, Picea). There are several reasons why tree effects on net N(min) are poorly predicted by leaf habit and phylogeny. For example, the amount of N mineralized from decomposing leaves might be less than the amount of N mineralized from organic matter pools that are less affected by leaf litter traits, such as dead roots and soil organic matter. Also, effects of plant traits and plant groups on net N(min) probably depend on site-specific factors such as stand age and soil type.

Impacts of cloud immersion on microclimate, photosynthesis and water relations of fraser fir in a temperate mountain cloud forest

Science.gov (United States)

Keith Reinhardt; William K. Smith

2010-01-01

The red spruce-Fraser fir ecosystem (Picea rubens Sarg.-Abies fraseri [Pursh] Poir.) of the southern Appalachian mountains is a temperate zone cloud forest immersed in clouds for 30 to 40 percent of a typical summer day, and experiencing immersion on about 65 percent of all days annually. We compared the microclimate,...

Methods for registration laser scanner point clouds in forest stands

International Nuclear Information System (INIS)

Bienert, A.; Pech, K.; Maas, H.-G.

2011-01-01

Laser scanning is a fast and efficient 3-D measurement technique to capture surface points describing the geometry of a complex object in an accurate and reliable way. Besides airborne laser scanning, terrestrial laser scanning finds growing interest for forestry applications. These two different recording platforms show large differences in resolution, recording area and scan viewing direction. Using both datasets for a combined point cloud analysis may yield advantages because of their largely complementary information. In this paper, methods will be presented to automatically register airborne and terrestrial laser scanner point clouds of a forest stand. In a first step, tree detection is performed in both datasets in an automatic manner. In a second step, corresponding tree positions are determined using RANSAC. Finally, the geometric transformation is performed, divided in a coarse and fine registration. After a coarse registration, the fine registration is done in an iterative manner (ICP) using the point clouds itself. The methods are tested and validated with a dataset of a forest stand. The presented registration results provide accuracies which fulfill the forestry requirements [de

Interactive Trunk Extraction from Forest Point Cloud

Directory of Open Access Journals (Sweden)

T. Mizoguchi

2014-06-01

Full Text Available For forest management or monitoring, it is required to constantly measure several parameters of each tree, such as height, diameter at breast height, and trunk volume. Terrestrial laser scanner has been used for this purpose instead of human workers to reduce time and cost for the measurement. In order to use point cloud captured by terrestrial laser scanner in the above applications, it is an important step to extract all trees or their trunks separately. For this purpose, we propose an interactive system in which a user can intuitively and efficiently extract each trunk by a simple editing on the distance image created from the point cloud. We demonstrate the effectiveness of our proposed system from various experiments.

Similar variation in carbon storage between deciduous and evergreen treeline species across elevational gradients.

Science.gov (United States)

Fajardo, Alex; Piper, Frida I; Hoch, Günter

2013-08-01

The most plausible explanation for treeline formation so far is provided by the growth limitation hypothesis (GLH), which proposes that carbon sinks are more restricted by low temperatures than by carbon sources. Evidence supporting the GLH has been strong in evergreen, but less and weaker in deciduous treeline species. Here a test is made of the GLH in deciduous-evergreen mixed species forests across elevational gradients, with the hypothesis that deciduous treeline species show a different carbon storage trend from that shown by evergreen species across elevations. Tree growth and concentrations of non-structural carbohydrates (NSCs) in foliage, branch sapwood and stem sapwood tissues were measured at four elevations in six deciduous-evergreen treeline ecotones (including treeline) in the southern Andes of Chile (40°S, Nothofagus pumilio and Nothofagus betuloides; 46°S, Nothofagus pumilio and Pinus sylvestris) and in the Swiss Alps (46°N, Larix decidua and Pinus cembra). Tree growth (basal area increment) decreased with elevation for all species. Regardless of foliar habit, NSCs did not deplete across elevations, indicating no shortage of carbon storage in any of the investigated tissues. Rather, NSCs increased significantly with elevation in leaves (P treeline species are sink limited when faced with decreasing temperatures. Despite the overall higher requirements of deciduous tree species for carbon storage, no indication was found of carbon limitation in deciduous species in the alpine treeline ecotone.

Age-dependent leaf physiology and consequences for crown-scale carbon uptake during the dry season in an Amazon evergreen forest.

Science.gov (United States)

Albert, Loren P; Wu, Jin; Prohaska, Neill; de Camargo, Plinio Barbosa; Huxman, Travis E; Tribuzy, Edgard S; Ivanov, Valeriy Y; Oliveira, Rafael S; Garcia, Sabrina; Smith, Marielle N; Oliveira Junior, Raimundo Cosme; Restrepo-Coupe, Natalia; da Silva, Rodrigo; Stark, Scott C; Martins, Giordane A; Penha, Deliane V; Saleska, Scott R

2018-03-04

Satellite and tower-based metrics of forest-scale photosynthesis generally increase with dry season progression across central Amazônia, but the underlying mechanisms lack consensus. We conducted demographic surveys of leaf age composition, and measured the age dependence of leaf physiology in broadleaf canopy trees of abundant species at a central eastern Amazon site. Using a novel leaf-to-branch scaling approach, we used these data to independently test the much-debated hypothesis - arising from satellite and tower-based observations - that leaf phenology could explain the forest-scale pattern of dry season photosynthesis. Stomatal conductance and biochemical parameters of photosynthesis were higher for recently mature leaves than for old leaves. Most branches had multiple leaf age categories simultaneously present, and the number of recently mature leaves increased as the dry season progressed because old leaves were exchanged for new leaves. These findings provide the first direct field evidence that branch-scale photosynthetic capacity increases during the dry season, with a magnitude consistent with increases in ecosystem-scale photosynthetic capacity derived from flux towers. Interactions between leaf age-dependent physiology and shifting leaf age-demographic composition are sufficient to explain the dry season photosynthetic capacity pattern at this site, and should be considered in vegetation models of tropical evergreen forests. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

Ecological Value of Soil Organic Matter at Tropical Evergreen Aglaia-Streblus Forest of Meru Betiri National Park, East Java, Indonesia

Directory of Open Access Journals (Sweden)

Hari Sulistiyowati

2016-09-01

Full Text Available As part of carbon pools, forest soil stores soil organic matter (SOM that contains many elements including organic C, N, P, and K. These elements contribute nutrients for biogeochemical cycles within the ecosystem. This study was done to determine the ecological value of forest soil organic matter at tropical evergreen Aglaia-Streblus forest of Meru Betiri National Park (MBNP, East Java, Indonesia. The data were sampled along gradient topography in Pringtali tropical forest of TMBNP. Direct measurements of soil moisture, temperature, and pH were taken in the field. The soil samples were extracted from 6 points of soil solum using soil auger, and then oven-dried to get value of dry-weight. The elements content of organic C, N, P, and K were analyzed and estimated at the laboratory. The ecoval of SOM was appraised using developed ecological valuation tool. The result showed that SOM contributed higher ecoval of organic C (66.03 Mg ha-1 than other elements. Compared to P and K elements, N had the highest stock of element content. However, comparing to other two tropical forest ecosystems of Asia the ecoval of SOM elements in TMBNP was relatively low because of its natural geomorphological features.The ecoval of SOM elements in TMBNP was relatively low because of its natural geomorphological features. The ecovals contributed about 2.440,64 - 6.955,50 USD or 31.271.923,73 - 89.120.837,23 IDR per hectare of ecological value (d to the ecosystem. This value was mainly contributed by organic C stock in the TMBNP forest SOM. It means the forest SOM had higher element content of organic C than N, P, and K elements. This d value is an indicator for TMBNP to protect the SOM elements meaning protecting their resources to sustain the biogeochemical cycles in the forest ecosystem. All the management and policy correlated to this protected area should consider this valuable information for their plan and actions.

Mountain cloud forest and grown-shade coffee plantations: A comparison of tree biodiversity in central Veracruz, Mexico

Energy Technology Data Exchange (ETDEWEB)

González-Zamora, A.; Esperón-Rodríguez, M.; Barradas, V.L.

2016-07-01

Aim of study: The objective of this work is to compare tree diversity and richness among one grown-shade coffee plantation (CAE) and two sites of montane cloud forests, one preserved (MCF1) and other perturbed (MCF2). We also develop an analysis of the importance of coffee plantations as a refuge of tree species, holding a potential role for conservation. Area of study: Our study area is the coffee region of Coatepec-Xico, in the state of Veracruz, Mexico. Material and methods: We compiled a list of all tree species in each site to determine tree diversity and floristic similarity (dissimilarity). We used different similarity indices and a cluster analysis to show relations among sites. Main results: 2721 individuals from 154 species were registered in the montane cloud forests as a whole. In the grown-shade coffee plantation we registered 2947 individuals from 64 species. The most similar sites were the perturbed montane cloud forest and the grown-shade coffee plantation and the least similar were the preserved montane cloud forest and the grown-shade coffee plantation. The high biodiversity found in all sites and the differences in tree composition between the two montane cloud forests supports evidence of the ecosystems richness in the region. Research highlight: Diversity differences among sites determine that the grown-shade coffee plantation is not substitute for montane cloud forest. CAE’s are developed under similar environmental conditions than the MCF; therefore, coexistence and recombination (replacement) of species make them particularly complementary. CAE’s in Veracruz have a potential role as refuge for biodiversity. (Author)

Biomass and water storage dynamics of epiphytes in old-growth and secondary montane cloud forest stands in Costa Rica

NARCIS (Netherlands)

Koehler, L.; Tobon, C.; Frumau, K.F.A.; Bruijnzeel, L.A.

2007-01-01

Epiphytic biomass, canopy humus and associated canopy water storage capacity are known to vary greatly between old-growth tropical montane cloud forests but for regenerating forests such data are virtually absent. The present study was conducted in an old-growth cloud forest and in a 30-year-old

The Microclimate of a Tropical Evergreen Forest.

Science.gov (United States)

1980-08-01

of Human Bioclimate - A Review. World Meteorological Organization Bulletin, Geneva, 56 pp. REFERENCES (con’t) Lee, R., 1978. Forest Micrometeorology...Geophysics, and Bioclimatology , Ser. B 24, 243-251. Pinker, R. (1980): The Microclimate of a dry tropical forest. (Accepted for publication in

Impacts of disturbance initiated by road construction in a subtropical cloud forest in the Luquillo Experimental Forest, Puerto Rico

Science.gov (United States)

Lydia P. Olander; F.N Scatena; Whendee L. Silver

1998-01-01

The impacts of road construction and the spread of exotic vegetation, which are common threats to upper elevation tropical forests, were evaluated in the subtropical cloud forests of Puerto Rico. The vegetation, soil and microclimate of 6-month-old road®lls, 35-year-old road®lls and mature forest with and without grass understories were compared. Recent road®lls had...

Birds' nesting parameters in four forest types in the Pantanal wetland

Directory of Open Access Journals (Sweden)

JB Pinho

Full Text Available We tested the heterogeneity/productivity hypothesis with respect to the abundance and richness of birds and the vegetation density hypothesis with respect to birds' nest predation rates, and determined the relative importance of forested vegetation formations for the conservation of birds in the Pantanal. We estimated the apparent nesting success, and the abundance and richness of nesting birds' in four forest types, by monitoring nests during two reproductive seasons in four forested physiognomies (two high productivity/heterogeneity evergreen forests = Cambará and Landi; two low productivity/heterogeneity dry forests = Cordilheira and Carvoeiro in the Pantanal wetland in Poconé, State of Mato Grosso, Brazil. We found 381 nests of 46 species (35 Passeriformes and 11 non-Passeriformes in the four forest types. Of these, we monitored 220 active nests belonging to 44 species, 101 during the reproductive season of 2001 and 119 in 2002. We supported the productivity/heterogeneity hypothesis since the two evergreen forests had higher nest abundance and one of them (Cambará had higher nesting species richness than the dry forests. The number of nests found in each habitat differed with most nests monitored in the Cambará forest (82%, followed by Landi (9%, Cordilheira (6% and Carvoeiro (3% forests. The total number of nests monitored was significantly higher in evergreen forests than in dry forests. Also, more species nested in evergreen (37 species than in dry (16 species forests. A Correspondence Analysis revealed that only Carvoeiros had a different nesting bird community. The overall apparent nesting success of 220 nests was 26.8%. We did not support the vegetation density hypothesis since nest predation rates were similar between evergreen (73.5% and dry (70% forests, and were higher in the Landi (85% than in the other three forests (69.2 to 72.2%. Our data indicate that Cambará forests seem to be a key nesting habitat for many bird species

Birds' nesting parameters in four forest types in the Pantanal wetland.

Science.gov (United States)

Pinho, J B; Marini, M A

2014-11-01

We tested the heterogeneity/productivity hypothesis with respect to the abundance and richness of birds and the vegetation density hypothesis with respect to birds' nest predation rates, and determined the relative importance of forested vegetation formations for the conservation of birds in the Pantanal. We estimated the apparent nesting success, and the abundance and richness of nesting birds' in four forest types, by monitoring nests during two reproductive seasons in four forested physiognomies (two high productivity/heterogeneity evergreen forests = Cambará and Landi; two low productivity/heterogeneity dry forests = Cordilheira and Carvoeiro) in the Pantanal wetland in Poconé, State of Mato Grosso, Brazil. We found 381 nests of 46 species (35 Passeriformes and 11 non-Passeriformes) in the four forest types. Of these, we monitored 220 active nests belonging to 44 species, 101 during the reproductive season of 2001 and 119 in 2002. We supported the productivity/heterogeneity hypothesis since the two evergreen forests had higher nest abundance and one of them (Cambará) had higher nesting species richness than the dry forests. The number of nests found in each habitat differed with most nests monitored in the Cambará forest (82%), followed by Landi (9%), Cordilheira (6%) and Carvoeiro (3%) forests. The total number of nests monitored was significantly higher in evergreen forests than in dry forests. Also, more species nested in evergreen (37 species) than in dry (16 species) forests. A Correspondence Analysis revealed that only Carvoeiros had a different nesting bird community. The overall apparent nesting success of 220 nests was 26.8%. We did not support the vegetation density hypothesis since nest predation rates were similar between evergreen (73.5%) and dry (70%) forests, and were higher in the Landi (85%) than in the other three forests (69.2 to 72.2%). Our data indicate that Cambará forests seem to be a key nesting habitat for many bird species of the

Mountain cloud forest and grown-shade coffee plantations: A comparison of tree biodiversity in central Veracruz, Mexico

Directory of Open Access Journals (Sweden)

Alfredo González-Zamora

2016-04-01

Full Text Available Aim of the study: The objective of this work is to compare tree diversity and richness among one grown-shade coffee plantation (CAE and two sites of montane cloud forests, one preserved (MCF1 and other perturbed (MCF2. We also develop an analysis of the importance of coffee plantations as a refuge of tree species, holding a potential role for conservation.Area of study: Our study area is the coffee region of Coatepec-Xico, in the state of Veracruz, Mexico.Material and methods: We compiled a list of all tree species in each site to determine tree diversity and floristic similarity (dissimilarity. We used different similarity indices and a cluster analysis to show relations among sites.Main results: 2721 individuals from 154 species were registered in the montane cloud forests as a whole. In the grown-shade coffee plantation we registered 2947 individuals from 64 species. The most similar sites were the perturbed montane cloud forest and the grown-shade coffee plantation and the least similar were the preserved montane cloud forest and the grown-shade coffee plantation. The high biodiversity found in all sites and the differences in tree composition between the two montane cloud forests supports evidence of the ecosystems richness in the region.Research highlight: Diversity differences among sites determine that the grown-shade coffee plantation is not substitute for montane cloud forest. CAE’s are developed under similar environmental conditions than the MCF; therefore, coexistence and recombination (replacement of species make them particularly complementary. CAE’s in Veracruz have a potential role as refuge for biodiversity.

Jewel scarabs (Chrysina sp.) in Honduras: key species for cloud forest conservation monitoring?

Science.gov (United States)

Jocque, M; Vanhove, M P M; Creedy, T J; Burdekin, O; Nuñez-Miño, J M; Casteels, J

2013-01-01

Jewel scarabs, beetles in the genus Chrysina Kirby (Coleoptera: Rutelinae: Scarabaeidae), receive their name from the bright, often gold, green elytra that reflect light like a precious stone. Jewel scarabs are commonly observed at light traps in Mesoamerican cloud forests, and their association with mountain forests makes them potentially interesting candidates for cloud forest conservation monitoring. The absence of survey protocols and identification tools, and the little ecological information available are barriers. In the present study, collection of Chrysina species assembled during biodiversity surveys by Operation Wallacea in Cusuco National Park (CNP), Honduras, were studied. The aim of this overview is to provide an easy to use identification tool for in the field, hopefully stimulating data collection on these beetles. Based on the data associated with the collection localities, elevation distribution of the species in the park was analyzed. The limited data points available were complemented with potential distribution areas generated with distribution models based on climate and elevation data. This study is aimed at initializing the development of a survey protocol for Chrysina species that can be used in cloud forest conservation monitoring throughout Central America. A list of Chrysina species recorded from Honduras so far is provided. The six identified and one unidentified species recorded from CNP are easy to identify in the field based on color and straightforward morphological characteristics. Literature research revealed ten species currently recorded from Honduras. This low species richness in comparison with surrounding Central American countries indicates the poor knowledge of this genus in Honduras. Chrysina species richness in CNP increases with elevation, thereby making the genus one of a few groups of organisms where this correlation is observed, and rendering it a suitable invertebrate representative for cloud forest habitats in

Quantifying and Modelling the Effect of Cloud Shadows on the Surface Irradiance at Tropical and Midlatitude Forests

Science.gov (United States)

Kivalov, Sergey N.; Fitzjarrald, David R.

2018-02-01

Cloud shadows lead to alternating light and dark periods at the surface, with the most abrupt changes occurring in the presence of low-level forced cumulus clouds. We examine multiyear irradiance time series observed at a research tower in a midlatitude mixed deciduous forest (Harvard Forest, Massachusetts, USA: 42.53{°}N, 72.17{°}W) and one made at a similar tower in a tropical rain forest (Tapajós National Forest, Pará, Brazil: 2.86{°}S, 54.96{°}W). We link the durations of these periods statistically to conventional meteorological reports of sky type and cloud height at the two forests and present a method to synthesize the surface irradiance time series from sky-type information. Four classes of events describing distinct sequential irradiance changes at the transition from cloud shadow and direct sunlight are identified: sharp-to-sharp, slow-to-slow, sharp-to-slow, and slow-to-sharp. Lognormal and the Weibull statistical distributions distinguish among cloudy-sky types. Observers' qualitative reports of `scattered' and `broken' clouds are quantitatively distinguished by a threshold value of the ratio of mean clear to cloudy period durations. Generated synthetic time series based on these statistics adequately simulate the temporal "radiative forcing" linked to sky type. Our results offer a quantitative way to connect the conventional meteorological sky type to the time series of irradiance experienced at the surface.

Forest vegetation of Xishuangbanna, south China

Institute of Scientific and Technical Information of China (English)

Zhu Hua

2006-01-01

Xishuangbanna of southern Yunnan is biogeographically located at a transitional zone from tropical southeast (SE) Asia to subtropical east Asia and is at the junction of the Indian and Burmese plates of Gondwana and the Eurasian plate of Laurasia. The region, though surprisingly far from the equator and at a relatively high altitude, has a rich tropical flora and a typical tropical rain forest in the lowland areas. Based on physiognomic and ecological characteristics, floristic composition and habitats combined, the primary vegetation in Xishuangbanna can be organized into four main vegetation types: tropical rain forest, tropical seasonal moist forest, tropical montane evergreen broad-leaved forest and tropical monsoon forest. The tropical rain forest can be classified into two subtypes, i.e. a tropical seasonal rain forest in the lowlands and a tropical montane rain forest at higher elevations. The tropical seasonal rain forest has almost the same forest profile and physiognomic characteristics as equatorial lowland rain forests and is a type of truly tropical rain forest. Because of conspicuous similarity on ecological and floristic characteristics, the tropical rain forest in Xishuangbanna is a type of tropical Asian rain forest. However, since the tropical rain forest of Xishuangbanna occurs at the northern edge of tropical SE Asia, it differs from typical lowland rain forests in equatorial areas in having some deciduous trees in the canopy layer, fewer megaphanerophytes and epiphytes but more abundant lianas and more plants with microphyll. It is a type of semi-evergreen rain forest at the northern edge of the tropical zone. The tropical montane rain forest occurs at wet montane habitats and is similar to the lower montane rain forest in equatorial Asia in floristic composition and physiognomy. It is a type of lower montane rain forests within the broader category of tropical rain forests. The tropical seasonal moist forest occurs on middle and upper

Age and distribution of an evergreen clonal shrub in the Coweeta basin: Rhododendron maximum L

Science.gov (United States)

Katherine J. Elliott; James M. Vose

2012-01-01

Rhododendron maximum L. is an evergreen, clonal shrub that forms a dominant sub-canopy layer and is a key species in southern Appalachian forests. We investigated the age and distribution of R. maximum across the Coweeta Basin, a 1626 ha watershed in western North Carolina. We selected 16 perennial, second-order streams and used a Global Positioning System to establish...

Inferred effects of cloud deposition on forest floor nutrient cycling and microbial properties along a short elevation gradient

International Nuclear Information System (INIS)

Lavoie, M.; Bradley, R.L.

2003-01-01

Higher cloud cover significantly decreases forest floor pH, decrease exchangeable cations, modifies mineral-N speciation and increases physiological stress within microbial communities. - Cloud water deposition often increases with elevation, and it is widely accepted that this cloud water increases acid loading to upland forest ecosystems. A study was undertaken in south-eastern Quebec to determine if a 250 m elevation gradient (i.e. 420-665 m), along a uniform sugar-maple stand on the slope of Mount Orford, corresponded to a pH gradient in the forest floor and to predictable changes in soil nutrient availability and microbial properties. Precipitation data from a nearby study, and a photographic survey, provided presumptive evidence that this elevation gradient corresponded to a strong gradient in cloud water deposition. Forest floor temperature did not differ significantly across elevations. Forest floor moisture content was significantly higher, whereas pH and exchangeable Ca and Mg were significantly lower, at the higher elevations. Average seasonal net nitrification rates, determined by long-term laboratory incubations, did not differ significantly across elevations, whereas average seasonal net ammonification rates were significantly higher at higher elevations. Basal respiration rates and microbial biomass did not differ significantly across elevations, but metabolic quotient was significantly higher at higher elevations indicating possible environmental stress on forest floor microbial communities due to cloud water deposition. Anaerobic N mineralisation rates were significantly higher at higher elevations suggesting that N-limited microbial communities frequently exposed to cloud cover can be important short-term sinks for atmospheric N, thereby contributing to increase the active-N fraction of forest floors. We conclude that, where no significant changes in vegetation or temperature occur, elevation gradients can still be used to understand the spatial

Upscaling from leaf to canopy chlorophyll/carotenoid pigment based vegetation indices reveal phenology of photosynthesis in temperate evergreen and deciduous trees

Science.gov (United States)

Wong, C. Y.; Bhathena, Y.; Arain, M. A.; Ensminger, I.

2017-12-01

Optically derived vegetation indices have been developed to provide information about plant status including photosynthetic activity. They reflect changes in leaf pigments, which vary seasonally in pigment composition, enabling them to be used as a proxy of photosynthetic phenology. Important pigments in photosynthetic activity are carotenoids and chlorophylls, which are associated with light harvesting and energy dissipation. In temperate forests, which consist of deciduous and evergreen trees, there are difficulties resolving evergreen phenology using the most widely used index, the normalized difference vegetation index (NDVI). NDVI works well in deciduous trees, which exhibit a "visible" phenological process of leaf growth in the spring, and leaf senescence and abscission in the autumn. Evergreen conifers stay green year-round and utilize "invisible" changes of overwintering pigment composition that NDVI cannot resolve, so carotenoid pigment sensitive vegetation indices have been suggested for evergreens. The aim of this study was to evaluate carotenoid based vegetation indices over the chlorophyll sensitive NDVI. For this purpose, we evaluated the greenness index, NDVI, and carotenoid pigment sensitive indices: photochemical reflectance index (PRI) and chlorophyll/carotenoid index (CCI) in red maple, white oak and eastern white pine for two years. We also measured leaf gas exchange and pigment concentrations. We observed that NDVI correlated with photosynthetic activity in deciduous trees, whereas PRI and CCI correlated with photosynthesis across both evergreen and deciduous trees. This pattern was consistent, upscaling from leaf- to canopy-scales indicating that the mechanisms involved in winter acclimation can be resolved at larger spatial scales. PRI and CCI detected seasonal changes in carotenoids and chlorophylls linked to photoprotection and are suitable as a proxy of photosynthetic activity. These findings have implications to improve our use and

Potential Distribution of Mountain Cloud Forest in Michoacán, Mexico: Prioritization for Conservation in the Context of Landscape Connectivity.

Science.gov (United States)

Correa Ayram, Camilo A; Mendoza, Manuel E; Etter, Andrés; Pérez Salicrup, Diego R

2017-07-01

Landscape connectivity is essential in biodiversity conservation because of its ability to reduce the effect of habitat fragmentation; furthermore is a key property in adapting to climate change. Potential distribution models and landscape connectivity studies have increased with regard to their utility to prioritizing areas for conservation. The objective of this study was to model the potential distribution of Mountain cloud forests in the Transversal Volcanic System, Michoacán and to analyze the role of these areas in maintaining landscape connectivity. Potential distribution was modeled for the Mountain cloud forests based on the maximum entropy approach using 95 occurrence points and 17 ecological variables at 30 m spatial resolution. Potential connectivity was then evaluated by using a probability of connectivity index based on graph theory. The percentage of variation (dPCk) was used to identify the individual contribution of each potential area of Mountain cloud forests in overall connectivity. The different ways in which the potential areas of Mountain cloud forests can contribute to connectivity were evaluated by using the three fractions derived from dPCk (dPCintrak, dPCfluxk, and dPCconnectork). We determined that 37,567 ha of the TVSMich are optimal for the presence of Mountain cloud forests. The contribution of said area in the maintenance of connectivity was low. The conservation of Mountain cloud forests is indispensable, however, in providing or receiving dispersal flows through TVSMich because of its role as a connector element between another habitat types. The knowledge of the potential capacity of Mountain cloud forests to promote structural and functional landscape connectivity is key in the prioritization of conservation areas.

The transitional semi-evergreen bushland in Ethiopia

DEFF Research Database (Denmark)

van Breugel, Paulo; Friis, Ib; Sebsebe, Demissew

2016-01-01

Question: Evergreen bushlands in Ethiopia have been inadequately studied and mapped. We address the question whether there is a transitional semi-ever-green bushland on the eastern escarpment of the Ethiopian Highlands, with unique floristic characteristics that distinguish it from the evergreen...... bushlands in other parts of Ethiopia and eastern Africa. Methods: Based on a review of the recent descriptions of evergreen bushlands in Ethiopia, we hypothesize that there is a distinct zone of natural semi-ever-green bushland, which is restricted to the eastern and southeastern escarpment of the Ethiopian...... Highlands. In contrast, evergreen bushlands in other parts of Ethiopia are considered to be of a secondary nature. To test this hypothesis, we carried out qualitative vegetation surveys in 354 locations across Ethiopia and classified the vegetation in these locations based on the occurrences of indicator...

77 FR 8895 - Public Land Order No. 7788; Withdrawal of National Forest System Land for the Red Cloud...

Science.gov (United States)

2012-02-15

... Land Order No. 7788; Withdrawal of National Forest System Land for the Red Cloud Campground; New Mexico... Cloud Campground within the Cibola National Forest, and to protect a capital investment in the... (FIRS) at 1-800-877-8339 to contact either of the above individuals during normal business hours. The...

Birds of a high-altitude cloud forest in Alta Verapaz, Guatemala.

Science.gov (United States)

Eisermann, Knut; Schulz, Ulrich

2005-01-01

The Northern Central American Highlands have been recognized as endemic bird area, but little is known about bird communities in Guatemalan cloud forests. From 1997 to 2001 a total of 142 bird species were recorded between 2000 and 2400 masl in cloud forest and agricultural clearings on Montaña Caquipec (Alta Verapaz, Guatemala). The bird community is described based on line transect counts within the forest. Pooling census data from undisturbed and disturbed forest, the Gray-breasted Wood-Wren (Henicorhina leucophrys) was found to be the most abundant species, followed in descending order by the Common Bush-Tanager (Chlorospingus ophthalmicus), the Paltry Tyrannulet (Zimmerius vilissimus), the Yellowish Flycatcher (Empidonax flavescens), the Ruddy-capped Nightingale-Thrush (Catharus frantzi), and the Amethyst-throated Hummingbird (Lampornis amethystinus). Bird communities in undisturbed and disturbed forest were found to be similar (Serensen similarity index 0.85), indicating low human impact. Of all recorded species, approximately 27% were Nearctic-Neotropical migratory birds. The most abundant one was the Wilson's Warbler (Wilsonia pusilla). The Montaña Caquipec is an important area for bird conservation, which is indicated by the presence of four species listed in the IUCN Red List (Highland Guan Penelopina nigra, Resplendent Quetzal Pharomachrus mocinno, Pink-headed Warbler Ergaticus versicolor, Golden-cheeked Warbler Dendroica chrysoparia), and 42 Mesoamerican endemics, of which 14 species are endemic to the Central American Highlands. The results presented here will be useful as baseline data for a long-term monitoring.

Evolutionarily stable strategy of carbon and nitrogen investments in forest leaves and its application in vegetation dynamic modeling

Science.gov (United States)

Weng, E.; Farrior, C.; Dybzinski, R.; Pacala, S. W.

2015-12-01

Leaf mass per area (LMA) and leaf lifespan (LL) are two highly correlated plant traits that are key to plant physiological and ecological properties. Usually, low LMA means short LL, high nitrogen (N) content per unit mass, and fast turnover rates of nutrients; high LMA leads to long LL, low N content, and slow turnover rates. Deciduous trees with low LMA and short lifespan leaves have low carbon cost but high nitrogen demand; and evergreen trees, with high LMA and long lifespan leaves, have high carbon cost but low nitrogen demand. These relationships lead to: 1) evergreen trees have higher leaf area index than deciduous trees; 2) evergreen trees' carbon use efficiency is lower than the deciduous trees' because of their thick leaves and therefore high maintenance respiration; 3) the advantage of evergreens trees brought by their extra leaves over deciduous trees diminishes with increase N in ecosystem. These facts determine who will win when trees compete with each other in a N-limited ecosystem. In this study, we formulate a mathematical model according to the relationships between LMA, LL, leaf nitrogen, and leaf building and maintenance cost, where LMA is the fundamental variable determining the other three. We analyze the evolutionarily stable strategies (ESSs) of LMA with this mathematical model by examining the benefits of carbon and nitrogen investments to leaves in ecosystems with different N. The model shows the ESS converges to low LMA at high N and high LMA at low N. At intermediate N, there are two ESSs at low and high ends of LMA, respectively. The ESS also leads to low forest productivity by outcompeting the possible high productive strategies. We design a simulation scheme in an individual-based competition model (LM3-PPA) to simulate forest dynamics as results of the competition between deciduous and evergreen trees in three different biomes, which are temperate deciduous forest, deciduous-evergreen mixed forest, and boreal evergreen forest. The

Detecting leaf phenology of seasonally moist tropical forests in South America with multi-temporal MODIS images.

Science.gov (United States)

Xiangming Xiao; Stephen Hagen; Qingyuan Zhang; Michael Keller; Berrien Moore III

2006-01-01

Leaf phenology of tropical evergreen forests affects carbon and water fluxes. In an earlier study of a seasonally moist evergreen tropical forest site in the Amazon basin, time series data of Enhanced Vegetation Index (EVI) from the VEGETATION and Moderate Resolution Imaging Spectroradiometer (MODIS) sensors showed an unexpected seasonal pattern, with higher EVI in the...

Species composition, diversity and stratification in subtropical evergreen broadleaf forests along a latitudinal thermal gradient in the Ryukyu Archipelago, Japan

Directory of Open Access Journals (Sweden)

S.M. Feroz

2015-07-01

Full Text Available A well-developed evergreen broadleaf forest exists in the northern part of Okinawa and in the central part of the Ishigaki Islands in the Ryukyu Archipelago, Japan. All woody plants were identified to species level and their heights and diameters were measured in a 750m2 plot in Okinawa and a 400m2 plot in the Ishigaki Islands. Species overlap, dominance, diversity, multi-strata structure, and spatial distribution were calculated. The floristic composition in Okinawa was found to be different from that in Ishigaki. The species overlap between strata was higher in Okinawa than in Ishigaki. Species diversity and evenness tended to increase from the top down in Okinawa and the reverse in Ishigaki. Mean tree weight of each stratum decreased and tree density increased from top down in both forests. This trend resembled the mean weight–density trajectory of self-thinning plant populations. The degree of stand stratification, species richness and species diversity for trees with DBH ⩾4.5  cm increased along the latitudinal thermal gradient in the Ryukyu Archipelago. Thus, trees in the lower strata of Okinawa and upper strata of Ishigaki are important for sustainable maintenance of higher woody species diversity in the Ryukyu Archipelago.

Understanding the role of fog in forest hydrology: Stable isotopes as tools for determining input and partitioning of cloud water in montane forests

Science.gov (United States)

Scholl, M.; Eugster, W.; Burkard, R.

2011-01-01

Understanding the hydrology of tropical montane cloud forests (TMCF) has become essential as deforestation of mountain areas proceeds at an increased rate worldwide. Passive and active cloud-water collectors, throughfall and stemflow collectors, visibility or droplet size measurements, and micrometeorological sensors are typically used to measure the fog water inputs to ecosystems. In addition, stable isotopes may be used as a natural tracer for fog and rain. Previous studies have shown that the isotopic signature of fog tends to be more enriched in the heavier isotopes 2H and 18O than that of rain, due to differences in condensation temperature and history. Differences between fog and rain isotopes are largest when rain is from synoptic-scale storms, and fog or orographic cloud water is generated locally. Smaller isotopic differences have been observed between rain and fog on mountains with orographic clouds, but only a few studies have been conducted. Quantifying fog deposition using isotope methods is more difficult in forests receiving mixed precipitation, because of limitations in the ability of sampling equipment to separate fog from rain, and because fog and rain may, under some conditions, have similar isotopic composition. This article describes the various types of fog most relevant to montane cloud forests and the importance of fog water deposition in the hydrologic budget. A brief overview of isotope hydrology provides the background needed to understand isotope applications in cloud forests. A summary of previous work explains isotopic differences between rain and fog in different environments, and how monitoring the isotopic signature of surface water, soil water and tree xylem water can yield estimates of the contribution of fog water to streamflow, groundwater recharge and transpiration. Next, instrumentation to measure fog and rain, and methods to determine isotopic concentrations in plant and soil water are discussed. The article concludes with

Historical reconstruction of climatic and elevation preferences and the evolution of cloud forest-adapted tree ferns in Mesoamerica.

Science.gov (United States)

Sosa, Victoria; Ornelas, Juan Francisco; Ramírez-Barahona, Santiago; Gándara, Etelvina

2016-01-01

Cloud forests, characterized by a persistent, frequent or seasonal low-level cloud cover and fragmented distribution, are one of the most threatened habitats, especially in the Neotropics. Tree ferns are among the most conspicuous elements in these forests, and ferns are restricted to regions in which minimum temperatures rarely drop below freezing and rainfall is high and evenly distributed around the year. Current phylogeographic data suggest that some of the cloud forest-adapted species remained in situ or expanded to the lowlands during glacial cycles and contracted allopatrically during the interglacials. Although the observed genetic signals of population size changes of cloud forest-adapted species including tree ferns correspond to predicted changes by Pleistocene climate change dynamics, the observed patterns of intraspecific lineage divergence showed temporal incongruence. Here we combined phylogenetic analyses, ancestral area reconstruction, and divergence time estimates with climatic and altitudinal data (environmental space) for phenotypic traits of tree fern species to make inferences about evolutionary processes in deep time. We used phylogenetic Bayesian inference and geographic and altitudinal distribution of tree ferns to investigate ancestral area and elevation and environmental preferences of Mesoamerican tree ferns. The phylogeny was then used to estimate divergence times and ask whether the ancestral area and elevation and environmental shifts were linked to climatic events and historical climatic preferences. Bayesian trees retrieved Cyathea, Alsophyla, Gymnosphaera and Sphaeropteris in monophyletic clades. Splits for species in these genera found in Mesoamerican cloud forests are recent, from the Neogene to the Quaternary, Australia was identified as the ancestral area for the clades of these genera, except for Gymnosphaera that was Mesoamerica. Climate tolerance was not divergent from hypothesized ancestors for the most significant

Historical reconstruction of climatic and elevation preferences and the evolution of cloud forest-adapted tree ferns in Mesoamerica

Directory of Open Access Journals (Sweden)

Victoria Sosa

2016-11-01

Full Text Available Background Cloud forests, characterized by a persistent, frequent or seasonal low-level cloud cover and fragmented distribution, are one of the most threatened habitats, especially in the Neotropics. Tree ferns are among the most conspicuous elements in these forests, and ferns are restricted to regions in which minimum temperatures rarely drop below freezing and rainfall is high and evenly distributed around the year. Current phylogeographic data suggest that some of the cloud forest-adapted species remained in situ or expanded to the lowlands during glacial cycles and contracted allopatrically during the interglacials. Although the observed genetic signals of population size changes of cloud forest-adapted species including tree ferns correspond to predicted changes by Pleistocene climate change dynamics, the observed patterns of intraspecific lineage divergence showed temporal incongruence. Methods Here we combined phylogenetic analyses, ancestral area reconstruction, and divergence time estimates with climatic and altitudinal data (environmental space for phenotypic traits of tree fern species to make inferences about evolutionary processes in deep time. We used phylogenetic Bayesian inference and geographic and altitudinal distribution of tree ferns to investigate ancestral area and elevation and environmental preferences of Mesoamerican tree ferns. The phylogeny was then used to estimate divergence times and ask whether the ancestral area and elevation and environmental shifts were linked to climatic events and historical climatic preferences. Results Bayesian trees retrieved Cyathea, Alsophyla, Gymnosphaera and Sphaeropteris in monophyletic clades. Splits for species in these genera found in Mesoamerican cloud forests are recent, from the Neogene to the Quaternary, Australia was identified as the ancestral area for the clades of these genera, except for Gymnosphaera that was Mesoamerica. Climate tolerance was not divergent from

Leaf traits show different relationships with shade tolerance in moist versus dry tropical forests.

Science.gov (United States)

Poorter, Lourens

2009-03-01

Shade tolerance is the central paradigm for understanding forest succession and dynamics, but there is considerable debate as to what the salient features of shade tolerance are, whether adult leaves show similar shade adaptations to seedling leaves, and whether the same leaf adaptations are found in forests under different climatic control. Here, adult leaf and metamer traits were measured for 39 tree species from a tropical moist semi-evergreen forest (1580 mm rain yr(-1)) and 41 species from a dry deciduous forest (1160 mm yr(-1)) in Bolivia. Twenty-six functional traits were measured and related to species regeneration light requirements.Adult leaf traits were clearly associated with shade tolerance. Different, rather than stronger, shade adaptations were found for moist compared with dry forest species. Shade adaptations exclusively found in the evergreen moist forest were related to tough and persistent leaves, and shade adaptations in the dry deciduous forest were related to high light interception and water use.These results suggest that, for forests differing in rainfall seasonality, there is a shift in the relative importance of functional leaf traits and performance trade-offs that control light partitioning. In the moist evergreen forest leaf traits underlying the growth-survival trade-off are important, whereas in the seasonally deciduous forest leaf traits underlying the growth trade-off between low and high light might become important.

Influence of meteorological parameters on interception of cloud droplets in a coniferous forest

Energy Technology Data Exchange (ETDEWEB)

Kroll, G; Winkler, P [Deutscher Wetterdienst, Meteorologisches Observatorium Hamburg (Germany, F.R.)

1989-11-01

The deposition of trace substances in a high elevated coniferous forest by interception of cloud droplets depends on numerous meteorological parameters. Sensitivity studies with a deposition model show that the variation of the vertical wind profile in the stand and the capture efficiency have a large influence on the deposition flux. Different drop size distributions with equal LWC's lead to changes of only 10% in the deposition flux. A higher ion concentration in small droplets has only a small influence on the trace substance deposition. A realistic estimate of the deposition is most likely achieved by using hourly observed meteorological parameters as model input values. The deposition of trace substances into a high elevated coniferous forest by interception of cloud droplets can be as high as the deposition via rain. (orig.).

A remotely sensed pigment index reveals photosynthetic phenology in evergreen conifers.

Science.gov (United States)

Gamon, John A; Huemmrich, K Fred; Wong, Christopher Y S; Ensminger, Ingo; Garrity, Steven; Hollinger, David Y; Noormets, Asko; Peñuelas, Josep

2016-11-15

In evergreen conifers, where the foliage amount changes little with season, accurate detection of the underlying "photosynthetic phenology" from satellite remote sensing has been difficult, presenting challenges for global models of ecosystem carbon uptake. Here, we report a close correspondence between seasonally changing foliar pigment levels, expressed as chlorophyll/carotenoid ratios, and evergreen photosynthetic activity, leading to a "chlorophyll/carotenoid index" (CCI) that tracks evergreen photosynthesis at multiple spatial scales. When calculated from NASA's Moderate Resolution Imaging Spectroradiometer satellite sensor, the CCI closely follows the seasonal patterns of daily gross primary productivity of evergreen conifer stands measured by eddy covariance. This discovery provides a way of monitoring evergreen photosynthetic activity from optical remote sensing, and indicates an important regulatory role for carotenoid pigments in evergreen photosynthesis. Improved methods of monitoring photosynthesis from space can improve our understanding of the global carbon budget in a warming world of changing vegetation phenology.

Endophytic Fungi of Various Medicinal Plants Collected From Evergreen Forest Baluran National Park and Its Potential as Laboratory Manual for Mycology Course

Directory of Open Access Journals (Sweden)

Siti Murdiyah

2017-03-01

Full Text Available Endophytic fungi found on a variety of medicinal plants may express particular benefit. These fungi provide an alternative to overcome the progressive microbial resistance and as an effort to combat infectious diseases that became one of the leading causes of mortality. The main objective of this study was to isolate endophytic fungi from leaf samples of five medicinal plants species collected from evergreen forests Baluran National Park and its use as laboratory manual for Micology. Research findings showed there were 3 isolates of endophytic fungi isolated from 2 medicinal plants namely Kesambi (Schleicera oleosa and Ketapang (Terminalia catappa. All three isolates formed sporangiophores as asexual reproductive structures, while the structure of sexual still undiscovered therefore its classification has not been determined. The validity tests also showed that the lab manual is feasible for use with the percentage achievement 85.37% and 88.56%.

Forest type effects on the retention of radiocesium in organic layers of forest ecosystems affected by the Fukushima nuclear accident

Science.gov (United States)

Koarashi, Jun; Atarashi-Andoh, Mariko; Matsunaga, Takeshi; Sanada, Yukihisa

2016-12-01

The Fukushima Daiichi nuclear power plant disaster caused serious radiocesium (137Cs) contamination of forest ecosystems over a wide area. Forest-floor organic layers play a key role in controlling the overall bioavailability of 137Cs in forest ecosystems; however, there is still an insufficient understanding of how forest types influence the retention capability of 137Cs in organic layers in Japanese forest ecosystems. Here we conducted plot-scale investigations on the retention of 137Cs in organic layers at two contrasting forest sites in Fukushima. In a deciduous broad-leaved forest, approximately 80% of the deposited 137Cs migrated to mineral soil located below the organic layers within two years after the accident, with an ecological half-life of approximately one year. Conversely, in an evergreen coniferous forest, more than half of the deposited 137Cs remained in the organic layers, with an ecological half-life of 2.1 years. The observed retention behavior can be well explained by the tree phenology and accumulation of 137Cs associated with litter materials with different degrees of degradation in the organic layers. Spatial and temporal patterns of gamma-ray dose rates depended on the retention capability. Our results demonstrate that enhanced radiation risks last longer in evergreen coniferous forests than in deciduous broad-leaved forests.

Changes in forest productivity across Alaska consistent with biome shift

Science.gov (United States)

Peter S.A. Beck; Glenn P. Juday; Claire Alix; Valerie A. Barber; Stephen E. Winslow; Emily E. Sousa; Patricia Heiser; James D. Herriges; Scott J. Goetz

2011-01-01

Global vegetation models predict that boreal forests are particularly sensitive to a biome shift during the 21st century. This shift would manifest itself first at the biome's margins, with evergreen forest expanding into current tundra while being replaced by grasslands or temperate forest at the biome's southern edge. We evaluated changes in forest...

The role of frugivorous birds and bats in the colonization of cloud forest plant species in burned areas in western Mexico

Directory of Open Access Journals (Sweden)

Rost, J.

2015-07-01

Full Text Available The extension of montane cloud forests in western Mexico is threatened by several disturbances that limit their extension. In this study we aim to assess the contribution of birds and bats in the dispersal and colonization of cloud–forest plants in contiguous surface–burned pine forests. We sampled seed rain and sapling establishment over one year in two surface–burned sites, which differed in the size of their closest cloud forest patch. A total of 17 plant species were found, most of which were late–successional trees, shrubs and climbers. Distance influenced the seed rain of only one dispersed taxon (Solanum sp. and had no effect on the sapling distribution of this or other plants. In turn, marked differences were found between sites, with more seeds dispersed and higher sapling density in the site that was next to the larger cloud forest patch. The role of long–distance dispersers and the existence of seed banks before fire could explain the little importance of distance from seed source on seed dispersal and sapling distribution. Nevertheless, dispersal by birds and bats before or after fire facilitates the regeneration and conservation of cloud forests in disturbed areas formerly occupied by other habitats.

Structure, richness and composition of arboreal plants in a cloud thinning forest of Tolima (Colombia)

International Nuclear Information System (INIS)

Campo Kurmen, Juan Manuel

2010-01-01

Structure, richness, and floristic composition of the woody elements of the selective logging forest of the Vereda Dantas, (Ibague, Tolima, Colombia), where studied in a 0.1 ha plot sampled for all individuals ≥2.5 cm dbh. the forest is characterized by scarcity of lianas and hemiepiphytic, absence of typical families of the Colombian cloud forests between 2000 and 2500 m (Araceae, Ericaceae, Myrtaceae, Meliaceae and Aquifoliaceae), and richness increment of the Sabiaceae and Euphorbiaceae. Compared to others cloud forest from the Colombian Andes and the Neotropic, it has, fewer individuals (237 individuals ≥2.5 cm dbh per 0.1 ha) and more large trees (39.7% of individuals ≥10 cm dbh per 0.1 ha). The forest has a lower woody species richness (75 species ≥2.5 cm dbh per 0.1 ha). Apparently, the effects of selective timber extraction on structure, richness, and floristic composition are decrease floristic richness and density of individuals, decrease of lianas density and richness, and more individuals of secondary species, likes: Hedyosmum goudotianum Slms-Laubach var. goudatianum, Miconia resima Naud, and Palicourea calophlebia Standl.

Clusia nubium (Clusiaceae): a new species from cloud-forests of southwestern Ecuador

DEFF Research Database (Denmark)

Gustafsson, Mats; Borchsenius, Finn

2016-01-01

Clusia nubium from southwestern Ecuador is described as a species new to science. It grows as a hemiepiphyte in lower montane cloud forest. The species belongs to Clusia sect. Retinostemon, a largely Andean group characterized by male flowers with a resin-secreting synandrium of completely fused...

First experimental evidence for carbon starvation at warm temperatures in epiphytic orchids of tropical cloud forests

Science.gov (United States)

Hoch, Guenter; Roemer, Helena; Fioroni, Tiffany; Olmedo, Inayat; Kahmen, Ansgar

2017-04-01

Tropical cloud forests are among the most climate sensitive ecosystems world-wide. The lack of a strong seasonality and the additional dampening of temperature fluctuations by the omnipresence of clouds and fog produce year-round constant climatic conditions. With climate change the presence of clouds and fog is, however, predicted to be reduced. The disappearance of the cooling fog cover will have dramatic consequences for air temperatures, that are predicted to increase locally well over 5 °C by the end of the 21st century. Especially the large number of endemic epiphytic orchids in tropical cloud forests that contribute substantially to the biological diversity of these ecosystems, but are typically adapted to a very narrow climate envelope, are speculated to be very sensitive to the anticipated rise in temperature. In a phytotron experiment we investigated the effect of increasing temperatures on the carbon balance (gas-exchange and the carbon reserve household) of 10 epiphytic orchid species from the genera Dracula, native to tropical, South-American cloud forests. The orchids were exposed to three temperature treatments: i) a constant temperature treatment (23°C/13°C, day/night) simulating natural conditions, ii) a slow temperature ramp of +0.75 K every 10 days, and iii) a fast temperature ramp of +1.5 K every 10 days. CO2 leaf gas-exchanges was determined every 10 days, and concentrations of low molecular weight sugars and starch were analyses from leaf samples throughout the experiment. We found that increasing temperatures had only minor effects on day-time leaf respiration, but led to a moderate increase of respiration during night-time. In contrast to the rather minor effects of higher temperatures on respiration, there was a dramatic decline of net-photosynthesis above day-time temperatures of 29°C, and a complete stop of net-carbon uptake at 33°C in all investigated species. This high sensitivity of photosynthesis to warming was independent of the

Expansion of deciduous tall shrubs but not evergreen dwarf shrubs inhibited by reindeer in Scandes mountain range.

Science.gov (United States)

Vowles, Tage; Gunnarsson, Bengt; Molau, Ulf; Hickler, Thomas; Klemedtsson, Leif; Björk, Robert G

2017-11-01

One of the most palpable effects of warming in Arctic ecosystems is shrub expansion above the tree line. However, previous studies have found that reindeer can influence plant community responses to warming and inhibit shrubification of the tundra.We revisited grazed (ambient) and ungrazed study plots (exclosures), at the southern as well as the northern limits of the Swedish alpine region, to study long-term grazing effects and vegetation changes in response to increasing temperatures between 1995 and 2011, in two vegetation types (shrub heath and mountain birch forest).In the field layer at the shrub heath sites, evergreen dwarf shrubs had increased in cover from 26% to 49% but were unaffected by grazing. Deciduous dwarf and tall shrubs also showed significant, though smaller, increases over time. At the birch forest sites, the increase was similar for evergreen dwarf shrubs (20-48%) but deciduous tall shrubs did not show the same consistent increase over time as in the shrub heath.The cover and height of the shrub layer were significantly greater in exclosures at the shrub heath sites, but no significant treatment effects were found on species richness or diversity.July soil temperatures and growing season thawing degree days (TDD) were higher in exclosures at all but one site, and there was a significant negative correlation between mean shrub layer height and soil TDD at the shrub heath sites. Synthesis . This study shows that shrub expansion is occurring rapidly in the Scandes mountain range, both above and below the tree line. Tall, deciduous shrubs had benefitted significantly from grazing exclosure, both in terms of cover and height, which in turn lowered summer soil temperatures. However, the overriding vegetation shift across our sites was the striking increase in evergreen dwarf shrubs, which were not influenced by grazing. As the effects of an increase in evergreen dwarf shrubs and more recalcitrant plant litter may to some degree counteract some of

Markedly Divergent Tree Assemblage Responses to Tropical Forest Loss and Fragmentation across a Strong Seasonality Gradient.

Science.gov (United States)

Orihuela, Rodrigo L L; Peres, Carlos A; Mendes, Gabriel; Jarenkow, João A; Tabarelli, Marcelo

2015-01-01

We examine the effects of forest fragmentation on the structure and composition of tree assemblages within three seasonal and aseasonal forest types of southern Brazil, including evergreen, Araucaria, and deciduous forests. We sampled three southernmost Atlantic Forest landscapes, including the largest continuous forest protected areas within each forest type. Tree assemblages in each forest type were sampled within 10 plots of 0.1 ha in both continuous forests and 10 adjacent forest fragments. All trees within each plot were assigned to trait categories describing their regeneration strategy, vertical stratification, seed-dispersal mode, seed size, and wood density. We detected differences among both forest types and landscape contexts in terms of overall tree species richness, and the density and species richness of different functional groups in terms of regeneration strategy, seed dispersal mode and woody density. Overall, evergreen forest fragments exhibited the largest deviations from continuous forest plots in assemblage structure. Evergreen, Araucaria and deciduous forests diverge in the functional composition of tree floras, particularly in relation to regeneration strategy and stress tolerance. By supporting a more diversified light-demanding and stress-tolerant flora with reduced richness and abundance of shade-tolerant, old-growth species, both deciduous and Araucaria forest tree assemblages are more intrinsically resilient to contemporary human-disturbances, including fragmentation-induced edge effects, in terms of species erosion and functional shifts. We suggest that these intrinsic differences in the direction and magnitude of responses to changes in landscape structure between forest types should guide a wide range of conservation strategies in restoring fragmented tropical forest landscapes worldwide.

Markedly Divergent Tree Assemblage Responses to Tropical Forest Loss and Fragmentation across a Strong Seasonality Gradient.

Directory of Open Access Journals (Sweden)

Rodrigo L L Orihuela

Full Text Available We examine the effects of forest fragmentation on the structure and composition of tree assemblages within three seasonal and aseasonal forest types of southern Brazil, including evergreen, Araucaria, and deciduous forests. We sampled three southernmost Atlantic Forest landscapes, including the largest continuous forest protected areas within each forest type. Tree assemblages in each forest type were sampled within 10 plots of 0.1 ha in both continuous forests and 10 adjacent forest fragments. All trees within each plot were assigned to trait categories describing their regeneration strategy, vertical stratification, seed-dispersal mode, seed size, and wood density. We detected differences among both forest types and landscape contexts in terms of overall tree species richness, and the density and species richness of different functional groups in terms of regeneration strategy, seed dispersal mode and woody density. Overall, evergreen forest fragments exhibited the largest deviations from continuous forest plots in assemblage structure. Evergreen, Araucaria and deciduous forests diverge in the functional composition of tree floras, particularly in relation to regeneration strategy and stress tolerance. By supporting a more diversified light-demanding and stress-tolerant flora with reduced richness and abundance of shade-tolerant, old-growth species, both deciduous and Araucaria forest tree assemblages are more intrinsically resilient to contemporary human-disturbances, including fragmentation-induced edge effects, in terms of species erosion and functional shifts. We suggest that these intrinsic differences in the direction and magnitude of responses to changes in landscape structure between forest types should guide a wide range of conservation strategies in restoring fragmented tropical forest landscapes worldwide.

Water relations and microclimate around the upper limit of a cloud forest in Maui, Hawai'i.

Science.gov (United States)

Gotsch, Sybil G; Crausbay, Shelley D; Giambelluca, Thomas W; Weintraub, Alexis E; Longman, Ryan J; Asbjornsen, Heidi; Hotchkiss, Sara C; Dawson, Todd E

2014-07-01

The goal of this study was to determine the effects of atmospheric demand on both plant water relations and daily whole-tree water balance across the upper limit of a cloud forest at the mean base height of the trade wind inversion in the tropical trade wind belt. We measured the microclimate and water relations (sap flow, water potential, stomatal conductance, pressure-volume relations) of Metrosideros polymorpha Gaudich. var. polymorpha in three habitats bracketing the cloud forest's upper limit in Hawai'i to understand the role of water relations in determining ecotone position. The subalpine shrubland site, located 100 m above the cloud forest boundary, had the highest vapor pressure deficit, the least amount of rainfall and the highest levels of nighttime transpiration (EN) of all three sites. In the shrubland site, on average, 29% of daily whole-tree transpiration occurred at night, while on the driest day of the study 50% of total daily transpiration occurred at night. While EN occurred in the cloud forest habitat, the proportion of total daily transpiration that occurred at night was much lower (4%). The average leaf water potential (Ψleaf) was above the water potential at the turgor loss point (ΨTLP) on both sides of the ecotone due to strong stomatal regulation. While stomatal closure maintained a high Ψleaf, the minimum leaf water potential (Ψleafmin) was close to ΨTLP, indicating that drier conditions may cause drought stress in these habitats and may be an important driver of current landscape patterns in stand density. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Object-Based Coregistration of Terrestrial Photogrammetric and ALS Point Clouds in Forested Areas

Science.gov (United States)

Polewski, P.; Erickson, A.; Yao, W.; Coops, N.; Krzystek, P.; Stilla, U.

2016-06-01

Airborne Laser Scanning (ALS) and terrestrial photogrammetry are methods applicable for mapping forested environments. While ground-based techniques provide valuable information about the forest understory, the measured point clouds are normally expressed in a local coordinate system, whose transformation into a georeferenced system requires additional effort. In contrast, ALS point clouds are usually georeferenced, yet the point density near the ground may be poor under dense overstory conditions. In this work, we propose to combine the strengths of the two data sources by co-registering the respective point clouds, thus enriching the georeferenced ALS point cloud with detailed understory information in a fully automatic manner. Due to markedly different sensor characteristics, coregistration methods which expect a high geometric similarity between keypoints are not suitable in this setting. Instead, our method focuses on the object (tree stem) level. We first calculate approximate stem positions in the terrestrial and ALS point clouds and construct, for each stem, a descriptor which quantifies the 2D and vertical distances to other stem centers (at ground height). Then, the similarities between all descriptor pairs from the two point clouds are calculated, and standard graph maximum matching techniques are employed to compute corresponding stem pairs (tiepoints). Finally, the tiepoint subset yielding the optimal rigid transformation between the terrestrial and ALS coordinate systems is determined. We test our method on simulated tree positions and a plot situated in the northern interior of the Coast Range in western Oregon, USA, using ALS data (76 x 121 m2) and a photogrammetric point cloud (33 x 35 m2) derived from terrestrial photographs taken with a handheld camera. Results on both simulated and real data show that the proposed stem descriptors are discriminative enough to derive good correspondences. Specifically, for the real plot data, 24

Contrasting ozone sensitivity in related evergreen and deciduous shrubs

International Nuclear Information System (INIS)

Calatayud, Vicent; Marco, Francisco; Cervero, Julia; Sanchez-Pena, Gerardo; Sanz, Maria Jose

2010-01-01

Plant responses to enhanced ozone levels have been studied in two pairs of evergreen-deciduous species (Pistacia terebinthus vs. P. lentiscus; Viburnum lantana vs. V. tinus) in Open Top Chambers. Ozone induced widespread visible injury, significantly reduced CO 2 assimilation and stomatal conductance (g s ), impaired Rubisco efficiency and regeneration capacity (V c,max, J max ) and altered fluorescence parameters only in the deciduous species. Differences in stomatal conductance could not explain the observed differences in sensitivity. In control plants, deciduous species showed higher superoxide dismutase (SOD) activity than their evergreen counterparts, suggesting metabolic differences that could make them more prone to redox imbalances. Ozone induced increases in SOD and/or peroxidase activities in all the species, but only evergreens were able to cope with the oxidative stress. The relevancy of these results for the effective ozone flux approach and for the current ozone Critical Levels is also discussed. - Mediterranean evergreen shrubs have a constitutively higher capacity to tolerate ozone stress than their deciduous relatives.

Fog reduces transpiration in tree species of the Canarian relict heath-laurel cloud forest (Garajonay National Park, Spain).

Science.gov (United States)

Ritter, Axel; Regalado, Carlos M; Aschan, Guido

2009-04-01

The ecophysiologic role of fog in the evergreen heath-laurel 'laurisilva' cloud forests of the Canary Islands has not been unequivocally demonstrated, although it is generally assumed that fog water is important for the survival and the distribution of this relict paleoecosystem of the North Atlantic Macaronesian archipelagos. To determine the role of fog in this ecosystem, we combined direct transpiration measurements of heath-laurel tree species, obtained with Granier's heat dissipation probes, with micrometeorological and artificial fog collection measurements carried out in a 43.7-ha watershed located in the Garajonay National Park (La Gomera, Canary Islands, Spain) over a 10-month period. Median ambient temperature spanned from 7 to 15 degrees C under foggy conditions whereas higher values, ranging from 9 to 21 degrees C, were registered during fog-free periods. Additionally, during the periods when fog water was collected, global solar radiation values were linearly related (r2=0.831) to those under fog-free conditions, such that there was a 75+/-1% reduction in median radiation in response to fog. Fog events greatly reduced median diurnal tree transpiration, with rates about 30 times lower than that during fog-free conditions and approximating the nighttime rates in both species studied (the needle-like leaf Erica arborea L. and the broadleaf Myrica faya Ait.). This large decrease in transpiration in response to fog was independent of the time of the day, tree size and species and micrometeorological status, both when expressed on a median basis and in cumulative terms for the entire 10-month measuring period. We conclude that, in contrast to the turbulent deposition of fog water droplets on the heath-laurel species, which may be regarded as a localized hydrological phenomenon that is important for high-altitude wind-exposed E. arborea trees, the cooler, wetter and shaded microenvironment provided by the cloud immersion belt represents a large-scale effect

Wildfire and forest disease interaction lead to greater loss of soil nutrients and carbon.

Science.gov (United States)

Cobb, Richard C; Meentemeyer, Ross K; Rizzo, David M

2016-09-01

Fire and forest disease have significant ecological impacts, but the interactions of these two disturbances are rarely studied. We measured soil C, N, Ca, P, and pH in forests of the Big Sur region of California impacted by the exotic pathogen Phytophthora ramorum, cause of sudden oak death, and the 2008 Basin wildfire complex. In Big Sur, overstory tree mortality following P. ramorum invasion has been extensive in redwood and mixed evergreen forests, where the pathogen kills true oaks and tanoak (Notholithocarpus densiflorus). Sampling was conducted across a full-factorial combination of disease/no disease and burned/unburned conditions in both forest types. Forest floor organic matter and associated nutrients were greater in unburned redwood compared to unburned mixed evergreen forests. Post-fire element pools were similar between forest types, but lower in burned-invaded compared to burned-uninvaded plots. We found evidence disease-generated fuels led to increased loss of forest floor C, N, Ca, and P. The same effects were associated with lower %C and higher PO4-P in the mineral soil. Fire-disease interactions were linear functions of pre-fire host mortality which was similar between the forest types. Our analysis suggests that these effects increased forest floor C loss by as much as 24.4 and 21.3 % in redwood and mixed evergreen forests, respectively, with similar maximum losses for the other forest floor elements. Accumulation of sudden oak death generated fuels has potential to increase fire-related loss of soil nutrients at the region-scale of this disease and similar patterns are likely in other forests, where fire and disease overlap.

Small mammals from the Chelemhá Cloud Forest Reserve, Alta Verapaz, Guatemala

Science.gov (United States)

Matson, Jason O.; Ordóñez-Garza, Nicté; Woodman, Neal; Bulmer, Walter; Eckerlin, Ralph P.; Hanson, J. Delton

2014-01-01

We surveyed the small mammals of remnant mixed hardwood-coniferous cloud forest at elevations ranging from 2,100–2,300 m in the Chelemhá Cloud Forest Reserve, Alta Verapaz, Guatemala. Removal-trapping using a combination of live traps, snap traps, and pitfall traps for 6 days in January 2007 resulted in 175 captures of 15 species of marsupials, shrews, and rodents. This diversity of small mammals is the highest that we have recorded from a single locality of the 10 visited during eight field seasons in the highlands of Guatemala. Based on captures, the most abundant species in the community of small mammals is Peromyscus grandis (n = 50), followed by Handleyomys rhabdops (n = 27), Heteromys desmarestianus(n = 18), Reithrodontomys mexicanus (n = 17), Handleyomys saturatior (n = 16), Sorex veraepacis (n = 15), and Scotinomys teguina (n = 13). The remaining eight species were represented by one to five individuals.

'Linkage' pharmaceutical evergreening in Canada and Australia

Science.gov (United States)

Faunce, Thomas A; Lexchin, Joel

2007-01-01

'Evergreening' is not a formal concept of patent law. It is best understood as a social idea used to refer to the myriad ways in which pharmaceutical patent owners utilise the law and related regulatory processes to extend their high rent-earning intellectual monopoly privileges, particularly over highly profitable (either in total sales volume or price per unit) 'blockbuster' drugs. Thus, while the courts are an instrument frequently used by pharmaceutical brand name manufacturers to prolong their patent royalties, 'evergreening' is rarely mentioned explicitly by judges in patent protection cases. The term usually refers to threats made to competitors about a brand-name manufacturer's tactical use of pharmaceutical patents (including over uses, delivery systems and even packaging), not to extension of any particular patent over an active product ingredient. This article focuses in particular on the 'evergreening' potential of so-called 'linkage' provisions, imposed on the regulatory (safety, quality and efficacy) approval systems for generic pharmaceuticals of Canada and Australia, by specific articles in trade agreements with the US. These 'linkage' provisions have also recently appeared in the Korea-US Free Trade Agreement (KORUSFTA). They require such drug regulators to facilitate notification of, or even prevent, any potential patent infringement by a generic pharmaceutical manufacturer. This article explores the regulatory lessons to be learnt from Canada's and Australia's shared experience in terms of minimizing potential adverse impacts of such 'linkage evergreening' provisions on drug costs and thereby potentially on citizen's access to affordable, essential medicines. PMID:17543113

Contrasting ozone sensitivity in related evergreen and deciduous shrubs

Energy Technology Data Exchange (ETDEWEB)

Calatayud, Vicent, E-mail: vicent@ceam.e [Fundacion CEAM, c/ Charles R. Darwin 14, Parque Tecnologico, 46980 Paterna, Valencia (Spain); Marco, Francisco; Cervero, Julia [Fundacion CEAM, c/ Charles R. Darwin 14, Parque Tecnologico, 46980 Paterna, Valencia (Spain); Sanchez-Pena, Gerardo [SPCAN, Dir. Gral. de Medio Natural y Politica Forestal, Ministerio de Medio Ambiente, y Medio Rural y Marino, Rios Rosas 24, 28003 Madrid (Spain); Sanz, Maria Jose [Fundacion CEAM, c/ Charles R. Darwin 14, Parque Tecnologico, 46980 Paterna, Valencia (Spain)

2010-12-15

Plant responses to enhanced ozone levels have been studied in two pairs of evergreen-deciduous species (Pistacia terebinthus vs. P. lentiscus; Viburnum lantana vs. V. tinus) in Open Top Chambers. Ozone induced widespread visible injury, significantly reduced CO{sub 2} assimilation and stomatal conductance (g{sub s}), impaired Rubisco efficiency and regeneration capacity (V{sub c,max,}J{sub max}) and altered fluorescence parameters only in the deciduous species. Differences in stomatal conductance could not explain the observed differences in sensitivity. In control plants, deciduous species showed higher superoxide dismutase (SOD) activity than their evergreen counterparts, suggesting metabolic differences that could make them more prone to redox imbalances. Ozone induced increases in SOD and/or peroxidase activities in all the species, but only evergreens were able to cope with the oxidative stress. The relevancy of these results for the effective ozone flux approach and for the current ozone Critical Levels is also discussed. - Mediterranean evergreen shrubs have a constitutively higher capacity to tolerate ozone stress than their deciduous relatives.

Variation of Annual ET Determined from Water Budgets Across Rural Southeastern Basins Differing in Forest Types

Science.gov (United States)

Younger, S. E.; Jackson, C. R.

2017-12-01

In the Southeastern United States, evapotranspiration (ET) typically accounts for 60-70% of precipitation. Watershed and plot scale experiments show that evergreen forests have higher ET rates than hardwood forests and pastures. However, some plot experiments indicate that certain hardwood species have higher ET than paired evergreens. The complexity of factors influencing ET in mixed land cover watersheds makes identifying the relative influences difficult. Previous watershed scale studies have relied on regression to understand the influences or low flow analysis to indicate growing season differences among watersheds. Existing studies in the southeast investigating ET rates for watersheds with multiple forest cover types have failed to identify a significant forest type effect, but these studies acknowledge small sample sizes. Trends of decreasing streamflow have been recognized in the region and are generally attributed to five key factors, 1.) influences from multiple droughts, 2.) changes in distribution of precipitation, 3.) reforestation of agricultural land, 4.) increasing consumptive uses, or 5.) a combination of these and other factors. This study attempts to address the influence of forest type on long term average annual streamflow and on stream low flows. Long term annual ET rates were calculated as ET = P-Q for 46 USGS gaged basins with daily data for the 1982 - 2014 water years, >40% forest cover, and no large reservoirs. Land cover data was regressed against ET to describe the relationship between each of the forest types in the National Land Cover Database. Regression analysis indicates evergreen land cover has a positive relationship with ET while deciduous and total forest have a negative relationship with ET. Low flow analysis indicates low flows tend to be lower in watersheds with more evergreen cover, and that low flows increase with increasing deciduous cover, although these relationships are noisy. This work suggests considering forest

Western equatorial African forest-savanna mosaics: a legacy of late Holocene climatic change?

Directory of Open Access Journals (Sweden)

A. Ngomanda

2009-10-01

Full Text Available Past vegetation and climate changes reconstructed using two pollen records from Lakes Maridor and Nguène, located in the coastal savannas and inland rainforest of Gabon, respectively, provide new insights into the environmental history of western equatorial African rainforests during the last 4500 cal yr BP. These pollen records indicate that the coastal savannas of western equatorial Africa did not exist during the mid-Holocene and instead the region was covered by evergreen rainforests. From ca. 4000 cal yr BP a progressive decline of inland evergreen rainforest, accompanied by the expansion of semi-deciduous rainforest, occurred synchronously with grassland colonisation in the coastal region of Gabon. The contraction of moist evergreen rainforest and the establishment of coastal savannas in Gabon suggest decreasing humidity from ca. 4000 cal yr BP. The marked reduction in evergreen rainforest and subsequent savanna expansion was followed from 2700 cal yr BP by the colonization of secondary forests dominated by the palm, Elaeis guineensis, and the shrub, Alchornea cordifolia (Euphorbiaceae. A return to wetter climatic conditions from about 1400 cal yr BP led to the renewed spread of evergreen rainforest inland, whereas a forest-savanna mosaic still persists in the coastal region. There is no evidence to suggest that the major environmental changes observed were driven by human impact.

Do Cloud Properties in a Puerto Rican Tropical Montane Cloud Forest Depend on Occurrence of Long-Range Transported African Dust?

Science.gov (United States)

Spiegel, Johanna K.; Buchmann, Nina; Mayol-Bracero, Olga L.; Cuadra-Rodriguez, Luis A.; Valle Díaz, Carlos J.; Prather, Kimberly A.; Mertes, Stephan; Eugster, Werner

2014-09-01

We investigated cloud properties of warm clouds in a tropical montane cloud forest at Pico del Este (1,051 m a.s.l.) in the northeastern part of Puerto Rico to address the question of whether cloud properties in the Caribbean could potentially be affected by African dust transported across the Atlantic Ocean. We analyzed data collected during 12 days in July 2011. Cloud droplet size spectra were measured using the FM-100 fog droplet spectrometer that measured droplet size distributions in the range from 2 to 49 µm, primarily during fog events. The droplet size spectra revealed a bimodal structure, with the first peak ( D < 6 µm) being more pronounced in terms of droplet number concentrations, whereas the second peak (10 µm < D < 20 µm) was found to be the one relevant for total liquid water content (LWC) of the cloud. We identified three major clusters of characteristic droplet size spectra by means of hierarchical clustering. All clusters differed significantly from each other in droplet number concentration (), effective diameter (ED), and median volume diameter (MVD). For the cluster comprising the largest droplets and the lowest droplet number concentrations, we found evidence of inhomogeneous mixing in the cloud. Contrastingly, the other two clusters revealed microphysical behavior, which could be expected under homogeneous mixing conditions. For those conditions, an increase in cloud condensation nuclei—e.g., from processed African dust transported to the site—is supposed to lead to an increased droplet concentration. In fact, one of these two clusters showed a clear shift of cloud droplet size spectra towards smaller droplet diameters. Since this cluster occurred during periods with strong evidence for the presence of long-range transported African dust, we hypothesize a link between the observed dust episodes and cloud characteristics in the Caribbean at our site, which is similar to the anthropogenic aerosol indirect effect.

Effects of competition and facilitation on species assemblage in two types of tropical cloud forest.

Directory of Open Access Journals (Sweden)

Wenxing Long

Full Text Available Competition and facilitation between tree individuals are two kinds of non-random processes influencing the structure and functioning of forest communities, but how these two plant-plant interactions change along gradient of resources or environments remains very much a matter of debate. We developed a null model to test the size-distance regression, and assessed the effects of competition and facilitation (including interspecific interactions, intraspecific interactions and overall species interactions on each adult tree species assemblage [diameter at breast height (dbh ≥5 cm] across two types of tropical cloud forest with different environmental and resource regimes. The null model test revealed that 17% to 27% tree species had positive dbh-distance correlations while 11% to 19% tree species showed negative dbh-distance correlations within these two forest types, indicating that both competition and facilitation processes existed during the community assembly. The importance of competition for heterospecific species, and the intensity of competition for both heterospecific and overall species increased from high to low resources for all the shared species spanning the two forests. The importance of facilitation for conspecific and overall species, as well as that the intensity of facilitation for both heterospecific and conspecific species increased with increasing low air temperature stress for all the shared species spanning the two forests. Our results show that both competition and facilitation processes simultaneously affect parts of species assemblage in the tropical cloud forests. Moreover, the fact that nearly 50% species assemblage is not detected with our approaches suggest that tree species in these tropical forest systems are assembled with multiple ecological processes, and that there is a need to explore the processes other than the two biotic interactions in further researches.

Establishing Mixtures of Redcedar In Poor Oak-Hickory Forests

Science.gov (United States)

Leon S. Minckler

1966-01-01

Oak-history forests on the poorest sites in the Upper Mississippi Valley have both low productivity and little esthetic appeal. A mixture of the native evergreen redcedar would add bearty and increase wildlife values.

Dispersal limitation drives successional pathways in Central Siberian forests under current and intensified fire regimes.

Science.gov (United States)

Tautenhahn, Susanne; Lichstein, Jeremy W; Jung, Martin; Kattge, Jens; Bohlman, Stephanie A; Heilmeier, Hermann; Prokushkin, Anatoly; Kahl, Anja; Wirth, Christian

2016-06-01

Fire is a primary driver of boreal forest dynamics. Intensifying fire regimes due to climate change may cause a shift in boreal forest composition toward reduced dominance of conifers and greater abundance of deciduous hardwoods, with potential biogeochemical and biophysical feedbacks to regional and global climate. This shift has already been observed in some North American boreal forests and has been attributed to changes in site conditions. However, it is unknown if the mechanisms controlling fire-induced changes in deciduous hardwood cover are similar among different boreal forests, which differ in the ecological traits of the dominant tree species. To better understand the consequences of intensifying fire regimes in boreal forests, we studied postfire regeneration in five burns in the Central Siberian dark taiga, a vast but poorly studied boreal region. We combined field measurements, dendrochronological analysis, and seed-source maps derived from high-resolution satellite images to quantify the importance of site conditions (e.g., organic layer depth) vs. seed availability in shaping postfire regeneration. We show that dispersal limitation of evergreen conifers was the main factor determining postfire regeneration composition and density. Site conditions had significant but weaker effects. We used information on postfire regeneration to develop a classification scheme for successional pathways, representing the dominance of deciduous hardwoods vs. evergreen conifers at different successional stages. We estimated the spatial distribution of different successional pathways under alternative fire regime scenarios. Under intensified fire regimes, dispersal limitation of evergreen conifers is predicted to become more severe, primarily due to reduced abundance of surviving seed sources within burned areas. Increased dispersal limitation of evergreen conifers, in turn, is predicted to increase the prevalence of successional pathways dominated by deciduous hardwoods

Diversity patterns in the flora of the Campo-Ma'an rain forest, Cameroon: do tree species tell it all?

NARCIS (Netherlands)

Tchouto, M.G.P.; Boer, de W.F.; Wilde, de J.J.F.E.; Maesen, van der L.J.G.

2006-01-01

This study describes diversity patterns in the flora of the Campo-Ma¿an rain forest, in south Cameroon. In this area, the structure and composition of the forests change progressively from the coastal forest on sandy shorelines through the lowland evergreen forest rich in Caesalpinioideae with

Seasonality of weather and tree phenology in a tropical evergreen mountain rain forest.

Science.gov (United States)

Bendix, J; Homeier, J; Cueva, E Ortiz; Emck, P; Breckle, S-W; Richter, M; Beck, E

2006-07-01

Flowering and fruiting as phenological events of 12 tree species in an evergreen tropical mountain rain forest in southern Ecuador were examined over a period of 3-4 years. Leaf shedding of two species was observed for 12 months. Parallel to the phenological recordings, meteorological parameters were monitored in detail and related to the flowering and fruiting activity of the trees. In spite of the perhumid climate of that area, a high degree of intra- and inter-specific synchronisation of phenological traits was apparent. With the exception of one species that flowered more or less continuously, two groups of trees could be observed, one of which flowered during the less humid months (September to October) while the second group started to initiate flowers towards the end of that phase and flowered during the heavy rains (April to July). As reflected by correlation coefficients, the all-time series of meteorological parameters showed a distinct seasonality of 8-12 months, apparently following the quasi-periodic oscillation of precipitation and related cloudiness. As revealed by power spectrum analysis and Markov persistence, rainfall and minimum temperature appear to be the only parameters with a periodicity free of long-term variations. The phenological events of most of the plant species showed a similar periodicity of 8-12 months, which followed the annual oscillation of relatively less and more humid periods and thus was in phase or in counter-phase with the oscillations of the meteorological parameters. Periods of unusual cold or dryness, presumably resulting from underlying longer-term trends or oscillations (such as ENSO), affected the homogeneity of quasi-12-month flowering events, fruit maturation and also the production of germinable seeds. Some species show underlying quasi-2-year-oscillations, for example that synchronise with the development of air temperature; others reveal an underlying decrease or increase in flowering activity over the

Seasonal ozone uptake by a warm-temperate mixed deciduous and evergreen broadleaf forest in western Japan estimated by the Penman–Monteith approach combined with a photosynthesis-dependent stomatal model

International Nuclear Information System (INIS)

Kitao, Mitsutoshi; Komatsu, Masabumi; Hoshika, Yasutomo; Yazaki, Kenichi; Yoshimura, Kenichi; Fujii, Saori; Miyama, Takafumi; Kominami, Yuji

2014-01-01

Canopy-level stomatal conductance over a warm-temperate mixed deciduous and evergreen broadleaf forest in Japan was estimated by the Penman–Monteith approach, as compensated by a semi-empirical photosynthesis-dependent stomatal model, where photosynthesis, relative humidity, and CO 2 concentration were assumed to regulate stomatal conductance. This approach, using eddy covariance data and routine meteorological observations at a flux tower site, permits the continuous estimation of canopy-level O 3 uptake, even when the Penman–Monteith approach is unavailable (i.e. in case of direct evaporation from soil or wet leaves). Distortion was observed between the AOT40 exposure index and O 3 uptake through stomata, as AOT40 peaked in April, but with O 3 uptake occurring in July. Thus, leaf pre-maturation in the predominant deciduous broadleaf tree species (Quercus serrata) might suppress O 3 uptake in springtime, even when the highest O 3 concentrations were observed. -- Highlights: • We estimate canopy-level O 3 uptake in a warm-temperate mixed forest in Japan. • The Penman–Monteith approach is compensated by a photosynthesis-dependent model. • Stomatal conductance can be estimated, even in a partly-opened or wet canopy. • The estimated O 3 dose peaks in summer though O 3 exposure peaks in spring. -- Estimation of seasonal O 3 uptake over a mixed-temperate forest compensated by a photosynthesis-dependent stomatal model

Altered dynamics of broad-leaved tree species in a Chinese subtropical montane mixed forest: the role of an anomalous extreme 2008 ice storm episode.

Science.gov (United States)

Ge, Jielin; Xiong, Gaoming; Wang, Zhixian; Zhang, Mi; Zhao, Changming; Shen, Guozhen; Xu, Wenting; Xie, Zongqiang

2015-04-01

Extreme climatic events can trigger gradual or abrupt shifts in forest ecosystems via the reduction or elimination of foundation species. However, the impacts of these events on foundation species' demography and forest dynamics remain poorly understood. Here we quantified dynamics for both evergreen and deciduous broad-leaved species groups, utilizing a monitoring permanent plot in a subtropical montane mixed forest in central China from 2001 to 2010 with particular relevance to the anomalous 2008 ice storm episode. We found that both species groups showed limited floristic alterations over the study period. For each species group, size distribution of dead individuals approximated a roughly irregular and flat shape prior to the ice storm and resembled an inverse J-shaped distribution after the ice storm. Furthermore, patterns of mortality and recruitment displayed disequilibrium behaviors with mortality exceeding recruitment for both species groups following the ice storm. Deciduous broad-leaved species group accelerated overall diameter growth, but the ice storm reduced evergreen small-sized diameter growth. We concluded that evergreen broad-leaved species were more susceptible to ice storms than deciduous broad-leaved species, and ice storm events, which may become more frequent with climate change, might potentially threaten the perpetuity of evergreen-dominated broad-leaved forests in this subtropical region in the long term. These results underscore the importance of long-term monitoring that is indispensible to elucidate causal links between forest dynamics and climatic perturbations.

Ecological Structure of a Tropical Urban Forest in the Bang Kachao Peninsula, Bangkok

Directory of Open Access Journals (Sweden)

Montathip Sommeechai

2018-01-01

Full Text Available Rapid urbanization has changed the structure and function of natural ecosystems, especially floodplain ecosystems in SE Asia. The ecological structure of vegetation stands and the usefulness of satellite images was investigated to characterize a disturbed tropical urban forest located in the Chao Phraya River lower floodplain, Thailand. Nine sample plots were established on the Bang Kachao Peninsula (BKP within 4 tropical forest types in an urban area: rehabilitation forest, home-garden agroforestry, mangrove and park. The tree habitats were beach forest, swamp forest, moist evergreen forest, dry evergreen forest, mangrove forest and abandoned orchard or home-garden. Normalized difference vegetation index (NDVI values obtained from Landsat 7 satellite images were correlated with plant structure from field surveys. NDVI had the highest relationship with stand factors for number of families, number of species, Shannon-Weiner index and total basal area. Linear regression predicted well the correlation between NDVI and stand factors for families and basal area. NDVI trends reflected urban tropical forest typing and biodiversity, being high in rehabilitation and mangrove forests, moderate in home-gardens and low in parks. We suggest that the application of NDVI for assessments can be useful for future planning, monitoring and management of the BKP and hence may contribute for increasing biodiversity and complexity of these urban forests.

Spatial and seasonal variations of leaf area index (LAI) in subtropical secondary forests related to floristic composition and stand characters

Science.gov (United States)

Zhu, Wenjuan; Xiang, Wenhua; Pan, Qiong; Zeng, Yelin; Ouyang, Shuai; Lei, Pifeng; Deng, Xiangwen; Fang, Xi; Peng, Changhui

2016-07-01

Leaf area index (LAI) is an important parameter related to carbon, water, and energy exchange between canopy and atmosphere and is widely applied in process models that simulate production and hydrological cycles in forest ecosystems. However, fine-scale spatial heterogeneity of LAI and its controlling factors have yet to be fully understood in Chinese subtropical forests. We used hemispherical photography to measure LAI values in three subtropical forests (Pinus massoniana-Lithocarpus glaber coniferous and evergreen broadleaved mixed forests, Choerospondias axillaris deciduous broadleaved forests, and L. glaber-Cyclobalanopsis glauca evergreen broadleaved forests) from April 2014 to January 2015. Spatial heterogeneity of LAI and its controlling factors were analysed using geostatistical methods and the generalised additive models (GAMs) respectively. Our results showed that LAI values differed greatly in the three forests and their seasonal variations were consistent with plant phenology. LAI values exhibited strong spatial autocorrelation for the three forests measured in January and for the L. glaber-C. glauca forest in April, July, and October. Obvious patch distribution pattern of LAI values occurred in three forests during the non-growing period and this pattern gradually dwindled in the growing season. Stem number, crown coverage, proportion of evergreen conifer species on basal area basis, proportion of deciduous species on basal area basis, and forest types affected the spatial variations in LAI values in January, while stem number and proportion of deciduous species on basal area basis affected the spatial variations in LAI values in July. Floristic composition, spatial heterogeneity, and seasonal variations should be considered for sampling strategy in indirect LAI measurement and application of LAI to simulate functional processes in subtropical forests.

Frost and leaf-size gradients in forests: global patterns and experimental evidence.

Science.gov (United States)

Lusk, Christopher H; Clearwater, Michael J; Laughlin, Daniel C; Harrison, Sandy P; Prentice, Iain Colin; Nordenstahl, Marisa; Smith, Benjamin

2018-05-16

Explanations of leaf size variation commonly focus on water availability, yet leaf size also varies with latitude and elevation in environments where water is not strongly limiting. We provide the first conclusive test of a prediction of leaf energy balance theory that may explain this pattern: large leaves are more vulnerable to night-time chilling, because their thick boundary layers impede convective exchange with the surrounding air. Seedlings of 15 New Zealand evergreens spanning 12-fold variation in leaf width were exposed to clear night skies, and leaf temperatures were measured with thermocouples. We then used a global dataset to assess several climate variables as predictors of leaf size in forest assemblages. Leaf minus air temperature was strongly correlated with leaf width, ranging from -0.9 to -3.2°C in the smallest- and largest-leaved species, respectively. Mean annual temperature and frost-free period were good predictors of evergreen angiosperm leaf size in forest assemblages, but no climate variable predicted deciduous leaf size. Although winter deciduousness makes large leaves possible in strongly seasonal climates, large-leaved evergreens are largely confined to frost-free climates because of their susceptibility to radiative cooling. Evergreen leaf size data can therefore be used to enhance vegetation models, and to infer palaeotemperatures from fossil leaf assemblages. © 2018 The Authors New Phytologist © 2018 New Phytologist Trust.

Modeling forest dynamics along climate gradients in Bolivia

Science.gov (United States)

Seiler, C.; Hutjes, R. W. A.; Kruijt, B.; Quispe, J.; Añez, S.; Arora, V. K.; Melton, J. R.; Hickler, T.; Kabat, P.

2014-05-01

Dynamic vegetation models have been used to assess the resilience of tropical forests to climate change, but the global application of these modeling experiments often misrepresents carbon dynamics at a regional level, limiting the validity of future projections. Here a dynamic vegetation model (Lund Potsdam Jena General Ecosystem Simulator) was adapted to simulate present-day potential vegetation as a baseline for climate change impact assessments in the evergreen and deciduous forests of Bolivia. Results were compared to biomass measurements (819 plots) and remote sensing data. Using regional parameter values for allometric relations, specific leaf area, wood density, and disturbance interval, a realistic transition from the evergreen Amazon to the deciduous dry forest was simulated. This transition coincided with threshold values for precipitation (1400 mm yr-1) and water deficit (i.e., potential evapotranspiration minus precipitation) (-830 mm yr-1), beyond which leaf abscission became a competitive advantage. Significant correlations were found between modeled and observed values of seasonal leaf abscission (R2 = 0.6, p days. Decreasing rainfall trends were simulated to reduce GPP in the Amazon. The current model setup provides a baseline for assessing the potential impacts of climate change in the transition zone from wet to dry tropical forests in Bolivia.

Forest Classification Based on Forest texture in Northwest Yunnan Province

Science.gov (United States)

Wang, Jinliang; Gao, Yan; Wang, Xiaohua; Fu, Lei

2014-03-01

Forest texture is an intrinsic characteristic and an important visual feature of a forest ecological system. Full utilization of forest texture will be a great help in increasing the accuracy of forest classification based on remote sensed data. Taking Shangri-La as a study area, forest classification has been based on the texture. The results show that: (1) From the texture abundance, texture boundary, entropy as well as visual interpretation, the combination of Grayscale-gradient co-occurrence matrix and wavelet transformation is much better than either one of both ways of forest texture information extraction; (2) During the forest texture information extraction, the size of the texture-suitable window determined by the semi-variogram method depends on the forest type (evergreen broadleaf forest is 3×3, deciduous broadleaf forest is 5×5, etc.). (3)While classifying forest based on forest texture information, the texture factor assembly differs among forests: Variance Heterogeneity and Correlation should be selected when the window is between 3×3 and 5×5 Mean, Correlation, and Entropy should be used when the window in the range of 7×7 to 19×19 and Correlation, Second Moment, and Variance should be used when the range is larger than 21×21.

Forest Classification Based on Forest texture in Northwest Yunnan Province

International Nuclear Information System (INIS)

Wang, Jinliang; Gao, Yan; Fu, Lei; Wang, Xiaohua

2014-01-01

Forest texture is an intrinsic characteristic and an important visual feature of a forest ecological system. Full utilization of forest texture will be a great help in increasing the accuracy of forest classification based on remote sensed data. Taking Shangri-La as a study area, forest classification has been based on the texture. The results show that: (1) From the texture abundance, texture boundary, entropy as well as visual interpretation, the combination of Grayscale-gradient co-occurrence matrix and wavelet transformation is much better than either one of both ways of forest texture information extraction; (2) During the forest texture information extraction, the size of the texture-suitable window determined by the semi-variogram method depends on the forest type (evergreen broadleaf forest is 3×3, deciduous broadleaf forest is 5×5, etc.). (3)While classifying forest based on forest texture information, the texture factor assembly differs among forests: Variance Heterogeneity and Correlation should be selected when the window is between 3×3 and 5×5; Mean, Correlation, and Entropy should be used when the window in the range of 7×7 to 19×19; and Correlation, Second Moment, and Variance should be used when the range is larger than 21×21

FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45 m telescope (FUGIN): Molecular clouds toward W 33; possible evidence for a cloud-cloud collision triggering O star formation

Science.gov (United States)

Kohno, Mikito; Torii, Kazufumi; Tachihara, Kengo; Umemoto, Tomofumi; Minamidani, Tetsuhiro; Nishimura, Atsushi; Fujita, Shinji; Matsuo, Mitsuhiro; Yamagishi, Mitsuyoshi; Tsuda, Yuya; Kuriki, Mika; Kuno, Nario; Ohama, Akio; Hattori, Yusuke; Sano, Hidetoshi; Yamamoto, Hiroaki; Fukui, Yasuo

2018-05-01

We observed molecular clouds in the W 33 high-mass star-forming region associated with compact and extended H II regions using the NANTEN2 telescope as well as the Nobeyama 45 m telescope in the J = 1-0 transitions of 12CO, 13CO, and C18O as part of the FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45 m telescope (FUGIN) legacy survey. We detected three velocity components at 35 km s-1, 45 km s-1, and 58 km s-1. The 35 km s-1 and 58 km s-1 clouds are likely to be physically associated with W 33 because of the enhanced 12CO J = 3-2 to J = 1-0 intensity ratio as R_3-2/1-0} > 1.0 due to the ultraviolet irradiation by OB stars, and morphological correspondence between the distributions of molecular gas and the infrared and radio continuum emissions excited by high-mass stars. The two clouds show complementary distributions around W 33. The velocity separation is too large to be gravitationally bound, and yet not explained by expanding motion by stellar feedback. Therefore, we discuss whether a cloud-cloud collision scenario likely explains the high-mass star formation in W 33.

Functional trait strategies of trees in dry and wet tropical forests are similar but differ in their consequences for succession.

Science.gov (United States)

Lohbeck, Madelon; Lebrija-Trejos, Edwin; Martínez-Ramos, Miguel; Meave, Jorge A; Poorter, Lourens; Bongers, Frans

2014-01-01

Global plant trait studies have revealed fundamental trade-offs in plant resource economics. We evaluated such trait trade-offs during secondary succession in two species-rich tropical ecosystems that contrast in precipitation: dry deciduous and wet evergreen forests of Mexico. Species turnover with succession in dry forest largely relates to increasing water availability and in wet forest to decreasing light availability. We hypothesized that while functional trait trade-offs are similar in the two forest systems, the successful plant strategies in these communities will be different, as contrasting filters affect species turnover. Research was carried out in 15 dry secondary forest sites (5-63 years after abandonment) and in 17 wet secondary forest sites (dry and wet forest and compare trait trade-offs. We evaluated whether multivariate plant strategies changed during succession, by calculating a 'Community-Weighted Mean' plant strategy, based on species scores on the first two PCA-axes. Trait spectra reflected two main trade-off axes that were similar for dry and wet forest species: acquisitive versus conservative species, and drought avoiding species versus evergreen species with large animal-dispersed seeds. These trait associations were consistent when accounting for evolutionary history. Successional changes in the most successful plant strategies reflected different functional trait spectra depending on the forest type. In dry forest the community changed from having drought avoiding strategies early in succession to increased abundance of evergreen strategies with larger seeds late in succession. In wet forest the community changed from species having mainly acquisitive strategies to those with more conservative strategies during succession. These strategy changes were explained by increasing water availability during dry forest succession and increasing light scarcity during wet forest succession. Although similar trait spectra were observed among dry and

Assessing the performance of aerial image point cloud and spectral metrics in predicting boreal forest canopy cover

Science.gov (United States)

Melin, M.; Korhonen, L.; Kukkonen, M.; Packalen, P.

2017-07-01

Canopy cover (CC) is a variable used to describe the status of forests and forested habitats, but also the variable used primarily to define what counts as a forest. The estimation of CC has relied heavily on remote sensing with past studies focusing on satellite imagery as well as Airborne Laser Scanning (ALS) using light detection and ranging (lidar). Of these, ALS has been proven highly accurate, because the fraction of pulses penetrating the canopy represents a direct measurement of canopy gap percentage. However, the methods of photogrammetry can be applied to produce point clouds fairly similar to airborne lidar data from aerial images. Currently there is little information about how well such point clouds measure canopy density and gaps. The aim of this study was to assess the suitability of aerial image point clouds for CC estimation and compare the results with those obtained using spectral data from aerial images and Landsat 5. First, we modeled CC for n = 1149 lidar plots using field-measured CCs and lidar data. Next, this data was split into five subsets in north-south direction (y-coordinate). Finally, four CC models (AerialSpectral, AerialPointcloud, AerialCombi (spectral + pointcloud) and Landsat) were created and they were used to predict new CC values to the lidar plots, subset by subset, using five-fold cross validation. The Landsat and AerialSpectral models performed with RMSEs of 13.8% and 12.4%, respectively. AerialPointcloud model reached an RMSE of 10.3%, which was further improved by the inclusion of spectral data; RMSE of the AerialCombi model was 9.3%. We noticed that the aerial image point clouds managed to describe only the outermost layer of the canopy and missed the details in lower canopy, which was resulted in weak characterization of the total CC variation, especially in the tails of the data.

Changes in soil carbon and nutrients following 6 years of litter removal and addition in a tropical semi-evergreen rain forest

Directory of Open Access Journals (Sweden)

E. V. J. Tanner

2016-11-01

Full Text Available Increasing atmospheric CO2 and temperature may increase forest productivity, including litterfall, but the consequences for soil organic matter remain poorly understood. To address this, we measured soil carbon and nutrient concentrations at nine depths to 2 m after 6 years of continuous litter removal and litter addition in a semi-evergreen rain forest in Panama. Soils in litter addition plots, compared to litter removal plots, had higher pH and contained greater concentrations of KCl-extractable nitrate (both to 30 cm; Mehlich-III extractable phosphorus and total carbon (both to 20 cm; total nitrogen (to 15 cm; Mehlich-III calcium (to 10 cm; and Mehlich-III magnesium and lower bulk density (both to 5 cm. In contrast, litter manipulation did not affect ammonium, manganese, potassium or zinc, and soils deeper than 30 cm did not differ for any nutrient. Comparison with previous analyses in the experiment indicates that the effect of litter manipulation on nutrient concentrations and the depth to which the effects are significant are increasing with time. To allow for changes in bulk density in calculation of changes in carbon stocks, we standardized total carbon and nitrogen on the basis of a constant mineral mass. For 200 kg m−2 of mineral soil (approximately the upper 20 cm of the profile about 0.5 kg C m−2 was “missing” from the litter removal plots, with a similar amount accumulated in the litter addition plots. There was an additional 0.4 kg C m−2 extra in the litter standing crop of the litter addition plots compared to the control. This increase in carbon in surface soil and the litter standing crop can be interpreted as a potential partial mitigation of the effects of increasing CO2 concentrations in the atmosphere.

Land cover and forest formation distributions for St. Kitts, Nevis, St. Eustatius, Grenada and Barbados from decision tree classification of cloud-cleared satellite imagery

Science.gov (United States)

Helmer, E.H.; Kennaway, T.A.; Pedreros, D.H.; Clark, M.L.; Marcano-Vega, H.; Tieszen, L.L.; Ruzycki, T.R.; Schill, S.R.; Carrington, C.M.S.

2008-01-01

Satellite image-based mapping of tropical forests is vital to conservation planning. Standard methods for automated image classification, however, limit classification detail in complex tropical landscapes. In this study, we test an approach to Landsat image interpretation on four islands of the Lesser Antilles, including Grenada and St. Kitts, Nevis and St. Eustatius, testing a more detailed classification than earlier work in the latter three islands. Secondly, we estimate the extents of land cover and protected forest by formation for five islands and ask how land cover has changed over the second half of the 20th century. The image interpretation approach combines image mosaics and ancillary geographic data, classifying the resulting set of raster data with decision tree software. Cloud-free image mosaics for one or two seasons were created by applying regression tree normalization to scene dates that could fill cloudy areas in a base scene. Such mosaics are also known as cloud-filled, cloud-minimized or cloud-cleared imagery, mosaics, or composites. The approach accurately distinguished several classes that more standard methods would confuse; the seamless mosaics aided reference data collection; and the multiseason imagery allowed us to separate drought deciduous forests and woodlands from semi-deciduous ones. Cultivated land areas declined 60 to 100 percent from about 1945 to 2000 on several islands. Meanwhile, forest cover has increased 50 to 950%. This trend will likely continue where sugar cane cultivation has dominated. Like the island of Puerto Rico, most higher-elevation forest formations are protected in formal or informal reserves. Also similarly, lowland forests, which are drier forest types on these islands, are not well represented in reserves. Former cultivated lands in lowland areas could provide lands for new reserves of drier forest types. The land-use history of these islands may provide insight for planners in countries currently considering

Floristic structure and biomass distribution of a tropical seasonal rain forest in Xishuangbanna, southwest China

Energy Technology Data Exchange (ETDEWEB)

Shanmughavel, P.; Zheng Zheng; Sha Liqing; Cao Min [Chinese Academy of Sciences, Kunming (China). Dept. of Forest Ecology

2001-07-01

The aim of this research was to study the forest community structure, tree species diversity and biomass production of a tropical seasonal rain forest in Xishuangbanna, southwest China. The community structure showed a diversified species composition and supported many species of economic significance. This tropical rain forest in closely related to Malaysian forests. The biomass and its distribution were studied using standard regression analysis and the clear-cut method for shrubs and herbs. The total biomass was 360.9 t/ha and its allocation in different layers was: tree layer 352.5 t/ha, shrub layer 4.7 t/ha, liana 3.1 t/ha and herb layer 0.5 t/ha. Most of the biomass was concentrated in the trees: stem 241.2 t/ha, root 69.6 t/ha, branch 37.2 t/ha and leaves 4.3 t/ha. The DBH class allocation of the tree biomass was concentrated in the middle DBH class. The biomass of six DBH classes from 20 to 80 cm was 255.4 t/ha. There are twenty-six species with biomass over 0.5% of the total biomass of the tree layer, and three species with biomass over 5%, i.e., Pometia tomentosa, Barringtonia macrostachya (5.4%) and Terminalia myriocarpa (5.2%). Data on stem, branch, leaves and root of the individual tree species were used to develop regression models. D{sup 2}H was found to be the best estimator of the biomass in this tropical rain forest. However, higher biomass figures have been reported from tropical forests elsewhere e.g., 415-520 t/ha in the tropical forests of Cambodia, the tropical moist mixed dipterocarp forests, and the tropical moist logged moist evergreen-high, medium, and low yield forests of Sri Lanka. In some forests, lower accumulation of biomass was reported, e.g., 10-295 t/ha in the tropical moist forests of Bangladesh, the tropical moist dense forest of Cambodia, the tropical dry forests of India, the tropical moist forests of Peninsular-Malaysia, the tropical moist mixed dipterocarp forests of Sarawak-Malaysia, the tropical evergreen forests of

Spatial Heterogeneity of the Forest Canopy Scales with the Heterogeneity of an Understory Shrub Based on Fractal Analysis

Directory of Open Access Journals (Sweden)

Catherine K. Denny

2017-04-01

Full Text Available Spatial heterogeneity of vegetation is an important landscape characteristic, but is difficult to assess due to scale-dependence. Here we examine how spatial patterns in the forest canopy affect those of understory plants, using the shrub Canada buffaloberry (Shepherdia canadensis (L. Nutt. as a focal species. Evergreen and deciduous forest canopy and buffaloberry shrub presence were measured with line-intercept sampling along ten 2-km transects in the Rocky Mountain foothills of west-central Alberta, Canada. Relationships between overstory canopy and understory buffaloberry presence were assessed for scales ranging from 2 m to 502 m. Fractal dimensions of both canopy and buffaloberry were estimated and then related using box-counting methods to evaluate spatial heterogeneity based on patch distribution and abundance. Effects of canopy presence on buffaloberry were scale-dependent, with shrub presence negatively related to evergreen canopy cover and positively related to deciduous cover. The effect of evergreen canopy was significant at a local scale between 2 m and 42 m, while that of deciduous canopy was significant at a meso-scale between 150 m and 358 m. Fractal analysis indicated that buffaloberry heterogeneity positively scaled with evergreen canopy heterogeneity, but was unrelated to that of deciduous canopy. This study demonstrates that evergreen canopy cover is a determinant of buffaloberry heterogeneity, highlighting the importance of spatial scale and canopy composition in understanding canopy-understory relationships.

Annotated bibliography of South African indigenous evergreen forest ecology

CSIR Research Space (South Africa)

Geldenhuys, CJ

1985-01-01

Full Text Available Annotated references to 519 publications are presented, together with keyword listings and keyword, regional, place name and taxonomic indices. This bibliography forms part of the first phase of the activities of the Forest Biome Task Group....

[Historic record of Gastrotheca ovifera (Anura: Hemiphractidae): decline evidence in Venezuelan coastal cloud forests].

Science.gov (United States)

Valera-Leal, Javier; Acevedo, Aldemar; Pérez-Sánchez, Antonio; Vega, Jorge; Manzanilla, Jesús

2011-03-01

G. ovifera is a marsupial frog of the cloud and riparian forest from Western and Litoral sections of the Venezuelan Cordillera de la Costa (820-2 000m). This amphibian is considered as an endangered species by the IUCN Species Red List, due to its population decline in pristine and well preserved environments. This conservation status is based on anecdotic interpretations. We collected disperse data from museum records (national and international) and explored the possible association between collection records and precipitation data available for the Henri Pittier National Park (PNHP). Likewise, we carried out a systematic population monitoring of G. ovifera in historic and additional localities among the cloud forest of Rancho Grande, PNHP. We found 106 individuals in 11 zoological collections deposited during 1929-2007. After an effort of 646 hours/person we did not detect G. ovifera individuals in the evaluated localities; as well as no statistical significant associations between the annual precipitation average and the historic records of the species during 1941-1997 period (r = -0.054, p = 0.820, n = 19). We discussed the distribution, fluctuation and population changes of this species, analyzing it conservation status.

Different Patterns of Changes in the Dry Season Diameter at Breast Height of Dominant and Evergreen Tree Species in a Mature Subtropical Forest in South China

Institute of Scientific and Technical Information of China (English)

Jun-Hua Yan; Guo-Yi Zhou; De-Qiang Zhang; Xu-Li Tang; Xu Wang

2006-01-01

Information on changes in diameter at breast height (DBH) is important for net primary production (NPP)estimates, timing of forest inventory, and forest management. In the present study, patterns of DBH change were measured under field conditions during the dry season for three dominant and native tree species in a monsoon evergreen broad-leaved forest in the Dinghushan Biosphere Reserve. For each tree species,different patterns of DBH change were observed. In the case of the fast-growing tree species Castanopsis chinensis Hance, large diurnal fluctuations occur, with a peak DBH in the early morning (around 05:00 h) that decreases to a minimum by about 14:00 h. Both Schima superba Gardn. et Chemp and Cryptocarya chinensis (Hance) Hemsl. exhibited less diurnal swelling and shrinkage. Diurnal fluctuations for these species were observed on a few occasions over the period of observation. Graphical comparisons and statistical analysis of changes in DBH with meteorological variables indicate that for different trees, the different changes in DBH observed responded to different meteorological variables. Large stem changes were found to occur for Ca. chinensis trees that were associated with variations in solar radiation. However, both S. superba and Cr. chinensis were found to be less sensitive to solar radiation. Changes in the DBH of these two species were found to be controlled mainly by soil temperature and soil moisture. During the later dry season, with a lower soil temperature and soil moisture, all three tree species stopped growing and only negligible shrinkage, expansion, or fluctuation occurred, suggesting that the optimum time to measure tree growth in the Dinghushan Biosphere Reserve is the later dry season.

Detailed forest formation mapping in the land cover map series for the Caribbean islands

Science.gov (United States)

Helmer, E. H.; Schill, S.; Pedreros, D. H.; Tieszen, L. L.; Kennaway, T.; Cushing, M.; Ruzycki, T.

2006-12-01

Forest formation and land cover maps for several Caribbean islands were developed from Landsat ETM+ imagery as part of a multi-organizational project. The spatially explicit data on forest formation types will permit more refined estimates of some forest attributes. The woody vegetation classification scheme relates closely to that of Areces-Malea et al. (1), who classify Caribbean vegetation according to standards of the US Federal Geographic Data Committee (FGDC, 1997), with modifications similar to those in Helmer et al. (2). For several of the islands, we developed image mosaics that filled cloudy parts of scenes with data from other scene dates after using regression tree normalization (3). The regression tree procedure permitted us to develop mosaics for wet and drought seasons for a few of the islands. The resulting multiseason imagery facilitated separation between classes such as seasonal evergreen forest, semi-deciduous forest (including semi-evergreen forest), and drought deciduous forest or woodland formations. We used decision tree classification methods to classify the Landsat image mosaics to detailed forest formations and land cover for Puerto Rico (4), St. Kitts and Nevis, St. Lucia, St. Vincent and the Grenadines and Grenada. The decision trees classified a stack of raster layers for each mapping area that included the Landsat image bands and various ancillary raster data layers. For Puerto Rico, for example, the ancillary data included climate parameters (5). For some islands, the ancillary data included topographic derivatives such as aspect, slope and slope position, SRTM (6) or other topographic data. Mapping forest formations with decision tree classifiers, ancillary geospatial data, and cloud-free image mosaics, accurately distinguished spectrally similar forest formations, without the aid of ecological zone maps, on the islands where the approach was used. The approach resulted in maps of forest formations with comparable or better detail

A remotely sensed pigment index reveals photosynthetic phenology in evergreen conifers

OpenAIRE

Gamon, John A.

2016-01-01

In evergreen conifers, where the foliage amount changes little with season, accurate detection of the underlying “photosynthetic phenology” from satellite remote sensing has been difficult, presenting challenges for global models of ecosystem carbon uptake. Here, we report a close correspondence between seasonally changing foliar pigment levels, expressed as chlorophyll/carotenoid ratios, and evergreen photosynthetic activity, leading to a “chlorophyll/carotenoid index” (CCI) that tracks ever...

Rain chemistry and cloud composition and microphysics in a Caribbean tropical montane cloud forest under the influence of African dust

Science.gov (United States)

Torres-Delgado, Elvis; Valle-Diaz, Carlos J.; Baumgardner, Darrel; McDowell, William H.; González, Grizelle; Mayol-Bracero, Olga L.

2015-04-01

It is known that huge amounts of mineral dust travels thousands of kilometers from the Sahara and Sahel regions in Africa over the Atlantic Ocean reaching the Caribbean, northern South America and southern North America; however, not much is understood about how the aging process that takes place during transport changes dust properties, and how the presence of this dust affects cloud's composition and microphysics. This African dust reaches the Caribbean region mostly in the summer time. In order to improve our understanding of the role of long-range transported African dust (LRTAD) in cloud formation processes in a tropical montane cloud forest (TMCF) in the Caribbean region we had field campaigns measuring dust physical and chemical properties in summer 2013, as part of the Puerto Rico African Dust and Cloud Study (PRADACS), and in summer 2014, as a part of the Luquillo Critical Zone Observatory (LCZO) and in collaboration with the Saharan Aerosol Long-Range Transport and Aerosol-Cloud-Interaction Experiment (SALTRACE). Measurements were performed at the TMCF of Pico del Este (PE, 1051 masl) and at the nature reserve of Cabezas de San Juan (CSJ, 60 masl). In both stations we monitored meteorological parameters (e.g., temperature, wind speed, wind direction). At CSJ, we measured light absorption and scattering at three wavelengths (467, 528 and 652 nm). At PE we collected cloud and rainwater and monitored cloud microphysical properties (e.g., liquid water content, droplet size distribution, droplet number concentration, effective diameter and median volume diameter). Data from aerosol models, satellites, and back-trajectories were used together with CSJ measurements to classify air masses and samples collected at PE in the presence or absence of dust. Soluble ions, insoluble trace metals, pH and conductivity were measured for cloud and rainwater. Preliminary results for summer 2013 showed that in the presence of LRTAD (1) the average conductivity of cloud water

The Role of African Dust Particles on Cloud Chemistry and Microphysics in a Tropical Montane Cloud Forest in the Caribbean

Science.gov (United States)

Torres-Delgado, E.; Valle-Diaz, C. J.; Baumgardner, D.; McDowell, W. H.; Gonzalez, G.; Mayol-Bracero, O. L.

2015-12-01

Huge amounts of African dust travels thousands of kilometers from the Sahara and Sahel regions to the Caribbean, northern South America and southern North America. However, not much is understood about how the aging process that takes place during transport changes dust properties, and how it affects cloud's composition and microphysics. In order to improve our understanding of the role of long-range transported African dust (LRTAD) in cloud formation processes we had field campaigns measuring dust physical and chemical properties in summers of 2013, 2014 and 2015, as part of the Puerto Rico African Dust and Cloud Study (PRADACS), and of the Luquillo Critical Zone Observatory (LCZO). Measurements were performed at the tropical montane cloud forest (TMCF) of Pico del Este (PE, 1051 masl) and at the nature reserve of Cabezas de San Juan (CSJ, 60 masl). In both ground stations we monitored meteorological parameters (e.g., temperature, wind speed, wind direction). At CSJ, we measured light absorption and scattering at three wavelengths (467, 528 and 652 nm). At PE we collected cloud and rainwater for chemical analyses and monitored cloud microphysical properties (e.g., liquid water content, droplet size distribution, droplet number concentration, effective diameter and median volume diameter). Summer 2015 was the first attempt to characterize microphysical properties of the summer period (June to August) at PE, where dust is in its higher concentrations of the year. Samples were classified using data from models and satellites together with CSJ measurements as low or high dust influenced. Soluble ions, insoluble trace metals, pH, conductivity, total and dissolved organic carbon and total and dissolved nitrogen were measured for cloud and rainwater. Enrichment factor analysis was used to determine sea and crustal contribution of species by sample, as well as the neutralization factor and fractional acidity. Some preliminary results show cloud water conductivity for low

78 FR 45288 - Frank Sherman, Evergreen Trails, Inc., Cabana Coaches, LLC, TMS West Coast, Inc. and FSCS...

Science.gov (United States)

2013-07-26

... DEPARTMENT OF TRANSPORTATION Surface Transportation Board [STB Docket No. MCF 21054] Frank Sherman, Evergreen Trails, Inc., Cabana Coaches, LLC, TMS West Coast, Inc. and FSCS Corporation--Intra-Corporate Family Transaction Exemption Frank Sherman, Evergreen Trails, Inc. (Evergreen), Cabana Coaches, LLC...

Does water stress, nutrient limitation, or H-toxicity explain the differential stature among Heath Forest types in Central Kalimantan, Indonesia?

NARCIS (Netherlands)

Vernimmen, R.R.E.; Bruijnzeel, L.A.; Proctor, J.; Verhoef, H.A.; Klomp, N.

2013-01-01

To investigate the causes of the reduced stature of heath forest compared to lowland evergreen rain forest (LERF), the quantity and quality of small litterfall (LF), the standing crop of litter on the forest floor (LSC), and the annual rates of litter decay were determined over a period of 12 months

Exploring interactions between payment for hydrologic service policies, landowner decisions, and ecohydrology in a Mexican cloud forest watershed: Is there a disconnect between the policy and the resource?

Science.gov (United States)

Asbjornsen, H.; Geissert, D.; Gomez-Tagle, A.; Holwerda, F.; Manson, R.; Perez-Maqueo, O.; Munoz-Villers, L.; Scullion, J.

2013-05-01

Payment for hydrologic service (PHS) programs are increasingly being used as a means to incentivize watershed protection by compensating upstream 'water producers' with payments made by downstream 'water consumers'. However, the effectiveness of PHS programs in achieving their target goals is often poorly understood. Here, we draw from insights obtained from socioeconomic and ecohydrological research in Veracruz, Mexico to explore interactions between PHS policies, landowner decisions, and hydrologic services. GIS analysis of land-cover changes during 2003-2009 combined with interviews of PHS participants indicated that despite lower deforestation rates on properties receiving PES payments, other factors were likely to have a greater influence on land use decisions than PHS payments per se, including opportunity costs and personal conservation ethic. The interviews also highlighted a general lack of trust and cooperation between the citizen participants and government administrators, which was reflected in the relatively low level of knowledge of the PHS programs' regulations and goals, the role of forests in protecting water resources, and a low level of co-financing by the private sector. An important premise of PHS programs is that protecting existing forest cover (and planting trees) will enhance water supply, especially in upland cloud forests that are due to their perceived role as water producers. Measurements of climate, steamflow, canopy fog interception, plant transpiration, soil water dynamics, and hydrologic flow paths were collected over a 3-year period to assess stand water balance and streamflow response under four different land covers: mature cloud forest, pasture, regenerating cloud forest, pine reforestation. Results suggested relatively minor additional inputs of fog to increasing streamflow in cloud forest watersheds, while conversion of forest to pasture did not markedly decrease dry season flows, but did increase annual flows due to lower

Uav-Based Photogrammetric Point Clouds and Hyperspectral Imaging for Mapping Biodiversity Indicators in Boreal Forests

Science.gov (United States)

Saarinen, N.; Vastaranta, M.; Näsi, R.; Rosnell, T.; Hakala, T.; Honkavaara, E.; Wulder, M. A.; Luoma, V.; Tommaselli, A. M. G.; Imai, N. N.; Ribeiro, E. A. W.; Guimarães, R. B.; Holopainen, M.; Hyyppä, J.

2017-10-01

Biodiversity is commonly referred to as species diversity but in forest ecosystems variability in structural and functional characteristics can also be treated as measures of biodiversity. Small unmanned aerial vehicles (UAVs) provide a means for characterizing forest ecosystem with high spatial resolution, permitting measuring physical characteristics of a forest ecosystem from a viewpoint of biodiversity. The objective of this study is to examine the applicability of photogrammetric point clouds and hyperspectral imaging acquired with a small UAV helicopter in mapping biodiversity indicators, such as structural complexity as well as the amount of deciduous and dead trees at plot level in southern boreal forests. Standard deviation of tree heights within a sample plot, used as a proxy for structural complexity, was the most accurately derived biodiversity indicator resulting in a mean error of 0.5 m, with a standard deviation of 0.9 m. The volume predictions for deciduous and dead trees were underestimated by 32.4 m3/ha and 1.7 m3/ha, respectively, with standard deviation of 50.2 m3/ha for deciduous and 3.2 m3/ha for dead trees. The spectral features describing brightness (i.e. higher reflectance values) were prevailing in feature selection but several wavelengths were represented. Thus, it can be concluded that structural complexity can be predicted reliably but at the same time can be expected to be underestimated with photogrammetric point clouds obtained with a small UAV. Additionally, plot-level volume of dead trees can be predicted with small mean error whereas identifying deciduous species was more challenging at plot level.

Vegetation response following Phytophthora ramorum eradication treatments in southwest Oregon forests

Science.gov (United States)

Ellen Michaels Goheen; Everett Hansen; Alan Kanaskie; Wendy Sutton; Paul Reeser

2008-01-01

Sudden oak death, caused by Phytophthora ramorum, was identified in late July 2001 in forest stands in Curry County on the southwest Oregon coast where it was killing tanoak (Lithocarpus densiflorus) and infecting Pacific rhododendron (Rhododendron macrophyllum) and evergreen huckleberry (Vaccinium...

Regional Distribution of Forest Height and Biomass from Multisensor Data Fusion

Science.gov (United States)

Yu, Yifan; Saatchi, Sassan; Heath, Linda S.; LaPoint, Elizabeth; Myneni, Ranga; Knyazikhin, Yuri

2010-01-01

Elevation data acquired from radar interferometry at C-band from SRTM are used in data fusion techniques to estimate regional scale forest height and aboveground live biomass (AGLB) over the state of Maine. Two fusion techniques have been developed to perform post-processing and parameter estimations from four data sets: 1 arc sec National Elevation Data (NED), SRTM derived elevation (30 m), Landsat Enhanced Thematic Mapper (ETM) bands (30 m), derived vegetation index (VI) and NLCD2001 land cover map. The first fusion algorithm corrects for missing or erroneous NED data using an iterative interpolation approach and produces distribution of scattering phase centers from SRTM-NED in three dominant forest types of evergreen conifers, deciduous, and mixed stands. The second fusion technique integrates the USDA Forest Service, Forest Inventory and Analysis (FIA) ground-based plot data to develop an algorithm to transform the scattering phase centers into mean forest height and aboveground biomass. Height estimates over evergreen (R2 = 0.86, P forests (R2 = 0.93, P forests were less accurate because of the winter acquisition of SRTM data and loss of scattering phase center from tree ]surface interaction. We used two methods to estimate AGLB; algorithms based on direct estimation from the scattering phase center produced higher precision (R2 = 0.79, RMSE = 25 Mg/ha) than those estimated from forest height (R2 = 0.25, RMSE = 66 Mg/ha). We discuss sources of uncertainty and implications of the results in the context of mapping regional and continental scale forest biomass distribution.

Spatial pattern of tree diversity and evenness across forest types in Majella National Park, Italy

Directory of Open Access Journals (Sweden)

Mohammad Redowan

2015-09-01

Full Text Available Background Estimation of tree diversity at broader scale is important for conservation planning. Tree diversity should be measured and understood in terms of diversity and evenness, two integral components to describe the structure of a biological community. Variation of the tree diversity and evenness with elevation, topographic relief, aspect, terrain shape, slope, soil nutrient, solar radiation etc. are well documented. Methods Present study explores the variation of tree diversity (measured as Shannon diversity and evenness indices of Majella National Park, Italy with five available forest types namely evergreen oak woods, deciduous oak woods, black/aleppo pine stands, hop-hornbeam forest and beech forest, using satellite, environmental and field data. Results Hop-hornbeam forest was found to be most diverse and even while evergreen Oak woods was the lowest diverse and even. Diversity and evenness of forest types were concurrent to each other i.e. forest type which was more diverse was also more even. As a broad pattern, majority portion of the study area belonged to medium diversity and high evenness class. Conclusions Satellite images and other GIS data proved useful tools in monitoring variation of tree diversity and evenness across various forest types. Present study findings may have implications in prioritizing conservation zones of high tree diversity at Majella.

Direct damage to vegetation caused by acid rain and polluted cloud: definition of critical levels for forest trees.

Science.gov (United States)

Cape, J N

1993-01-01

The concept of critical levels was developed in order to define short-term and long-term average concentrations of gaseous pollutants above which plants may be damaged. Although the usual way in which pollutants in precipitation (wet deposition) influence vegetation is by affecting soil processes, plant foliage exposed to fog and cloud, which often contain much greater concentrations of pollutant ions than rain, may be damaged directly. The idea of a critical level has been extended to define concentrations of pollutants in wet deposition above which direct damage to plants is likely. Concentrations of acidity and sulphate measured in mountain and coastal cloud are summarised. Vegetation at risk of injury is identified as montane forest growing close to the cloud base, where ion concentrations are highest. The direct effects of acidic precipitation on trees are reviewed, based on experimental exposure of plants to simulated acidic rain, fog or mist. Although most experiments have reported results in terms of pH (H(+) concentration), the accompanying anion is important, with sulphate being more damaging than nitrate. Both conifers and broadleaved tree seedlings showing subtle changes in the structural characteristics of leaf surfaces after exposure to mist or rain at or about pH 3.5, or sulphate concentration of 150 micromol litre(-1). Visible lesions on leaf surfaces occur at around pH 3 (500 micromol litre(-1) sulphate), broadleaved species tending to be more sensitive than conifers. Effects on photosynthesis and water relations, and interactions with other stresses (e.g. frost), have usually been observed only for treatments which have also caused visible injury to the leaf surface. Few experiments on the direct effects of polluted cloud have been conducted under field conditions with mature trees, which unlike seedlings in controlled conditions, may suffer a growth reduction in the absence of visible injury. Although leaching of cations (Ca(2+), Mg(2+), K(+)) is

Rainfall, fog and throughfall dynamics in a sub-tropical ridge-top cloud forest, National Park of Garajonay (La Gomera, Canary Islands, Spain)

NARCIS (Netherlands)

García-Santos, G.; Bruijnzeel, L.A.

2011-01-01

Mixed tree-heath/beech forest is a type of subtropical montane cloud forest found on wind- and fog-exposed ridges in the Canary Islands. With a dry season of 5 months and an annual precipitation of 600-700 mm, the extra water inputs through fog interception assume particular importance in this

Functional trait strategies of trees in dry and wet tropical forests are similar but differ in their consequences for succession.

Directory of Open Access Journals (Sweden)

Madelon Lohbeck

Full Text Available Global plant trait studies have revealed fundamental trade-offs in plant resource economics. We evaluated such trait trade-offs during secondary succession in two species-rich tropical ecosystems that contrast in precipitation: dry deciduous and wet evergreen forests of Mexico. Species turnover with succession in dry forest largely relates to increasing water availability and in wet forest to decreasing light availability. We hypothesized that while functional trait trade-offs are similar in the two forest systems, the successful plant strategies in these communities will be different, as contrasting filters affect species turnover. Research was carried out in 15 dry secondary forest sites (5-63 years after abandonment and in 17 wet secondary forest sites (<1-25 years after abandonment. We used 11 functional traits measured on 132 species to make species-trait PCA biplots for dry and wet forest and compare trait trade-offs. We evaluated whether multivariate plant strategies changed during succession, by calculating a 'Community-Weighted Mean' plant strategy, based on species scores on the first two PCA-axes. Trait spectra reflected two main trade-off axes that were similar for dry and wet forest species: acquisitive versus conservative species, and drought avoiding species versus evergreen species with large animal-dispersed seeds. These trait associations were consistent when accounting for evolutionary history. Successional changes in the most successful plant strategies reflected different functional trait spectra depending on the forest type. In dry forest the community changed from having drought avoiding strategies early in succession to increased abundance of evergreen strategies with larger seeds late in succession. In wet forest the community changed from species having mainly acquisitive strategies to those with more conservative strategies during succession. These strategy changes were explained by increasing water availability during

Response of epiphytic bryophytes to simulated N deposition in a subtropical montane cloud forest in southwestern China.

Science.gov (United States)

Song, Liang; Liu, Wen-Yao; Ma, Wen-Zhang; Qi, Jin-Hua

2012-11-01

A field manipulation experiment was conducted in a subtropical montane cloud forest in southwestern China to determine the possible responses of epiphytic bryophytes to increasing nitrogen (N) deposition from community to physiology level, and to find sensitive epiphytic bryophytes that may be used as indicators for assessing the degree of N pollution. N addition had significantly negative effects on species richness and cover of the epiphytic bryophyte community. Harmful effects of high N loads were recorded for chlorophyll, growth, and vitality of the species tested. The decline of some epiphytic bryophytes may result from detrimental effects on degradation to photosynthetic pigments. Bazzania himalayana (Mitt.) Schiffn., Bazzania ovistipula (Steph.) Mizut., and Homaliodendron flabellatum (Sm.) Fleisch. are candidates in atmospheric nitrogen monitoring. Epiphytic bryophytes in the montane cloud forest are very sensitive to increasing N deposition and often difficult to recover once they have been destroyed, providing early detection of enhanced N pollution for trees or even the whole forest ecosystem. The inference that increasing N pollution may lead to loss of biodiversity is a concern to the developing economy in western China, and should alert the government to the adverse impacts caused by increased industrial pollution during the process of China's West Development.

Forests of hope: Costa Rica. Restoring hope in the clouds.

Science.gov (United States)

Bowen, L

1996-01-01

The rapid population growth in Central America has created pressure on the largest tract of cloud forest spanning the Talamanca Mountains in Costa Rica and Panama. Of immediate concern is restoring hope in the forest and improving the standard of living among local people. Such is the goal of the Amistad Conservation and Development (AMISCONDE) project in the communities of Cerro Punta, Panama, and San Rafael in Costa Rica. Through agriculture, forestry, animal husbandry, environmental education, and community development, AMISCONDE aims to restore the degraded lands in the reserve's buffer zone and improve the income of the people. All the local people, the farmers, women and children have benefited from the project. Some of the activities carried out to meet its objectives include helping the farmers improve the productivity and marketability of their products by teaching them new technologies and giving agricultural credits to farmers, women, and youth groups. In addition, AMISCONDE conducts training courses to address the economic, social and educational needs of women and communities. It is assured that the community and the group will be prepared to continue on their own after the official AMISCONDE office is gone.

Biology and Ecology of Alchisme grossa in a Cloud Forest of the Bolivian Yungas

OpenAIRE

Torrico-Bazoberry, Daniel; Caceres-Sanchez, Liliana; Saavedra-Ulloa, Daniela; Flores-Prado, Luis; Niemeyer, Hermann M.; Pinto, Carlos F.

2014-01-01

Treehoppers (Membracidae) exhibit different levels of sociality, from solitary to presocial. Although they are one of the best biological systems to study the evolution of maternal care in insects, information on the biology of species in this group is scarce. This work describes the biology and ecology of Alchisme grossa (Fairmaire) (Hemiptera: Membracidae) in a rain cloud forest of Bolivia. This subsocial membracid utilizes two host-plant species, Brugmansia suaveolens (Humb. & Bonpl. ex Wi...

Mapping forests in monsoon Asia with ALOS PALSAR 50-m mosaic images and MODIS imagery in 2010.

Science.gov (United States)

Qin, Yuanwei; Xiao, Xiangming; Dong, Jinwei; Zhang, Geli; Roy, Partha Sarathi; Joshi, Pawan Kumar; Gilani, Hammad; Murthy, Manchiraju Sri Ramachandra; Jin, Cui; Wang, Jie; Zhang, Yao; Chen, Bangqian; Menarguez, Michael Angelo; Biradar, Chandrashekhar M; Bajgain, Rajen; Li, Xiangping; Dai, Shengqi; Hou, Ying; Xin, Fengfei; Moore, Berrien

2016-02-11

Extensive forest changes have occurred in monsoon Asia, substantially affecting climate, carbon cycle and biodiversity. Accurate forest cover maps at fine spatial resolutions are required to qualify and quantify these effects. In this study, an algorithm was developed to map forests in 2010, with the use of structure and biomass information from the Advanced Land Observation System (ALOS) Phased Array L-band Synthetic Aperture Radar (PALSAR) mosaic dataset and the phenological information from MODerate Resolution Imaging Spectroradiometer (MOD13Q1 and MOD09A1) products. Our forest map (PALSARMOD50 m F/NF) was assessed through randomly selected ground truth samples from high spatial resolution images and had an overall accuracy of 95%. Total area of forests in monsoon Asia in 2010 was estimated to be ~6.3 × 10(6 )km(2). The distribution of evergreen and deciduous forests agreed reasonably well with the median Normalized Difference Vegetation Index (NDVI) in winter. PALSARMOD50 m F/NF map showed good spatial and areal agreements with selected forest maps generated by the Japan Aerospace Exploration Agency (JAXA F/NF), European Space Agency (ESA F/NF), Boston University (MCD12Q1 F/NF), Food and Agricultural Organization (FAO FRA), and University of Maryland (Landsat forests), but relatively large differences and uncertainties in tropical forests and evergreen and deciduous forests.

LBA-ECO TG-07 Soil Trace Gas Flux and Root Mortality, Tapajos National Forest

Science.gov (United States)

R.K. Varner; M.M. Keller

2009-01-01

This data set reports the results of an experiment that tested the short-term effects of root mortality on the soil-atmosphere fluxes of nitrous oxide, nitric oxide, methane, and carbon dioxide in a tropical evergreen forest. Weekly trace gas fluxes are provided for treatment and control plots on sand and clay tropical forest soils in two comma separated ASCII files....

Spatiotemporal variation of mosquito diversity (Diptera: Culicidae) at places with different land-use types within a neotropical montane cloud forest matrix.

Science.gov (United States)

Abella-Medrano, Carlos Antonio; Ibáñez-Bernal, Sergio; MacGregor-Fors, Ian; Santiago-Alarcon, Diego

2015-09-24

Land-use change has led to a dramatic decrease in total forest cover, contributing to biodiversity loss and changes of ecosystems' functions. Insect communities of medical importance can be favored by anthropogenic alterations, increasing the risk of novel zoonotic diseases. The response of mosquito (Diptera: Culicidae) abundance and richness to five land-use types (shade coffee plantation, cattle field, urban forest, peri-urban forest, well-preserved montane cloud forest) and three seasons ("dry", "rainy" and "cold") embedded in a neotropical montane cloud forest landscape was evaluated. Standardized collections were performed using 8 CDC miniature black-light traps, baited with CO2 throughout the year. Generalized additive mixed models were used to describe the seasonal and spatial trends of both species richness and abundance. Rank abundance curves and ANCOVAs were used to detect changes in the spatial and temporal structure of the mosquito assemblage. Two cluster analyses were conducted, using 1-βsim and the Morisita-Horn index to evaluate species composition shifts based on incidences and abundances. A total of 2536 adult mosquitoes were collected, belonging to 9 genera and 10 species; the dominant species in the study were: Aedes quadrivittatus, Wyeomyia adelpha, Wy. arthrostigma, and Culex restuans. Highest richness was recorded in the dry season, whereas higher abundance was detected during the rainy season. The urban forest had the highest species richness (n = 7) when compared to all other sites. Species composition cluster analyses show that there is a high degree of similarity in species numbers across sites and seasons throughout the year. However, when considering the abundance of such species, the well-preserved montane cloud forest showed significantly higher abundance. Moreover, the urban forest is only 30 % similar to other sites in terms of species abundances, indicating a possible isolating role of the urban environment. Mosquito

Domestication, Conservation, and Livelihoods: A Case Study of Piper peepuloides Roxb.—An Important Nontimber Forest Product in South Meghalaya, Northeast India

Directory of Open Access Journals (Sweden)

H. Tynsong

2013-01-01

Full Text Available Wild pepper (Piper peepuloides Roxb., family: Piperaceae is an evergreen climber which grows wild in tropical evergreen forests and subtropical evergreen forests of northeast India. This plant grows luxuriantly in the areas with high rainfall at lower elevations ranging from 100 to 800 m above mean sea level. In Meghalaya, to meet the market demand, farmers have domesticated it in arecanut agroforests and betel leaf agroforests. We found that the mean density of wild pepper in arecanut agroforest is 585 stem/ha and only 85 stem/ha in natural forest. In India, wild pepper is used in a variety of Ayurvedic medicines. Local people of Meghalaya uses powdered dry seeds mixed with honey and egg yolk for the treatment of severe cough. The study reveals that the average gross annual production of wild pepper is 7 quintals/ha, and final market price fetches Rs. 336,000/ha, out of which 42% of the money goes to the grower, 16% to local trader, 23% to dealer, 17% to retailer, 1.2% to wages of labourers, and 0.6% to transport.

Whole-plant allocation to storage and defense in juveniles of related evergreen and deciduous shrub species.

Science.gov (United States)

Wyka, T P; Karolewski, P; Żytkowiak, R; Chmielarz, P; Oleksyn, J

2016-05-01

In evergreen plants, old leaves may contribute photosynthate to initiation of shoot growth in the spring. They might also function as storage sites for carbohydrates and nitrogen (N). We hence hypothesized that whole-plant allocation of carbohydrates and N to storage in stems and roots may be lower in evergreen than in deciduous species. We selected three species pairs consisting of an evergreen and a related deciduous species: Mahonia aquifolium (Pursh) Nutt. and Berberis vulgaris L. (Berberidaceae), Prunus laurocerasus L. and Prunus serotina Ehrh. (Rosaceae), and Viburnum rhytidophyllum Hemsl. and Viburnum lantana L. (Adoxaceae). Seedlings were grown outdoors in pots and harvested on two dates during the growing season for the determination of biomass, carbohydrate and N allocation ratios. Plant size-adjusted pools of nonstructural carbohydrates in stems and roots were lower in the evergreen species of Berberidaceae and Adoxaceae, and the slope of the carbohydrate pool vs plant biomass relationship was lower in the evergreen species of Rosaceae compared with the respective deciduous species, consistent with the leading hypothesis. Pools of N in stems and roots, however, did not vary with leaf habit. In all species, foliage contained more than half of the plant's nonstructural carbohydrate pool and, in late summer, also more than half of the plant's N pool, suggesting that in juvenile individuals of evergreen species, leaves may be a major storage site. Additionally, we hypothesized that concentration of defensive phenolic compounds in leaves should be higher in evergreen than in deciduous species, because the lower carbohydrate pool in stems and roots of the former restricts their capacity for regrowth following herbivory and also because of the need to protect their longer-living foliage. Our results did not support this hypothesis, suggesting that evergreen plants may rely predominantly on structural defenses. In summary, our study indicates that leaf habit has

Impact of deforestation in the Amazon basin on cloud climatology.

Science.gov (United States)

Wang, Jingfeng; Chagnon, Frédéric J F; Williams, Earle R; Betts, Alan K; Renno, Nilton O; Machado, Luiz A T; Bisht, Gautam; Knox, Ryan; Bras, Rafael L

2009-03-10

Shallow clouds are prone to appear over deforested surfaces whereas deep clouds, much less frequent than shallow clouds, favor forested surfaces. Simultaneous atmospheric soundings at forest and pasture sites during the Rondonian Boundary Layer Experiment (RBLE-3) elucidate the physical mechanisms responsible for the observed correlation between clouds and land cover. We demonstrate that the atmospheric boundary layer over the forested areas is more unstable and characterized by larger values of the convective available potential energy (CAPE) due to greater humidity than that which is found over the deforested area. The shallow convection over the deforested areas is relatively more active than the deep convection over the forested areas. This greater activity results from a stronger lifting mechanism caused by mesoscale circulations driven by deforestation-induced heterogeneities in land cover.

Comparison of vertical distribution of live and dead fine root biomass in six types of Cuban forests

Czech Academy of Sciences Publication Activity Database

Fiala, K.; Hernandéz, L.; Holub, Petr

2017-01-01

Roč. 29, č. 3 (2017), s. 275-281 ISSN 0128-1283 R&D Projects: GA MZe QJ1220007; GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:86652079 Keywords : Evergreen forests * mangroves * root dry mass * semi-deciduous forests * soil depth Subject RIV: GK - Forestry OBOR OECD: Forestry Impact factor: 0.466, year: 2016

Influence of summer marine fog and low cloud stratus on water relations of evergreen woody shrubs (Arctostaphylos: Ericaceae) in the chaparral of central California.

Science.gov (United States)

Vasey, Michael C; Loik, Michael E; Parker, V Thomas

2012-10-01

Mediterranean-type climate (MTC) regions around the world are notable for cool, wet winters and hot, dry summers. A dominant vegetation type in all five MTC regions is evergreen, sclerophyllous shrubland, called chaparral in California. The extreme summer dry season in California is moderated by a persistent low-elevation layer of marine fog and cloud cover along the margin of the Pacific coast. We tested whether late dry season water potentials (Ψ(min)) of chaparral shrubs, such as Arctostaphylos species in central California, are influenced by this coast-to-interior climate gradient. Lowland coastal (maritime) shrubs were found to have significantly less negative Ψ(min) than upland interior shrubs (interior), and stable isotope (δ(13)C) values exhibited greater water use efficiency in the interior. Post-fire resprouter shrubs (resprouters) had significantly less negative Ψ(min) than co-occurring obligate seeder shrubs (seeders) in interior and transitional chaparral, possibly because resprouters have deeper root systems with better access to subsurface water than shallow-rooted seeders. Unexpectedly, maritime resprouters and seeders did not differ significantly in their Ψ(min), possibly reflecting more favorable water availability for shrubs influenced by the summer marine layer. Microclimate and soil data also suggest that maritime habitats have more favorable water availability than the interior. While maritime seeders constitute the majority of local Arctostaphylos endemics, they exhibited significantly greater vulnerability to xylem cavitation than interior seeders. Because rare seeders in maritime chaparral are more vulnerable to xylem cavitation than interior seeders, the potential breakdown of the summer marine layer along the coast is of potential conservation concern.

Litterfall, litter decomposition and nitrogen mineralization in old-growth evergreen and secondary deciduous Nothofagus forests in south-central Chile Aporte, descomposición de hojarasca y mineralización de nitrógeno en bosques siempreverdes de antiguo crecimiento y bosques secundarios deciduos, centro-sur de Chile

Directory of Open Access Journals (Sweden)

JEROEN STAELENS

2011-03-01

Full Text Available South Chilean forest ecosystems represent one of the largest areas of old-growth temperate rainforests remaining in the Southern hemisphere and have a high ecological value, but suffer from deforestation, invasion by exotic species, fragmentation, and increasing atmospheric nitrogen (N deposition. To support sustainable forest management, more knowledge is required on nutrient cycling of these ecosystems. Therefore, a descriptive study of nutrient dynamics was done in four Valdivian rainforests in the lower Andes range of south Chile: old-growth and altered evergreen stands and unmanaged and managed secondary deciduous stands. Time series were measured for (i mass (four year and nutrient content (N, K, Ca, and Mg; one year of litterfall, (ii decomposition and nutrient dynamics (N, C, K, Ca, Mg, and P; one year of leaf litter and Saxegothaea conspicua bark litter, and (iii in situ topsoil net N mineralization (one year. Litterfall in the four stands ranged from 3.5 to 5.8 ton ha-1 yr-1, was temporarily lower in the managed than in the unmanaged deciduous stand and had a different seasonality in the evergreen stands than in the deciduous stands. Leaf litter decomposed faster (on average 32 % mass loss after one year than bark litter (8 % but without significant differences between leaf litter types. Net N in evergreen leaf litter decreased during decomposition but increased in deciduous leaf litter. Net soil N mineralization was fastest in the pristine evergreen stand, intermediate in the deciduous stands and slowest in the altered evergreen forest. Given the absence of replicated stands, the definite impact of forest type or management regime on the internal nutrient cycling cannot be demonstrated. Nevertheless, the results suggest that management can affect nutrient turnover by altering species composition and forest structure, while recent (five years selective logging in secondary deciduous forest did not affect litter decomposition or N

Mapping forest functional type in a forest-shrubland ecotone using SPOT imagery and predictive habitat distribution modelling

Science.gov (United States)

Assal, Timothy J.; Anderson, Patrick J.; Sibold, Jason

2015-01-01

The availability of land cover data at local scales is an important component in forest management and monitoring efforts. Regional land cover data seldom provide detailed information needed to support local management needs. Here we present a transferable framework to model forest cover by major plant functional type using aerial photos, multi-date Système Pour l’Observation de la Terre (SPOT) imagery, and topographic variables. We developed probability of occurrence models for deciduous broad-leaved forest and needle-leaved evergreen forest using logistic regression in the southern portion of the Wyoming Basin Ecoregion. The model outputs were combined into a synthesis map depicting deciduous and coniferous forest cover type. We evaluated the models and synthesis map using a field-validated, independent data source. Results showed strong relationships between forest cover and model variables, and the synthesis map was accurate with an overall correct classification rate of 0.87 and Cohen’s kappa value of 0.81. The results suggest our method adequately captures the functional type, size, and distribution pattern of forest cover in a spatially heterogeneous landscape.

Effects of litter manipulation on litter decomposition in a successional gradients of tropical forests in southern China

DEFF Research Database (Denmark)

Chen, Hao; Gurmesa, Geshere A.; Liu, Lei

2014-01-01

Global changes such as increasing CO2, rising temperature, and land-use change are likely to drive shifts in litter inputs to forest floors, but the effects of such changes on litter decomposition remain largely unknown. We initiated a litter manipulation experiment to test the response of litter...... decomposition to litter removal/addition in three successional forests in southern China, namely masson pine forest (MPF), mixed coniferous and broadleaved forest (MF) and monsoon evergreen broadleaved forest (MEBF). Results showed that litter removal decreased litter decomposition rates by 27%, 10% and 8...

Efficacy of generic allometric equations for estimating biomass: a test in Japanese natural forests.

Science.gov (United States)

Ishihara, Masae I; Utsugi, Hajime; Tanouchi, Hiroyuki; Aiba, Masahiro; Kurokawa, Hiroko; Onoda, Yusuke; Nagano, Masahiro; Umehara, Toru; Ando, Makoto; Miyata, Rie; Hiura, Tsutom

2015-07-01

Accurate estimation of tree and forest biomass is key to evaluating forest ecosystem functions and the global carbon cycle. Allometric equations that estimate tree biomass from a set of predictors, such as stem diameter and tree height, are commonly used. Most allometric equations are site specific, usually developed from a small number of trees harvested in a small area, and are either species specific or ignore interspecific differences in allometry. Due to lack of site-specific allometries, local equations are often applied to sites for which they were not originally developed (foreign sites), sometimes leading to large errors in biomass estimates. In this study, we developed generic allometric equations for aboveground biomass and component (stem, branch, leaf, and root) biomass using large, compiled data sets of 1203 harvested trees belonging to 102 species (60 deciduous angiosperm, 32 evergreen angiosperm, and 10 evergreen gymnosperm species) from 70 boreal, temperate, and subtropical natural forests in Japan. The best generic equations provided better biomass estimates than did local equations that were applied to foreign sites. The best generic equations included explanatory variables that represent interspecific differences in allometry in addition to stem diameter, reducing error by 4-12% compared to the generic equations that did not include the interspecific difference. Different explanatory variables were selected for different components. For aboveground and stem biomass, the best generic equations had species-specific wood specific gravity as an explanatory variable. For branch, leaf, and root biomass, the best equations had functional types (deciduous angiosperm, evergreen angiosperm, and evergreen gymnosperm) instead of functional traits (wood specific gravity or leaf mass per area), suggesting importance of other traits in addition to these traits, such as canopy and root architecture. Inclusion of tree height in addition to stem diameter improved

Forest managment options for sequestering carbon in Mexico

International Nuclear Information System (INIS)

Masera, O.R.; Bellon, M.R.; Segura, G.

1995-01-01

This paper identifies and examines economic response options to avoid carbon emissions and increase carbon sequestration in Mexican forests. A ''Policy'' scenario covering the years 2000, 2010 and 2030 and a ''Technical Potential'' scenario (year 2030) are developed to examine the potential carbon sequestration and costs of each response option. Benefit-cost analyses for three case studies, including management of a pulpwood plantation, a native temperate forest and a native tropical evergreen forest are presented and discussed. The study suggests that a large potential for reducing carbon emissions and increasing carbon sequestration exists in Mexican forests. However, the achievement of this potential will require important reforms to the current institutional setting of the forest sector. The management of native temperate and tropical forests offers the most promising alternatives for carbon sequestration. The cost effectiveness of commercial plantations critically depends on very high site productivity. Restoration of degraded forest lands; particularly through the establishment of energy plantations, also shows a large carbon sequestration potential. (Author)

Rapid forest clearing in a Myanmar proposed national park threatens two newly discovered species of geckos (Gekkonidae: Cyrtodactylus.

Directory of Open Access Journals (Sweden)

Grant M Connette

Full Text Available Myanmar's recent transition from military rule towards a more democratic government has largely ended decades of political and economic isolation. Although Myanmar remains heavily forested, increased development in recent years has been accompanied by exceptionally high rates of forest loss. In this study, we document the rapid progression of deforestation in and around the proposed Lenya National Park, which includes some of the largest remaining areas of lowland evergreen rainforest in mainland Southeast Asia. The globally unique forests in this area are rich in biodiversity and remain a critical stronghold for many threatened and endangered species, including large charismatic fauna such as tiger and Asian elephant. We also conducted a rapid assessment survey of the herpetofauna of the proposed national park, which resulted in the discovery of two new species of bent-toed geckos, genus Cyrtodactylus. We describe these new species, C. lenya sp. nov. and C. payarhtanensis sp. nov., which were found in association with karst (i.e., limestone rock formations within mature lowland wet evergreen forest. The two species were discovered less than 35 km apart and are each known from only a single locality. Because of the isolated nature of the karst formations in the proposed Lenya National Park, these geckos likely have geographical ranges restricted to the proposed protected area and are threatened by approaching deforestation. Although lowland evergreen rainforest has vanished from most of continental Southeast Asia, Myanmar can still take decisive action to preserve one of the most biodiverse places on Earth.

Rapid forest clearing in a Myanmar proposed national park threatens two newly discovered species of geckos (Gekkonidae: Cyrtodactylus).

Science.gov (United States)

Connette, Grant M; Oswald, Patrick; Thura, Myint Kyaw; LaJeunesse Connette, Katherine J; Grindley, Mark E; Songer, Melissa; Zug, George R; Mulcahy, Daniel G

2017-01-01

Myanmar's recent transition from military rule towards a more democratic government has largely ended decades of political and economic isolation. Although Myanmar remains heavily forested, increased development in recent years has been accompanied by exceptionally high rates of forest loss. In this study, we document the rapid progression of deforestation in and around the proposed Lenya National Park, which includes some of the largest remaining areas of lowland evergreen rainforest in mainland Southeast Asia. The globally unique forests in this area are rich in biodiversity and remain a critical stronghold for many threatened and endangered species, including large charismatic fauna such as tiger and Asian elephant. We also conducted a rapid assessment survey of the herpetofauna of the proposed national park, which resulted in the discovery of two new species of bent-toed geckos, genus Cyrtodactylus. We describe these new species, C. lenya sp. nov. and C. payarhtanensis sp. nov., which were found in association with karst (i.e., limestone) rock formations within mature lowland wet evergreen forest. The two species were discovered less than 35 km apart and are each known from only a single locality. Because of the isolated nature of the karst formations in the proposed Lenya National Park, these geckos likely have geographical ranges restricted to the proposed protected area and are threatened by approaching deforestation. Although lowland evergreen rainforest has vanished from most of continental Southeast Asia, Myanmar can still take decisive action to preserve one of the most biodiverse places on Earth.

Improving winter leaf area index estimation in evergreen coniferous forests and its significance in carbon and water fluxes modeling

Science.gov (United States)

Wang, R.; Chen, J. M.; Luo, X.

2016-12-01

Modeling of carbon and water fluxes at the continental and global scales requires remotely sensed LAI as inputs. For evergreen coniferous forests (ENF), severely underestimated winter LAI has been one of the issues for mostly available remote sensing products, which could cause negative bias in the modeling of Gross Primary Productivity (GPP) and evapotranspiration (ET). Unlike deciduous trees which shed all the leaves in winter, conifers retains part of their needles and the proportion of the retained needles depends on the needle longevity. In this work, the Boreal Ecosystem Productivity Simulator (BEPS) was used to model GPP and ET at eight FLUXNET Canada ENF sites. Two sets of LAI were used as the model inputs: the 250m 10-day University of Toronto (U of T) LAI product Version 2 and the corrected LAI based on the U of T LAI product and the needle longevity of the corresponding tree species at individual sites. Validating model daily GPP (gC/m2) against site measurements, the mean RMSE over eight sites decreases from 1.85 to 1.15, and the bias changes from -0.99 to -0.19. For daily ET (mm), mean RMSE decreases from 0.63 to 0.33, and the bias changes from -0.31 to -0.16. Most of the improvements occur in the beginning and at the end of the growing season when there is large correction of LAI and meanwhile temperature is still suitable for photosynthesis and transpiration. For the dormant season, the improvement in ET simulation mostly comes from the increased interception of precipitation brought by the elevated LAI during that time. The results indicate that model performance can be improved by the application the corrected LAI. Improving the winter RS LAI can make a large impact on land surface carbon and energy budget.

Remarkable fly (Diptera) diversity in a patch of Costa Rican cloud forest: Why inventory is a vital science

Science.gov (United States)

All flies (Diptera) collected for one year from a four-hectare (150 X 266 meter) patch of cloud forest at 1600 meters above sea level at Zurquí de Moravia, San José Province, Costa Rica (hereafter referred to as Zurquí), revealed an astounding 4,348 species. These amount to more than half the number...

Geospatial monitoring and prioritization of forest fire incidences in Andhra Pradesh, India.

Science.gov (United States)

Manaswini, G; Sudhakar Reddy, C

2015-10-01

Forest fire has been identified as one of the key environmental issue for long-term conservation of biodiversity and has impact on global climate. Spatially multiple observations are necessary for monitoring of forest fires in tropics for understanding conservation efficacy and sustaining biodiversity in protected areas. The present work was carried out to estimate the spatial extent of forest burnt areas and fire frequency using Resourcesat Advanced Wide Field Sensor (AWiFS) data (2009, 2010, 2012, 2013 and 2014) in Andhra Pradesh, India. The spatio-temporal analysis shows that an area of 7514.10 km(2) (29.22% of total forest cover) has been affected by forest fires. Six major forest types are distributed in Andhra Pradesh, i.e. semi-evergreen, moist deciduous, dry deciduous, dry evergreen, thorn and mangroves. Of the total forest burnt area, dry deciduous forests account for >75%. District-wise analysis shows that Kurnool, Prakasam and Cuddapah have shown >100 km(2) of burnt area every year. The total forest burnt area estimate covering protected areas ranges between 6.9 and 22.3% during the study period. Spatial burnt area analysis for protected areas in 2014 indicates 37.2% of fire incidences in the Nagarjunasagar Srisailam Tiger Reserve followed by 20.2 % in the Sri Lankamalleswara Wildlife Sanctuary, 20.1% in the Sri Venkateswara Wildlife Sanctuary and 17.4% in the Gundla Brahmeswaram Wildlife Sanctuary. The analysis of cumulative fire occurrences from 2009 to 2014 has helped in delineation of conservation priority hotspots using a spatial grid cell approach. Conservation priority hotspots I and II are distributed in major parts of study area including protected areas of the Nagarjunasagar Srisailam Tiger Reserve and Gundla Brahmeswaram Wildlife Sanctuary. The spatial database generated will be useful in studies related to influence of fires on species adaptability, ecological damage assessment and conservation planning.

Birds of a high-altitude cloud forest in Alta Verapaz, Guatemala

Directory of Open Access Journals (Sweden)

Knut Eisermann

2005-09-01

Full Text Available The Northern Central American Highlands have been recognized as endemic bird area, but little is known about bird communities in Guatemalan cloud forests. From 1997 to 2001 a total of 142 bird species were recorded between 2 000 and 2 400 masl in cloud forest and agricultural clearings on Montaña Caquipec (Alta Verapaz, Guatemala. The bird community is described based on line transect counts within the forest. Pooling census data from undisturbed and disturbed forest, the Gray-breasted Wood-Wren (Henicorhina leucophrys was found to be the most abundant species, followed in descending order by the Common Bush-Tanager (Chlorospingus ophthalmicus, the Paltry Tyrannulet (Zimmerius vilissimus, the Yellowish Flycatcher (Empidonax flavescens, the Ruddy-capped Nightingale-Thrush (Catharus frantzii, and the Amethyst-throated Hummingbird (Lampornis amethystinus. Bird communities in undisturbed and disturbed forest were found to be similar (Sørensen similarity index 0.85, indicating low human impact. Of all recorded species, ~27% were Nearctic-Neotropical migratory birds. The most abundant one was the Wilson’s Warbler (Wilsonia pusilla. The Montaña Caquipec is an important area for bird conservation, which is indicated by the presence of four species listed in the IUCN Red List (Highland Guan Penelopina nigra, Resplendent Quetzal Pharomachrus mocinno, Pink-headed Warbler Ergaticus versicolor, Golden-cheeked Warbler Dendroica chrysoparia, and 42 Mesoamerican endemics, of which 14 species are endemic to the Central American Highlands. The results presented here will be useful as baseline data for a long-term monitoring. Rev. Biol. Trop. 53(3-4: 577-594. Epub 2005 Oct 3.Las alturas del norte de Centroamérica han sido reconocidas como región de aves endémicas, pero se conoce poco sobre las comunidades de aves en bosques nubosos de Guatemala. De 1997 a 2001 se han detectado 142 especies de aves entre 2 000 y 2 400 msnm en el bosque nuboso y áreas agr

[Characteristics of floor litter and soil arthropod community in different types ot subtropical forest in Ailao Mountain of Yunnan, Southwest China].

Science.gov (United States)

Yang, Zhao; Yang, Xiao-Dong

2011-11-01

By using line transect method, an investigation was conducted on the floor litter and soil arthropod community in a mid mountain wet evergreen broad-leaved forest, a mossy dwarf forest, and a Populus bonatii forest in Ailao Mountain of Yunnan in April (dry and hot season), June (rainy season), and December (dry and cold season), 2005. In both dry and rainy seasons, the existing floor litter mass, C storage, and C/N ratio in the three forests all increased in the order of mossy dwarf forest > P. bonatii forest > evergreen broad-leaved forest, but the N storage had less difference. In the floor litter layer of the forests, Acari and Collembola were the dominant groups of soil arthropod community, while Diptera larvae, Coleoptera, ants, and Homoptera were the common groups. The Sorenson coefficients of soil arthropod community in the three forests were extremely great. No significant differences were observed in the soil arthropod density (ind x m(-2)) in the floor litter layer among the three forests, but the relative density (ind x g(-1)) of soil arthropods was higher in the evergreen broad-leaved forest and P. bonatii forest than in the mossy dwarf forest. In the three forests, the density of soil arthropods was significantly higher in dry season than in rainy season, but the Shannon diversity index had less difference. There were significant positive correlations between the existing floor litter mass and the individual density (ind x m(-2)) and dominant groups of soil arthropod communities in dry and hot season (April), but negative correlations between the existing floor litter mass and the relative density (ind x g(-1)) of soil arthropod communities and Acari in dry and cold season (December). The individual densities of Collembola and Coleoptera also had positive correlations with the N storage of the existing floor litter mass in the three forests. It was considered that the floor litter and the development of soil arthropod community in the litter layer of

Effects of LiDAR point density and landscape context on the retrieval of urban forest biomass

Science.gov (United States)

Singh, K. K.; Chen, G.; McCarter, J. B.; Meentemeyer, R. K.

2014-12-01

Light Detection and Ranging (LiDAR), as an alternative to conventional optical remote sensing, is being increasingly used to accurately estimate aboveground forest biomass ranging from individual tree to stand levels. Recent advancements in LiDAR technology have resulted in higher point densities and better data accuracies, which however pose challenges to the procurement and processing of LiDAR data for large-area assessments. Reducing point density cuts data acquisition costs and overcome computational challenges for broad-scale forest management. However, how does that impact the accuracy of biomass estimation in an urban environment containing a great level of anthropogenic disturbances? The main goal of this study is to evaluate the effects of LiDAR point density on the biomass estimation of remnant forests in the rapidly urbanizing regions of Charlotte, North Carolina, USA. We used multiple linear regression to establish the statistical relationship between field-measured biomass and predictor variables (PVs) derived from LiDAR point clouds with varying densities. We compared the estimation accuracies between the general Urban Forest models (no discrimination of forest type) and the Forest Type models (evergreen, deciduous, and mixed), which was followed by quantifying the degree to which landscape context influenced biomass estimation. The explained biomass variance of Urban Forest models, adjusted R2, was fairly consistent across the reduced point densities with the highest difference of 11.5% between the 100% and 1% point densities. The combined estimates of Forest Type biomass models outperformed the Urban Forest models using two representative point densities (100% and 40%). The Urban Forest biomass model with development density of 125 m radius produced the highest adjusted R2 (0.83 and 0.82 at 100% and 40% LiDAR point densities, respectively) and the lowest RMSE values, signifying the distance impact of development on biomass estimation. Our evaluation

Geospatial analysis of forest fragmentation in Uttara Kannada District, India

Institute of Scientific and Technical Information of China (English)

Ramachandra T V; Bharath Setturu; Subash Chandran

2016-01-01

Background: Landscapes consist of heterogeneous interacting dynamic elements with complex ecological,economic and cultural attributes. These complex interactions help in the sustenance of natural resources through bio-geochemical and hydrological cycling. The ecosystem functions are altered with changes in the landscape structure. Fragmentation of large contiguous forests to small and isolated forest patches either by natural phenomena or anthropogenic activities leads to drastic changes in forest patch sizes, shape, connectivity and internal heterogeneity, which restrict the movement leading to inbreeding among Meta populations with extirpation of species.Methods: Landscape dynamics are assessed through land use analysis by way of remote sensing data acquired at different time periods. Forest fragmentation is assessed at the pixel level through computation of two indicators,i.e., Pf(the ratio of pixels that are forested to the total non-water pixels in the window) and Pff(the proportion of all adjacent(cardinal directions only) pixel pairs that include at least one forest pixel, for which both pixels are forested).Results: Uttara Kannada District has the distinction of having the highest forest cover in Karnataka State, India. This region has been experiencing changes in its forest cover and consequent alterations in functional abilities of its ecosystem. Temporal land use analyses show the trend of deforestation, evident from the reduction of evergreen-semi evergreen forest cover from 57.31 %(1979) to 32.08 %(2013) Forest fragmentation at the landscape level shows a decline of interior forests 64.42 %(1979) to 25.62 %(2013) and transition of non-forest categories such as crop land, plantations and built-up areas, amounting now to 47.29 %. PCA prioritized geophysical and socio variables responsible for changes in the landscape structure at local levels.Conclusion: Terrestrial forest ecosystems in Uttara Kannada District of Central Western Ghats have been

Interactions between payments for hydrologic services, landowner decisions, and ecohydrological consequences: synergies and disconnection in the cloud forest zone of central Veracruz, Mexico

Directory of Open Access Journals (Sweden)

Heidi Asbjornsen

2017-06-01

hydrologic services and people's decisions, behavior, and knowledge regarding forest conservation and water. Using central Veracruz as our case study, we identify areas of both synchrony and disconnection between PHS goals and outcomes. Mature and regenerating cloud forests (targeted by PHS were found to produce enhanced hydrologic services relative to areas converted to pasture, including reduced peak flows during large rain events and maintenance of dry-season base flows. However, unexpectedly, these hydrologic benefits from cloud forests were not necessarily greater than those from other vegetation types. Consequently, the location of forests in strategic watershed positions (e.g., where deforestation risk or hydrologic recharge are high may be more critical than forest type in promoting hydrologic functions within watersheds and should be considered when targeting PHS payments. While our results suggest that participation in PHS improved the level of knowledge among watershed inhabitants about forest-water relationships, a mismatch existed between payment amounts and landowner opportunity costs, which may contribute to the modest success in targeting priority areas within watersheds. Combined, these findings underscore the complexity of factors that influence motivations for PHS participation and land use decisions and behavior, and the importance of integrating understanding of both ecohydrological and socioeconomic dynamics into PHS design and implementation. We conclude by identifying opportunities for improving the design of PHS programs and recommending priority areas for future research and monitoring, both in Mexico and globally.

Tropical Montane Cloud Forests: Hydrometeorological variability in three neighbouring catchments with different forest cover

Science.gov (United States)

Ramírez, Beatriz H.; Teuling, Adriaan J.; Ganzeveld, Laurens; Hegger, Zita; Leemans, Rik

2017-09-01

Mountain areas are characterized by a large heterogeneity in hydrological and meteorological conditions. This heterogeneity is currently poorly represented by gauging networks and by the coarse scale of global and regional climate and hydrological models. Tropical Montane Cloud Forests (TMCFs) are found in a narrow elevation range and are characterized by persistent fog. Their water balance depends on local and upwind temperatures and moisture, therefore, changes in these parameters will alter TMCF hydrology. Until recently the hydrological functioning of TMCFs was mainly studied in coastal regions, while continental TMCFs were largely ignored. This study contributes to fill this gap by focusing on a TMCF which is located on the northern eastern Andes at an elevation of 1550-2300 m asl, in the Orinoco river basin highlands. In this study, we describe the spatial and seasonal meteorological variability, analyse the corresponding catchment hydrological response to different land cover, and perform a sensitivity analysis on uncertainties related to rainfall interpolation, catchment area estimation and streamflow measurements. Hydro-meteorological measurements, including hourly solar radiation, temperature, relative humidity, wind speed, precipitation, soil moisture and streamflow, were collected from June 2013 to May 2014 at three gauged neighbouring catchments with contrasting TMCF/grassland cover and less than 250 m elevation difference. We found wetter and less seasonally contrasting conditions at higher elevations, indicating a positive relation between elevation and fog or rainfall persistence. This pattern is similar to that of other eastern Andean TMCFs, however, the study site had higher wet season rainfall and lower dry season rainfall suggesting that upwind contrasts in land cover and moisture can influence the meteorological conditions at eastern Andean TMCFs. Contrasting streamflow dynamics between the studied catchments reflect the overall system response

Potential Effects of Climate Change on the Distribution of Cold-Tolerant Evergreen Broadleaved Woody Plants in the Korean Peninsula.

Directory of Open Access Journals (Sweden)

Kyung Ah Koo

Full Text Available Climate change has caused shifts in species' ranges and extinctions of high-latitude and altitude species. Most cold-tolerant evergreen broadleaved woody plants (shortened to cold-evergreens below are rare species occurring in a few sites in the alpine and subalpine zones in the Korean Peninsula. The aim of this research is to 1 identify climate factors controlling the range of cold-evergreens in the Korean Peninsula; and 2 predict the climate change effects on the range of cold-evergreens. We used multimodel inference based on combinations of climate variables to develop distribution models of cold-evergreens at a physiognomic-level. Presence/absence data of 12 species at 204 sites and 6 climatic factors, selected from among 23 candidate variables, were used for modeling. Model uncertainty was estimated by mapping a total variance calculated by adding the weighted average of within-model variation to the between-model variation. The range of cold-evergreens and model performance were validated by true skill statistics, the receiver operating characteristic curve and the kappa statistic. Climate change effects on the cold-evergreens were predicted according to the RCP 4.5 and RCP 8.5 scenarios. Multimodel inference approach excellently projected the spatial distribution of cold-evergreens (AUC = 0.95, kappa = 0.62 and TSS = 0.77. Temperature was a dominant factor in model-average estimates, while precipitation was minor. The climatic suitability increased from the southwest, lowland areas, to the northeast, high mountains. The range of cold-evergreens declined under climate change. Mountain-tops in the south and most of the area in the north remained suitable in 2050 and 2070 under the RCP 4.5 projection and 2050 under the RCP 8.5 projection. Only high-elevations in the northeastern Peninsula remained suitable under the RCP 8.5 projection. A northward and upper-elevational range shift indicates change in species composition at the alpine and

Potential Effects of Climate Change on the Distribution of Cold-Tolerant Evergreen Broadleaved Woody Plants in the Korean Peninsula.

Science.gov (United States)

Koo, Kyung Ah; Kong, Woo-Seok; Nibbelink, Nathan P; Hopkinson, Charles S; Lee, Joon Ho

2015-01-01

Climate change has caused shifts in species' ranges and extinctions of high-latitude and altitude species. Most cold-tolerant evergreen broadleaved woody plants (shortened to cold-evergreens below) are rare species occurring in a few sites in the alpine and subalpine zones in the Korean Peninsula. The aim of this research is to 1) identify climate factors controlling the range of cold-evergreens in the Korean Peninsula; and 2) predict the climate change effects on the range of cold-evergreens. We used multimodel inference based on combinations of climate variables to develop distribution models of cold-evergreens at a physiognomic-level. Presence/absence data of 12 species at 204 sites and 6 climatic factors, selected from among 23 candidate variables, were used for modeling. Model uncertainty was estimated by mapping a total variance calculated by adding the weighted average of within-model variation to the between-model variation. The range of cold-evergreens and model performance were validated by true skill statistics, the receiver operating characteristic curve and the kappa statistic. Climate change effects on the cold-evergreens were predicted according to the RCP 4.5 and RCP 8.5 scenarios. Multimodel inference approach excellently projected the spatial distribution of cold-evergreens (AUC = 0.95, kappa = 0.62 and TSS = 0.77). Temperature was a dominant factor in model-average estimates, while precipitation was minor. The climatic suitability increased from the southwest, lowland areas, to the northeast, high mountains. The range of cold-evergreens declined under climate change. Mountain-tops in the south and most of the area in the north remained suitable in 2050 and 2070 under the RCP 4.5 projection and 2050 under the RCP 8.5 projection. Only high-elevations in the northeastern Peninsula remained suitable under the RCP 8.5 projection. A northward and upper-elevational range shift indicates change in species composition at the alpine and subalpine

Comparison of passive fog gauges for determining fog duration and fog interception by a Puerto Rican elfin cloud forest

NARCIS (Netherlands)

Holwerda, F; Bruijnzeel, L.A.; Scatena, F.N.

2011-01-01

Between 5 March and 10 May 2001, the performance of three types of passive fog gauges (wire harp WH, standard fog collector SC and Juvik gauge JU) was compared at a wind-exposed Puerto Rican elfin cloud forest site. The gauges were used to determine the timing and duration of fog, as well as

A comparison of 137Cs radioactivity in localized evergreen and deciduous plant species

International Nuclear Information System (INIS)

Rangel, R.C.

1996-05-01

A vegetation study at the Comanche Peak Steam Electric Station (CPSES) near Glen Rose, Texas was conducted in 1991 and 1992. The CPSES is a commercial nuclear power plant owned and operated by Texas Utilities Electric of Dallas, Texas. The US Nuclear Regulatory Commission (USNRC) requires the CPSES to routinely sample broadleaf vegetation in place of milk samples. Few commercial dairies exist in the vicinity. Broadleaf tree species are scarce because the climate and local limestone geology have produced a dry rolling hill topography. An evergreen juniper is the dominant tree species. Few broadleaves during the winter season have hindered year-round sampling. This study compares the environmental 137 Cs concentrations between broadleaf and evergreen foliage at CPSES. Soil 137 Cs concentrations from each vegetation location were also compared to the foliage 137 Cs concentrations. The study's objective was to determine if the deciduous and evergreen vegetation 137 Cs concentrations are statistically the same

Diversity and habitat differentiation of mosses and liverworts in the cloud forest of. Monteverde, Costa Rica

Directory of Open Access Journals (Sweden)

Gradstein S. Rob

2001-07-01

Full Text Available An inventory of the understory and canopy of 4 ha oflower montane cloud forest at Monteverde, Costa Rica, yielded 190 bryophyte species: 133 hepatics, 56 mosses and 1 homwort. Thick branches of the lower canopy were by far the richest habitat in terms of number of species (99, trunks from 1m upwards had 65 species, lianas, shrubs, saplings, or living leaves in the understory had about 36-46 species each, and 16 species were found on rotten logs. The figures are illustrative of the great diversification of microhabitats of bryophytes in a tropical montane cloud forest. About 36% ofthe species, including more than half ofthe corticolous ones, occurred exclusively in the canopy. It appeared thatthe percentage ofbryophyte species restricted to the canopy may be the same in lowland and montane rain forests, in spite of the great differences in species abundance and composition in the two kinds of forest.  Ciento noventa especies de briofitas (133 hepáticas, 56 musgos, 1 antocerote fueron encontradas en un inventario hecho en 4 hectáreas del sotobosque y el dosel en el bosque nublado (1500 m de Monteverde, Costa Rica. Las ramas gruesas del dosel fueron la porción más rica en termino de numero de especies (99, en troncos había 65 especies, lianas, arbustos, árboles juveniles o hojas vivas en el sotobosque tenían entre 36-46 especies cada una, y 16 especies fueron encontradas en troncos en descomposición. Las cifras ilustran la gran diversidad de microhabitats de briofitas en el bosque nublado. Cerca de 36% de las especies, incluyendo mas de la mitad de los corticolos, se presentaron exclusivamente en el dosel. Parece que el porcentaje de especies de briofitas restringidas al dosel podría ser el mismo en bosques de tierras bajas y en bosques nublados, a pesar de la gran diferencia en abundancia y composición taxonómica de las briofitas en las dos clases de bosque.

Xeromorphic traits help to maintain photosynthesis in the perhumid climate of a Taiwanese cloud forest.

Science.gov (United States)

Pariyar, Shyam; Chang, Shih-Chieh; Zinsmeister, Daniel; Zhou, Haiyang; Grantz, David A; Hunsche, Mauricio; Burkhardt, Juergen

2017-07-01

Previous flux measurements in the perhumid cloud forest of northeastern Taiwan have shown efficient photosynthesis of the endemic tree species Chamaecyparis obtusa var. formosana even under foggy conditions in which leaf surface moisture would be expected. We hypothesized this to be the result of 'xeromorphic' traits of the Chamaecyparis leaves (hydrophobicity, stomatal crypts, stomatal clustering), which could prevent coverage of stomata by precipitation, fog, and condensation, thereby maintaining CO 2 uptake. Here we studied the amount, distribution, and composition of moisture accumulated on Chamaecyparis leaf surfaces in situ in the cloud forest. We studied the effect of surface tension on gas penetration to stomata using optical O 2 microelectrodes in the laboratory. We captured the dynamics of condensation to the leaf surfaces with an environmental scanning electron microscope (ESEM). In spite of substantial surface hydrophobicity, the mean water film thickness on branchlets under foggy conditions was 80 µm (upper surface) and 40 µm (lower surface). This amount of water could cover stomata and prevent CO 2 uptake. This is avoided by the clustered arrangement of stomata within narrow clefts and the presence of Florin rings. These features keep stomatal pores free from water due to surface tension and provide efficient separation of plant and atmosphere in this perhumid environment. Air pollutants, particularly hygroscopic aerosol, may disturb this functionality by enhancing condensation and reducing the surface tension of leaf surface water.

Effects of environmental factors and soil properties on topographic variations of soil respiration

OpenAIRE

Tamai, K.

2010-01-01

Soil respiration rates were measured along different parts of a slope in (a) an evergreen forest with common brown forest soil and (b) a deciduous forest with immature soil. The effects of soil temperature, soil moisture and soil properties were estimated individually, and the magnitudes of these effects in the deciduous and evergreen forests were compared. In the evergreen forest with common brown forest soil, soil properties had the greatest effect on soil respiration rates, followed by soi...

75 FR 76727 - Evergreen Wind Power III, LLC; Supplemental Notice that Initial Market-Based Rate Filing Includes...

Science.gov (United States)

2010-12-09

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER11-2201-000] Evergreen Wind Power III, LLC; Supplemental Notice that Initial Market-Based Rate Filing Includes Request for... proceeding of Evergreen Wind Power III, LLC's application for market-based rate authority, with an...

Evergreen oak leaves as natural monitor in environmental pollution

International Nuclear Information System (INIS)

Capannesi, G.; Rosada, A.; Caroli, S.

1988-01-01

Evergreen oak was chosen as a possible biological monitor of environmental pollution. It was shown that there was a direct relationship between the concentration of elements in leaves and the presence of pollution sources, i.e. the density of vehicular traffic. (author) 12 figs.; 3 tabs

Climatic Characteristics of the Subtropical Mountainous Cloud Forest at the Yuanyang Lake Long-Term Ecological Research Site, Taiwan

Directory of Open Access Journals (Sweden)

I-Ling Lai

2006-12-01

Full Text Available To better understand the climatic characteristics in a subtropical mountainous cloud forest at the Yuanyang Lake long-term ecological research site, weather data collected from January 1994 to December 2004 were analyzed in the present study. The obvious seasonal changes in climatic factors were observed at this site. The annual mean air temperature was 12.7°C. The lowest temperature was recorded in February (monthly mean 5.9°C, and the highest one was taken in July (monthly mean 18.1°C. Winter featured light rain with a prolonged occurrence of fog, resulting in a large reduction of radiation. In summer, fog occurred once in the early morning and the other time from afternoon to evening. The latter one was associated with the wind direction changes and usually accompanied with short moderate to heavy convective rain. Consequently the photosynthetic photon flux density (PPFD was high in the morning but reduced drastically in the afternoon. Typhoons occurred in the summer had contributed to 37% of the annual rainfall, usually resulting in torrential rain events and sharp increases in the water level of this lake. As a matter of fact, perhumid environment of this site was attributed to abundant rainfall (mean annual precipitation 3396 mm and high frequency (up to 40% of foggy time. Such conditions would reduce the intensity of solar radiation and PPFD. The average annual solar radiation at the site was 2475 MJ m-2, and annual PPFD was 5713 mol m-2. The average degree of reduction of PPFD under foggy condition was up to 88%. Such climatic characteristics are suggested to constrain the growth of plants and play an important role in competition among plant species in this cloud forest. It is considered that the distinct seasonal fluctuation in environmental factors, perhumid and dim light conditions are the most distinguished characteristics of this subtropical mountainous cloud forest ecosystem.

Geospatial analysis of forest fragmentation in Uttara Kannada District, India

Directory of Open Access Journals (Sweden)

Ramachandra T V

2016-04-01

Full Text Available Background: Landscapes consist of heterogeneous interacting dynamic elements with complex ecological, economic and cultural attributes. These complex interactions help in the sustenance of natural resources through bio-geochemical and hydrological cycling. The ecosystem functions are altered with changes in the landscape structure. Fragmentation of large contiguous forests to small and isolated forest patches either by natural phenomena or anthropogenic activities leads to drastic changes in forest patch sizes, shape, connectivity and internal heterogeneity, which restrict the movement leading to inbreeding among Meta populations with extirpation of species. Methods: Landscape dynamics are assessed through land use analysis by way of remote sensing data acquired at different time periods. Forest fragmentation is assessed at the pixel level through computation of two indicators, i.e., Pf (the ratio of pixels that are forested to the total non-water pixels in the window and Pff (the proportion of all adjacent (cardinal directions only pixel pairs that include at least one forest pixel, for which both pixels are forested. Results: Uttara Kannada District has the distinction of having the highest forest cover in Karnataka State, India. This region has been experiencing changes in its forest cover and consequent alterations in functional abilities of its ecosystem. Temporal land use analyses show the trend of deforestation, evident from the reduction of evergreen - semi evergreen forest cover from 57.31 % (1979 to 32.08 % (2013 Forest fragmentation at the landscape level shows a decline of interior forests 64.42 % (1979 to 25.62 % (2013 and transition of non-forest categories such as crop land, plantations and built-up areas, amounting now to 47.29 %. PCA prioritized geophysical and socio variables responsible for changes in the landscape structure at local levels. Conclusion: Terrestrial forest ecosystems in Uttara Kannada District of Central

SPECIES-SPECIFIC FOREST VARIABLE ESTIMATION USING NON-PARAMETRIC MODELING OF MULTI-SPECTRAL PHOTOGRAMMETRIC POINT CLOUD DATA

Directory of Open Access Journals (Sweden)

J. Bohlin

2012-07-01

Full Text Available The recent development in software for automatic photogrammetric processing of multispectral aerial imagery, and the growing nation-wide availability of Digital Elevation Model (DEM data, are about to revolutionize data capture for forest management planning in Scandinavia. Using only already available aerial imagery and ALS-assessed DEM data, raster estimates of the forest variables mean tree height, basal area, total stem volume, and species-specific stem volumes were produced and evaluated. The study was conducted at a coniferous hemi-boreal test site in southern Sweden (lat. 58° N, long. 13° E. Digital aerial images from the Zeiss/Intergraph Digital Mapping Camera system were used to produce 3D point-cloud data with spectral information. Metrics were calculated for 696 field plots (10 m radius from point-cloud data and used in k-MSN to estimate forest variables. For these stands, the tree height ranged from 1.4 to 33.0 m (18.1 m mean, stem volume from 0 to 829 m3 ha-1 (249 m3 ha-1 mean and basal area from 0 to 62.2 m2 ha-1 (26.1 m2 ha-1 mean, with mean stand size of 2.8 ha. Estimates made using digital aerial images corresponding to the standard acquisition of the Swedish National Land Survey (Lantmäteriet showed RMSEs (in percent of the surveyed stand mean of 7.5% for tree height, 11.4% for basal area, 13.2% for total stem volume, 90.6% for pine stem volume, 26.4 for spruce stem volume, and 72.6% for deciduous stem volume. The results imply that photogrammetric matching of digital aerial images has significant potential for operational use in forestry.

Radiation budget, soil heat flux and latent heat flux at the forest floor in warm, temperate mixed forest

International Nuclear Information System (INIS)

Tamai, K.; Abe, T.; Araki, M.; Ito, H.

1998-01-01

Seasonal changes in the radiation budget and soil heat flux of a forest floor were measured in a mixed forest located in Kyoto, Japan. The basal area at breast height in the survey forest was about 15·82 m 2 ha −1 , for evergreen trees, and 12·46 m 2 ha −1 , for deciduous trees. The sky view factor was 16 and 22% at the survey site in the foliate and defoliate seasons, respectively. The small difference between the sky view factor in the two seasons was reflected in the seasonal change in the radiation budget of the forest floor. Namely, the net long-wave radiation changed rapidly in leafing and falling days, and the rate of net short-wave radiation was highest in April. The distinctive characteristic of the radiation budget was that the rates of available radiation in the daytime and at night were almost equal in September and October. Latent heat flux at the forest floor was estimated to be around 94 MJ m −2 annually, from our measurement with the simulation model. (author)

Input of trace substances to coniferous forests by fog interception at high elevations of Black Forest

International Nuclear Information System (INIS)

Winkler, P.; Pahl, S.

1993-10-01

The deposition of trace substances to a coniferous forest has been estimated by means of a one-dimensional cloud droplet deposition model. For a period of 21 months the liquid water content has been measured and 89 samples of cloud water from the weather station Feldberg have been analysed for chemical composition. These data and meteorological routine observations have been used as input parameters for the deposition model. Deposition calculations to a 40 years old coniferous forest for the period 1982-1991 showed that the cloud water deposition amounts to 33% of the precipitation amount on the average and varies between 23 and 43% in single years. The highest cloud water deposition rates occur during fall and winter. The trace substance concentration in cloud water has been found to be higher than in precipitation, by a factor between 6 and 12, depending on the type of ions. Typically seasonal variations of normalized ion concentrations could be shown to exist as well as dependencies on wind direction. Air mass transport from the industries of the Stuttgart area resulted in higher trace substance concentrations in cloud water. The deposition of trace substances via fog interception during the summer months is as high and in the winter months higher than that by wet deposition. The forests at high elevations of Black Forest are charged appreciably by fog interception. (orig.). 31 figs., 5 tabs., 39 refs [de

Characteristics of fog and fogwater fluxes in a Puerto Rican elfin cloud

NARCIS (Netherlands)

Eugster, W.; Burkard, R.; Holwerda, F.; Scatena, F.N.; Bruijnzeel, L.A.

2006-01-01

The Luquillo Mountains of northeastern Puerto Rico harbours important fractions of tropical montane cloud forests. Although it is well known that the frequent occurrence of dense fog is a common climatic characteristic of cloud forests around the world, it is poorly understood how fog processes

A comparison of {sup 137}Cs radioactivity in localized evergreen and deciduous plant species

Energy Technology Data Exchange (ETDEWEB)

Rangel, R.C.

1996-05-01

A vegetation study at the Comanche Peak Steam Electric Station (CPSES) near Glen Rose, Texas was conducted in 1991 and 1992. The CPSES is a commercial nuclear power plant owned and operated by Texas Utilities Electric of Dallas, Texas. The US Nuclear Regulatory Commission (USNRC) requires the CPSES to routinely sample broadleaf vegetation in place of milk samples. Few commercial dairies exist in the vicinity. Broadleaf tree species are scarce because the climate and local limestone geology have produced a dry rolling hill topography. An evergreen juniper is the dominant tree species. Few broadleaves during the winter season have hindered year-round sampling. This study compares the environmental {sup 137}Cs concentrations between broadleaf and evergreen foliage at CPSES. Soil {sup 137}Cs concentrations from each vegetation location were also compared to the foliage {sup 137}Cs concentrations. The study`s objective was to determine if the deciduous and evergreen vegetation {sup 137}Cs concentrations are statistically the same.

'Linkage' pharmaceutical evergreening in Canada and Australia

OpenAIRE

Faunce, Thomas A; Lexchin, Joel

2007-01-01

'Evergreening' is not a formal concept of patent law. It is best understood as a social idea used to refer to the myriad ways in which pharmaceutical patent owners utilise the law and related regulatory processes to extend their high rent-earning intellectual monopoly privileges, particularly over highly profitable (either in total sales volume or price per unit) 'blockbuster' drugs. Thus, while the courts are an instrument frequently used by pharmaceutical brand name manufacturers to prolong...

Factors influencing density of the Northern Mealy Amazon in three forest types of a modified rainforest landscape in Mesoamerica

Directory of Open Access Journals (Sweden)

Miguel Ángel. De Labra-Hernández

2017-06-01

Full Text Available The high rate of conversion of tropical moist forest to secondary forest makes it imperative to evaluate forest metric relationships of species dependent on primary, old-growth forest. The threatened Northern Mealy Amazon (Amazona guatemalae is the largest mainland parrot, and occurs in tropical moist forests of Mesoamerica that are increasingly being converted to secondary forest. However, the consequences of forest conversion for this recently taxonomically separated parrot species are poorly understood. We measured forest metrics of primary evergreen, riparian, and secondary tropical moist forest in Los Chimalapas, Mexico. We also used point counts to estimate density of Northern Mealy Amazons in each forest type during the nonbreeding (Sept 2013 and breeding (March 2014 seasons. We then examined how parrot density was influenced by forest structure and composition, and how parrots used forest types within tropical moist forest. Overall, parrot density was high in the breeding season, with few parrots present during the nonbreeding season. During the breeding season, primary forest had significantly greater density of 18.9 parrots/km² in evergreen forest and 35.9 parrots/km² in riparian forest, compared with only 3.4 parrots/km² in secondary forest. Secondary forest had significantly lower tree species richness, density, diameter, total height, and major branch ramification height, as well as distinct tree species composition compared with both types of primary forest. The number of parrots recorded at point counts was related to density of large, tall trees, characteristic of primary forest, and parrots used riparian forest more than expected by availability. Hence, the increased conversion of tropical moist forest to secondary forest is likely to lead to reduced densities of forest-dependent species such as the Northern Mealy Amazon. Furthermore, the species' requirement for primary tropical moist forest highlights the need to reevaluate

A Phenology-Based Method for Monitoring Woody and Herbaceous Vegetation in Mediterranean Forests from NDVI Time Series

OpenAIRE

David Helman; Itamar M. Lensky; Naama Tessler; Yagil Osem

2015-01-01

We present an efficient method for monitoring woody (i.e., evergreen) and herbaceous (i.e., ephemeral) vegetation in Mediterranean forests at a sub pixel scale from Normalized Difference Vegetation Index (NDVI) time series derived from the Moderate Resolution Imaging Spectroradiometer (MODIS). The method is based on the distinct development periods of those vegetation components. In the dry season, herbaceous vegetation is absent or completely dry in Mediterranean forests. Thus the mean NDVI ...

Gap formation and carbon cycling in the Brazilian Amazon: measurement using high-resolution optical remote sensing and studies in large forest plots

Science.gov (United States)

F. D. B. Espirito-Santo; M. M. Keller; E. Linder; R. C. Oliveira Junior; C. Pereira; C. G. Oliveira

2013-01-01

Background: The dynamics of gaps plays a role in the regimes of tree mortality, production of coarse woody debris (CWD) and the variability of light in the forest understory. Aims: To quantify the area affected by, and the carbon fluxes associated with, natural gap-phase disturbances in a tropical lowland evergreen rain forest by use of ground measurements and high-...

Relating ring width of Mediterranean evergreen species to seasonal and annual variations of precipitation and temperature

Science.gov (United States)

Nijland, W.; Jansma, E.; Addink, E. A.; Domínguez Delmás, M.; de Jong, S. M.

2011-05-01

Plant growth in Mediterranean landscapes is limited by the typical summer-dry climate. Forests in these areas are only marginally productive and may be quite susceptible to modern climate change. To improve our understanding of forest sensitivity to annual and seasonal climatic variability, we use tree-ring measurements of two Mediterranean evergreen tree species: Quercus ilex L. and Arbutus unedo L. We sampled 34 stems of these species on three different types of substrates in the Peyne study area in southern France. The resulting chronologies were analysed in combination with 38 yr of monthly precipitation and temperature data to reconstruct the response of stem growth to climatic variability. Results indicate a strong positive response to May and June precipitation, as well as a significant positive influence of early-spring temperatures and a negative growth response to summer heat. Comparison of the data with more detailed productivity measurements in two contrasting years confirms these observations and shows a strong productivity limiting effect of low early-summer precipitation. The results show that tree-ring data from Q.ilex and A.unedo can provide valuable information about the response of these tree species to climate variability, improving our ability to predict the effects of climate change in Mediterranean ecosystems.

Regeneration of different plant functional types in a Masson pine forest following pine wilt disease.

Science.gov (United States)

Hu, Guang; Xu, Xuehong; Wang, Yuling; Lu, Gao; Feeley, Kenneth J; Yu, Mingjian

2012-01-01

Pine wilt disease is a severe threat to the native pine forests in East Asia. Understanding the natural regeneration of the forests disturbed by pine wilt disease is thus critical for the conservation of biodiversity in this realm. We studied the dynamics of composition and structure within different plant functional types (PFTs) in Masson pine forests affected by pine wilt disease (PWD). Based on plant traits, all species were assigned to four PFTs: evergreen woody species (PFT1), deciduous woody species (PFT2), herbs (PFT3), and ferns (PFT4). We analyzed the changes in these PFTs during the initial disturbance period and during post-disturbance regeneration. The species richness, abundance and basal area, as well as life-stage structure of the PFTs changed differently after pine wilt disease. The direction of plant community regeneration depended on the differential response of the PFTs. PFT1, which has a higher tolerance to disturbances, became dominant during the post-disturbance regeneration, and a young evergreen-broad-leaved forest developed quickly after PWD. Results also indicated that the impacts of PWD were dampened by the feedbacks between PFTs and the microclimate, in which PFT4 played an important ecological role. In conclusion, we propose management at the functional type level instead of at the population level as a promising approach in ecological restoration and biodiversity conservation.

Parameterized approximation of lacunarity functions derived from airborne laser scanning point clouds of forested areas

Science.gov (United States)

Székely, Balázs; Kania, Adam; Varga, Katalin; Heilmeier, Hermann

2017-04-01

Lacunarity, a measure of the spatial distribution of the empty space is found to be a useful descriptive quantity of the forest structure. Its calculation, based on laser-scanned point clouds, results in a four-dimensional data set. The evaluation of results needs sophisticated tools and visualization techniques. To simplify the evaluation, it is straightforward to use approximation functions fitted to the results. The lacunarity function L(r), being a measure of scale-independent structural properties, has a power-law character. Previous studies showed that log(log(L(r))) transformation is suitable for analysis of spatial patterns. Accordingly, transformed lacunarity functions can be approximated by appropriate functions either in the original or in the transformed domain. As input data we have used a number of laser-scanned point clouds of various forests. The lacunarity distribution has been calculated along a regular horizontal grid at various (relative) elevations. The lacunarity data cube then has been logarithm-transformed and the resulting values became the input of parameter estimation at each point (point of interest, POI). This way at each POI a parameter set is generated that is suitable for spatial analysis. The expectation is that the horizontal variation and vertical layering of the vegetation can be characterized by this procedure. The results show that the transformed L(r) functions can be typically approximated by exponentials individually, and the residual values remain low in most cases. However, (1) in most cases the residuals may vary considerably, and (2) neighbouring POIs often give rather differing estimates both in horizontal and in vertical directions, of them the vertical variation seems to be more characteristic. In the vertical sense, the distribution of estimates shows abrupt changes at places, presumably related to the vertical structure of the forest. In low relief areas horizontal similarity is more typical, in higher relief areas

Quantifying Sediment Transport in a Premontane Transitional Cloud Forest

Science.gov (United States)

Waring, E. R.; Brumbelow, J. K.

2013-12-01

Quantifying sediment transport is a difficult task in any watershed, and relatively little direct measurement has occurred in tropical, mountainous watersheds. The Howler Monkey Watershed (2.2 hectares) is located in a premontane transitional cloud forest in San Isidro de Peñas Blancas, Costa Rica. In June 2012, a V-notch stream-gaging weir was built in the catchment with a 8 ft by 6 ft by 4 ft concrete stilling basin. Sediment captured by the weir was left untouched for an 11 month time period. To collect the contents of the weir, the stream was rerouted and the weir was drained. The stilling basin contents were systematically sampled, and samples were taken to a lab and characterized using sieve and hydrometer tests. The wet volume of the remaining sediment was obtained, and dry mass was estimated. Particle size distribution of samples were obtained from lab tests, with 96% of sediment trapped by the weir being sand or coarser. The efficiency of the weir as a sediment collector was evaluated by comparing particle fall velocities to residence time of water in the weir under baseflow conditions. Under these assumptions, only two to three percent of the total mass of soil transported in the stream is thought to have been suspended in the water and lost over the V-notch. Data were compared to the Universal Soil Loss Equation (USLE), a widely accepted method for predicting soil loss in agricultural watersheds. As expected, application of the USLE to a tropical rainforest was problematic with uncertainty in parameters yielding a soil loss estimate varying by a factor of 50. Continued monitoring of sediment transport should yield data for improved methods of soil loss estimation applicable to tropical mountainous forests.

Remarkable fly (Diptera) diversity in a patch of Costa Rican cloud forest: Why inventory is a vital science

Science.gov (United States)

Art Borkent; Brian V. Brown; Peter H. Adler; Dalton de Souza Amorim; Kevin Barber; Daniel Bickel; Stephanie Boucher; Scott E. Brooks; John Burger; Zelia L. Burington; Renato S. Capellari; Daniel N. R. Costa; Jeffrey M. Cumming; Greg Curler; Carl W. Dick; John H. Epler; Eric Fisher; Stephen D. Gaimari; Jon Gelhaus; David A. Grimaldi; John Hash; Martin Hauser; Heikki Hippa; Sergio Ibanez-Bernal; Mathias Jaschhof; Elena P. Kameneva; Peter H. Kerr; Valery Korneyev; Cheslavo A. Korytkowski; Giar-Ann Kung; Gunnar Mikalsen Kvifte; Owen Lonsdale; Stephen A. Marshall; Wayne N. Mathis; Verner Michelsen; Stefan Naglis; Allen L. Norrbom; Steven Paiero; Thomas Pape; Alessandre Pereira-Colavite; Marc Pollet; Sabrina Rochefort; Alessandra Rung; Justin B. Runyon; Jade Savage; Vera C. Silva; Bradley J. Sinclair; Jeffrey H. Skevington; John O. Stireman; John Swann; F. Christian Thompson; Pekka Vilkamaa; Terry Wheeler; Terry Whitworth; Maria Wong; D. Monty Wood; Norman Woodley; Tiffany Yau; Thomas J. Zavortink; Manuel A. Zumbado

2018-01-01

Study of all flies (Diptera) collected for one year from a four-hectare (150 x 266 meter) patch of cloud forest at 1,600 meters above sea level at Zurquí de Moravia, San José Province, Costa Rica (hereafter referred to as Zurquí), revealed an astounding 4,332 species. This amounts to more than half the number of named species of flies for all of Central America....

The effect of the tropical cloud (fog) forest on the spatial distribution of cesium-137 in soils in the Henri Pittier National Park (Edo, Aragua, Venezuela)

International Nuclear Information System (INIS)

LaBrecque, J.J.; Rosales, P.A.; Cordoves, P.R.

2002-01-01

Soils were collected at different elevations (m.a.s.l.) near the two roadways, that pass through the Henri Pittier National Park (Edo, Aragua, Venezuela) in order to determine the distribution of the concentrations of the 137 Cs fallout and its relation to the tropical cloud forest. Duplicate samples were taken at most elevations between 2-5 cm below the soil surface to confirm that the samples were representative of the area. In many cases, it was difficult or impossible to locate areas that were undisturbed by man or nature. The 137 Cs (Bq/kg) content was determined by conventional high resolution gamma ray spectroscopy employing a standard comparison method. The background of the 137 Cs fallout in soils, below the cloud (fog) baseline was calculated to be about 5 Bq/kg on both the south (land) side and north (ocean) side for both roadways. The concentrations of 137 Cs (Bq/kg) were between 2-3 times higher at the baseline of the cloud (fog) on both sides of the mountain range. The 137 Cs values at the highest elevations (1105 and 1625 m.a.s.l.) near the roadways were about 5-6 times higher than the determined background levels. Our estimates of the baseline of the cloud (fog) are in good agreement with other visual observations. It was concluded that the distribution of 137 Cs in soils in cloud forests can be employed to estimate the baseline and the concentrations of 137 Cs fallout can be related to the relative density of the cloud (fog) when it was deposited. (author)

Effects of logging and recruitment on community phylogenetic structure in 32 permanent forest plots of Kampong Thom, Cambodia.

Science.gov (United States)

Toyama, Hironori; Kajisa, Tsuyoshi; Tagane, Shuichiro; Mase, Keiko; Chhang, Phourin; Samreth, Vanna; Ma, Vuthy; Sokh, Heng; Ichihashi, Ryuji; Onoda, Yusuke; Mizoue, Nobuya; Yahara, Tetsukazu

2015-02-19

Ecological communities including tropical rainforest are rapidly changing under various disturbances caused by increasing human activities. Recently in Cambodia, illegal logging and clear-felling for agriculture have been increasing. Here, we study the effects of logging, mortality and recruitment of plot trees on phylogenetic community structure in 32 plots in Kampong Thom, Cambodia. Each plot was 0.25 ha; 28 plots were established in primary evergreen forests and four were established in secondary dry deciduous forests. Measurements were made in 1998, 2000, 2004 and 2010, and logging, recruitment and mortality of each tree were recorded. We estimated phylogeny using rbcL and matK gene sequences and quantified phylogenetic α and β diversity. Within communities, logging decreased phylogenetic diversity, and increased overall phylogenetic clustering and terminal phylogenetic evenness. Between communities, logging increased phylogenetic similarity between evergreen and deciduous plots. On the other hand, recruitment had opposite effects both within and between communities. The observed patterns can be explained by environmental homogenization under logging. Logging is biased to particular species and larger diameter at breast height, and forest patrol has been effective in decreasing logging. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Effects of environmental factors and soil properties on topographic variations of soil respiration

Directory of Open Access Journals (Sweden)

K. Tamai

2010-03-01

Full Text Available Soil respiration rates were measured along different parts of a slope in (a an evergreen forest with common brown forest soil and (b a deciduous forest with immature soil. The effects of soil temperature, soil moisture and soil properties were estimated individually, and the magnitudes of these effects in the deciduous and evergreen forests were compared. In the evergreen forest with common brown forest soil, soil properties had the greatest effect on soil respiration rates, followed by soil moisture and soil temperature. These results may be explained by the fact that different soil properties matured within different environments. It can be argued that the low soil respiration rates in the low parts of the slope in the evergreen forest resulted from soil properties and not from wet soil conditions. In the deciduous forest, soil respiration rates were more strongly affected by soil moisture and soil temperature than by soil properties. These effects were likely due to the immaturity of the forest soil.

Comparison of Laser and Stereo Optical, SAR and InSAR Point Clouds from Air- and Space-Borne Sources in the Retrieval of Forest Inventory Attributes

Directory of Open Access Journals (Sweden)

Xiaowei Yu

2015-11-01

Full Text Available It is anticipated that many of the future forest mapping applications will be based on three-dimensional (3D point clouds. A comparison study was conducted to verify the explanatory power and information contents of several 3D remote sensing data sources on the retrieval of above ground biomass (AGB, stem volume (VOL, basal area (G, basal-area weighted mean diameter (Dg and Lorey’s mean height (Hg at the plot level, utilizing the following data: synthetic aperture radar (SAR Interferometry, SAR radargrammetry, satellite-imagery having stereo viewing capability, airborne laser scanning (ALS with various densities (0.8–6 pulses/m2 and aerial stereo imagery. Laser scanning is generally known as the primary source providing a 3D point cloud. However, photogrammetric, radargrammetric and interferometric techniques can be used to produce 3D point clouds from space- and air-borne stereo images. Such an image-based point cloud could be utilized in a similar manner as ALS providing that accurate digital terrain model is available. In this study, the performance of these data sources for providing point cloud data was evaluated with 91 sample plots that were established in Evo, southern Finland within a boreal forest zone and surveyed in 2014 for this comparison. The prediction models were built using random forests technique with features derived from each data sources as independent variables and field measurements of forest attributes as response variable. The relative root mean square errors (RMSEs varied in the ranges of 4.6% (0.97 m–13.4% (2.83 m for Hg, 11.7% (3.0 cm–20.6% (5.3 cm for Dg, 14.8% (4.0 m2/ha–25.8% (6.9 m2/ha for G, 15.9% (43.0 m3/ha–31.2% (84.2 m3/ha for VOL and 14.3% (19.2 Mg/ha–27.5% (37.0 Mg/ha for AGB, respectively, depending on the data used. Results indicate that ALS data achieved the most accurate estimates for all forest inventory attributes. For image-based 3D data, high-altitude aerial images and WorldView-2

FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45 m telescope (FUGIN). III. Possible evidence for formation of NGC 6618 cluster in M 17 by cloud-cloud collision

Science.gov (United States)

Nishimura, Atsushi; Minamidani, Tetsuhiro; Umemoto, Tomofumi; Fujita, Shinji; Matsuo, Mitsuhiro; Hattori, Yusuke; Kohno, Mikito; Yamagishi, Mitsuyoshi; Tsuda, Yuya; Kuriki, Mika; Kuno, Nario; Torii, Kazufumi; Tsutsumi, Daichi; Okawa, Kazuki; Sano, Hidetoshi; Tachihara, Kengo; Ohama, Akio; Fukui, Yasuo

2018-05-01

We present 12CO (J = 1-0), 13CO (J = 1-0), and C18O (J = 1-0) images of the M 17 giant molecular clouds obtained as part of the FUGIN (FOREST Ultra-wide Galactic Plane Survey In Nobeyama) project. The observations cover the entire area of the M 17 SW and M 17 N clouds at the highest angular resolution (˜19″) to date, which corresponds to ˜0.18 pc at the distance of 2.0 kpc. We find that the region consists of four different velocity components: a very low velocity (VLV) clump, a low velocity component (LVC), a main velocity component (MVC), and a high velocity component (HVC). The LVC and the HVC have cavities. Ultraviolet photons radiated from NGC 6618 cluster penetrate into the N cloud up to ˜5 pc through the cavities and interact with molecular gas. This interaction is correlated with the distribution of young stellar objects in the N cloud. The LVC and the HVC are distributed complementarily after the HVC is displaced by 0.8 pc toward the east-southeast direction, suggesting that collision of the LVC and the HVC created the cavities in both clouds. The collision velocity and timescale are estimated to be 9.9 km s-1 and 1.1 × 105 yr, respectively. The high collision velocity can provide a mass accretion rate of up to 10^{-3} M_{⊙}yr-1, and the high column density (4 × 1023 cm-2) might result in massive cluster formation. The scenario of cloud-cloud collision likely explains well the stellar population and the formation history of the NGC 6618 cluster proposed by Hoffmeister et al. (2008, ApJ, 686, 310).

Evaluating the effect of alternative carbon allocation schemes in a land surface model (CLM4.5) on carbon fluxes, pools, and turnover in temperate forests

Science.gov (United States)

Montané, Francesc; Fox, Andrew M.; Arellano, Avelino F.; MacBean, Natasha; Alexander, M. Ross; Dye, Alex; Bishop, Daniel A.; Trouet, Valerie; Babst, Flurin; Hessl, Amy E.; Pederson, Neil; Blanken, Peter D.; Bohrer, Gil; Gough, Christopher M.; Litvak, Marcy E.; Novick, Kimberly A.; Phillips, Richard P.; Wood, Jeffrey D.; Moore, David J. P.

2017-09-01

How carbon (C) is allocated to different plant tissues (leaves, stem, and roots) determines how long C remains in plant biomass and thus remains a central challenge for understanding the global C cycle. We used a diverse set of observations (AmeriFlux eddy covariance tower observations, biomass estimates from tree-ring data, and leaf area index (LAI) measurements) to compare C fluxes, pools, and LAI data with those predicted by a land surface model (LSM), the Community Land Model (CLM4.5). We ran CLM4.5 for nine temperate (including evergreen and deciduous) forests in North America between 1980 and 2013 using four different C allocation schemes: i. dynamic C allocation scheme (named "D-CLM4.5") with one dynamic allometric parameter, which allocates C to the stem and leaves to vary in time as a function of annual net primary production (NPP); ii. an alternative dynamic C allocation scheme (named "D-Litton"), where, similar to (i), C allocation is a dynamic function of annual NPP, but unlike (i) includes two dynamic allometric parameters involving allocation to leaves, stem, and coarse roots; iii.-iv. a fixed C allocation scheme with two variants, one representative of observations in evergreen (named "F-Evergreen") and the other of observations in deciduous forests (named "F-Deciduous"). D-CLM4.5 generally overestimated gross primary production (GPP) and ecosystem respiration, and underestimated net ecosystem exchange (NEE). In D-CLM4.5, initial aboveground biomass in 1980 was largely overestimated (between 10 527 and 12 897 g C m-2) for deciduous forests, whereas aboveground biomass accumulation through time (between 1980 and 2011) was highly underestimated (between 1222 and 7557 g C m-2) for both evergreen and deciduous sites due to a lower stem turnover rate in the sites than the one used in the model. D-CLM4.5 overestimated LAI in both evergreen and deciduous sites because the leaf C-LAI relationship in the model did not match the observed leaf C

Fragmentation patterns of evergreen oak woodlands in Southwestern Iberia

DEFF Research Database (Denmark)

Costa, A.; Madeira, M.; Lima Santos, J.

2014-01-01

Mediterranean evergreen oak woodlands (composed of Quercus suber L. and Quercus rotundifolia Lam.) are becoming increasingly fragmented in the human-modified landscapes of Southwestern Portugal and Spain. Previous studies have largely neglected to assess the spatial changes of oak woodlands...... patterns of oak recruitment and therefore, its study may be helpful in highlighting future baselines for the sustainable management of oak woodlands....

Foliar uptake, carbon fluxes and water status are affected by the timing of daily fog in saplings from a threatened cloud forest.

Science.gov (United States)

Berry, Z Carter; White, Joseph C; Smith, William K

2014-05-01

In cloud forests, foliar uptake (FU) of water has been reported for numerous species, possibly acting to relieve daily water and carbon stress. While the prevalence of FU seems common, how daily variation in fog timing may affect this process has not been studied. We examined the quantity of FU, water potentials, gas exchange and abiotic variation at the beginning and end of a 9-day exposure to fog in a glasshouse setting. Saplings of Abies fraseri (Pursh) Poir. and Picea rubens Sarg. were exposed to morning (MF), afternoon (AF) or evening fog (EF) regimes to assess the ability to utilize fog water at different times of day and after sustained exposure to simulated fog. The greatest amount of FU occurred during MF (up to 50%), followed by AF (up to 23%) and then EF, which surprisingly had no FU. There was also a positive relationship between leaf conductance and FU, suggesting a role of stomata in FU. Moreover, MF and AF lead to the greatest improvements in daily water balance and carbon gain, respectively. Foliar uptake was important for improving plant ecophysiology but was influenced by diurnal variation in fog. With climate change scenarios predicting changes to cloud patterns and frequency that will likely alter diurnal patterns, cloud forests that rely on this water subsidy could be affected. © The Author 2014. Published by Oxford University Press. All rights reserved.

Forest resilience to drought varies across biomes.

Science.gov (United States)

Gazol, Antonio; Camarero, Jesus Julio; Vicente-Serrano, Sergio M; Sánchez-Salguero, Raúl; Gutiérrez, Emilia; de Luis, Martin; Sangüesa-Barreda, Gabriel; Novak, Klemen; Rozas, Vicente; Tíscar, Pedro A; Linares, Juan C; Martín-Hernández, Natalia; Martínez Del Castillo, Edurne; Ribas, Montse; García-González, Ignacio; Silla, Fernando; Camisón, Alvaro; Génova, Mar; Olano, José M; Longares, Luis A; Hevia, Andrea; Tomás-Burguera, Miquel; Galván, J Diego

2018-05-01

Forecasted increase drought frequency and severity may drive worldwide declines in forest productivity. Species-level responses to a drier world are likely to be influenced by their functional traits. Here, we analyse forest resilience to drought using an extensive network of tree-ring width data and satellite imagery. We compiled proxies of forest growth and productivity (TRWi, absolutely dated ring-width indices; NDVI, Normalized Difference Vegetation Index) for 11 tree species and 502 forests in Spain corresponding to Mediterranean, temperate, and continental biomes. Four different components of forest resilience to drought were calculated based on TRWi and NDVI data before, during, and after four major droughts (1986, 1994-1995, 1999, and 2005), and pointed out that TRWi data were more sensitive metrics of forest resilience to drought than NDVI data. Resilience was related to both drought severity and forest composition. Evergreen gymnosperms dominating semi-arid Mediterranean forests showed the lowest resistance to drought, but higher recovery than deciduous angiosperms dominating humid temperate forests. Moreover, semi-arid gymnosperm forests presented a negative temporal trend in the resistance to drought, but this pattern was absent in continental and temperate forests. Although gymnosperms in dry Mediterranean forests showed a faster recovery after drought, their recovery potential could be constrained if droughts become more frequent. Conversely, angiosperms and gymnosperms inhabiting temperate and continental sites might have problems to recover after more intense droughts since they resist drought but are less able to recover afterwards. © 2018 John Wiley & Sons Ltd.

Effect of feeding some evergreen tropical browse plant leaves on ...

African Journals Online (AJOL)

A feeding trial was conducted with thirty (30) weaner rabbits to investigate the nutritive potentials of some evergreen tropical browse plant leaves (Ficcus thoningii, Vitex doniana, Daniela oliveri, Sarcocephalus latifolia). Mixed breed rabbits were used and randomly assigned to five (5) treatments (T1 - T5). The rabbits in ...

The Green Ocean Amazon Experiment (GoAmazon2014/5) Observes Pollution Affecting Gases, Aerosols, Clouds, and Rainfall over the Rain Forest

Energy Technology Data Exchange (ETDEWEB)

Martin, S. T. [Harvard University, Cambridge, Massachusetts; Artaxo, P. [University of São Paulo, São Paulo, Brazil; Machado, L. [National Institute for Space Research, São José dos Campos, Brazil; Manzi, A. O. [National Institute of Amazonian Research, Manaus, Amazonas, Brazil; Souza, R. A. F. [Amazonas State University, Amazonas, Brazil; Schumacher, C. [Texas A& amp,M University, College Station, Texas; Wang, J. [Brookhaven National Laboratory, Upton, New York; Biscaro, T. [National Institute for Space Research, São José dos Campos, Brazil; Brito, J. [University of São Paulo, São Paulo, Brazil; Calheiros, A. [National Institute for Space Research, São José dos Campos, Brazil; Jardine, K. [Lawrence Berkeley National Lab, Berkeley, California; Medeiros, A. [Amazonas State University, Amazonas, Brazil; Portela, B. [National Institute of Amazonian Research, Manaus, Amazonas, Brazil; de Sá, S. S. [Harvard University, Cambridge, Massachusetts; Adachi, K. [Meteorological Research Institute, Tsukuba, Ibaraki, Japan; Aiken, A. C. [Los Alamos National Laboratory, Los Alamos, New Mexico; Albrecht, R. [University of São Paulo, São Paulo, Brazil; Alexander, L. [Pacific Northwest National Laboratory, Richland, Washington; Andreae, M. O. [Max Planck Institute for Chemistry, Mainz, Germany; Barbosa, H. M. J. [University of São Paulo, São Paulo, Brazil; Buseck, P. [Arizona State University, Tempe, Arizona; Chand, D. [Pacific Northwest National Laboratory, Richland, Washington; Comstock, J. M. [Pacific Northwest National Laboratory, Richland, Washington; Day, D. A. [University of Colorado Boulder, Boulder, Colorado; Dubey, M. [Los Alamos National Laboratory, Los Alamos, New Mexico; Fan, J. [Pacific Northwest National Laboratory, Richland, Washington; Fast, J. [Pacific Northwest National Laboratory, Richland, Washington; Fisch, G. [Aeronautic and Space Institute, São José dos Campos, Brazil; Fortner, E. [Aerodyne, Inc., Billerica, Massachusetts; Giangrande, S. [Brookhaven National Laboratory, Upton, New York; Gilles, M. [Lawrence Berkeley National Lab, Berkeley, California; Goldstein, A. H. [University of California, Berkeley, Berkeley, California; Guenther, A. [University of California, Irvine, Irvine, California; Hubbe, J. [Pacific Northwest National Laboratory, Richland, Washington; Jensen, M. [Brookhaven National Laboratory, Upton, New York; Jimenez, J. L. [University of Colorado Boulder, Boulder, Colorado; Keutsch, F. N. [Harvard University, Cambridge, Massachusetts; Kim, S. [University of California, Irvine, Irvine, California; Kuang, C. [Brookhaven National Laboratory, Upton, New York; Laskin, A. [Pacific Northwest National Laboratory, Richland, Washington; McKinney, K. [Harvard University, Cambridge, Massachusetts; Mei, F. [Pacific Northwest National Laboratory, Richland, Washington; Miller, M. [Rutgers, The State University of New Jersey, New Brunswick, New Jersey; Nascimento, R. [Amazonas State University, Amazonas, Brazil; Pauliquevis, T. [Federal University of São Paulo, São Paulo, Brazil; Pekour, M. [Pacific Northwest National Laboratory, Richland, Washington; Peres, J. [University of São Paulo, São Paulo, Brazil; Petäjä, T. [University of Helsinki, Helsinki, Finland; Pöhlker, C. [Max Planck Institute for Chemistry, Mainz, Germany; Pöschl, U. [Max Planck Institute for Chemistry, Mainz, Germany; Rizzo, L. [Federal University of São Paulo, São Paulo, Brazil; Schmid, B. [Pacific Northwest National Laboratory, Richland, Washington; Shilling, J. E. [Pacific Northwest National Laboratory, Richland, Washington; Dias, M. A. Silva [University of São Paulo, São Paulo, Brazil; Smith, J. N. [University of California, Irvine, Irvine, California; Tomlinson, J. M. [Pacific Northwest National Laboratory, Richland, Washington; Tóta, J. [Federal University of West Para, Santarém, Pará, Brazil; Wendisch, M. [University of Leipzig, Leipzig, Germany

2017-05-01

The Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) experiment took place around the urban region of Manaus in central Amazonia across two years. The urban pollution plume was used to study the susceptibility of gases, aerosols, clouds, and rainfall to human activities in a tropical environment. Many aspects of air quality, weather, terrestrial ecosystems, and climate work differently in the tropics than in the more thoroughly studied USA, employed an unparalleled suite of measurements at nine ground sites and onboard two aircraft to investigate the flow of background air into Manaus, the emissions into the air over the city, and the advection of the pollution downwind of the city. Herein, to visualize this train of processes and its effects, observations aboard a low-flying aircraft are presented. Comparative measurements within and adjacent to the plume followed the emissions of biogenic volatile organic carbon compounds (BVOCs) from the tropical forest, their transformations by the atmospheric oxidant cycle, alterations of this cycle by the influence of the pollutants, transformations of the chemical products into aerosol particles, the relationship of these particles to cloud condensation nuclei (CCN) activity, and the differences in cloud properties and rainfall for background compared to polluted conditions. The observations of the GoAmazon2014/5 experiment illustrate how the hydrologic cycle, radiation balance, and carbon recycling may be affected by present-day as well as future economic development and pollution over the Amazonian tropical forest.

Relating ring width of Mediterranean evergreen species to seasonal and annual variations of precipitation and temperature

Directory of Open Access Journals (Sweden)

W. Nijland

2011-05-01

Full Text Available Plant growth in Mediterranean landscapes is limited by the typical summer-dry climate. Forests in these areas are only marginally productive and may be quite susceptible to modern climate change. To improve our understanding of forest sensitivity to annual and seasonal climatic variability, we use tree-ring measurements of two Mediterranean evergreen tree species: Quercus ilex L. and Arbutus unedo L. We sampled 34 stems of these species on three different types of substrates in the Peyne study area in southern France. The resulting chronologies were analysed in combination with 38 yr of monthly precipitation and temperature data to reconstruct the response of stem growth to climatic variability. Results indicate a strong positive response to May and June precipitation, as well as a significant positive influence of early-spring temperatures and a negative growth response to summer heat. Comparison of the data with more detailed productivity measurements in two contrasting years confirms these observations and shows a strong productivity limiting effect of low early-summer precipitation. The results show that tree-ring data from Q.ilex and A.unedo can provide valuable information about the response of these tree species to climate variability, improving our ability to predict the effects of climate change in Mediterranean ecosystems.

Foliage efficiency of forest-forming species in the climatic gradients of Eurasia

Directory of Open Access Journals (Sweden)

V. A. Usoltsev

2017-08-01

Full Text Available The paperis of the scientific area of biogeography and devoted to a new aspect in the study of biological productivity of forest ecosystems on a geographical basis, expressed indirectly by climate parameters, namely, the foliage efficiency that until now is not investigated at the global level. Foliage efficiency is the ratio of net primary production (NPP to foliage biomass and is expressed in relative units. Some features of change of foliage efficiency of vicarious forest-forming species in Eurasian transcontinental gradients are showed for the first time using the voluminous factual material. The set of published biomass and NPP data (t/ha obtained in a number of 2192 plots is compiled. Using multiple regression analysis technique, the statistically significant changes in foliage efficiency values according to two transcontinental gradients, namely by zonal belts and continentality of climate, are stated for each forest-forming species. The species-specificity of age dynamics of stem volume and foliage efficiency is shown. It is monotonically decreased almost for all tree species in the following order: spruce and fir, pine, birch, oak, larch and aspen-poplar. When climate continentality increasing, foliage efficiency values of mature forests is dropping, most intensively in pines, less intensive in deciduous forests and virtually no changes in spruce-fir communities. In zonal gradient from the northern temperate to the subequatorial belt, foliage efficiency of deciduous species decreases, but it of the evergreen spruce and pine increases in the same direction. One of the possible causes of these opposite zonal trends of foliage efficiency in evergreen and deciduous species consists in different conditions of physiological processes in the year cycle, in particular, in year-round assimilates accumulation in the first and seasonal one in the second.

Predicting the responses of forest distribution and aboveground biomass to climate change under RCP scenarios in southern China.

Science.gov (United States)

Dai, Erfu; Wu, Zhuo; Ge, Quansheng; Xi, Weimin; Wang, Xiaofan

2016-11-01

In the past three decades, our global climate has been experiencing unprecedented warming. This warming has and will continue to significantly influence the structure and function of forest ecosystems. While studies have been conducted to explore the possible responses of forest landscapes to future climate change, the representative concentration pathways (RCPs) scenarios under the framework of the Coupled Model Intercomparison Project Phase 5 (CMIP5) have not been widely used in quantitative modeling research of forest landscapes. We used LANDIS-II, a forest dynamic landscape model, coupled with a forest ecosystem process model (PnET-II), to simulate spatial interactions and ecological succession processes under RCP scenarios, RCP2.6, RCP4.5 and RCP8.5, respectively. We also modeled a control scenario of extrapolating current climate conditions to examine changes in distribution and aboveground biomass (AGB) among five different forest types for the period of 2010-2100 in Taihe County in southern China, where subtropical coniferous plantations dominate. The results of the simulation show that climate change will significantly influence forest distribution and AGB. (i) Evergreen broad-leaved forests will expand into Chinese fir and Chinese weeping cypress forests. The area percentages of evergreen broad-leaved forests under RCP2.6, RCP4.5, RCP8.5 and the control scenarios account for 18.25%, 18.71%, 18.85% and 17.46% of total forest area, respectively. (ii) The total AGB under RCP4.5 will reach its highest level by the year 2100. Compared with the control scenarios, the total AGB under RCP2.6, RCP4.5 and RCP8.5 increases by 24.1%, 64.2% and 29.8%, respectively. (iii) The forest total AGB increases rapidly at first and then decreases slowly on the temporal dimension. (iv) Even though the fluctuation patterns of total AGB will remain consistent under various future climatic scenarios, there will be certain responsive differences among various forest types. © 2016

Journal of Earth System Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

The dominant forest type is tropical semi-evergreen which comprises 21,678 km2 (35.2%) of the total forest area of Western Ghats, followed by wet evergreen forest (30.6%), moist deciduous forest (24.8%) and dry deciduous forest (8.1%) in 2013. Even though it has the highest population density among the hotspots, there ...

Leaf gas exchange of understory spruce-fir saplings in relict cloud forests, southern Appalachian Mountains, USA

Energy Technology Data Exchange (ETDEWEB)

Reinhardt, K.; Smith, W.K. [Wake Forest Univ., Winston-Salem, NC (United States). Dept. of Biology

2008-01-15

Global climate change is expected to increase regional cloud ceiling levels in many mountainous forested areas of the world. This study investigated environmental influences on the gas exchange physiology of understory red spruce and Fraser fir trees at 2 sites in the Appalachian mountains. The study hypothesized that the humid, cloudy environment would influence the photosynthetic performance of the trees, and that the species would adapt to low, diffuse light. The study also predicted that leaf conductance to carbon dioxide (CO{sub 2}) would be high as a result of low leaf-to-air-vapour pressure deficit (LAVD). The study demonstrated that leaf conductance decreased exponentially as LAVD increased. Predawn leaf water potentials remained stable, while late afternoon values declined. It was concluded that leaf gas exchange was correlated with the response of leaf conductance and LAVD. The cloudy, humid environment strongly influenced tree leaf gas exchange and water relations. It was suggested that further research is needed to investigate cloud impacts on carbon gain and water relations. 72 refs., 1 tab., 8 figs.

Physiological and morphological responses to permanent and intermittent waterlogging in seedlings of four evergreen trees of temperate swamp forests.

Science.gov (United States)

Zúñiga-Feest, Alejandra; Bustos-Salazar, Angela; Alves, Fernanda; Martinez, Vanessa; Smith-Ramírez, Cecilia

2017-06-01

Waterlogging decreases a plant's metabolism, stomatal conductance (gs) and photosynthetic rate (A); however, some evergreen species show acclimation to waterlogging. By studying both the physiological and morphological responses to waterlogging, the objective of this study was to assess the acclimation capacity of four swamp forest species that reside in different microhabitats. We proposed that species (Luma apiculata [D.C.] Burret. and Drimys winteri J.R. et G. Forster.) abundant in seasonally and intermittently waterlogged areas (SIWA) would have a higher acclimation capacity than species abundant in the inner swamp (Blepharocalyx cruckshanksii [H et A.] Mied. and Myrceugenia exsucca [D.C.] Berg.) where permanent waterlogging occurs (PWA); it was expected that the species from SIWA would maintain leaf expansion and gas exchange rates during intermittent waterlogging treatments. Conversely, we expected that PWA species would have higher constitutive waterlogging tolerance, and this would be reflected in the formation of lenticels and adventitious roots. Over the course of 2 months, we subjected seedlings to different waterlogging treatments: (i) permanent (sudden, SW), (ii) intermittent (gradual) or (iii) control (field capacity, C). Survival after waterlogging was high (≥80%) for all species and treatments, and only the growth rate of D. winteri subjected to SW was affected. Drimys winteri plants had low, but constant A and g during both waterlogging treatments. Conversely, L. apiculata had the highest A and g values, and g increased significantly during the first several days of waterlogging. In general, seedlings of all species subjected to waterlogging produced more adventitious roots and fully expanded leaves and had higher specific leaf area (SLA) and stomatal density (StD) than seedlings in the C treatment. From the results gathered here, we partially accept our hypothesis as all species showed high tolerance to waterlogging, maintained growth, and had

Changes in forest productivity across Alaska consistent with biome shift.

Science.gov (United States)

Beck, Pieter S A; Juday, Glenn P; Alix, Claire; Barber, Valerie A; Winslow, Stephen E; Sousa, Emily E; Heiser, Patricia; Herriges, James D; Goetz, Scott J

2011-04-01

Global vegetation models predict that boreal forests are particularly sensitive to a biome shift during the 21st century. This shift would manifest itself first at the biome's margins, with evergreen forest expanding into current tundra while being replaced by grasslands or temperate forest at the biome's southern edge. We evaluated changes in forest productivity since 1982 across boreal Alaska by linking satellite estimates of primary productivity and a large tree-ring data set. Trends in both records show consistent growth increases at the boreal-tundra ecotones that contrast with drought-induced productivity declines throughout interior Alaska. These patterns support the hypothesized effects of an initiating biome shift. Ultimately, tree dispersal rates, habitat availability and the rate of future climate change, and how it changes disturbance regimes, are expected to determine where the boreal biome will undergo a gradual geographic range shift, and where a more rapid decline. © 2011 Blackwell Publishing Ltd/CNRS.

Impact of cloudiness on net ecosystem exchange of carbon dioxide in different types of forest ecosystems in China

Directory of Open Access Journals (Sweden)

M. Zhang

2010-02-01

Full Text Available Clouds can significantly affect carbon exchange process between forest ecosystems and the atmosphere by influencing the quantity and quality of solar radiation received by ecosystem's surface and other environmental factors. In this study, we analyzed the effects of cloudiness on net ecosystem exchange of carbon dioxide (NEE in a temperate broad-leaved Korean pine mixed forest at Changbaishan (CBS and a subtropical evergreen broad-leaved forest at Dinghushan (DHS, based on the flux data obtained during June–August from 2003 to 2006. The results showed that the response of NEE of forest ecosystems to photosynthetically active radiation (PAR differed under clear skies and cloudy skies. Compared with clear skies, the light-saturated maximum photosynthetic rate (P_ec,max at CBS under cloudy skies during mid-growing season (from June to August increased by 34%, 25%, 4% and 11% in 2003, 2004, 2005 and 2006, respectively. In contrast, P_ec,max of the forest ecosystem at DHS was higher under clear skies than under cloudy skies from 2004 to 2006. When the clearness index (k_t ranged between 0.4 and 0.6, the NEE reached its maximum at both CBS and DHS. However, the NEE decreased more dramatically at CBS than at DHS when k_t exceeded 0.6. The results indicate that cloudy sky conditions are beneficial to net carbon uptake in the temperate forest ecosystem and the subtropical forest ecosystem. Under clear skies, vapor pressure deficit (VPD and air temperature increased due to strong light. These environmental conditions led to greater decrease in gross ecosystem photosynthesis (GEP and greater increase in ecosystem respiration (R_e at CBS than at DHS. As a result, clear sky conditions caused more reduction of NEE in the temperate forest ecosystem than in the subtropical forest ecosystem. The response of NEE of different forest ecosystems to the changes in

Forest stand dynamics and sudden oak death: Mortality in mixed-evergreen forests dominated by coast live oak

Science.gov (United States)

L.B. Brown; B. Allen-Diaz

2009-01-01

Sudden oak death (SOD), caused by the recently discovered non-native invasive pathogen, Phytophthora ramorum, has already killed tens of thousands of native coast live oak and tanoak trees in California. Little is known of potential short and long term impacts of this novel plant–pathogen interaction on forest structure and composition. Coast live...

Data-based perfect-deficit approach to understanding climate extremes and forest carbon assimilation capacity

International Nuclear Information System (INIS)

Wei, Suhua; Yi, Chuixiang; Hendrey, George; Eaton, Timothy; Rustic, Gerald; Wang, Shaoqiang; Liu, Heping; Krakauer, Nir Y; Wang, Weiguo; Desai, Ankur R; Montagnani, Leonardo; Tha Paw U, Kyaw; Falk, Matthias; Black, Andrew; Bernhofer, Christian; Grünwald, Thomas; Laurila, Tuomas; Cescatti, Alessandro; Moors, Eddy

2014-01-01

Several lines of evidence suggest that the warming climate plays a vital role in driving certain types of extreme weather. The impact of warming and of extreme weather on forest carbon assimilation capacity is poorly known. Filling this knowledge gap is critical towards understanding the amount of carbon that forests can hold. Here, we used a perfect-deficit approach to identify forest canopy photosynthetic capacity (CPC) deficits and analyze how they correlate to climate extremes, based on observational data measured by the eddy covariance method at 27 forest sites over 146 site-years. We found that droughts severely affect the carbon assimilation capacities of evergreen broadleaf forest (EBF) and deciduous broadleaf forest. The carbon assimilation capacities of Mediterranean forests were highly sensitive to climate extremes, while marine forest climates tended to be insensitive to climate extremes. Our estimates suggest an average global reduction of forest CPC due to unfavorable climate extremes of 6.3 Pg C (∼5.2% of global gross primary production) per growing season over 2001–2010, with EBFs contributing 52% of the total reduction

A mistletoe tale: postglacial invasion of Psittacanthus schiedeanus (Loranthaceae) to Mesoamerican cloud forests revealed by molecular data and species distribution modeling.

Science.gov (United States)

Ornelas, Juan Francisco; Gándara, Etelvina; Vásquez-Aguilar, Antonio Acini; Ramírez-Barahona, Santiago; Ortiz-Rodriguez, Andrés Ernesto; González, Clementina; Mejía Saules, María Teresa; Ruiz-Sanchez, Eduardo

2016-04-12

Ecological adaptation to host taxa is thought to result in mistletoe speciation via race formation. However, historical and ecological factors could also contribute to explain genetic structuring particularly when mistletoe host races are distributed allopatrically. Using sequence data from nuclear (ITS) and chloroplast (trnL-F) DNA, we investigate the genetic differentiation of 31 Psittacanthus schiedeanus (Loranthaceae) populations across the Mesoamerican species range. We conducted phylogenetic, population and spatial genetic analyses on 274 individuals of P. schiedeanus to gain insight of the evolutionary history of these populations. Species distribution modeling, isolation with migration and Bayesian inference methods were used to infer the evolutionary transition of mistletoe invasion, in which evolutionary scenarios were compared through posterior probabilities. Our analyses revealed shallow levels of population structure with three genetic groups present across the sample area. Nine haplotypes were identified after sequencing the trnL-F intergenic spacer. These haplotypes showed phylogeographic structure, with three groups with restricted gene flow corresponding to the distribution of individuals/populations separated by habitat (cloud forest localities from San Luis Potosí to northwestern Oaxaca and Chiapas, localities with xeric vegetation in central Oaxaca, and localities with tropical deciduous forests in Chiapas), with post-glacial population expansions and potentially corresponding to post-glacial invasion types. Similarly, 44 ITS ribotypes suggest phylogeographic structure, despite the fact that most frequent ribotypes are widespread indicating effective nuclear gene flow via pollen. Gene flow estimates, a significant genetic signal of demographic expansion, and range shifts under past climatic conditions predicted by species distribution modeling suggest post-glacial invasion of P. schiedeanus mistletoes to cloud forests. However, Approximate

Evaluating the effect of alternative carbon allocation schemes in a land surface model (CLM4.5 on carbon fluxes, pools, and turnover in temperate forests

Directory of Open Access Journals (Sweden)

F. Montané

2017-09-01

Full Text Available How carbon (C is allocated to different plant tissues (leaves, stem, and roots determines how long C remains in plant biomass and thus remains a central challenge for understanding the global C cycle. We used a diverse set of observations (AmeriFlux eddy covariance tower observations, biomass estimates from tree-ring data, and leaf area index (LAI measurements to compare C fluxes, pools, and LAI data with those predicted by a land surface model (LSM, the Community Land Model (CLM4.5. We ran CLM4.5 for nine temperate (including evergreen and deciduous forests in North America between 1980 and 2013 using four different C allocation schemes: i. dynamic C allocation scheme (named "D-CLM4.5" with one dynamic allometric parameter, which allocates C to the stem and leaves to vary in time as a function of annual net primary production (NPP; ii. an alternative dynamic C allocation scheme (named "D-Litton", where, similar to (i, C allocation is a dynamic function of annual NPP, but unlike (i includes two dynamic allometric parameters involving allocation to leaves, stem, and coarse roots; iii.–iv. a fixed C allocation scheme with two variants, one representative of observations in evergreen (named "F-Evergreen" and the other of observations in deciduous forests (named "F-Deciduous". D-CLM4.5 generally overestimated gross primary production (GPP and ecosystem respiration, and underestimated net ecosystem exchange (NEE. In D-CLM4.5, initial aboveground biomass in 1980 was largely overestimated (between 10 527 and 12 897 g C m−2 for deciduous forests, whereas aboveground biomass accumulation through time (between 1980 and 2011 was highly underestimated (between 1222 and 7557 g C m−2 for both evergreen and deciduous sites due to a lower stem turnover rate in the sites than the one used in the model. D-CLM4.5 overestimated LAI in both evergreen and deciduous sites because the leaf C–LAI relationship in the model did not match the

Species-specific and seasonal differences in chlorophyll fluorescence and photosynthetic light response among three evergreen species in a Madrean sky island mixed conifer forest

Science.gov (United States)

Potts, D. L.; Minor, R. L.; Braun, Z.; Barron-Gafford, G. A.

2012-12-01

-use efficiency (AQE) was similar among P. strobiformis and P. ponderosa and least in P. menziesii (repeated-measures ANOVA; species, F2,8 = 13.83, P = 0.002). Across all three species, monsoon onset increased AQE (repeated-measures ANOVA; time, F1,8= 10.04, P = 0.01). Likewise, P. strobiformis and P. ponderosa shared a similar, greater light compensation point than P. menziesii (repeated-measures ANOVA; species, F2,8 = 5.89, P = 0.02). However, across species, monsoon onset did not influence light compensation points. These results support the hypothesis that the monsoon has species-specific effects on evergreen physiological performance and are broadly consistent with predictions of stress tolerance based on species' latitudinal and elevational range distributions. Moreover, with year-to-year rainfall variability predicted to increase under future climate scenarios, species-specific functional traits related to stress tolerance and photosynthesis may promote ecosystem functional resilience in Madrean sky island mixed conifer forests.

Artocarpus hirsutus Lam. of Moraceae is a large evergreen tree with ...

Indian Academy of Sciences (India)

Artocarpus hirsutus Lam. of Moraceae is a large evergreen tree with milky latex. This species occurs wild and is also cultivated for its fruit, which is edible. Leaves are simple and dark green. The branchlets are covered with rust-brown hairs. Inflorescence is axillary. The female inflorescence is globose with individualjlowers ...

Cross-border forest disturbance and the role of natural rubber in mainland Southeast Asia using annual Landsat time series

DEFF Research Database (Denmark)

Grogan, Kenneth; Pflugmacher, Dirk; Hostert, Patrick

2015-01-01

) are there cross border differences in frontier and non-frontier forest disturbance rates between Cambodia and Vietnam, 3) what proportion of disturbances in frontier and non-frontier forests can be accounted for by the impact of rubber plantations, and 4) is there a relationship between global market prices...... rates related to rubber plantation expansion and price fluctuations of natural rubber. This suggests links between localized land cover/use change and international market forces, irrespective of differing political and socioeconomic backgrounds. Our study underlines the value of using dense Landsat...... that this approach can provide accurate forest disturbance maps but that accuracy is affected by forest type. Highest accuracies were found in evergreen forest (90%), with lower accuracies in mixed (80%) and dry-deciduous forest types (83%). Our final map considering all forest types yielded an overall accuracy...

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.

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

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.

Wet season water distribution in a tropical Andean cloud forest of Boyacá (Colombia) during the dry climate of El Niño

Science.gov (United States)

Garcia-Santos, G.; Berdugo, M. B.

2010-07-01

Fog has been demonstrated as the only source of moisture during the dry climate of El Niño in the tropical Andean cloud forest of Boyacá region in Colombia, yet its importance for the forest is virtually unknown. We assessed fog water distribution during the wet season inside the forest and outside in a practically deforested area. Water intercepted by plant was measured at different vertical stratus. Soil moisture in the first centimetres was also measured. During the anomalous drier wet season there was lack of rainfall and the total recorded cloud water was lower compared with the same period during the previous year. Our results indicated that the upper part of the forest mass intercepts most of the fog water compared with lower stratus when the fog event starts. However upper most stratus became rapidly drier after the event, which is explained because water is released to the atmosphere due to high heat atmosphere-leaves interface fluctuations caused by wind and solar radiation, flows towards a different water potential and drips from the leaves. Low amount of fog dripped from tree foliage into the soil, indicating a large water storage capacity of the epiphyte and bryophyte vegetation. Despite the small amount of throughfall, understory vegetation and litter remained wet, which might be explained by the water flowing through the epiphyte vegetation or the high capacity of the understory to absorb moisture from the air. Soil water did not infiltrate in depth, which underlines the importance of fog as water and cool source for seedling growth and shallow rooted understory species, especially during drier conditions.

How competitive is drought deciduousness in tropical forests? A combined eco-hydrological and eco-evolutionary approach

Science.gov (United States)

Vico, Giulia; Dralle, David; Feng, Xue; Thompson, Sally; Manzoni, Stefano

2017-06-01

Drought-deciduous and evergreen species are both common in tropical forests, where there is the need to cope with water shortages during periodic dry spells and over the course of the dry season. Which phenological strategy is favored depends on the long-term balance of carbon costs and gains that leaf phenology imposes as a result of the alternation of wet and dry seasons and the unpredictability of rainfall events. This study integrates a stochastic eco-hydrological framework with key plant economy traits to derive the long-term average annual net carbon gain of trees exhibiting different phenological strategies in tropical forests. The average net carbon gain is used as a measure of fitness to assess which phenological strategies are more productive and more evolutionarily stable (i.e. not prone to invasion by species with a different strategy). The evergreen strategy results in a higher net carbon gain and more evolutionarily stable communities with increasing wet season lengths. Reductions in the length of the wet season or the total rainfall, as predicted under climate change scenarios, should promote a shift towards more drought-deciduous communities, with ensuing implications for ecosystem functioning.

Response of Termite (Blattodea: Termitoidae) Assemblages to Lower Subtropical Forest Succession: A Case Study in Dinghushan Biosphere Reserve, China.

Science.gov (United States)

Li, Zhi-Qiang; Ke, Yun-Ling; Zeng, Wen-Hui; Zhang, Shi-Jun; Wu, Wen-Jing

2016-02-01

Termite (Blattodea: Termitoidae) assemblages have important ecological functions and vary in structure between habitats, but have not been studied in lower subtropical forests. To examine whether differences in the richness and relative abundance of termite species and functional groups occur in lower subtropical regions, termite assemblages were sampled in Dinghushan Biosphere Reserve, China, among pine forest, pine and broad-leaved mixed forest (mixed forest), and monsoon evergreen broad-leaved forest (monsoon forest). The dominant functional group was wood-feeding termites (family Termitidae), and the mixed forest hosted the greatest richness and relative abundance. Soil-feeding termites were absent from the lower subtropical system, while humus-feeding termites were sporadically distributed in mixed forest and monsoon forest. The species richness and functional group abundance of termites in our site may be linked to the forest succession. Altitude, soil temperature, air temperature, surface air relative humidity, and litter depth were significant influences on species and functional group diversity.

Alpine forest-tundra ecotone response to temperature change,Sayan Mountains, Siberia

Science.gov (United States)

Ranson, K Jon; Kharuk, Vyetcheslav I.

2007-01-01

Models of climate change predict shifts of vegetation zones. Tree response to climate trends is most likely observable in the forest-tundra ecotone, where temperature mainly limits tree growth. There is evidence of vegetation change on the northern treeline However, observations on alpine tree line response are controversial. In this NEESPI related study we show that during the past three decades in the forest-tundra ecotone of the Sayan Mountains, Siberia, there was an increase in forest stand crown closure, regeneration propagation into the alpine tundra, and transformation of prostrate Siberian pine and fir into arboreal forms. We found that these changes occurred since the mid 1980s, and strongly correlates with positive temperature (and to a lesser extent, precipitation) trends. Improving climate for forest growth( i.e., warmer temperatures and increased precipitation) provides competitive advantages to Siberian pine in the alpine forest-tundra ecotone, as well as in areas typically dominated by larch, where it has been found to be forming a secondary canopy layer. Substitution of deciduous conifer, larch, for evergreen conifers, decreases albedo and provides positive feedback for temperature increase.

Soil seed banks along elevational gradients in tropical, subtropical and subalpine forests in Yunnan Province, southwest China

Institute of Scientific and Technical Information of China (English)

Xiaqin Luo; Min Cao; Min Zhang; Xiaoyang Song; Jieqiong Li; Akihiro Nakamura; Roger Kitching

2017-01-01

Soil seed banks are a vital part of ecosystems and influence community dynamics and regeneration.Although soil seed banks in different habitats have been reported,how soil seed banks vary with elerational gradients in different climatic zones is still unknown.This paper investigates seed density,species composition and nonconstituent species of forest soil seed banks in Yunnan Province,southwest China.Similarity between the soil seed bank and standing vegetation was also examined.We collected soil samples from sites spanning 12 elevations in tropical rain forests,subtropical evergreen broadleaved forests and subalpine coniferous forests,and transported them to a glasshouse for germination trials for species identification.The soil seed banks of tropical and subtropical forests had much higher seed densities and species richness than those of subalpine forests.Seeds of woody species dominated the soil seed banks of tropical and subtropical forests,while herbs dominated those of subalpine forests.The nonconstituent species in the soil seed banks were all herbs and were most abundant in tropical forests,followed by subtropical forests but were completely absent from subalpine forests.

Soil seed banks along elevational gradients in tropical, subtropical and subalpine forests in Yunnan Province, southwest China

Directory of Open Access Journals (Sweden)

Xiaqin Luo

2017-10-01

Full Text Available Soil seed banks are a vital part of ecosystems and influence community dynamics and regeneration. Although soil seed banks in different habitats have been reported, how soil seed banks vary with elevational gradients in different climatic zones is still unknown. This paper investigates seed density, species composition and nonconstituent species of forest soil seed banks in Yunnan Province, southwest China. Similarity between the soil seed bank and standing vegetation was also examined. We collected soil samples from sites spanning 12 elevations in tropical rain forests, subtropical evergreen broad-leaved forests and subalpine coniferous forests, and transported them to a glasshouse for germination trials for species identification. The soil seed banks of tropical and subtropical forests had much higher seed densities and species richness than those of subalpine forests. Seeds of woody species dominated the soil seed banks of tropical and subtropical forests, while herbs dominated those of subalpine forests. The nonconstituent species in the soil seed banks were all herbs and were most abundant in tropical forests, followed by subtropical forests but were completely absent from subalpine forests.

3 The Traditional Cloth Dyeing Enterprise.cdr

African Journals Online (AJOL)

Administrator

reconnaissance visits and necessary changes ... difficulty in accessing fuelwood for boiling .... precipitation of 600 mm up to over 4000 mm, and a mean annual temperature of 15–28 °C. ... Found in evergreen fringing forest along water, swamp forest, ... drier evergreen forest and thickets, from sea-level up to 1500 m altitude.

Floristic composition of the dry tropical forest in biological reserve (sanctuary "Los Besotes" and phenology of the dominant arboreal species (Valledupar, Cesar, Colombia

Directory of Open Access Journals (Sweden)

Mary Lee Berdugo Lattke

2015-01-01

Full Text Available Based on the floristic composition and structural aspects, the formation tropical dry forest of the reserve "Los Besotes" (Valledupar, Cesar; 248 y 1046m of altitude was characterized. In 35 individuals from nine dominant tree species in two forest types, the phenological characteristics were assessed. Seven monitoring were performed along one year according to the scheme of distribution of rainfall. The leaf fall in the forests of Myrcianthes aff. fragrans and Brosimum alicastrum did not exceed 20% regardless of the climatic period (drought or rainy seasons. In others dominant understory species the leaf fall was less than 40%, thus species of the canopy are classified as evergreen while those of the understory as semideciduous. Blooming peaked during the dry season while fruit production peaked during the two rainy seasons. In the forest ofBursera simaruba and Pterocarpus acapulcensis the leaf fall exceeded 60% in the dry season, while in the rainy season was only 30%. The leaf fall increased to 60% in others dominant understory species. Both canopy as well as understory species are deciduous. Blooming was observed during the dry season (December to March, and July, but it is also likely to occur in October; fruit production was observed at the end of the rainy season. In the tropical dry forest formation evergreen plant communities with low values of leaf fall (40% and deciduous communities with values greater than 60% are recognized.

Detecting Inter-Annual Variations in the Phenology of Evergreen Conifers Using Long-Term MODIS Vegetation Index Time Series

Directory of Open Access Journals (Sweden)

Laura Ulsig

2017-01-01

Full Text Available Long-term observations of vegetation phenology can be used to monitor the response of terrestrial ecosystems to climate change. Satellite remote sensing provides the most efficient means to observe phenological events through time series analysis of vegetation indices such as the Normalized Difference Vegetation Index (NDVI. This study investigates the potential of a Photochemical Reflectance Index (PRI, which has been linked to vegetation light use efficiency, to improve the accuracy of MODIS-based estimates of phenology in an evergreen conifer forest. Timings of the start and end of the growing season (SGS and EGS were derived from a 13-year-long time series of PRI and NDVI based on a MAIAC (multi-angle implementation of atmospheric correction processed MODIS dataset and standard MODIS NDVI product data. The derived dates were validated with phenology estimates from ground-based flux tower measurements of ecosystem productivity. Significant correlations were found between the MAIAC time series and ground-estimated SGS (R2 = 0.36–0.8, which is remarkable since previous studies have found it difficult to observe inter-annual phenological variations in evergreen vegetation from satellite data. The considerably noisier NDVI product could not accurately predict SGS, and EGS could not be derived successfully from any of the time series. While the strongest relationship overall was found between SGS derived from the ground data and PRI, MAIAC NDVI exhibited high correlations with SGS more consistently (R2 > 0.6 in all cases. The results suggest that PRI can serve as an effective indicator of spring seasonal transitions, however, additional work is necessary to confirm the relationships observed and to further explore the usefulness of MODIS PRI for detecting phenology.

Leaf litter copepods from a cloud forest mountain top in Honduras (Copepoda: Cyclopidae, Canthocamptidae).

Science.gov (United States)

Fiers, Frank; Jocque, Merlijn

2013-01-01

Five different species of Copepoda were extracted from a leaf litter sample collected on the top (at 2000 m a.s.l.) of a cloud forested mountain in El Cusuco National Park, Honduras. Three of them, one Cyclopidae and two Canthocamptidae are new to science, and are described herein. Olmeccyclops hondo sp. nov. is the second representative thus far known of this New World genus. Moraria catracha sp. nov. and Moraria cusuca sp. nov. are the first formally described members of the genus occurring in Central America. The concept of a "Moraria-group" is considered to be an artificial grouping and is limited here to the genera Moraria and Morariopsis only. The distributional range of this group is essentially Holarctic, with the mountainous regions in Honduras, and probably in west Nicaragua, as the southernmost limits in the New World.

Removal of PM10 by Forests as a Nature-Based Solution for Air Quality Improvement in the Metropolitan City of Rome

Directory of Open Access Journals (Sweden)

Federica Marando

2016-07-01

Full Text Available Nature-based solutions have been identified by the European Union as being critical for the enhancement of environmental qualities in cities, where urban and peri-urban forests play a key role in air quality amelioration through pollutant removal. A remote sensing and geographic information system (GIS approach was applied to the Metropolitan City (MC of Rome to assess the seasonal particulate matter (PM10 removal capacity of evergreen (broadleaves and conifers and deciduous species. Moreover, a monetary evaluation of PM10 removal was performed on the basis of pollution externalities calculated for Europe. Deciduous broadleaves represent the most abundant tree functional group and also yielded the highest total annual PM10 deposition values (1769 Mg. By contrast, PM10 removal efficiency (Mg·ha−1 was 15%–22% higher in evergreen than in deciduous species. To assess the different removal capacity of the three functional groups in an area with homogeneous environmental conditions, a study case was performed in a peri-urban forest protected natural reserve (Castelporziano Presidential Estate. This study case highlighted the importance of deciduous species in summer and of evergreen communities as regards the annual PM10 removal balance. The monetary evaluation indicated that the overall PM10 removal value of the MC of Rome amounted to 161.78 million Euros. Our study lends further support to the crucial role played by nature-based solutions for human well-being in urban areas.

The photochemical reflectance index provides an optical indicator of spring photosynthetic activation in evergreen conifers.

Science.gov (United States)

Wong, Christopher Y S; Gamon, John A

2015-04-01

In evergreens, the seasonal down-regulation and reactivation of photosynthesis is largely invisible and difficult to assess with remote sensing. This invisible phenology may be changing as a result of climate change. To better understand the mechanism and timing of these hidden physiological transitions, we explored several assays and optical indicators of spring photosynthetic activation in conifers exposed to a boreal climate. The photochemical reflectance index (PRI), chlorophyll fluorescence, and leaf pigments for evergreen conifer seedlings were monitored over 1 yr of a boreal climate with the addition of gas exchange during the spring. PRI, electron transport rate, pigment levels, light-use efficiency and photosynthesis all exhibited striking seasonal changes, with varying kinetics and strengths of correlation, which were used to evaluate the mechanisms and timing of spring activation. PRI and pigment pools were closely timed with photosynthetic reactivation measured by gas exchange. The PRI provided a clear optical indicator of spring photosynthetic activation that was detectable at leaf and stand scales in conifers. We propose that PRI might provide a useful metric of effective growing season length amenable to remote sensing and could improve remote-sensing-driven models of carbon uptake in evergreen ecosystems. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Detection System of HTTP DDoS Attacks in a Cloud Environment Based on Information Theoretic Entropy and Random Forest

Directory of Open Access Journals (Sweden)

Mohamed Idhammad

2018-01-01

Full Text Available Cloud Computing services are often delivered through HTTP protocol. This facilitates access to services and reduces costs for both providers and end-users. However, this increases the vulnerabilities of the Cloud services face to HTTP DDoS attacks. HTTP request methods are often used to address web servers’ vulnerabilities and create multiple scenarios of HTTP DDoS attack such as Low and Slow or Flooding attacks. Existing HTTP DDoS detection systems are challenged by the big amounts of network traffic generated by these attacks, low detection accuracy, and high false positive rates. In this paper we present a detection system of HTTP DDoS attacks in a Cloud environment based on Information Theoretic Entropy and Random Forest ensemble learning algorithm. A time-based sliding window algorithm is used to estimate the entropy of the network header features of the incoming network traffic. When the estimated entropy exceeds its normal range the preprocessing and the classification tasks are triggered. To assess the proposed approach various experiments were performed on the CIDDS-001 public dataset. The proposed approach achieves satisfactory results with an accuracy of 99.54%, a FPR of 0.4%, and a running time of 18.5s.

The effect of climate and soil conditions on tree species turnover in a Tropical Montane Cloud Forest in Costa Rica.

Science.gov (United States)

Häger, Achim

2010-12-01

On a global level, Tropical Montane Cloud Forests constitute important centers of vascular plant diversity. Tree species turnover along environmental gradients plays an important role in larger scale diversity patterns in tropical mountains. This study aims to estimate the magnitude of beta diversity across the Tilardn mountain range in North-Western Costa Rica, and to elucidate the impact of climate and soil conditions on tree species turnover at a local scale. Seven climate stations measuring rainfall, horizontal precipitation (clouds and wind-driven rain) and temperatures were installed along a 2.5km transect ranging from 1200 m.a.s.l. on the Atlantic to 1200 m.a.s.l. on the Pacific slope. The ridge top climate station was located at 1500 m.a.s.l. Climate data were recorded from March through December 2003. Additionally, seven 0.05 ha plots were established. On all plots soil moisture was monitored for one year, furthermore soil type and soil chemistry were assessed. Woody plants with a diameter at breast height (dbh) > or = 5 cm were identified to species. Species' distributions were explored by feeding pairwise Serensen measures between plots into a Principal Component Analysis. Relationships between floristic similarity and environmental variables were analyzed using Mantel tests. Pronounced gradients in horizontal precipitation, temperatures and soil conditions were found across the transect. In total, 483 woody plants were identified, belonging to 132 species. Environmental gradients were paralleled by tree species turnover; the plots could be divided in three distinctive floristic units which reflected different topographic positions on the transect (lower slopes, mid slopes and ridge). Most notably there was a complete species turnover between the ridge and the lower Pacific slope. Floristic similarity was negatively correlated with differences in elevation, horizontal precipitation, temperatures and soil conditions between plots. It is suggested that

Effect of Simulated N Deposition on Soil Exchangeable Cations in Three Forest Types of Subtropical China

Institute of Scientific and Technical Information of China (English)

LU Xian-Kai; MO Jiang-Ming; P.GUNDERSERN; ZHU Wei-Xing; ZHOU Guo-Yi; LI De-Jun; ZHANG Xu

2009-01-01

The effects of simulated nitrogen (N) deposition on soil exchangeable cations were studied in three forest types of subtropical China.Four N treatments with three replications were designed for the monsoon evergreen broadleaf forest (mature forest):control (0 kg N ha-1 year-1),low N (50 kg N ha-1 year-1),medium N (100 kg N ha-1 year-1) and high N (150 kg N ha-1 ycar-1),and only three treatments (i.e.,control,low N,medium N) were established for the pine and mixed forests.Nitrogen had been applied continuously for 26 months before the measurement.The mature forest responded more rapidly and intensively to N additions than the pine and mixed forests,and exhibited some significant negative symptoms,e.g.,soil acidification,Al mobilization and leaching of base cations from soil.The pine and mixed forests responded slowly to N additions and exhibited no significant response of soil cations.Response of soil exchangeable cations to N deposition varied in the forests of subtropical China,depending on soil N status and land-nse history.

Forest Cover Estimation in Ireland Using Radar Remote Sensing: A Comparative Analysis of Forest Cover Assessment Methodologies

Science.gov (United States)

Devaney, John; Barrett, Brian; Barrett, Frank; Redmond, John; O`Halloran, John

2015-01-01

Quantification of spatial and temporal changes in forest cover is an essential component of forest monitoring programs. Due to its cloud free capability, Synthetic Aperture Radar (SAR) is an ideal source of information on forest dynamics in countries with near-constant cloud-cover. However, few studies have investigated the use of SAR for forest cover estimation in landscapes with highly sparse and fragmented forest cover. In this study, the potential use of L-band SAR for forest cover estimation in two regions (Longford and Sligo) in Ireland is investigated and compared to forest cover estimates derived from three national (Forestry2010, Prime2, National Forest Inventory), one pan-European (Forest Map 2006) and one global forest cover (Global Forest Change) product. Two machine-learning approaches (Random Forests and Extremely Randomised Trees) are evaluated. Both Random Forests and Extremely Randomised Trees classification accuracies were high (98.1–98.5%), with differences between the two classifiers being minimal (forest area and an increase in overall accuracy of SAR-derived forest cover maps. All forest cover products were evaluated using an independent validation dataset. For the Longford region, the highest overall accuracy was recorded with the Forestry2010 dataset (97.42%) whereas in Sligo, highest overall accuracy was obtained for the Prime2 dataset (97.43%), although accuracies of SAR-derived forest maps were comparable. Our findings indicate that spaceborne radar could aid inventories in regions with low levels of forest cover in fragmented landscapes. The reduced accuracies observed for the global and pan-continental forest cover maps in comparison to national and SAR-derived forest maps indicate that caution should be exercised when applying these datasets for national reporting. PMID:26262681

Using transient ERT mapping to monitor infiltration pathways in a semi-arid cloud forest in Oman

Science.gov (United States)

Friesen, J.; Werban, U.; Pohle, M.; Bawain, A.; Hildebrandt, A.; Attinger, S.

2011-12-01

In forests rainfall partitioning provides highly organized rainfall patterns caused by rainfall funneling through vegetation structure. The patterns of rainfall partitioning have already been studied in great detail at a cloud forest enclosure in Dhofar, Oman. How those organized rainfall patterns on the surface advance into the root zone and deeper is the focus of this work. Trees in the Dhofar Mountains function as excellent natural fog catchers that funnel extracted fog water through stemflow directly into the ground. Stemflow may provide a direct pathway from the stem along the roots to deeper soil water reservoirs. By doing so, trees might also contribute to groundwater recharge, and hence deforestation might have a negative effect on the aquifer. Electric resistivity tomography (ERT) has already proven useful for visualization of root water uptake in a tree orchard, by observing local increases of resistivity from soil drying. In our approach we aim at using ERT data for observing the local decrease of resistivity from soil wetting near stems. For this we will use the advantage of ERT to look into the near surface area (down to 3-4m) and deeper subsurface (10-15m). With a large number of subsequent ERT measurements we will obtain a time series of ERT data. Transient ERT data, starting before the monsoon season and ending after the monsoon season, aim at providing information about recharge patterns during and uptake patterns after monsoon. To determine the effect of vegetation we conducted field observation for two land cover types, forest and grassland. The ERT measurements are support by a network of stemflow, throughfall, and rain gage observations. Results already show a clear distinction between grassland and forested land cover.

Elevated ozone negatively affects photosynthesis of current-year leaves but not previous-year leaves in evergreen Cyclobalanopsis glauca seedlings

International Nuclear Information System (INIS)

Zhang, Weiwei; Feng, Zhaozhong; Wang, Xiaoke; Niu, Junfeng

2014-01-01

To assess the effects of leaf age/layer on the response of photosynthesis to chronic ozone (O 3 ), Cyclobalanopsis glauca seedlings, a dominant evergreen broadleaf tree species in sub-tropical regions, were exposed to either ambient air (AA) or elevated O 3 (AA + 60 ppb O 3 , E-O 3 ) for two growing seasons in open-top chambers. Chlorophyll content, gas exchange and chlorophyll a fluorescence were investigated three times throughout the 2nd year of O 3 exposure. Results indicated that E-O 3 decreased photosynthetic parameters, particularly light-saturated photosynthesis rate, stomatal conductance and effective quantum yield of PSII photochemistry of current-year leaves but not previous-year leaves. Stomatal conductance of plants grown under ambient conditions partially contributed to the different response to E-O 3 between leaf layers. Light radiation or other physiological and biochemical processes closely related to photosynthesis might play important roles. All suggested that leaf ages or layers should be considered when assessing O 3 risk on evergreen woody species. -- Highlights: • Response of evergreen Cyclobalanopsis glauca to O 3 was investigated. • Elevated O 3 significantly reduced photosynthesis of current-year leaves. • Previous-year leaves showed little response to O 3 . • Stomatal conductance contributes to the response difference to O 3 among leaf ages. -- Impacts of elevated O 3 on photosynthesis of evergreen woody species depend on leaf ages

Modeling gross primary production of an evergreen needleleaf forest using MODIS and climate data

Science.gov (United States)

Xiangming Xiao; Qingyuan Zhang; David Hollinger; John Aber; Berrien, III Moore

2005-01-01

Forest canopies are composed of photosynthetically active vegetation (PAV, chloroplasts) and nonphotosynthetic vegetation (NPV, e.g., cell wall, vein, branch). The fraction of photosynthetically active radiation (PAR) absorbed by the canopy (FAPAR) should be partitioned into FAPARPAV and FAPARNPV. Gross primary production (...

Detection of Single Tree Stems in Forested Areas from High Density ALS Point Clouds Using 3d Shape Descriptors

Science.gov (United States)

Amiri, N.; Polewski, P.; Yao, W.; Krzystek, P.; Skidmore, A. K.

2017-09-01

Airborne Laser Scanning (ALS) is a widespread method for forest mapping and management purposes. While common ALS techniques provide valuable information about the forest canopy and intermediate layers, the point density near the ground may be poor due to dense overstory conditions. The current study highlights a new method for detecting stems of single trees in 3D point clouds obtained from high density ALS with a density of 300 points/m2. Compared to standard ALS data, due to lower flight height (150-200 m) this elevated point density leads to more laser reflections from tree stems. In this work, we propose a three-tiered method which works on the point, segment and object levels. First, for each point we calculate the likelihood that it belongs to a tree stem, derived from the radiometric and geometric features of its neighboring points. In the next step, we construct short stem segments based on high-probability stem points, and classify the segments by considering the distribution of points around them as well as their spatial orientation, which encodes the prior knowledge that trees are mainly vertically aligned due to gravity. Finally, we apply hierarchical clustering on the positively classified segments to obtain point sets corresponding to single stems, and perform ℓ1-based orthogonal distance regression to robustly fit lines through each stem point set. The ℓ1-based method is less sensitive to outliers compared to the least square approaches. From the fitted lines, the planimetric tree positions can then be derived. Experiments were performed on two plots from the Hochficht forest in Oberösterreich region located in Austria.We marked a total of 196 reference stems in the point clouds of both plots by visual interpretation. The evaluation of the automatically detected stems showed a classification precision of 0.86 and 0.85, respectively for Plot 1 and 2, with recall values of 0.7 and 0.67.

Evaluation of the MODIS LAI product using independent lidar-derived LAI: A case study in mixed conifer forest

Science.gov (United States)

Jennifer L. R. Jensen; Karen S. Humes; Andrew T. Hudak; Lee A. Vierling; Eric Delmelle

2011-01-01

This study presents an alternative assessment of the MODIS LAI product for a 58,000 ha evergreen needleleaf forest located in the western Rocky Mountain range in northern Idaho by using lidar data to model (R2=0.86, RMSE=0.76) and map LAI at higher resolution across a large number of MODIS pixels in their entirety. Moderate resolution (30 m) lidar-based LAI estimates...

Botanical Survey in Moyo Island, West Nusa Tenggara, Indonesia: Inventory of Flora Collection at Forest

Directory of Open Access Journals (Sweden)

Trimanto Trimanto

2017-05-01

Full Text Available Nusa Tenggara consists of some small islands, one of them is Moyo Island. The diversity of plant species in this island is not really known for certain. This research was determined to observe the diversity of plant spe-cies in Moyo Island forest. The research was conducted in April 2013 by using floristic analysis method. The characteristic of Moyo Island forest is lowland evergreen rain forest. The results showed there were 60 tree species recorded in Moyo Island forest. There were many fruiting trees and seedling from the trees which show healthy growth, indicated that the plant regeneration in this forest is went well. The diversity of Pteri-dophytes and orchids were not high. Epiphytic fern which often found in the forest were Drynaria quersifolia and Platycerium bifurcatum and terrestrial orchid that dominated in the forest was Nervilia aragoana. Tuber plant was often found in this forest and grew prolifically were Tacca, Dioscorea and Amorphophallus. In coastal area lived a population of Pandanus tectorius. There were three new record plants found. The first was epiphytic orchid: Pteroceras javanica, the second was the epiphytic plant: Hoya verticillata and wild tuber plant: Tacca leontopetaloides.

Mercury dynamics and mass balance in a subtropical forest, southwestern China

Directory of Open Access Journals (Sweden)

M. Ma

2016-04-01

Full Text Available The mid-subtropical forest area in southwest China was affected by anthropogenic mercury (Hg emissions over the past 3 decades. We quantified mercury dynamics on the forest field and measured fluxes and pools of Hg in litterfall, throughfall, stream water and forest soil in an evergreen broadleaved forest field in southwestern China. Total Hg (THg input by the throughfall and litterfall was assessed at 32.2 and 42.9 µg m−2 yr−1, respectively, which was remarkably higher than those observed from other forest fields in the background of North America and Europe. Hg fluxes across the soil–air interface (18.6 mg m−2 yr−1 and runoff and/or stream flow (7.2 µg m−2 yr−1 were regarded as the dominant ways for THg export from the forest field. The forest field hosts an enormous amount of atmospheric Hg, and its reserves is estimated to be 25 341 µg m2. The ratio of output to input Hg fluxes (0.34 is higher compared with other study sites. The higher output / input ratio may represent an important ecological risk for the downstream aquatic ecosystems, even if the forest field could be an effective sink of Hg.

Using indigenous knowledge to link hyper-temporal land cover mapping with land use in the Venezuelan Amazon: "The Forest Pulse".

Science.gov (United States)

Olivero, Jesús; Ferri, Francisco; Acevedo, Pelayo; Lobo, Jorge M; Fa, John E; Farfán, Miguel Á; Romero, David; Real, Raimundo

2016-12-01

Remote sensing and traditional ecological knowledge (TEK) can be combined to advance conservation of remote tropical regions, e.g. Amazonia, where intensive in situ surveys are often not possible. Integrating TEK into monitoring and management of these areas allows for community participation, as well as for offering novel insights into sustainable resource use. In this study, we developed a 250 m resolution land-cover map of the Western Guyana Shield (Venezuela) based on remote sensing, and used TEK to validate its relevance for indigenous livelihoods and land uses. We first employed a hyper-temporal remotely sensed vegetation index to derive a land classification system. During a 1 300 km, eight day fluvial expedition in roadless areas in the Amazonas State (Venezuela), we visited six indigenous communities who provided geo-referenced data on hunting, fishing and farming activities. We overlaid these TEK data onto the land classification map, to link land classes with indigenous use. We characterized land classes using patterns of greenness temporal change and topo-hydrological information, and proposed 12 land-cover types, grouped into five main landscapes: 1) water bodies; 2) open lands/forest edges; 3) evergreen forests; 4) submontane semideciduous forests, and 5) cloud forests. Each land cover class was identified with a pulsating profile describing temporal changes in greenness, hence we labelled our map as "The Forest Pulse". These greenness profiles showed a slightly increasing trend, for the period 2000 to 2009, in the land classes representing grassland and scrubland, and a slightly decreasing trend in the classes representing forests. This finding is consistent with a gain in carbon in grassland as a consequence of climate warming, and also with some loss of vegetation in the forests. Thus, our classification shows potential to assess future effects of climate change on landscape. Several classes were significantly connected with agriculture, fishing

N : P Stoichiometry in a Forested Runoff during Storm Events: Comparisons with Regions and Vegetation Types

Directory of Open Access Journals (Sweden)

Lanlan Guo

2012-01-01

Full Text Available Nitrogen and phosphorus are considered the most important limiting elements in terrestrial and aquatic ecosystems. however, very few studies have focused on which is from forested streams, a bridge between these two systems. To fill this gap, we examined the concentrations of dissolved N and P in storm waters from forested watersheds of five regions in Japan, to characterize nutrient limitation and its potential controlling factors. First, dissolved N and P concentrations and the N : P ratio on forested streams were higher during storm events relative to baseflow conditions. Second, significantly higher dissolved inorganic N concentrations were found in storm waters from evergreen coniferous forest streams than those from deciduous broadleaf forest streams in Aichi, Kochi, Mie, Nagano, and with the exception of Tokyo. Finally, almost all the N : P ratios in the storm water were generally higher than 34, implying that the storm water should be P-limited, especially for Tokyo.

N : P stoichiometry in a forested runoff during storm events: comparisons with regions and vegetation types.

Science.gov (United States)

Guo, Lanlan; Chen, Yi; Zhang, Zhao; Fukushima, Takehiko

2012-01-01

Nitrogen and phosphorus are considered the most important limiting elements in terrestrial and aquatic ecosystems. however, very few studies have focused on which is from forested streams, a bridge between these two systems. To fill this gap, we examined the concentrations of dissolved N and P in storm waters from forested watersheds of five regions in Japan, to characterize nutrient limitation and its potential controlling factors. First, dissolved N and P concentrations and the N : P ratio on forested streams were higher during storm events relative to baseflow conditions. Second, significantly higher dissolved inorganic N concentrations were found in storm waters from evergreen coniferous forest streams than those from deciduous broadleaf forest streams in Aichi, Kochi, Mie, Nagano, and with the exception of Tokyo. Finally, almost all the N : P ratios in the storm water were generally higher than 34, implying that the storm water should be P-limited, especially for Tokyo.

The Next Generation Library Catalog: A Comparative Study of the OPACs of Koha, Evergreen, and Voyager

Directory of Open Access Journals (Sweden)

Sharon Q. Yang

2010-09-01

Full Text Available Open source has been the center of attention in the library world for the past several years. Koha and Evergreen are the two major open-source integrated library systems (ILSs, and they continue to grow in maturity and popularity. The question remains as to how much we have achieved in open-source development toward the next-generation catalog compared to commercial systems. Little has been written in the library literature to answer this question. This paper intends to answer this question by comparing  the next-generation features of the OPACs of two open-source ILSs (Koha and Evergreen and one proprietary ILS (Voyager’s WebVoyage.

BAECC Biogenic Aerosols - Effects on Clouds and Climate

Energy Technology Data Exchange (ETDEWEB)

Petäjä, Tuukka [Univ. of Helsinki (Finland); Moisseev, Dmitri [Univ. of Helsinki (Finland); Sinclair, Victoria [Univ. of Helsinki (Finland); O' Connor, Ewan J. [Finnish Meteorological Institute, Helsinki (Finland); Manninen, Antti J. [Univ. of Helsinki (Finland); Levula, Janne [Univ. of Helsinki (Finland); Väänänen, Riikka [Univ. of Helsinki (Finland); Heikkinen, Liine [Univ. of Helsinki (Finland); Äijälä, Mikko [Univ. of Helsinki (Finland); Aalto, Juho [Univ. of Helsinki (Finland); Bäck, Jaana [University of Helsinki, Finland

2015-11-01

“Biogenic Aerosols - Effects on Clouds and Climate (BAECC)”, featured the U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) Program’s 2nd Mobile Facility (AMF2) in Hyytiälä, Finland. It operated for an 8-month intensive measurement campaign from February to September 2014. The main research goal was to understand the role of biogenic aerosols in cloud formation. One of the reasons to perform BAECC study in Hyytiälä was the fact that it hosts SMEAR-II (Station for Measuring Forest Ecosystem-Atmosphere Relations), which is one of the world’s most comprehensive surface in-situ observation sites in a boreal forest environment. The station has been measuring atmospheric aerosols, biogenic emissions and an extensive suite of parameters relevant to atmosphere-biosphere interactions continuously since 1996. The BAECC enables combining vertical profiles from AMF2 with surface-based in-situ SMEAR-II observations and allows the processes at the surface to be directly related to processes occurring throughout the entire tropospheric column. With the inclusion of extensive surface precipitation measurements, and intensive observation periods involving aircraft flights and novel radiosonde launches, the complementary observations of AMF2 and SMEAR-II provide a unique opportunity for investigating aerosol-cloud interactions, and cloud-to-precipitation processes. The BAECC dataset will initiate new opportunities for evaluating and improving models of aerosol sources and transport, cloud microphysical processes, and boundary-layer structures.

Climate and Vegetation Effects on Temperate Mountain Forest ...

Science.gov (United States)

Current forest composition may be resilient to typical climatic variability; however, climate trends, combined with projected changes in species composition, may increase tree vulnerability to water stress. A shift in forest composition toward tree species with higher water use has implications for biogenic emissions and deposition of reactive nitrogen and carbon compounds. Forest evapotranspiration (ET) can vary greatly at daily and seasonal time scales, but compared to carbon fluxes, often exhibits relatively consistent inter-annual behavior. The processes controlling ET involve the combined effects of physical and biological factors. Atmospheric conditions that promote high ET, consisting of high radiation and vapor pressure deficit (D), are often characterized by rainless periods when soil water supply to vegetation may be limiting and plant stomata may close to prevent excessive water loss. In contrast, periods of high ecosystem water availability require frequent precipitation and are characterized by low D. Thus, the combination of these contrasting conditions throughout a growing season may explain some of the consistency in ET. Additionally, vegetation composition is also an important factor in determining ET. In mixed species forests, physiological differences in water use strategies (e.g. isohydric/anisohydric species) can produce conservative water use throughout wet and dry phases of the growing season. Furthermore, transpiration by evergreen specie

[Effects of forest regeneration patterns on the quantity and chemical structure of soil solution dissolved organic matter in a subtropical forest.

Science.gov (United States)

Yuan, Xiao Chun; Lin, Wei Sheng; Pu, Xiao Ting; Yang, Zhi Rong; Zheng, Wei; Chen, Yue Min; Yang, Yu Sheng

2016-06-01

Using the negative pressure sampling method, the concentrations and spectral characte-ristics of dissolved organic matter (DOM) of soil solution were studied at 0-15, 15-30, 30-60 cm layers in Castanopsis carlesii forest (BF), human-assisted naturally regenerated C. carlesii forest (RF), C. carlesii plantation (CP) in evergreen broad-leaved forests in Sanming City, Fujian Pro-vince. The results showed that the overall trend of dissolved organic carbon (DOC) concentrations in soil solution was RF>CP>BF, and the concentration of dissolved organic nitrogen (DON) was highest in C. carlesii plantation. The concentrations of DOC and DON in surface soil (0-15 cm) were all significantly higher than in the subsurface (30-60 cm). The aromatic index (AI) was in the order of RF>CP>BF, and as a whole, the highest AI was observed in the surface soil. Higher fluorescence intensity and a short wave absorption peak (320 nm) were observed in C. carlesii plantation, suggesting the surface soil of C. carlesii plantation was rich in decomposed substance content, while the degree of humification was lower. A medium wave absorption peak (380 nm) was observed in human-assisted naturally regenerated C. carlesii forest, indicating the degree of humification was higher which would contribute to the storage of soil fertility. In addition, DOM characte-ristics in 30-60 cm soil solution were almost unaffected by forest regeneration patterns.

Deforestation and Forest Fragmentation in South Ecuador since the 1970s - Losing a Hotspot of Biodiversity.

Science.gov (United States)

Tapia-Armijos, María Fernanda; Homeier, Jürgen; Espinosa, Carlos Iván; Leuschner, Christoph; de la Cruz, Marcelino

2015-01-01

Deforestation and fragmentation are major components of global change; both are contributing to the rapid loss of tropical forest area with important implications for ecosystem functioning and biodiversity conservation. The forests of South Ecuador are a biological 'hotspot' due to their high diversity and endemism levels. We examined the deforestation and fragmentation patterns in this area of high conservation value using aerial photographs and Aster satellite scenes. The registered annual deforestation rates of 0.75% (1976-1989) and 2.86% (1989-2008) for two consecutive survey periods, the decreasing mean patch size and the increasing isolation of the forest fragments show that the area is under severe threat. Approximately 46% of South Ecuador's original forest cover had been converted by 2008 into pastures and other anthropogenic land cover types. We found that deforestation is more intense at lower elevations (premontane evergreen forest and shrubland) and that the deforestation front currently moves in upslope direction. Improved awareness of the spatial extent, dynamics and patterns of deforestation and forest fragmentation is urgently needed in biologically diverse areas like South Ecuador.

Detailed maps of tropical forest types are within reach: forest tree communities for Trinidad and Tobago mapped with multiseason Landsat and multiseason fine-resolution imagery

Science.gov (United States)

Eileen H. Helmer; Thomas S. Ruzycki; Jay Benner; Shannon M. Voggesser; Barbara P. Scobie; Courtenay Park; David W. Fanning; Seepersad. Ramnarine

2012-01-01

Tropical forest managers need detailed maps of forest types for REDD+, but spectral similarity among forest types; cloud and scan-line gaps; and scarce vegetation ground plots make producing such maps with satellite imagery difficult. How can managers map tropical forest tree communities with satellite imagery given these challenges? Here we describe a case study of...

Detecting Forest Cover and Ecosystem Service Change Using ...

African Journals Online (AJOL)

user

Mpigi, than in Butambala by 5.99%, disturbed forest was 3%, farm land ... climate change impacts on ecosystem services requires more attention and ... While these conceptual models usually assume relatively a causal-effect ... images with relatively low cloud cover or free-cloud imagery during the time period of interest.

Abiotic factors affect the recruitment and biomass of perennial grass and evergreen shrub seedlings in denuded areas of Patagonian Monte rangelands.

Science.gov (United States)

Bosco, Tomás; Bertiller, Mónica Beatriz; Carrera, Analía Lorena

2018-07-15

Assessing the ability of key species to cope with environmental stresses in disturbed areas is an important issue for recovery of degraded arid ecosystem. Our objective was to evaluate the effect of soil moisture, exposure to UV radiation, and presence/absence of litter with different chemistry on soil N, recruitment and biomass of seedlings of perennial grass (Poa ligularis and Nassella tenuis) and evergreen shrub species (Atriplex lampa and Larrea divaricata) in denuded areas. We carried out a microcosm experiment with soil blocks (28 cm depth) sowed with seeds of the target species, subjected to different levels of litter type (perennial grass-evergreen shrub mixture, evergreen shrub mixture, and no litter), UV radiation (near ambient and reduced UV), and soil water (high: 15-25% and low 5-15%). Periodically, during 6 months, we assessed soil-N (total and inorganic) at two depths and species seedling recruitment at microcosms. Additionally, emerged seedlings of each species were transplanted to individual pots containing soil and subjected to the same previous factors during 12 months. Then, all plants were harvested and biomass assessed. Only inorganic soil-N at the upper soil varied among treatments increasing with the presence of evergreen shrub litter, exposure to ambient UV, and high soil water. Inorganic soil-N, promoted by near ambient UV and high soil water, had a positive effect on recruitment of perennial grasses and A. lampa. Both litter types promoted the recruitment of perennial grasses. Evergreen shrub litter and high soil water promoted the recruitment of L. divaricata. Seedling biomass of perennial grasses increased with high soil water and reduced UV. Ambient UV had positive or null effects on biomass of evergreen shrub seedlings. High soil water increased biomass of L. divaricata seedlings. We concluded that soil water appeared as the most limiting factor for seedling recruitment of all species whereas inorganic soil N limited the

Leaf litter nitrogen concentration as related to climatic factors in Eurasian forests

DEFF Research Database (Denmark)

Liu, Chunjiang; Berg, Bjørn; Kutsch, Werner

2006-01-01

The aim of this study is to determine the patterns of nitrogen (N) concentrations in leaf litter of forest trees as functions of climatic factors, annual average temperature (Temp, °C) and annual precipitation (Precip, dm) and of forest type (coniferous vs. broadleaf, deciduous vs. evergreen, Pinus...... concentration and Temp and Precip by means of regression analysis. Leaf litter data from N2-fixing species were excluded from the analysis. Results: Over the Eurasian continent, leaf litter N concentration increased with increasing Temp and Precip within functional groups such as conifers, broadleaf, deciduous....... In the context of global warming, these regression equations are useful for a better understanding and modelling of the effects of geographical and climatic factors on leaf litter N at a regional and continental scale....

Avifauna del bosque mesófilo de montaña del noreste de Hidalgo, México Avifauna of the tropical montane cloud forest of northeastern Hidalgo, Mexico

Directory of Open Access Journals (Sweden)

Miguel Angel Martínez-Morales

2007-06-01

Full Text Available Este trabajo presenta los resultados de un inventario avifaunístico realizado de 1997 a 1999 en fragmentos de bosque mesófilo de montaña del noreste de Hidalgo, México. Se registraron 41 familias y 181 especies de aves mediante observaciones visuales y auditivas en 2 057 puntos de conteo, lo que representó el 98% de las especies esperadas en el área de estudio, para el período y método de muestreo utilizado. Se detectaron 16 especies restringidas al bosque mesófilo, 11 endémicas de México y 3 de distribución restringida. Adicionalmente, con base en la legislación mexicana vigente, 28 de las especies registradas están incluidas dentro de alguna categoría de riesgo de conservación. Esta comunidad de aves estuvo dominada por especies de aves pequeñas, raras (poco abundantes y residentes. Es probable que las más vulnerables de sufrir extinciones locales sean las especies raras y restringidas al bosque mesófilo, donde están incluidas las 3 especies de distribución restringida (Dendrortyx barbatus, Glaucidium sanchezi y Cyanolyca nana. La avifauna del bosque mesófilo de esta región incluye al 40% de la avifauna estatal, lo que destaca la relevancia de este tipo de vegetación y una urgente necesidad de establecer estrategias de manejo para su conservación.This study shows the results of bird census carried out from 1997 to 1999 in cloud forest fragments of northeastern Hidalgo, Mexico. Forty-one bird families and 181 species were recorded through visual and acoustic detections in 2 057 point counts. This represents 98% of the expected species richness for the sampling period and method used. Sixteen species restricted to the cloud forest were detected, 11 Mexican endemic species, and 3 restricted-range species were recorded. Additionally, 28 species are included within some category of conservation concern according to the present Mexican legislation. This bird community was dominated by small, rare (low in abundance, and

Increasing carbon discrimination rates and depth of water uptake favor the growth of Mediterranean evergreen trees in the ecotone with temperate deciduous forests.

Science.gov (United States)

Barbeta, Adrià; Peñuelas, Josep

2017-12-01

Tree populations at the low-altitudinal or -latitudinal limits of species' distributional ranges are predicted to retreat toward higher altitudes and latitudes to track the ongoing changes in climate. Studies have focused on the climatic sensitivity of the retreating species, whereas little is known about the potential replacements. Competition between tree species in forest ecotones will likely be strongly influenced by the ecophysiological responses to heat and drought. We used tree-ring widths and δ 13 C and δ 18 O chronologies to compare the growth rates and long-term ecophysiological responses to climate in the temperate-Mediterranean ecotone formed by the deciduous Fagus sylvatica and the evergreen Quercus ilex at the low altitudinal and southern latitudinal limit of F. sylvatica (NE Iberian Peninsula). F. sylvatica growth rates were similar to those of other southern populations and were surprisingly not higher than those of Q. ilex, which were an order of magnitude higher than those in nearby drier sites. Higher Q. ilex growth rates were associated with high temperatures, which have increased carbon discrimination rates in the last 25 years. In contrast, stomatal regulation in F. sylvatica was proportional to the increase in atmospheric CO 2 . Tree-ring δ 18 O for both species were mostly correlated with δ 18 O in the source water. In contrast to many previous studies, relative humidity was not negatively correlated with tree-ring δ 18 O but had a positive effect on Q. ilex tree-ring δ 18 O. Furthermore, tree-ring δ 18 O decreased in Q. ilex over time. The sensitivity of Q. ilex to climate likely reflects the uptake of deep water that allowed it to benefit from the effect of CO 2 fertilization, in contrast to the water-limited F. sylvatica. Consequently, Q. ilex is a strong competitor at sites currently dominated by F. sylvatica and could be favored by increasingly warmer conditions. © 2017 John Wiley & Sons Ltd.

Fogwater Inputs to a Cloud Forest in Puerto Rico

Science.gov (United States)

Eugster, W.; Burkard, R.; Holwerda, F.; Bruijnzeel, S.; Scatena, F. N.; Siegwolf, R.

2002-12-01

Fog is highly persistent at upper elevations of humid tropical mountains and is an important pathway for water and nutrient inputs to mountain forest ecosystems. Measurements of fogwater fluxes were performed in the Luquillo mountains of Puerto Rico using the eddy covariance approach and a Caltech-type active strand cloudwater collector. Rainfall and throughfall were collected between 25 June--7 August 2002. Samples of fog, rain, stemflow and throughfall were analyzed for inorganic ion and stable isotope concentrations (δ18O and δD). Initial results indicate that fog inputs can occur during periods without rain and last for up to several days. The isotope ratios in rainwater and fogwater are rather similar, indicative of the proximity of the Carribbean Sea and the close interrelation between the origins of fog and rain at our experimental site. Largest differences in isotope ratios for fog were found between daytime convective and nighttime stable conditions. Throughfall was always exceeding rainfall, indicating (a) the relevance of fogwater inputs and (b) the potentially significant undersampling of rainfall due to relatively high wind speeds (5.7 m/s mean) and the exposition of our field site close to a mountain ridge. Our size-resolved measurements of cloud droplets (40 size bins between 2 and 50 μm aerodynamic diameter) indicate that the liquid water content of fog in the Luquillo mountains is 5 times higher than previously assumed, and thus does not differ from the values reported from other mountain ranges in other climate zones. Average deposition rates are 0.88 mm and 6.5 mm per day for fog and rain, respectively.

Seasonal patterns of leaf gas exchange and water relations in dry rain forest trees of contrasting leaf phenology.

Science.gov (United States)

Choat, Brendan; Ball, Marilyn C; Luly, Jon G; Donnelly, Christine F; Holtum, Joseph A M

2006-05-01

Diurnal and seasonal patterns of leaf gas exchange and water relations were examined in tree species of contrasting leaf phenology growing in a seasonally dry tropical rain forest in north-eastern Australia. Two drought-deciduous species, Brachychiton australis (Schott and Endl.) A. Terracc. and Cochlospermum gillivraei Benth., and two evergreen species, Alphitonia excelsa (Fenzal) Benth. and Austromyrtus bidwillii (Benth.) Burret. were studied. The deciduous species had higher specific leaf areas and maximum photosynthetic rates per leaf dry mass in the wet season than the evergreens. During the transition from wet season to dry season, total canopy area was reduced by 70-90% in the deciduous species and stomatal conductance (g(s)) and assimilation rate (A) were markedly lower in the remaining leaves. Deciduous species maintained daytime leaf water potentials (Psi(L)) at close to or above wet season values by a combination of stomatal regulation and reduction in leaf area. Thus, the timing of leaf drop in deciduous species was not associated with large negative values of daytime Psi(L) (greater than -1.6 MPa) or predawn Psi(L) (greater than -1.0 MPa). The deciduous species appeared sensitive to small perturbations in soil and leaf water status that signalled the onset of drought. The evergreen species were less sensitive to the onset of drought and g(s) values were not significantly lower during the transitional period. In the dry season, the evergreen species maintained their canopies despite increasing water-stress; however, unlike Eucalyptus species from northern Australian savannas, A and g(s) were significantly lower than wet season values.

A practical and automated approach to large area forest disturbance mapping with remote sensing.

Directory of Open Access Journals (Sweden)

Mutlu Ozdogan

Full Text Available In this paper, I describe a set of procedures that automate forest disturbance mapping using a pair of Landsat images. The approach is built on the traditional pair-wise change detection method, but is designed to extract training data without user interaction and uses a robust classification algorithm capable of handling incorrectly labeled training data. The steps in this procedure include: i creating masks for water, non-forested areas, clouds, and cloud shadows; ii identifying training pixels whose value is above or below a threshold defined by the number of standard deviations from the mean value of the histograms generated from local windows in the short-wave infrared (SWIR difference image; iii filtering the original training data through a number of classification algorithms using an n-fold cross validation to eliminate mislabeled training samples; and finally, iv mapping forest disturbance using a supervised classification algorithm. When applied to 17 Landsat footprints across the U.S. at five-year intervals between 1985 and 2010, the proposed approach produced forest disturbance maps with 80 to 95% overall accuracy, comparable to those obtained from traditional approaches to forest change detection. The primary sources of mis-classification errors included inaccurate identification of forests (errors of commission, issues related to the land/water mask, and clouds and cloud shadows missed during image screening. The approach requires images from the peak growing season, at least for the deciduous forest sites, and cannot readily distinguish forest harvest from natural disturbances or other types of land cover change. The accuracy of detecting forest disturbance diminishes with the number of years between the images that make up the image pair. Nevertheless, the relatively high accuracies, little or no user input needed for processing, speed of map production, and simplicity of the approach make the new method especially practical for

Automatic Mapping of Forest Stands Based on Three-Dimensional Point Clouds Derived from Terrestrial Laser-Scanning

Directory of Open Access Journals (Sweden)

Tim Ritter

2017-07-01

Full Text Available Mapping of exact tree positions can be regarded as a crucial task of field work associated with forest monitoring, especially on intensive research plots. We propose a two-stage density clustering approach for the automatic mapping of tree positions, and an algorithm for automatic tree diameter estimates based on terrestrial laser-scanning (TLS point cloud data sampled under limited sighting conditions. We show that our novel approach is able to detect tree positions in a mixed and vertically structured stand with an overall accuracy of 91.6%, and with omission- and commission error of only 5.7% and 2.7% respectively. Moreover, we were able to reproduce the stand’s diameter in breast height (DBH distribution, and to estimate single trees DBH with a mean average deviation of ±2.90 cm compared with tape measurements as reference.

Individual tree detection in intact forest and degraded forest areas in the north region of Mato Grosso State, Brazilian Amazon

Science.gov (United States)

Santos, E. G.; Jorge, A.; Shimabukuro, Y. E.; Gasparini, K.

2017-12-01

The State of Mato Grosso - MT has the second largest area with degraded forest among the states of the Brazilian Legal Amazon. Land use and land cover change processes that occur in this region cause the loss of forest biomass, releasing greenhouse gases that contribute to the increase of temperature on earth. These degraded forest areas lose biomass according to the intensity and magnitude of the degradation type. The estimate of forest biomass, commonly performed by forest inventory through sample plots, shows high variance in degraded forest areas. Due to this variance and complexity of tropical forests, the aim of this work was to estimate forest biomass using LiDAR point clouds in three distinct forest areas: one degraded by fire, another by selective logging and one area of intact forest. The approach applied in these areas was the Individual Tree Detection (ITD). To isolate the trees, we generated Canopy Height Models (CHM) images, which are obtained by subtracting the Digital Elevation Model (MDE) and the Digital Terrain Model (MDT), created by the cloud of LiDAR points. The trees in the CHM images are isolated by an algorithm provided by the Quantitative Ecology research group at the School of Forestry at Northern Arizona University (SILVA, 2015). With these points, metrics were calculated for some areas, which were used in the model of biomass estimation. The methodology used in this work was expected to reduce the error in biomass estimate in the study area. The cloud points of the most representative trees were analyzed, and thus field data was correlated with the individual trees found by the proposed algorithm. In a pilot study, the proposed methodology was applied generating the individual tree metrics: total height and area of the crown. When correlating 339 isolated trees, an unsatisfactory R² was obtained, as heights found by the algorithm were lower than those obtained in the field, with an average difference of 2.43 m. This shows that the

Effects of logging and recruitment on community phylogenetic structure in 32 permanent forest plots of Kampong Thom, Cambodia

OpenAIRE

Toyama, Hironori; Kajisa, Tsuyoshi; Tagane, Shuichiro; Mase, Keiko; Chhang, Phourin; Samreth, Vanna; Ma, Vuthy; Sokh, Heng; Ichihashi, Ryuji; Onoda, Yusuke; Mizoue, Nobuya; Yahara, Tetsukazu

2015-01-01

Ecological communities including tropical rainforest are rapidly changing under various disturbances caused by increasing human activities. Recently in Cambodia, illegal logging and clear-felling for agriculture have been increasing. Here, we study the effects of logging, mortality and recruitment of plot trees on phylogenetic community structure in 32 plots in Kampong Thom, Cambodia. Each plot was 0.25 ha; 28 plots were established in primary evergreen forests and four were established in se...

Examining the patterns and dynamics of species abundance distributions in succession of forest communities by model selection

Science.gov (United States)

Luo, Shao-Ming; Chen, Ping; He, Xiao; Guo, Wei; Li, Bailian

2018-01-01

There are a few common species and many rare species in a biological community or a multi-species collection in given space and time. This hollow distribution curve is called species abundance distribution (SAD). Few studies have examined the patterns and dynamics of SADs during the succession of forest communities by model selection. This study explored whether the communities in different successional stages followed different SAD models and whether there existed a best SAD model to reveal their intrinsic quantitative features of structure and dynamics in succession. The abundance (the number of individuals) of each vascular plant was surveyed by quadrat sampling method from the tree, shrub and herb layers in two typical communities (i.e., the evergreen needle- and broad-leaved mixed forest and the monsoon evergreen broad-leaved forest) in southern subtropical Dinghushan Biosphere Reserve, South China. The sites of two forest communities in different successional stages are both 1 ha in area. We collected seven widely representative SAD models with obviously different function forms and transformed them into the same octave (log2) scale. These models are simultaneously confronted with eight datasets from four layers of two communities, and their goodness-of-fits to the data were evaluated by the chi-squared test, the adjusted coefficient of determination and the information criteria. The results indicated that: (1) the logCauchy model followed all the datasets and was the best among seven models; (2) the fitness of each model to the data was not directly related to the successional stage of forest community; (3) according to the SAD curves predicted by the best model (i.e., the logCauchy), the proportion of rare species decreased but that of common ones increased in the upper layers with succession, while the reverse was true in the lower layers; and (4) the difference of the SADs increased between the upper and the lower layers with succession. We concluded that

Carbon emissions and sequestration in forests: Case studies from seven developing countries

Energy Technology Data Exchange (ETDEWEB)

Makundi, W.; Sathaye, J. (eds.) (Lawrence Berkeley Lab., CA (United States)); Cerutti, O.M.; Ordonez, M.J.; Minjarez, R.D. (Universidad Nacional Autonoma de Mexico, Mexico City (Mexico) Centro de Ecologia)

1992-08-01

Estimates of carbon emissions from deforestation in Mexico are derived for the year 1985 and for two contrasting scenarios in 2025. Carbon emissions are calculated through an in-depth review of the existing information on forest cover deforestation mtes and area affected by forest fires as well as on forests' carbon-related biological characteristics. The analysis covers both tropical -- evergreen and deciduous -- and temperate -- coniferous and broadleaf -- closed forests. Emissions from the forest sector are also compared to those from energy and industry. Different policy options for promoting the sustainable management of forest resources in the country are discussed. The analysis indicates that approximately 804,000 hectares per year of closed forests suffered from major perturbations in the mid 1980's in Mexico, leading to an annual deforestation mte of 668,000 hectares. Seventy five percent of total deforestation is concentrated in tropical forests. The resulting annual carbon balance is estimated in 53.4 million tons per year, and the net committed emissions in 45.5 million tons or 41% and 38%, respectively, of the country's total for 1985--87. The annual carbon balance from the forest sector in 2025 is expected to decline to 16.5 million tons in the low emissions scenario and to 22.9 million tons in the high emissions scenario. Because of the large uncertainties in some of the primary sources of information, the stated figures should be taken as preliminary estimates.

Ten Years of Forest Cover Change in the Sierra Nevada Detected Using Landsat Satellite Image Analysis

Science.gov (United States)

Potter, Christopher S.

2014-01-01

The Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) methodology was applied to detected changes in forest vegetation cover for areas burned by wildfires in the Sierra Nevada Mountains of California between the periods of 1975- 79 and 1995-1999. Results for areas burned by wildfire between 1995 and 1999 confirmed the importance of regrowing forest vegetation over 17% of the combined burned areas. A notable fraction (12%) of the entire 5-km (unburned) buffer area outside the 1995-199 fires perimeters showed decline in forest cover, and not nearly as many regrowing forest areas, covering only 3% of all the 1995-1999 buffer areas combined. Areas burned by wildfire between 1975 and 1979 confirmed the importance of disturbed (or declining evergreen) vegetation covering 13% of the combined 1975- 1979 burned areas. Based on comparison of these results to ground-based survey data, the LEDAPS methodology should be capable of fulfilling much of the need for consistent, low-cost monitoring of changes due to climate and biological factors in western forest regrowth following stand-replacing disturbances.

Urban forest topographical mapping using UAV LIDAR

Science.gov (United States)

Putut Ash Shidiq, Iqbal; Wibowo, Adi; Kusratmoko, Eko; Indratmoko, Satria; Ardhianto, Ronni; Prasetyo Nugroho, Budi

2017-12-01

Topographical data is highly needed by many parties, such as government institution, mining companies and agricultural sectors. It is not just about the precision, the acquisition time and data processing are also carefully considered. In relation with forest management, a high accuracy topographic map is necessary for planning, close monitoring and evaluating forest changes. One of the solution to quickly and precisely mapped topography is using remote sensing system. In this study, we test high-resolution data using Light Detection and Ranging (LiDAR) collected from unmanned aerial vehicles (UAV) to map topography and differentiate vegetation classes based on height in urban forest area of University of Indonesia (UI). The semi-automatic and manual classifications were applied to divide point clouds into two main classes, namely ground and vegetation. There were 15,806,380 point clouds obtained during the post-process, in which 2.39% of it were detected as ground.

Ecological Importance of Small-Diameter Trees to the Structure, Diversity and Biomass of a Tropical Evergreen Forest at Rabi, Gabon.

Science.gov (United States)

Memiaghe, Hervé R; Lutz, James A; Korte, Lisa; Alonso, Alfonso; Kenfack, David

2016-01-01

Tropical forests have long been recognized for their biodiversity and ecosystem services. Despite their importance, tropical forests, and particularly those of central Africa, remain understudied. Until recently, most forest inventories in Central Africa have focused on trees ≥10 cm in diameter, even though several studies have shown that small-diameter tree population may be important to demographic rates and nutrient cycling. To determine the ecological importance of small-diameter trees in central African forests, we used data from a 25-ha permanent plot that we established in the rainforest of Gabon to study the diversity and dynamics of these forests. Within the plot, we censused 175,830 trees ≥1 cm dbh from 54 families, 192 genera, and 345 species. Average tree density was 7,026 trees/ha, basal area 31.64 m2/ha, and above-ground biomass 369.40 Mg/ha. Fabaceae, Ebenaceae and Euphorbiaceae were the most important families by basal area, density and above-ground biomass. Small-diameter trees (1 cm ≥ dbh tree population, 16.5% of basal area, and 4.8% of the above-ground biomass. They also had diversity 18% higher at family level, 34% higher at genus level, and 42% higher at species level than trees ≥10 cm dbh. Although the relative contribution of small-diameter trees to biomass was comparable to other forests globally, their contribution to forest density, and diversity was disproportionately higher. The high levels of diversity within small-diameter classes may give these forests high levels of structural resilience to anthropogenic/natural disturbance and a changing climate.

Evidence of a reduction in cloud condensation nuclei activity of water-soluble aerosols caused by biogenic emissions in a cool-temperate forest.

Science.gov (United States)

Müller, Astrid; Miyazaki, Yuzo; Tachibana, Eri; Kawamura, Kimitaka; Hiura, Tsutom

2017-08-16

Biogenic organic aerosols can affect cloud condensation nuclei (CCN) properties, and subsequently impact climate change. Large uncertainties exist in how the difference in the types of terrestrial biogenic sources and the abundance of organics relative to sulfate affect CCN properties. For the submicron water-soluble aerosols collected for two years in a cool-temperate forest in northern Japan, we show that the hygroscopicity parameter κ CCN (0.44 ± 0.07) exhibited a distinct seasonal trend with a minimum in autumn (κ CCN  = 0.32-0.37); these κ CCN values were generally larger than that of ambient particles, including water-insoluble fractions. The temporal variability of κ CCN was controlled by the water-soluble organic matter (WSOM)-to-sulfate ratio (R 2  > 0.60), where the significant reduction of κ CCN in autumn was linked to the increased WSOM/sulfate ratio. Positive matrix factorization analysis indicates that α-pinene-derived secondary organic aerosol (SOA) substantially contributed to the WSOM mass (~75%) in autumn, the majority of which was attributable to emissions from litter/soil microbial activity near the forest floor. These findings suggest that WSOM, most likely α-pinene SOA, originated from the forest floor can significantly suppress the aerosol CCN activity in cool-temperate forests, which have implications for predicting climate effects by changes in biogenic emissions in future.

Geography of Global Forest Carbon Stocks & Dynamics

Science.gov (United States)

Saatchi, S. S.; Yu, Y.; Xu, L.; Yang, Y.; Fore, A.; Ganguly, S.; Nemani, R. R.; Zhang, G.; Lefsky, M. A.; Sun, G.; Woodall, C. W.; Naesset, E.; Seibt, U. H.

2014-12-01

Spatially explicit distribution of carbon stocks and dynamics in global forests can greatly reduce the uncertainty in the terrestrial portion of the global carbon cycle by improving estimates of emissions and uptakes from land use activities, and help with green house gas inventory at regional and national scales. Here, we produce the first global distribution of carbon stocks in living woody biomass at ~ 100 m (1-ha) resolution for circa 2005 from a combination of satellite observations and ground inventory data. The total carbon stored in live woody biomass is estimated to be 337 PgC with 258 PgC in aboveground and 79 PgC in roots, and partitioned globally in boreal (20%), tropical evergreen (50%), temperate (12%), and woodland savanna and shrublands (15%). We use a combination of satellite observations of tree height, remote sensing data on deforestation and degradation to quantify the dynamics of these forests at the biome level globally and provide geographical distribution of carbon storage dynamics in terms sinks and sources globally.

The feature and distribution of 137Cs in the forest soil

International Nuclear Information System (INIS)

Narazaki, Yukinori

2002-01-01

The 137 Cs concentration in an undisturbed upper layer of naked land in Fukuoka Prefecture decreased exponentially from 1969 to 1999 with the apparent half-life of 7 years. The ratio of 137 Cs concentration in the lower layer of the soil to that in the upper layer was about 1/5. The concentration of 137 Cs, 40 K, and stable Cs and the soil profile consisting of loss on ignition, pH, and electric conductivity were determined in the 48 samples collected in the forests and the neighboring naked land from 1991 to 1998. The 137 Cs concentration in the forest soils ranged from 1 to 424 Bq/kg dry wt, 131 Bq/kg dry wt on average, although 137 Cs was hardly detected in the naked soil around the forest. There was no regional difference in the distribution of the 137 Cs concentration, and it varied with pH and electric conductivity in the soil. Further, it tended to be higher in the deciduous woodland than in the evergreen woodland. (author)

Aspectos florísticos e fitossociológicos de um trecho de Floresta Estacional Perenifólia na Fazenda Trairão, Bacia do rio das Pacas, Querência-MT Floristic and phytosociological aspects of a Seasonal Evergreen Forest area in the Trairão Farm, rio das Pacas Basin, Querência-MT

Directory of Open Access Journals (Sweden)

Sustanis Horn Kunz

2008-01-01

Full Text Available A borda sul da região amazônica apresenta um tipo peculiar de floresta, denominada de Floresta Estacional Perenifólia, que atualmente vem sofrendo severos impactos ambientais devido à expansão da fronteira agrícola no Norte do Estado de Mato Grosso. Diante da falta de estudos neste tipo florestal, objetivou-se identificar a composição florística e a estrutura fitossociológica do componente arbóreo de um trecho florestal na Fazenda Trairão em Querência-MT. A amostragem da vegetação consistiu na distribuição de 200 pontos-quadrantes, sendo considerados os quatro indivíduos mais próximos de cada ponto que tivessem DAP (diâmetro à altura do peito igual ou superior a 10 cm. A densidade total foi de 728 ind./ha, distribuídos em 49 espécies, 39 gêneros e 24 famílias. A família que apresentou maior riqueza foi Fabaceae (cinco espécies, seguida por Burseraceae e Euphorbiaceae, cada uma com quatro espécies, consideradas também as mais ricas em trechos de Floresta Amazônica. As espécies de maior Valor de Importância (VI foram Ocotea leucoxylon (Sw. Laness., Xylopia amazonica R.E. Fr., Myrcia multiflora (Lam. DC., Chaetocarpus echinocarpus (Baill. Ducke e Protium pilosissimum Engl., mas não tiveram a mesma representatividade em outros trechos de Floresta Estacional Perenifólia, evidenciando diferenças estruturais desta unidade fitogeográfica. A comunidade avaliada possui porte fino, pois a maioria dos indivíduos concentra-se nas classes de diâmetro entre 10 e 14,9 cm e altura entre 10,6 e 16,5 m. O índice de Shannon (3,17 é considerado baixo por se tratar de floresta amazônica, na qual a diversidade é superior a 4,0.The southern border of the Amazon region presents a peculiar type of forest called Seasonal Evergreen Forest, which has currently undergone several environmental impacts due to the agriculture frontier expansion from the Northern state of Mato Grosso. Due to the lack of studies on this type of forest

Morphological and phenological shoot plasticity in a Mediterranean evergreen oak facing long-term increased drought.

Science.gov (United States)

Limousin, Jean-Marc; Rambal, Serge; Ourcival, Jean-Marc; Rodríguez-Calcerrada, Jesus; Pérez-Ramos, Ignacio M; Rodríguez-Cortina, Raquel; Misson, Laurent; Joffre, Richard

2012-06-01

Mediterranean trees must adjust their canopy leaf area to the unpredictable timing and severity of summer drought. The impact of increased drought on the canopy dynamics of the evergreen Quercus ilex was studied by measuring shoot growth, leaf production, litterfall, leafing phenology and leaf demography in a mature forest stand submitted to partial throughfall exclusion for 7 years. The leaf area index rapidly declined in the throughfall-exclusion plot and was 19% lower than in the control plot after 7 years of treatment. Consequently, leaf litterfall was significantly lower in the dry treatment. Such a decline in leaf area occurred through a change in branch allometry with a decreased number of ramifications produced and a reduction of the leaf area supported per unit sapwood area of the shoot (LA/SA). The leafing phenology was slightly delayed and the median leaf life span was slightly longer in the dry treatment. The canopy dynamics in both treatments were driven by water availability with a 1-year lag: leaf shedding and production were reduced following dry years; in contrast, leaf turnover was increased following wet years. The drought-induced decrease in leaf area, resulting from both plasticity in shoot development and slower leaf turnover, appeared to be a hydraulic adjustment to limit canopy transpiration and maintain leaf-specific hydraulic conductivity under drier conditions.

Forest Cover Mapping in Iskandar Malaysia Using Satellite Data

Science.gov (United States)

Kanniah, K. D.; Mohd Najib, N. E.; Vu, T. T.

2016-09-01

Malaysia is the third largest country in the world that had lost forest cover. Therefore, timely information on forest cover is required to help the government to ensure that the remaining forest resources are managed in a sustainable manner. This study aims to map and detect changes of forest cover (deforestation and disturbance) in Iskandar Malaysia region in the south of Peninsular Malaysia between years 1990 and 2010 using Landsat satellite images. The Carnegie Landsat Analysis System-Lite (CLASlite) programme was used to classify forest cover using Landsat images. This software is able to mask out clouds, cloud shadows, terrain shadows, and water bodies and atmospherically correct the images using 6S radiative transfer model. An Automated Monte Carlo Unmixing technique embedded in CLASlite was used to unmix each Landsat pixel into fractions of photosynthetic vegetation (PV), non photosynthetic vegetation (NPV) and soil surface (S). Forest and non-forest areas were produced from the fractional cover images using appropriate threshold values of PV, NPV and S. CLASlite software was found to be able to classify forest cover in Iskandar Malaysia with only a difference between 14% (1990) and 5% (2010) compared to the forest land use map produced by the Department of Agriculture, Malaysia. Nevertheless, the CLASlite automated software used in this study was found not to exclude other vegetation types especially rubber and oil palm that has similar reflectance to forest. Currently rubber and oil palm were discriminated from forest manually using land use maps. Therefore, CLASlite algorithm needs further adjustment to exclude these vegetation and classify only forest cover.

Relationships between net primary productivity and stand age for several forest types and their influence on China's carbon balance.

Science.gov (United States)

Wang, Shaoqiang; Zhou, Lei; Chen, Jingming; Ju, Weimin; Feng, Xianfeng; Wu, Weixing

2011-06-01

Affected by natural and anthropogenic disturbances such as forest fires, insect-induced mortality and harvesting, forest stand age plays an important role in determining the distribution of carbon pools and fluxes in a variety of forest ecosystems. An improved understanding of the relationship between net primary productivity (NPP) and stand age (i.e., age-related increase and decline in forest productivity) is essential for the simulation and prediction of the global carbon cycle at annual, decadal, centurial, or even longer temporal scales. In this paper, we developed functions describing the relationship between national mean NPP and stand age using stand age information derived from forest inventory data and NPP simulated by the BEPS (Boreal Ecosystem Productivity Simulator) model in 2001. Due to differences in ecobiophysical characteristics of different forest types, NPP-age equations were developed for five typical forest ecosystems in China (deciduous needleleaf forest (DNF), evergreen needleleaf forest in tropic and subtropical zones (ENF-S), deciduous broadleaf forest (DBF), evergreen broadleaf forest (EBF), and mixed broadleaf forest (MBF)). For DNF, ENF-S, EBF, and MBF, changes in NPP with age were well fitted with a common non-linear function, with R(2) values equal to 0.90, 0.75, 0.66, and 0.67, respectively. In contrast, a second order polynomial was best suitable for simulating the change of NPP for DBF, with an R(2) value of 0.79. The timing and magnitude of the maximum NPP varied with forest types. DNF, EBF, and MBF reached the peak NPP at the age of 54, 40, and 32 years, respectively, while the NPP of ENF-S maximizes at the age of 13 years. The highest NPP of DBF appeared at 122 years. NPP was generally lower in older stands with the exception of DBF, and this particular finding runs counter to the paradigm of age-related decline in forest growth. Evaluation based on measurements of NPP and stand age at the plot-level demonstrates the reliability

A 50-m forest cover map in Southeast Asia from ALOS/PALSAR and its application on forest fragmentation assessment.

Directory of Open Access Journals (Sweden)

Jinwei Dong

Full Text Available Southeast Asia experienced higher rates of deforestation than other continents in the 1990s and still was a hotspot of forest change in the 2000s. Biodiversity conservation planning and accurate estimation of forest carbon fluxes and pools need more accurate information about forest area, spatial distribution and fragmentation. However, the recent forest maps of Southeast Asia were generated from optical images at spatial resolutions of several hundreds of meters, and they do not capture well the exceptionally complex and dynamic environments in Southeast Asia. The forest area estimates from those maps vary substantially, ranging from 1.73×10(6 km(2 (GlobCover to 2.69×10(6 km(2 (MCD12Q1 in 2009; and their uncertainty is constrained by frequent cloud cover and coarse spatial resolution. Recently, cloud-free imagery from the Phased Array Type L-band Synthetic Aperture Radar (PALSAR onboard the Advanced Land Observing Satellite (ALOS became available. We used the PALSAR 50-m orthorectified mosaic imagery in 2009 to generate a forest cover map of Southeast Asia at 50-m spatial resolution. The validation, using ground-reference data collected from the Geo-Referenced Field Photo Library and high-resolution images in Google Earth, showed that our forest map has a reasonably high accuracy (producer's accuracy 86% and user's accuracy 93%. The PALSAR-based forest area estimates in 2009 are significantly correlated with those from GlobCover and MCD12Q1 at national and subnational scales but differ in some regions at the pixel scale due to different spatial resolutions, forest definitions, and algorithms. The resultant 50-m forest map was used to quantify forest fragmentation and it revealed substantial details of forest fragmentation. This new 50-m map of tropical forests could serve as a baseline map for forest resource inventory, deforestation monitoring, reducing emissions from deforestation and forest degradation (REDD+ implementation, and

Nitrogen deposition's role in determining forest photosynthetic capacity; a FLUXNET synthesis

Science.gov (United States)

Fleischer, K.; Rebel, K.; van der Molen, M.; Erisman, J.; Wassen, M.; Dolman, H.

2011-12-01

There is growing evidence that nitrogen (N) deposition stimulates forest growth, as many forest ecosystems are N-limited. However, the significance of N deposition in determining the strength of the present and future terrestrial carbon sink is strongly debated. We investigated and quantified the effect of N deposition on ecosystem photosynthetic capacity (Amax) with the FLUXNET database, including 80 forest sites, covering the major forest types and climates of the world. The relative effect of climate and N deposition on photosynthesis was assessed with regression models. We found a significant positive correlation of Amax and N deposition for evergreen needleleaf forests in our dataset. We further found indications that foliar N and LAI scale positively with N deposition, reflecting the 2 mechanisms at which N is believed to cause an increase in carbon gain. We can support the hypothesis that foliar N is the principal scaling factor for canopy Amax across all forest types. Deciduous forests are less diverse in terms of climate and nutritional conditions for the included sites and these forests exhibited weak to no correlations with the included climate and N predictor variables. Quantifying the effect of N deposition on photosynthetic rates at the canopy level is an essential step for quantifying its contribution to the terrestrial carbon sink and for predicting vegetation response to N fertilization and global change in the future. The approach shows that eddy-covariance measurements of carbon fluxes at the canopy scale allow us to test hypotheses with respect to the expected nitrogen-photosynthesis relationships at the canopy scale.

[Effects of precipitation intensity on soil organic carbon fractions and their distribution under subtropical forests of South China].

Science.gov (United States)

Chen, Xiao-mei; Liu, Ju-xiu; Deng, Qi; Chu, Guo-wei; Zhou, Guo-yi; Zhang, De-qiang

2010-05-01

From December 2006 to June 2008, a field experiment was conducted to study the effects of natural precipitation, doubled precipitation, and no precipitation on the soil organic carbon fractions and their distribution under a successional series of monsoon evergreen broad-leaf forest, pine and broad-leaf mixed forest, and pine forest in Dinghushan Mountain of Southern China. Different precipitation treatments had no significant effects on the total organic carbon (TOC) concentration in the same soil layer under the same forest type (P > 0.05). In treatment no precipitation, particulate organic carbon (POC) and light fraction organic carbon (LFOC) were mainly accumulated in surface soil layer (0-10 cm); but in treatments natural precipitation and doubled precipitation, the two fractions were infiltrated to deeper soil layers. Under pine forest, soil readily oxidizable organic carbon (ROC) was significantly higher in treatment no precipitation than in treatments natural precipitation and doubled precipitation (P organic carbon storage. Precipitation intensity less affected TOC, but had greater effects on the labile components POC, ROC, and LFOC.

Leaf adaptations of evergreen and deciduous trees of semi-arid and humid savannas on three continents

NARCIS (Netherlands)

Tomlinson, K.W.; Poorter, L.; Sterck, F.J.; Borghetti, M.; Ward, D.; Bie, de S.; Langevelde, van F.

2013-01-01

1. Drought stress selects for a suite of plant traits at root, stem and leaf level. Two strategies are proposed for trees growing in seasonally water-stressed environments: drought tolerance and drought avoidance. These are respectively associated with evergreen phenology, where plants retain their

Deforestation and Forest Fragmentation in South Ecuador since the 1970s – Losing a Hotspot of Biodiversity

Science.gov (United States)

Tapia-Armijos, María Fernanda; Homeier, Jürgen; Espinosa, Carlos Iván; Leuschner, Christoph; de la Cruz, Marcelino

2015-01-01

Deforestation and fragmentation are major components of global change; both are contributing to the rapid loss of tropical forest area with important implications for ecosystem functioning and biodiversity conservation. The forests of South Ecuador are a biological ‘hotspot’ due to their high diversity and endemism levels. We examined the deforestation and fragmentation patterns in this area of high conservation value using aerial photographs and Aster satellite scenes. The registered annual deforestation rates of 0.75% (1976–1989) and 2.86% (1989–2008) for two consecutive survey periods, the decreasing mean patch size and the increasing isolation of the forest fragments show that the area is under severe threat. Approximately 46% of South Ecuador’s original forest cover had been converted by 2008 into pastures and other anthropogenic land cover types. We found that deforestation is more intense at lower elevations (premontane evergreen forest and shrubland) and that the deforestation front currently moves in upslope direction. Improved awareness of the spatial extent, dynamics and patterns of deforestation and forest fragmentation is urgently needed in biologically diverse areas like South Ecuador. PMID:26332681

137Cs dynamics in the forest of Fukushima after the nuclear power plant accident in March 2011

Science.gov (United States)

Endo, I.; Ohte, N.; Iseda, K.; Kobayashi, N.; Hirose, A.; Tanoi, K.

2013-12-01

The accident of Fukushima Daiichi nuclear power plant after the earthquake and Tsunami in March 11th 2011, caused large amount of radioactive Cesium (137Cs) emission into the environment. In the region of Fukushima Prefecture, forest dominates more than 70 % of the land area. River water from the forest area is used for food production and also for drinking water. Thus, it is important to understand the dynamics of 137Cs deposited in the forest to predict how the radioactive Cs diffuse and discharge from the forest catchments. We measured 137Cs concentration of the tree body, litter fall, throughfall, and stemflow, in order to clarify how 137Cs deposited on the above ground biomass of the forest are transported to the forest floor. We set forest site at the upstream part of Kami-Oguni River catchment, northern part of Fukushima Prefecture. Three plots (2 deciduous stands and 1 Japanese cedar (Cryptomeria japonica) plantation stand) were set in the forest site. Quercus serrata and C. japonica, which are representative tree species, were chosen at each plot and concentration of 137Cs on the bark, sapwood and heartwood were measured every 2 m from the ground to tree top. From each plot, 137Cs concentration of leaf litter was measured among species. Water samples of throughfall and stemflow were filtered and 137Cs concentration in suspended matter was measured. 137Cs was deposited on the bark of Q. serrata at high concentration (9-18 kBq/kg) but there were no clear relationship between tree height and concentration. 137Cs concentration of the sapwood (41 Bq/kg) was relatively higher than that of the heartwood (5 Bq/kg). It was suggested that 137Cs may be absorbed from bark and/or root. The concentration of 137Cs deposited in leaf litter varied from non-detected level to above 30 kBq/kg. The concentration was higher at evergreen tree than deciduous tree. It is considered that the litter of evergreen tree was derived from leaves on the tree canopy at the time of the

Tolerance of frugivorous birds to habitat disturbance in a tropical cloud forest

NARCIS (Netherlands)

Gomes, L.G.L.; Oostra, V.; Nijman, V.; Cleef, A.M.; Kappelle, M.

2008-01-01

In view of the continued decline in tropical forest cover around the globe, forest restoration has become a key tool in tropical rainforest conservation. One of the main - and least expensive - restoration strategies is natural forest regeneration. By aiding forest seed influx both into disturbed

Evaluating the Contribution of Climate Forcing and Forest Dynamics to Accelerating Carbon Sequestration by Forest Ecosystems in the Northeastern U.S.

Energy Technology Data Exchange (ETDEWEB)

Fitzjarrald, David Roy [Atmos Sciences Res Ctr

2013-09-11

We used 10 Hz eddy flux signals and 0.2 Hz incident radiation (global shortwave and PAR) records from Harvard Forest (Massachusetts) and Tapajos National Forest (Brazil) to establish empirical relationships among directly measured cloud type and cover percentage and corresponding PAR fluctuations and its diffuse fraction. In future work such a cloud characterization will be related to water and light use efficiency estimates for each of these ecosystems. We developed empirical relationships to link sky cover type and fraction (measured with the ceilometer) to incident direct and diffuse PAR. We developed a methodology for constructing synthetic incident solar radiation time series based on operational reports of sky cover and cloud type from National Weather Service METAR reports. The aim of this work is to document the temporal and spectral properties radiation incident on the canopy, as a first step toward developing a sky-type parameterization for the net carbon uptake models.

Mapping forest transition trends in Okomu reserve using Landsat ...

African Journals Online (AJOL)

DR. ALEX O. ONOJEGHUO

1 Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, United ... and improve upon the technical capacity of forest managers to improve forest management. Overall, the .... cloud cover or were totally free of such and acquired within the same season (as was the case in this ... Green (2), red (3) and.

A Comparison of the Pitfall Trap, Winkler Extractor and Berlese Funnel for Sampling Ground-Dwelling Arthropods in Tropical Montane Cloud Forests

Science.gov (United States)

Sabu, Thomas K.; Shiju, Raj T.; Vinod, KV.; Nithya, S.

2011-01-01

Little is known about the ground-dwelling arthropod diversity in tropical montane cloud forests (TMCF). Due to unique habitat conditions in TMCFs with continuously wet substrates and a waterlogged forest floor along with the innate biases of the pitfall trap, Berlese funnel and Winkler extractor are certain to make it difficult to choose the most appropriate method to sample the ground-dwelling arthropods in TMCFs. Among the three methods, the Winkler extractor was the most efficient method for quantitative data and pitfall trapping for qualitative data for most groups. Inclusion of floatation method as a complementary method along with the Winkler extractor would enable a comprehensive quantitative survey of ground-dwelling arthropods. Pitfall trapping is essential for both quantitative and qualitative sampling of Diplopoda, Opiliones, Orthoptera, and Diptera. The Winkler extractor was the best quantitative method for Psocoptera, Araneae, Isopoda, and Formicidae; and the Berlese funnel was best for Collembola and Chilopoda. For larval forms of different insect orders and the Acari, all the three methods were equally effective. PMID:21529148

Ozone slows stomatal response to light and leaf wounding in a Mediterranean evergreen broadleaf, Arbutus unedo.

Science.gov (United States)

Paoletti, Elena

2005-04-01

The effect of a 90-d ozone exposure (charcoal-filtered air or 110 nmol mol(-1) O3) on stomatal conductance (gs) was investigated in the Mediterranean evergreen broadleaf Arbutus unedo L. Ozone did not significantly reduce midday steady-state gs compared to controls. However, it slowed stomatal response to abrupt reduction of light intensity and to increasing water stress, applied by severing the leaf midrib. Ozone slowed stomatal closure, rather than aperture. Nevertheless, vein-cutting did not allow ozonated leaves to reach the pre-injury gs levels, like controls did, suggesting re-opening was still, slowly in progress. The sluggish behaviour was recorded 10 days after cessation of O3 exposure ("memory effect") and may affect stomatal control in response to sunflecks and leaf wounding. Mediterranean evergreen broadleaves are regarded as tolerant to O3 exposure. Nevertheless, measurements of steady-state gs at midday may not account for altered stomatal responses to stressors.

Three causes of variation in the photochemical reflectance index (PRI) in evergreen conifers.

Science.gov (United States)

Wong, Christopher Y S; Gamon, John A

2015-04-01

The photochemical reflectance index (PRI) reflects diurnal xanthophyll cycle activity and is also influenced by seasonally changing carotenoid : Chl pigment ratios. Both changing pigment pools and xanthophyll cycle activity contribute to photoprotection in evergreen conifers exposed to boreal winters, but they operate over different timescales, and their relative contribution to the PRI signal has often been unclear. To clarify these responses and their contribution to the PRI signal, leaf PRI, pigment composition, temperature and irradiance were monitored over 2 yr for two evergreen conifers (Pinus contorta and Pinus ponderosa) in a boreal climate. PRI was affected by three distinct processes operating over different timescales and exhibiting contrasting spectral responses. Over the 2 yr study period, the greatest change in PRI resulted from seasonally changing carotenoid : Chl pigment ratios, followed by a previously unreported shifting leaf albedo during periods of deep cold. Remarkably, the smallest change was attributable to the xanthophyll cycle. To properly distinguish these three effects, interpretation of PRI must consider temporal context, physiological responses to evolving environmental conditions, and spectral response. Consideration of the separate mechanisms affecting PRI over different timescales could greatly improve efforts to monitor changing photosynthetic activity using optical remote sensing. © 2014 The Authors New Phytologist © 2014 New Phytologist Trust.

Cloud attenuation studies of the six major climatic zones of Africa for Ka and V satellite system design

Directory of Open Access Journals (Sweden)

Temidayo Victor Omotosho

2014-01-01

Full Text Available Normal 0 false false false EN-GB X-NONE X-NONE Cloud cover statistics, cloud base and top height, cloud temperature, frequency of precipitation, freezing height, total cloud liquid water content (TCLWC and cloud attenuation data have been obtained for the six major climatic zones of Africa. The present results reveal a strong positive correlation between the monthly distribution of low cloud cover, cloud top height, cloud temperature, and frequency of precipitation in the six zones. The cumulative distribution of the TCLWC derived from radiosonde measurement in each climatic zone shows a departure from the TCLWC recommended by the ITU Study Group 3 data, with an exceedance percentage difference of 32% to 90% occurring 0.01% to 10% of the time. The underestimation of the TCLWC is greatest in the tropical rain forest. A comparison of the cloud attenuation cumulative distribution in the Ka and V bands reveals that the International Telecommunication Union – Region (ITU-R is an intergovernmental organization that develops rain model based on collected data around the world. This model underestimates the cloud attenuation in all of the six climatic zones by 2.0 dB and 4.7 dB for the arid Sahara desert, 1.3 dB and 3.0 dB in semi-arid North Africa, 1.3 dB and 1.5 dB in savannah North Africa, 2.0 dB and 3.6 dB in the tropical rain forest, 1.3 dB and 2.9 dB in savannah South Africa and 0.9 dB and 2.6 dB in semi-arid South Africa, respectively, at 30 and 50 GHz. Overall, the cloud attenuation in the tropical rain-forest zone is very high because of the high annual total cloud cover (98%, high annual frequency of precipitation (4.5, low annual clear sky amount (8%, high cloud depth (10,937 m, high 0°C isotherm height (4.7 km, high TCLWC (4.0 kg/m2 at 0.01% and low seasonal cloud base height (356 m.

Forest Dynamics in the Eastern Ghats of Tamil Nadu, India

Science.gov (United States)

Jayakumar, S.; Ramachandran, A.; Bhaskaran, G.; Heo, J.

2009-02-01

The primary deciduous forests in the Eastern Ghats (EG) of Tamil Nadu (TN) India have undergone many changes owing to various need-based forest managements, such as timber extraction for industry, railway sleepers, charcoal, and forest clearance for hydroelectric projects and agriculture, during preindependence and postindependence periods (i.e., from 1800 to 1980). The enactment of a forest conservation act during the 1980s changed the perception of forest managers from utilization to conservation. This study was taken up to assess the forests dynamics in the EG of TN spatially between 1990 and 2003 and nonspatially between 1900 and the 1980s. Landsat Thematic Mapper (TM) and Indian Remote Sensing satellite (IRS) 1D Linear Imaging and Self Scanning (LISS III) data were used to assess forests during 1990 and 2003, respectively. Field floristic survey and secondary data (such as published literature, floras, books, and forest working plans) were used to assess the forest dynamics in terms of forest type and species composition among the preindependence period, the postindependence period, and the present (i.e., before and after 1980). The satellite data analysis revealed a considerable amount of changes in all forest types during the 13 years. The comparison of species composition and forest types between the past and present revealed that need-based forest management along with anthropogenic activity have altered the primary deciduous forest in to secondary and postextraction secondary forests such as southern thorn and southern thorn scrub forests in the middle [400-900 m above mean sea level (MSL)] and lower slopes (900 m MSL) and plateau seemed not to be much affected by the forest management. The changes estimated by the satellite data processing in the major forest types such as evergreen, deciduous, southern thorn, and southern thorn scrub are really alarming because these changes have occurred after the implementation of a forest conservation act. The

A mangrove forest map of China in 2015: Analysis of time series Landsat 7/8 and Sentinel-1A imagery in Google Earth Engine cloud computing platform

Science.gov (United States)

Chen, Bangqian; Xiao, Xiangming; Li, Xiangping; Pan, Lianghao; Doughty, Russell; Ma, Jun; Dong, Jinwei; Qin, Yuanwei; Zhao, Bin; Wu, Zhixiang; Sun, Rui; Lan, Guoyu; Xie, Guishui; Clinton, Nicholas; Giri, Chandra

2017-09-01

Due to rapid losses of mangrove forests caused by anthropogenic disturbances and climate change, accurate and contemporary maps of mangrove forests are needed to understand how mangrove ecosystems are changing and establish plans for sustainable management. In this study, a new classification algorithm was developed using the biophysical characteristics of mangrove forests in China. More specifically, these forests were mapped by identifying: (1) greenness, canopy coverage, and tidal inundation from time series Landsat data, and (2) elevation, slope, and intersection-with-sea criterion. The annual mean Normalized Difference Vegetation Index (NDVI) was found to be a key variable in determining the classification thresholds of greenness, canopy coverage, and tidal inundation of mangrove forests, which are greatly affected by tide dynamics. In addition, the integration of Sentinel-1A VH band and modified Normalized Difference Water Index (mNDWI) shows great potential in identifying yearlong tidal and fresh water bodies, which is related to mangrove forests. This algorithm was developed using 6 typical Regions of Interest (ROIs) as algorithm training and was run on the Google Earth Engine (GEE) cloud computing platform to process 1941 Landsat images (25 Path/Row) and 586 Sentinel-1A images circa 2015. The resultant mangrove forest map of China at 30 m spatial resolution has an overall/users/producer's accuracy greater than 95% when validated with ground reference data. In 2015, China's mangrove forests had a total area of 20,303 ha, about 92% of which was in the Guangxi Zhuang Autonomous Region, Guangdong, and Hainan Provinces. This study has demonstrated the potential of using the GEE platform, time series Landsat and Sentine-1A SAR images to identify and map mangrove forests along the coastal zones. The resultant mangrove forest maps are likely to be useful for the sustainable management and ecological assessments of mangrove forests in China.

Selection and quality assessment of Landsat data for the North American forest dynamics forest history maps of the US

Science.gov (United States)

Schleeweis, Karen; Goward, Samuel N.; Huang, Chengquan; Dwyer, John L.; Dungan, Jennifer L.; Lindsey, Mary A.; Michaelis, Andrew; Rishmawi, Khaldoun; Masek, Jeffery G.

2016-01-01

Using the NASA Earth Exchange platform, the North American Forest Dynamics (NAFD) project mapped forest history wall-to-wall, annually for the contiguous US (1986–2010) using the Vegetation Change Tracker algorithm. As with any effort to identify real changes in remotely sensed time-series, data gaps, shifts in seasonality, misregistration, inconsistent radiometry and cloud contamination can be sources of error. We discuss the NAFD image selection and processing stream (NISPS) that was designed to minimize these sources of error. The NISPS image quality assessments highlighted issues with the Landsat archive and metadata including inadequate georegistration, unreliability of the pre-2009 L5 cloud cover assessments algorithm, missing growing-season imagery and paucity of clear views. Assessment maps of Landsat 5–7 image quantities and qualities are presented that offer novel perspectives on the growing-season archive considered for this study. Over 150,000+ Landsat images were considered for the NAFD project. Optimally, one high quality cloud-free image in each year or a total of 12,152 images would be used. However, to accommodate data gaps and cloud/shadow contamination 23,338 images were needed. In 220 specific path-row image years no acceptable images were found resulting in data gaps in the annual national map products.

Regional assessment of boreal forest productivity using an ecological process model and remote sensing parameter maps.

Science.gov (United States)

Kimball, J. S.; Keyser, A. R.; Running, S. W.; Saatchi, S. S.

2000-06-01

An ecological process model (BIOME-BGC) was used to assess boreal forest regional net primary production (NPP) and response to short-term, year-to-year weather fluctuations based on spatially explicit, land cover and biomass maps derived by radar remote sensing, as well as soil, terrain and daily weather information. Simulations were conducted at a 30-m spatial resolution, over a 1205 km(2) portion of the BOREAS Southern Study Area of central Saskatchewan, Canada, over a 3-year period (1994-1996). Simulations of NPP for the study region were spatially and temporally complex, averaging 2.2 (+/- 0.6), 1.8 (+/- 0.5) and 1.7 (+/- 0.5) Mg C ha(-1) year(-1) for 1994, 1995 and 1996, respectively. Spatial variability of NPP was strongly controlled by the amount of aboveground biomass, particularly photosynthetic leaf area, whereas biophysical differences between broadleaf deciduous and evergreen coniferous vegetation were of secondary importance. Simulations of NPP were strongly sensitive to year-to-year variations in seasonal weather patterns, which influenced the timing of spring thaw and deciduous bud-burst. Reductions in annual NPP of approximately 17 and 22% for 1995 and 1996, respectively, were attributed to 3- and 5-week delays in spring thaw relative to 1994. Boreal forest stands with greater proportions of deciduous vegetation were more sensitive to the timing of spring thaw than evergreen coniferous stands. Similar relationships were found by comparing simulated snow depth records with 10-year records of aboveground NPP measurements obtained from biomass harvest plots within the BOREAS region. These results highlight the importance of sub-grid scale land cover complexity in controlling boreal forest regional productivity, the dynamic response of the biome to short-term interannual climate variations, and the potential implications of climate change and other large-scale disturbances.

76 FR 51367 - China Shipping Container Lines Co., Ltd.; COSCO Container Lines Company Limited; Evergreen Line A...

Science.gov (United States)

2011-08-18

... FEDERAL MARITIME COMMISSION [Docket No. 11-12] China Shipping Container Lines Co., Ltd.; COSCO Container Lines Company Limited; Evergreen Line A Joint Service Agreement; Hanjin Shipping Co., Ltd... Maritime Commission (Commission) by China Shipping Container Lines Co., Ltd.; COSCO Container Lines Company...

The effects of boreal forest expansion on the summer Arctic frontal zone

Energy Technology Data Exchange (ETDEWEB)

Liess, Stefan; Snyder, Peter K.; Harding, Keith J. [University of Minnesota, Department of Soil, Water, and Climate, Saint Paul, MN (United States)

2012-05-15

Over the last 100 years, Arctic warming has resulted in a longer growing season in boreal and tundra ecosystems. This has contributed to a slow northward expansion of the boreal forest and a decrease in the surface albedo. Corresponding changes to the surface and atmospheric energy budgets have contributed to a broad region of warming over areas of boreal forest expansion. In addition, mesoscale and synoptic scale patterns have changed as a result of the excess energy at and near the surface. Previous studies have identified a relationship between the positioning of the boreal forest-tundra ecotone and the Arctic frontal zone in summer. This study examines the climate response to hypothetical boreal forest expansion and its influence on the summer Arctic frontal zone. Using the Weather Research and Forecasting model over the Northern Hemisphere, an experiment was performed to evaluate the atmospheric response to expansion of evergreen and deciduous boreal needleleaf forests into open shrubland along the northern boundary of the existing forest. Results show that the lower surface albedo with forest expansion leads to a local increase in net radiation and an average hemispheric warming of 0.6 C at and near the surface during June with some locations warming by 1-2 C. This warming contributes to changes in the meridional temperature gradient that enhances the Arctic frontal zone and strengthens the summertime jet. This experiment suggests that continued Northern Hemisphere high-latitude warming and boreal forest expansion might contribute to additional climate changes during the summer. (orig.)

A possible role of ground-based microorganisms on cloud formation in the atmosphere

Science.gov (United States)

Ekström, S.; Nozière, B.; Hultberg, M.; Alsberg, T.; Magnér, J.; Nilsson, E. D.; Artaxo, P.

2010-01-01

The formation of clouds is an important process for the atmosphere, the hydrological cycle, and climate, but some aspects of it are not completely understood. In this work, we show that microorganisms might affect cloud formation without leaving the Earth's surface by releasing biological surfactants (or biosurfactants) in the environment, that make their way into atmospheric aerosols and could significantly enhance their activation into cloud droplets. In the first part of this work, the cloud-nucleating efficiency of standard biosurfactants was characterized and found to be better than that of any aerosol material studied so far, including inorganic salts. These results identify molecular structures that give organic compounds exceptional cloud-nucleating properties. In the second part, atmospheric aerosols were sampled at different locations: a temperate coastal site, a marine site, a temperate forest, and a tropical forest. Their surface tension was measured and found to be below 30 mN/m, the lowest reported for aerosols, to our knowledge. This very low surface tension was attributed to the presence of biosurfactants, the only natural substances able to reach to such low values. The presence of strong microbial surfactants in aerosols would be consistent with the organic fractions of exceptional cloud-nucleating efficiency recently found in aerosols, and with the correlations between algae bloom and cloud cover reported in the Southern Ocean. The results of this work also suggest that biosurfactants might be common in aerosols and thus of global relevance. If this is confirmed, a new role for microorganisms on the atmosphere and climate could be identified.

Cloud shading and fog drip influence the metabolism of a coastal pine ecosystem.

Science.gov (United States)

Carbone, Mariah S; Park Williams, A; Ambrose, Anthony R; Boot, Claudia M; Bradley, Eliza S; Dawson, Todd E; Schaeffer, Sean M; Schimel, Joshua P; Still, Christopher J

2013-02-01

Assessing the ecological importance of clouds has substantial implications for our basic understanding of ecosystems and for predicting how they will respond to a changing climate. This study was conducted in a coastal Bishop pine forest ecosystem that experiences regular cycles of stratus cloud cover and inundation in summer. Our objective was to understand how these clouds impact ecosystem metabolism by contrasting two sites along a gradient of summer stratus cover. The site that was under cloud cover ~15% more of the summer daytime hours had lower air temperatures and evaporation rates, higher soil moisture content, and received more frequent fog drip inputs than the site with less cloud cover. These cloud-driven differences in environmental conditions translated into large differences in plant and microbial activity. Pine trees at the site with greater cloud cover exhibited less water stress in summer, larger basal area growth, and greater rates of sap velocity. The difference in basal area growth between the two sites was largely due to summer growth. Microbial metabolism was highly responsive to fog drip, illustrated by an observed ~3-fold increase in microbial biomass C with increasing summer fog drip. In addition, the site with more cloud cover had greater total soil respiration and a larger fractional contribution from heterotrophic sources. We conclude that clouds are important to the ecological functioning of these coastal forests, providing summer shading and cooling that relieve pine and microbial drought stress as well as regular moisture inputs that elevate plant and microbial metabolism. These findings are important for understanding how these and other seasonally dry coastal ecosystems will respond to predicted changes in stratus cover, rainfall, and temperature. © 2012 Blackwell Publishing Ltd.

Transporting dynamics of radioactive cesium in a forest ecosystem and its discharge processes

Energy Technology Data Exchange (ETDEWEB)

Iseda, Kohei; Ohte, Nobuhito; Tanoi, Keitaro; Endo, Izuki; Oda, Tomoki; Kato, Hiroyu [Graduate School of Agricultural and Life Sciences, University of Tokyo (Japan)

2014-07-01

A lot of radioactive substance including {sup 137}Cs, {sup 134}Cs fell out to Tohoku and Kanto region in particular Fukushima prefecture after the accident of Fukushima-daiichi nuclear power plant. Generally, cesium tends to attach to clay particle and organic matter. These clay particle and organic matter can potentially flow out from the forest through the river to the downstream not only as particulate matter but also dissolved matter. It is likely that behavior of cesium is similar to sediment locomotion. The objective of this study is to understand transporting dynamics of radioactive cesium inside and outside of the forest. We started investigations on transporting dynamics of cesium in the forest upper stream of Kami-Oguni river in Date city Fukushima prefecture located in about 50 km from the nuclear power plant since July 2012. We conducted river water sampling at 9 points along the river from the uppermost stream to the middle reaches during low flow condition once a month. We also sampled river water during storm event for 5 times in order to capture the change of {sup 137}Cs concentration in a flood stage. Samples were filtered and separated into particulate and dissolved matters using glass micro-fiber filters (GF/F). Samples were analyzed their {sup 137}Cs concentration by Germanium semiconductor detector at University of Tokyo. During low flow condition, {sup 137}Cs was detected only a very small amount both in particulate and dissolved matters. In contrast, during high flow condition, {sup 137}Cs was detected about 10-100 times higher than that of during low flow condition in particulate matter. We estimated discharge flux of {sup 137}Cs from the forest using the relations between water discharge and {sup 137}Cs concentration. It was 0.977 Bq/(m2 day ) (2012/8/31-2013/4/19). In the forest, we set 2 deciduous tree plots (Quercus serrata, Zelkova serrata and so on) and 1 evergreen confer plot (Cyptomeria japonica). Atmospheric depositions of {sup 137

Impacts of artificial reservoirs on floristic diversity and plant functional traits in dry forests after 15 years.

Science.gov (United States)

Lopes, S F; Vale, V S; Prado Júnior, J A; Schiavini, I

2015-08-01

Dams are of paramount importance to a wide variety of human services and many of their environmental problems are known; however, there are few studies in the world addressing the impacts on the native vegetation previously distant from water bodies which became close to the lakeshore created by a dam. Thus, this paper aims to analyze the responses of a dry forest to a dam after 15 years. For this, 20 random samples of 40 trees were made, 10 close to the lakeshore and 10 distant from it, by applying the central square point method. Close to the dam, we found higher values regarding basal area, number of trees, number of evergreen trees, and zoochoric syndrome, but there were lower values of Shannon's diversity index. Therefore, the impacts of the dam after 15 years caused several changes to the tree community. The greater basal area close to the dam suggests that water deficit during the dry season was decreased and plants have thicker trunks. On the other hand, this sector had much more zoochoric syndrome and a larger number of evergreen trees than plots which are distant from water, suggesting changes with regard to the community's ecological functions. Furthermore, structural floristic data shows that the sector close to the dam is less similar to other deciduous forests within the same geographical region than the sector distant from water, thus providing evidence of the impacts of dams on the tree community.

Impacts of artificial reservoirs on floristic diversity and plant functional traits in dry forests after 15 years

Directory of Open Access Journals (Sweden)

SF Lopes

Full Text Available AbstractDams are of paramount importance to a wide variety of human services and many of their environmental problems are known; however, there are few studies in the world addressing the impacts on the native vegetation previously distant from water bodies which became close to the lakeshore created by a dam. Thus, this paper aims to analyze the responses of a dry forest to a dam after 15 years. For this, 20 random samples of 40 trees were made, 10 close to the lakeshore and 10 distant from it, by applying the central square point method. Close to the dam, we found higher values regarding basal area, number of trees, number of evergreen trees, and zoochoric syndrome, but there were lower values of Shannon’s diversity index. Therefore, the impacts of the dam after 15 years caused several changes to the tree community. The greater basal area close to the dam suggests that water deficit during the dry season was decreased and plants have thicker trunks. On the other hand, this sector had much more zoochoric syndrome and a larger number of evergreen trees than plots which are distant from water, suggesting changes with regard to the community’s ecological functions. Furthermore, structural floristic data shows that the sector close to the dam is less similar to other deciduous forests within the same geographical region than the sector distant from water, thus providing evidence of the impacts of dams on the tree community.

Effect of Disturbance Regimes on Spatial Patterns of Tree Species in Three Sites in a Tropical Evergreen Forest in Vietnam

Directory of Open Access Journals (Sweden)

Do Thi Ngoc Le

2016-01-01

Full Text Available The effects of disturbance regimes on the spatial patterns of the five most abundant species were investigated in three sites in a tropical forest at Xuan Nha Nature Reserve, Vietnam. Three permanent one-ha plots were established in undisturbed forest (UDF, lightly disturbed forest (LDF, and highly disturbed forest (HDF. All trees ≥5 cm DBH were measured in twenty-five 20 m × 20 m subplots. A total of 57 tree species belonging to 26 families were identified in the three forest types. The UDF had the highest basal area (30 m2 ha−1, followed by the LDF (17 m2 ha−1 and the HDF (13.0 m2 ha−1. The UDF also had the highest tree density (751 individuals ha−1 while the HDF held the lowest (478 individuals ha−1. Across all species, there were 417 “juveniles,” 267 “subadults,” and 67 “adults” in the UDF, while 274 “juveniles,” 230 “subadults,” and 36 “adults” were recorded in the LDF. 238 “juveniles,” 227 “subadults,” and 13 “adults” were obtained in the HDF. The univariate and bivariate data with pair- and mark-correlation functions of intra- and interspecific interactions of the five most abundant species changed in the three forest types. Most species indicated clumping or regular distributions at small scale, but a high ratio of negative interspecific small-scale associations was recorded in both the LDF and HDF sites. These were, however, rare in the UDF.

Energy balance of a sparse coniferous high-latitude forest under winter conditions

DEFF Research Database (Denmark)

Gryning, Sven-Erik; Batchvarova, E.; Bruin, H.A.R. de

2001-01-01

was simulated for a three month period. For conditions with a cloud cover of less than 7 oktas good agreement between model predictions and measurements were found. For cloud cover 7 and 8 oktas a considerable spread can be observed. To apply the proposed energy balance model, the global radiation must......Measurements carried out in Northern Finland on radiation and turbulent fluxes over a sparse, sub-arctic boreal forest with snow covered ground were analysed. The measurements represent late winter conditions characterised by low solar elevation angles. During the experiment (12-24 March 1997) day...... and night were about equally long. At low solar elevation angles the forest shades most of the snow surface. Therefore an important part of the radiation never reaches the snow surface but is absorbed by the forest. The sensible heat flux above the forest was fairly large, reaching more than 100 W m(-2...

Input and output budgets of radiocesium concerning the forest floor in the mountain forest of Fukushima released from the TEPCO's Fukushima Dai-ichi nuclear power plant accident

International Nuclear Information System (INIS)

Niizato, Tadafumi; Abe, Hironobu; Mitachi, Katsuaki; Sasaki, Yoshito; Ishii, Yasuo; Watanabe, Takayoshi

2016-01-01

Estimations of radiocesium input and output concerning the forest floor within a mountain forest region have been conducted in the north and central part of the Abukuma Mountains of Fukushima, northeast Japan, after a 2–3 year period following the TEPCO Fukushima Dai-ichi nuclear power plant accident. The radiocesium input and output associated with surface washoff, throughfall, stemflow, and litterfall processes at experimental plots installed on the forest floor of evergreen Japanese cedars and deciduous Konara oaks have been monitored. Despite the high output potential in the mountainous forest of Fukushima, the results at both monitoring locations show the radiocesium input to be 4–50 times higher than the output during the summer monsoon in Fukushima. These results indicate that the radiocesium tends to be preserved in the forest ecosystem due to extremely low output ratios (0.05%–0.19%). Thus, the associated fluxes throughout the circulation process are key issues for the projecting the environmental fate of the radiocesium levels, along with the subsequent reconstruction of life emphasized within the setting. - Highlights: • Input and output budgets of radiocesium in the mountainous forest of Fukushima were investigated in 2013 and 2014. • "1"3"7Cs outputs were 4–50 times higher than the "1"3"7Cs outputs during the monsoons. • The proportion of "1"3"7Cs output to radiocesium inventories was in the range of 0.05%–0.19% during the monsoons. • Radiocesium tends to be preserved in the forest ecosystem due to extremely low output ratios. • The forest floor seems to be a sink of radiocesium contamination than a source for the other ecosystems.

Improved simulation of poorly drained forests using Biome-BGC.

Science.gov (United States)

Bond-Lamberty, Ben; Gower, Stith T; Ahl, Douglas E

2007-05-01

Forested wetlands and peatlands are important in boreal and terrestrial biogeochemical cycling, but most general-purpose forest process models are designed and parameterized for upland systems. We describe changes made to Biome-BGC, an ecophysiological process model, that improve its ability to simulate poorly drained forests. Model changes allowed for: (1) lateral water inflow from a surrounding watershed, and variable surface and subsurface drainage; (2) adverse effects of anoxic soil on decomposition and nutrient mineralization; (3) closure of leaf stomata in flooded soils; and (4) growth of nonvascular plants (i.e., bryophytes). Bryophytes were treated as ectohydric broadleaf evergreen plants with zero stomatal conductance, whose cuticular conductance to CO(2) was dependent on plant water content. Individual model changes were parameterized with published data, and ecosystem-level model performance was assessed by comparing simulated output to field data from the northern BOREAS site in Manitoba, Canada. The simulation of the poorly drained forest model exhibited reduced decomposition and vascular plant growth (-90%) compared with that of the well-drained forest model; the integrated bryophyte photosynthetic response accorded well with published data. Simulated net primary production, biomass and soil carbon accumulation broadly agreed with field measurements, although simulated net primary production was higher than observed data in well-drained stands. Simulated net primary production in the poorly drained forest was most sensitive to oxygen restriction on soil processes, and secondarily to stomatal closure in flooded conditions. The modified Biome-BGC remains unable to simulate true wetlands that are subject to prolonged flooding, because it does not track organic soil formation, water table changes, soil redox potential or anaerobic processes.

Il laser scanning e CloudCUBE per le grotte di Naica

Directory of Open Access Journals (Sweden)

Erminio Paolo Canevese

2008-03-01

Full Text Available Laser scanning and CloudCube for Naica caves On May 2007, Virtualgeo, a geomatic software development and communication company, took part in the first official expedition to Mexico. The Project, coined "Naica", involves researchers from ten universities, four companies and several laboratories. Virtualgeo carried out the survey by applying laser scanning technology to hypogeal caves covered with selenite crystals. The data was processed using CloudCUBE, a proprietary software designed to manage and model 3D point clouds. The first results of the laser scanning survey of a spectacular “forest of crystals” are presented here.

Il laser scanning e CloudCUBE per le grotte di Naica

Directory of Open Access Journals (Sweden)

Erminio Paolo Canevese

2008-03-01

Full Text Available Laser scanning and CloudCube for Naica cavesOn May 2007, Virtualgeo, a geomatic software development and communication company, took part in the first official expedition to Mexico. The Project, coined "Naica", involves researchers from ten universities, four companies and several laboratories. Virtualgeo carried out the survey by applying laser scanning technology to hypogeal caves covered with selenite crystals. The data was processed using CloudCUBE, a proprietary software designed to manage and model 3D point clouds. The first results of the laser scanning survey of a spectacular “forest of crystals” are presented here.

Automated Burned Area Delineation Using IRS AWiFS satellite data

Science.gov (United States)

Singhal, J.; Kiranchand, T. R.; Rajashekar, G.; Jha, C. S.

2014-12-01

India is endowed with a rich forest cover. Over 21% of country's area is covered by forest of varied composition and structure. Out of 67.5 million ha of Indian forests, about 55% of the forest cover is being subjected to fires each year, causing an economic loss of over 440 crores of rupees apart from other ecological effects. Studies carried out by Forest Survey of India reveals that on an average 53% forest cover of the country is prone to fires and 6.17% of the forests are prone to severe fire damage. Forest Survey of India in a countrywide study in 1995 estimated that about 1.45 million hectares of forest are affected by fire annually. According to Forest Protection Division of the Ministry of Environment and Forest (GOI), 3.73 million ha of forests are affected by fire annually in India. Karnataka is one of the southern states of India extending in between latitude 110 30' and 180 25' and longitudes 740 10' and 780 35'. As per Forest Survey of India's State of Forest Report (SFR) 2009, of the total geographic area of 191791sq.km, the state harbors 38284 sq.km of recorded forest area. Major forest types occurring in the study area are tropical evergreen and semi-evergreen, tropical moist and dry deciduous forests along with tropical scrub and dry grasslands. Typical forest fire season in the study area is from February-May with a peak during March-April every year, though sporadic fire episodes occur in other parts of the year sq.km, the state harbors 38284 sq.km of recorded forest area. Major forest types occurring in the study area are tropical evergreen and semi-evergreen, tropical moist and dry deciduous forests along with tropical scrub and dry grasslands. Significant area of the deciduous forests, scrub and grasslands is prone to recurrent forest fires every year. In this study we evaluate the feasibility of burned area mapping over a large area (Karnataka state, India) using a semi-automated detection algorithm applied to medium resolution multi

Preliminary inventory and classification of indigenous afromontane forests on the Blyde River Canyon Nature Reserve, Mpumalanga, South Africa

Directory of Open Access Journals (Sweden)

Beck Hans T

2004-08-01

Full Text Available Abstract Background Mixed evergreen forests form the smallest, most widely distributed and fragmented biome in southern Africa. Within South Africa, 44% of this vegetation type has been transformed. Afromontane forest only covers 0.56 % of South Africa, yet it contains 5.35% of South Africa's plant species. Prior to this investigation of the indigenous forests on the Blyde River Canyon Nature Reserve (BRCNR, very little was known about the size, floristic composition and conservation status of the forest biome conserved within the reserve. We report here an inventory of the forest size, fragmentation, species composition and the basic floristic communities along environmental gradients. Results A total of 2111 ha of forest occurs on Blyde River Canyon Nature Reserve. The forest is fragmented, with a total of 60 forest patches recorded, varying from 0.21 ha to 567 ha in size. On average, patch size was 23 ha. Two forest communities – high altitude moist afromontane forest and low altitude dry afromontane forest – are identified. Sub-communities are recognized based on canopy development and slope, respectively. An altitudinal gradient accounts for most of the variation within the forest communities. Conclusion BRCNR has a fragmented network of small forest patches that together make up 7.3% of the reserve's surface area. These forest patches host a variety of forest-dependent trees, including some species considered rare, insufficiently known, or listed under the Red Data List of South African Plants. The fragmented nature of the relatively small forest patches accentuates the need for careful fire management and stringent alien plant control.

Responses of Soil Acid Phosphomonoesterase Activity to Simulated Nitrogen Deposition in Three Forests of Subtropical China

Institute of Scientific and Technical Information of China (English)

HUANG Wen-Juan; LIU Shi-Zhong; CHU Guo-Wei; ZHANG De-Qiang; LI Yue-Lin; LU Xian-Kai; ZHANG Wei; HUANG Juan; D. OTIENO; Z. H. XU; LIU Ju-Xiu

2012-01-01

Soil acid phosphomonoesterase activity (APA) plays a vital role in controlling phosphorus (P) cycling and reflecting the current degree of P limitation Responses of soil APA to elevating nitrogen (N) deposition are important because of their potential applications in addressing the relationship between N and P in forest ecosystems.A study of responses of soll APA to simulated N deposition was conducted in three succession forests of subtropical China.The three forests include a Masson pine (Pinus massoniana) forest (MPF)—pioneer community,a coniferous and broad-leaved mixed forest (MF)—transition community and a monsoon evergreen broadleaved forest (MEBF)—climax community.Four N treatments were designed for MEBF:control (without N added),low-N (50 kg N ha-1 year-1),and medium-N (100 kg N ha-1 year-1) and high-N (150 kg N ha-1 year-1),and only three N treatments (i.e.,control,low-N,mediun-N) were established for MPF and MF.Results showed that soil APA was highest in MEBF.followed by MPF and MF.Soil APAs in both MPF and MF were not influenced by low-N treatments but depressed in medium-N trcatments.However,soil APA in MEBF exhibited negative responses to high N additions,indicating that the environment of enhanced N depositions would reduce P supply for the mature forest ecosystem.Soil APA and its responses to N additions in subtropical forests were closely related to the succession stages in the forests.

Carbon emissions and sequestration in forests: Case studies from seven developing countries. Volume 4: Mexico: Draft

Energy Technology Data Exchange (ETDEWEB)

Makundi, W.; Sathaye, J. [eds.] [Lawrence Berkeley Lab., CA (United States); Cerutti, O.M.; Ordonez, M.J.; Minjarez, R.D. [Universidad Nacional Autonoma de Mexico, Mexico City (Mexico) Centro de Ecologia

1992-08-01

Estimates of carbon emissions from deforestation in Mexico are derived for the year 1985 and for two contrasting scenarios in 2025. Carbon emissions are calculated through an in-depth review of the existing information on forest cover deforestation mtes and area affected by forest fires as well as on forests` carbon-related biological characteristics. The analysis covers both tropical -- evergreen and deciduous -- and temperate -- coniferous and broadleaf -- closed forests. Emissions from the forest sector are also compared to those from energy and industry. Different policy options for promoting the sustainable management of forest resources in the country are discussed. The analysis indicates that approximately 804,000 hectares per year of closed forests suffered from major perturbations in the mid 1980`s in Mexico, leading to an annual deforestation mte of 668,000 hectares. Seventy five percent of total deforestation is concentrated in tropical forests. The resulting annual carbon balance is estimated in 53.4 million tons per year, and the net committed emissions in 45.5 million tons or 41% and 38%, respectively, of the country`s total for 1985--87. The annual carbon balance from the forest sector in 2025 is expected to decline to 16.5 million tons in the low emissions scenario and to 22.9 million tons in the high emissions scenario. Because of the large uncertainties in some of the primary sources of information, the stated figures should be taken as preliminary estimates.

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...

A Phenology-Based Method for Monitoring Woody and Herbaceous Vegetation in Mediterranean Forests from NDVI Time Series

Directory of Open Access Journals (Sweden)

David Helman

2015-09-01

Full Text Available We present an efficient method for monitoring woody (i.e., evergreen and herbaceous (i.e., ephemeral vegetation in Mediterranean forests at a sub pixel scale from Normalized Difference Vegetation Index (NDVI time series derived from the Moderate Resolution Imaging Spectroradiometer (MODIS. The method is based on the distinct development periods of those vegetation components. In the dry season, herbaceous vegetation is absent or completely dry in Mediterranean forests. Thus the mean NDVI in the dry season was attributed to the woody vegetation (NDVIW. A constant NDVI value was assumed for soil background during this period. In the wet season, changes in NDVI were attributed to the development of ephemeral herbaceous vegetation in the forest floor and its maximum value to the peak green cover (NDVIH. NDVIW and NDVIH agreed well with field estimates of leaf area index and fraction of vegetation cover in two differently structured Mediterranean forests. To further assess the method’s assumptions, understory NDVI was retrieved form MODIS Bidirectional Reflectance Distribution Function (BRDF data and compared with NDVIH. After calibration, leaf area index and woody and herbaceous vegetation covers were assessed for those forests. Applicability for pre- and post-fire monitoring is presented as a potential use of this method for forest management in Mediterranean-climate regions.

Dynamics of soil inorganic nitrogen and their responses to nitrogen additions in three subtropical forests, south China

Institute of Scientific and Technical Information of China (English)

FANG Yun-ting; ZHU Wei-xing; MO Jiang-ming; ZHOU Guo-yi; GUNDERSEN Per

2006-01-01

Three forests with different historical land-use, forest age, and species assemblages in subtropical China were selected to evaluate current soil N status and investigate the responses of soil inorganic N dynamics to monthly ammonium nitrate additions.Results showed that the mature monsoon evergreen broadleaved forest that has been protected for more than 400 years exhibited an advanced soil N status than the pine (Pinus massoniana) and pine-broadleaf mixed forests, both originated from the 1930's clear-cut and pine plantation. Mature forests had greater extractable inorganic N pool, lower N retention capacity, higher inorganic N leaching,and higher soil C/N ratios. Mineral soil extractable NH4+-N and NO3--N concentrations were significantly increased by experimental N additions on several sampling dates, but repeated ANOVA showed that the effect was not significant over the whole year except NH4+-N in the mature forest. In contrast, inorganic N (both NH4+-N and NO3--N) in soil 20-cm below the surface was significantly elevated by the N additions. From 42% to 74% of N added was retained by the upper 20 cm soils in the pine and mixed forests, while 0%-70% was retained in the mature forest. Our results suggest that land-use history, forest age and species composition were likely to be some of the important factors that determine differing forest N retention responses to elevated N deposition in the study region.

Fog in a marginal agricultural area surrounded by montane Andean cloud forest during El Niño climate

Science.gov (United States)

García-Santos, G.

2010-07-01

The aim of the present study was to evaluate temporal variations of water inputs, rainfall and fog (cloud water), and its contribution to the water balance in a marginal agricultural area of potato surrounded by tropical montane cloud forest in Colombia. Fog in the air boundary layer was estimated using a cylindrical fog collector. Liquid water content of fog events were evaluated before and during natural climate event of El Niño. Our study shows the temporal variation of these two water inputs in both daily and monthly cycles on Boyacá at 2900 m a.s.l. Rainfall was the most frequently observed atmospheric phenomenon, being present on average 62% of the days per year, whereas fog was 45% of the time. Reflected on the lower frequency, annual amount of fog was 11% of precipitation. However during the anomalous dry climate of El Niño, total amount of rainfall was negligible and the few fog events were the only water source for plant growth. Estimated water crop requirements were higher than the water inputs. The survival of the crops was explained by meteorological conditions during dew and fog events. High relative humidity might have eased the plant’s water stress by decreasing transpiration and temperature in leaves and soil, affecting the water balance and the heat exchange between the atmosphere-land interfaces in the marginal agricultural areas during exceptional dry climate.

Human impacts on soil carbon dynamics of deep-rooted Amazonian forests

Science.gov (United States)

Nepstad, Daniel C.; Stone, Thomas A.; Davidson, Eric A.

1994-01-01

Deforestation and logging degrade more forest in eastern and southern Amazonia than in any other region of the world. This forest alteration affects regional hydrology and the global carbon cycle, but our current understanding of these effects is limited by incomplete knowledge of tropical forest ecosystems. It is widely agreed that roots are concentrated near the soil surface in moist tropical forests, but this generalization incorrectly implies that deep roots are unimportant in water and C budgets. Our results indicate that half of the closed-canopy forests of Brazilian Amazonic occur where rainfall is highly seasonal, and these forests rely on deeply penetrating roots to extract soil water. Pasture vegetation extracts less water from deep soil than the forest it replaces, thus increasing rates of drainage and decreasing rates of evapotranspiration. Deep roots are also a source of modern carbon deep in the soil. The soils of the eastern Amazon contain more carbon below 1 m depth than is present in above-ground biomass. As much as 25 percent of this deep soil C could have annual to decadal turnover times and may be lost to the atmosphere following deforestation. We compared the importance of deep roots in a mature, evergreen forest with an adjacent man-made pasture, the most common type of vegetation on deforested land in Amazonia. The study site is near the town of Paragominas, in the Brazilian state of Para, with a seasonal rainfall pattern and deeply-weathered, kaolinitic soils that are typical for large portions of Amazonia. Root distribution, soil water extraction, and soil carbon dynamics were studied using deep auger holes and shafts in each ecosystem, and the phenology and water status of the leaf canopies were measured. We estimated the geographical distribution of deeply-rooting forests using satellite imagery, rainfall data, and field measurements.

Stand, species, and individual traits impact transpiration in historically disturbed forests.

Science.gov (United States)

Blakely, B.; Rocha, A. V.; McLachlan, J. S.

2017-12-01

Historic logging disturbances have changed the structure and species composition of most Northern temperate forests. These changes impact the process of transpiration - which in turn impacts canopy surface temperature - but the links among structure, composition, and transpiration remain unclear. For this reason, ecosystem models typically use simplified structure and composition to simulate the impact of disturbances on forest transpiration. However, such simplifications ignore real variability among stands, species, and individual trees that may strongly influence transpiration across spatial and temporal scales. To capture this variability, we monitored transpiration in 48 individual trees of multiple species in both undisturbed (400+ yr) and historically logged (80 - 120 yr) forests. Using modern and historic forest surveys, we upscaled our observations to stand and regional scales to identify the key changes impacting transpiration. We extended these inferences by establishing a relationship between transpiration and measured surface temperature, linking disturbance-induced changes in structure and composition to local and regional climate. Despite greater potential evapotranspiration and basal area, undisturbed forest transpired less than disturbed (logged) forest. Transpiration was a strong predictor of surface temperature, and the canopy surface was warmer in undisturbed forest. Transpiration differences among disturbed and undisturbed forests resulted from (1) lesser transpiration and dampened seasonality in evergreen species (2) greater transpiration in younger individuals within a species, and (3) strong transpiration by large individuals. When transpiration was scaled to the stand or regional level in a simplified manner (e.g. a single transpiration rate for all deciduous individuals), the resulting estimates differed markedly from the original. Stand- species- and individual-level traits are therefore essential for understanding how transpiration and

Ozone slows stomatal response to light and leaf wounding in a Mediterranean evergreen broadleaf, Arbutus unedo

Energy Technology Data Exchange (ETDEWEB)

Paoletti, Elena [Istituto Protezione Piante, Consiglio Nazionale delle Ricerche, Via Madonna del Piano, I-50019 Sesto Fiorentino (Italy)]. E-mail: e.paoletti@ipp.cnr.it

2005-04-01

The effect of a 90-d ozone exposure (charcoal-filtered air or 110 nmol mol{sup -1} O{sub 3}) on stomatal conductance (g{sub s}) was investigated in the Mediterranean evergreen broadleaf Arbutus unedo L. Ozone did not significantly reduce midday steady-state g{sub s} compared to controls. However, it slowed stomatal response to abrupt reduction of light intensity and to increasing water stress, applied by severing the leaf midrib. Ozone slowed stomatal closure, rather than aperture. Nevertheless, vein-cutting did not allow ozonated leaves to reach the pre-injury g{sub s} levels, like controls did, suggesting re-opening was still, slowly in progress. The sluggish behaviour was recorded 10 days after cessation of O{sub 3} exposure ('memory effect') and may affect stomatal control in response to sunflecks and leaf wounding. Mediterranean evergreen broadleaves are regarded as tolerant to O{sub 3} exposure. Nevertheless, measurements of steady-state g{sub s} at midday may not account for altered stomatal responses to stressors. - In response to ozone exposure, stomata were slower in closing rather than in opening.

Ozone slows stomatal response to light and leaf wounding in a Mediterranean evergreen broadleaf, Arbutus unedo

International Nuclear Information System (INIS)

Paoletti, Elena

2005-01-01

The effect of a 90-d ozone exposure (charcoal-filtered air or 110 nmol mol -1 O 3 ) on stomatal conductance (g s ) was investigated in the Mediterranean evergreen broadleaf Arbutus unedo L. Ozone did not significantly reduce midday steady-state g s compared to controls. However, it slowed stomatal response to abrupt reduction of light intensity and to increasing water stress, applied by severing the leaf midrib. Ozone slowed stomatal closure, rather than aperture. Nevertheless, vein-cutting did not allow ozonated leaves to reach the pre-injury g s levels, like controls did, suggesting re-opening was still, slowly in progress. The sluggish behaviour was recorded 10 days after cessation of O 3 exposure ('memory effect') and may affect stomatal control in response to sunflecks and leaf wounding. Mediterranean evergreen broadleaves are regarded as tolerant to O 3 exposure. Nevertheless, measurements of steady-state g s at midday may not account for altered stomatal responses to stressors. - In response to ozone exposure, stomata were slower in closing rather than in opening

Mapping Forest Cover and Forest Cover Change with Airborne S-Band Radar

Directory of Open Access Journals (Sweden)

Ramesh K. Ningthoujam

2016-07-01

Full Text Available Assessments of forest cover, forest carbon stocks and carbon emissions from deforestation and degradation are increasingly important components of sustainable resource management, for combating biodiversity loss and in climate mitigation policies. Satellite remote sensing provides the only means for mapping global forest cover regularly. However, forest classification with optical data is limited by its insensitivity to three-dimensional canopy structure and cloud cover obscuring many forest regions. Synthetic Aperture Radar (SAR sensors are increasingly being used to mitigate these problems, mainly in the L-, C- and X-band domains of the electromagnetic spectrum. S-band has not been systematically studied for this purpose. In anticipation of the British built NovaSAR-S satellite mission, this study evaluates the benefits of polarimetric S-band SAR for forest characterisation. The Michigan Microwave Canopy Scattering (MIMICS-I radiative transfer model is utilised to understand the scattering mechanisms in forest canopies at S-band. The MIMICS-I model reveals strong S-band backscatter sensitivity to the forest canopy in comparison to soil characteristics across all polarisations and incidence angles. Airborne S-band SAR imagery over the temperate mixed forest of Savernake Forest in southern England is analysed for its information content. Based on the modelling results, S-band HH- and VV-polarisation radar backscatter and the Radar Forest Degradation Index (RFDI are used in a forest/non-forest Maximum Likelihood classification at a spatial resolution of 6 m (70% overall accuracy, κ = 0.41 and 20 m (63% overall accuracy, κ = 0.27. The conclusion is that S-band SAR such as from NovaSAR-S is likely to be suitable for monitoring forest cover and its changes.

How might Australian rainforest cloud interception respond to climate change?

Science.gov (United States)

Wallace, Jim; McJannet, Dave

2013-02-01

SummaryThe lower and upper montane rainforests in northern Queensland receive significant amounts of cloud interception that affect both in situ canopy wetness and downstream runoff. Cloud interception contributes 5-30% of the annual water input to the canopy and this increases to 40-70% of the monthly water input during the dry season. This occult water is therefore an important input to the canopy, sustaining the epiphytes, mosses and other species that depend on wet canopy conditions. The potential effect of climate change on cloud interception was examined using the relationship between cloud interception and cloud frequency derived from measurements made at four different rainforest locations. Any given change in cloud frequency produces a greater change in cloud interception and this 'amplification' increases from 1.1 to 1.7 as cloud frequency increases from 5% to 70%. This means that any changes in cloud frequency will have the greatest relative effects at the higher altitude sites where cloud interception is greatest. As cloud frequency is also a major factor affecting canopy wetness, any given change in cloud frequency will therefore have a greater impact on canopy wetness at the higher altitude sites. These changes in wetness duration will augment those due to changes in rainfall and may have important implications for the fauna and flora that depend on wet canopy conditions. We also found that the Australian rainforests may be more efficient (by ˜50% on average) in intercepting cloud water than American coniferous forests, which may be due to differences in canopy structure and exposure at the different sites.

UAV-BASED PHOTOGRAMMETRIC POINT CLOUDS – TREE STEM MAPPING IN OPEN STANDS IN COMPARISON TO TERRESTRIAL LASER SCANNER POINT CLOUDS

Directory of Open Access Journals (Sweden)

A. Fritz

2013-08-01

Full Text Available In both ecology and forestry, there is a high demand for structural information of forest stands. Forest structures, due to their heterogeneity and density, are often difficult to assess. Hence, a variety of technologies are being applied to account for this "difficult to come by" information. Common techniques are aerial images or ground- and airborne-Lidar. In the present study we evaluate the potential use of unmanned aerial vehicles (UAVs as a platform for tree stem detection in open stands. A flight campaign over a test site near Freiburg, Germany covering a target area of 120 × 75 [m2] was conducted. The dominant tree species of the site is oak (quercus robur with almost no understory growth. Over 1000 images with a tilt angle of 45° were shot. The flight pattern applied consisted of two antipodal staggered flight routes at a height of 55 [m] above the ground. We used a Panasonic G3 consumer camera equipped with a 14–42 [mm] standard lens and a 16.6 megapixel sensor. The data collection took place in leaf-off state in April 2013. The area was prepared with artificial ground control points for transformation of the structure-from-motion (SFM point cloud into real world coordinates. After processing, the results were compared with a terrestrial laser scanner (TLS point cloud of the same area. In the 0.9 [ha] test area, 102 individual trees above 7 [cm] diameter at breast height were located on in the TLS-cloud. We chose the software CMVS/PMVS-2 since its algorithms are developed with focus on dense reconstruction. The processing chain for the UAV-acquired images consists of six steps: a. cleaning the data: removing of blurry, under- or over exposed and off-site images; b. applying the SIFT operator [Lowe, 2004]; c. image matching; d. bundle adjustment; e. clustering; and f. dense reconstruction. In total, 73 stems were considered as reconstructed and located within one meter of the reference trees. In general stems were far less accurate

Patterns of leaf morphology and leaf N content in relation to winter temperatures in three evergreen tree species

Science.gov (United States)

Mediavilla, Sonia; Gallardo-López, Victoria; González-Zurdo, Patricia; Escudero, Alfonso

2012-09-01

The competitive equilibrium between deciduous and perennial species in a new scenario of climate change may depend closely on the productivity of leaves along the different seasons of the year and on the morphological and chemical adaptations required for leaf survival during the different seasons. The aim of the present work was to analyze such adaptations in the leaves of three evergreen species ( Quercus ilex, Q. suber and Pinus pinaster) and their responses to between-site differences in the intensity of winter harshness. We explore the hypothesis that the harshness of winter would contribute to enhancing the leaf traits that allow them to persist under conditions of stress. The results revealed that as winter harshness increases a decrease in leaf size occurs in all three species, together with an increase in the content of nitrogen per unit leaf area and a greater leaf mass per unit area, which seems to be achieved only through increased thickness, with no associated changes in density. P. pinaster was the species with the most intense response to the harshening of winter conditions, undergoing a more marked thickening of its needles than the two Quercus species. Our findings thus suggest that lower winter temperatures involve an increase in the cost of leaf production of evergreen species, which must be taken into account in the estimation of the final cost and benefit balance of evergreens. Such cost increases would be more pronounced for those species that, like P. pinaster, show a stronger response to the winter cold.

Ecosystem carbon stock influenced by plantation practice: implications for planting forests as a measure of climate change mitigation.

Directory of Open Access Journals (Sweden)

Chengzhang Liao

Full Text Available Uncertainties remain in the potential of forest plantations to sequestrate carbon (C. We synthesized 86 experimental studies with paired-site design, using a meta-analysis approach, to quantify the differences in ecosystem C pools between plantations and their corresponding adjacent primary and secondary forests (natural forests. Totaled ecosystem C stock in plant and soil pools was 284 Mg C ha(-1 in natural forests and decreased by 28% in plantations. In comparison with natural forests, plantations decreased aboveground net primary production, litterfall, and rate of soil respiration by 11, 34, and 32%, respectively. Fine root biomass, soil C concentration, and soil microbial C concentration decreased respectively by 66, 32, and 29% in plantations relative to natural forests. Soil available N, P and K concentrations were lower by 22, 20 and 26%, respectively, in plantations than in natural forests. The general pattern of decreased ecosystem C pools did not change between two different groups in relation to various factors: stand age ( or = 25 years, stand types (broadleaved vs. coniferous and deciduous vs. evergreen, tree species origin (native vs. exotic of plantations, land-use history (afforestation vs. reforestation and site preparation for plantations (unburnt vs. burnt, and study regions (tropic vs. temperate. The pattern also held true across geographic regions. Our findings argued against the replacement of natural forests by the plantations as a measure of climate change mitigation.

78 FR 69932 - Tedesco Family ESB Trust, et al.-Purchase of Certain Assets and Membership Interests-Evergreen...

Science.gov (United States)

2013-11-21

... Trails, Inc. d/b/a Horizon Coach Lines, et al. AGENCY: Surface Transportation Board, DOT. ACTION: Notice... Franmar's purchase of certain motor coach and non- motor coach assets of Evergreen Trails, Inc. d/b/a... (Family Trust), on behalf of Franmar Leasing, Inc. (Franmar), together with the Francis Tedesco Revocable...

Mapping forest tree species over large areas with partially cloudy Landsat imagery

Science.gov (United States)

Turlej, K.; Radeloff, V.

2017-12-01

Forests provide numerous services to natural systems and humankind, but which services forest provide depends greatly on their tree species composition. That makes it important to track not only changes in forest extent, something that remote sensing excels in, but also to map tree species. The main goal of our work was to map tree species with Landsat imagery, and to identify how to maximize mapping accuracy by including partially cloudy imagery. Our study area covered one Landsat footprint (26/28) in Northern Wisconsin, USA, with temperate and boreal forests. We selected this area because it contains numerous tree species and variable forest composition providing an ideal study area to test the limits of Landsat data. We quantified how species-level classification accuracy was affected by a) the number of acquisitions, b) the seasonal distribution of observations, and c) the amount of cloud contamination. We classified a single year stack of Landsat-7, and -8 images data with a decision tree algorithm to generate a map of dominant tree species at the pixel- and stand-level. We obtained three important results. First, we achieved producer's accuracies in the range 70-80% and user's accuracies in range 80-90% for the most abundant tree species in our study area. Second, classification accuracy improved with more acquisitions, when observations were available from all seasons, and is the best when images with up to 40% cloud cover are included. Finally, classifications for pure stands were 10 to 30 percentage points better than those for mixed stands. We conclude that including partially cloudy Landsat imagery allows to map forest tree species with accuracies that were previously only possible for rare years with many cloud-free observations. Our approach thus provides important information for both forest management and science.

Environmental conditions regulate the impact of plants on cloud formation.

Science.gov (United States)

Zhao, D F; Buchholz, A; Tillmann, R; Kleist, E; Wu, C; Rubach, F; Kiendler-Scharr, A; Rudich, Y; Wildt, J; Mentel, Th F

2017-02-20

The terrestrial vegetation emits large amounts of volatile organic compounds (VOC) into the atmosphere, which on oxidation produce secondary organic aerosol (SOA). By acting as cloud condensation nuclei (CCN), SOA influences cloud formation and climate. In a warming climate, changes in environmental factors can cause stresses to plants, inducing changes of the emitted VOC. These can modify particle size and composition. Here we report how induced emissions eventually affect CCN activity of SOA, a key parameter in cloud formation. For boreal forest tree species, insect infestation by aphids causes additional VOC emissions which modifies SOA composition thus hygroscopicity and CCN activity. Moderate heat increases the total amount of constitutive VOC, which has a minor effect on hygroscopicity, but affects CCN activity by increasing the particles' size. The coupling of plant stresses, VOC composition and CCN activity points to an important impact of induced plant emissions on cloud formation and climate.

Vegetation in karst terrain of southwestern China allocates more biomass to roots

Science.gov (United States)

Ni, J.; Luo, D. H.; Xia, J.; Zhang, Z. H.; Hu, G.

2015-07-01

In mountainous areas of southwestern China, especially Guizhou province, continuous, broadly distributed karst landscapes with harsh and fragile habitats often lead to land degradation. Research indicates that vegetation located in karst terrains has low aboveground biomass and land degradation that reduces vegetation biomass, but belowground biomass measurements are rarely reported. Using the soil pit method, we investigated the root biomass of karst vegetation in five land cover types: grassland, grass-scrub tussock, thorn-scrub shrubland, scrub-tree forest, and mixed evergreen and deciduous forest in Maolan, southern Guizhou province, growing in two different soil-rich and rock-dominated habitats. The results show that roots in karst vegetation, especially the coarse roots, and roots in rocky habitats are mostly distributed in the topsoil layers (89 % on the surface up to 20 cm depth). The total root biomass in all habitats of all vegetation degradation periods is 18.77 Mg ha-1, in which roots in rocky habitat have higher biomass than in earthy habitat, and coarse root biomass is larger than medium and fine root biomass. The root biomass of mixed evergreen and deciduous forest in karst habitat (35.83 Mg ha-1) is not greater than that of most typical, non-karst evergreen broad-leaved forests in subtropical regions of China, but the ratio of root to aboveground biomass in karst forest (0.37) is significantly greater than the mean ratio (0.26 ± 0.07) of subtropical evergreen forests. Vegetation restoration in degraded karst terrain will significantly increase the belowground carbon stock, forming a potential regional carbon sink.

Quantifying Biomass from Point Clouds by Connecting Representations of Ecosystem Structure

Science.gov (United States)

Hendryx, S. M.; Barron-Gafford, G.

2017-12-01

Quantifying terrestrial ecosystem biomass is an essential part of monitoring carbon stocks and fluxes within the global carbon cycle and optimizing natural resource management. Point cloud data such as from lidar and structure from motion can be effective for quantifying biomass over large areas, but significant challenges remain in developing effective models that allow for such predictions. Inference models that estimate biomass from point clouds are established in many environments, yet, are often scale-dependent, needing to be fitted and applied at the same spatial scale and grid size at which they were developed. Furthermore, training such models typically requires large in situ datasets that are often prohibitively costly or time-consuming to obtain. We present here a scale- and sensor-invariant framework for efficiently estimating biomass from point clouds. Central to this framework, we present a new algorithm, assignPointsToExistingClusters, that has been developed for finding matches between in situ data and clusters in remotely-sensed point clouds. The algorithm can be used for assessing canopy segmentation accuracy and for training and validating machine learning models for predicting biophysical variables. We demonstrate the algorithm's efficacy by using it to train a random forest model of above ground biomass in a shrubland environment in Southern Arizona. We show that by learning a nonlinear function to estimate biomass from segmented canopy features we can reduce error, especially in the presence of inaccurate clusterings, when compared to a traditional, deterministic technique to estimate biomass from remotely measured canopies. Our random forest on cluster features model extends established methods of training random forest regressions to predict biomass of subplots but requires significantly less training data and is scale invariant. The random forest on cluster features model reduced mean absolute error, when evaluated on all test data in leave

Seedling growth in greenhouse conditions of the forest species Dialium guianense (Aubl. Sandwith

Directory of Open Access Journals (Sweden)

Georgina Vargas Simon

2018-01-01

Full Text Available Dialium guianense is used for its wood and fruit production, and is a tropical tree species native to evergreen forests. Given the threat these forests face, the purpose of this work was to evaluate the initial growth of the plant under greenhouse conditions, for aiming in the development of propagation programs. Seedlings of the species were transplanted to nursery bags under a completely randomized design and grown for 10 months with an initial population of 200 plants. At the end of the experiment, the shoot and root reached lengths of 32.8 and 28.9 cm, respectively. The average number of composite leaves was 12.3 each with seven leaflets. The average biomass was 2.5 g for the shoot, 1.6 g for roots, and 3.7 g for leaves, with a shoot/root around four. The average relative growth rate (RGR was 15 mg g-1 day-. These characteristics indicate that D. guianense is a late successional species.

Parameterisation of Biome BGC to assess forest ecosystems in Africa

Science.gov (United States)

Gautam, Sishir; Pietsch, Stephan A.

2010-05-01

African forest ecosystems are an important environmental and economic resource. Several studies show that tropical forests are critical to society as economic, environmental and societal resources. Tropical forests are carbon dense and thus play a key role in climate change mitigation. Unfortunately, the response of tropical forests to environmental change is largely unknown owing to insufficient spatially extensive observations. Developing regions like Africa where records of forest management for long periods are unavailable the process-based ecosystem simulation model - BIOME BGC could be a suitable tool to explain forest ecosystem dynamics. This ecosystem simulation model uses descriptive input parameters to establish the physiology, biochemistry, structure, and allocation patterns within vegetation functional types, or biomes. Undocumented parameters for larger-resolution simulations are currently the major limitations to regional modelling in African forest ecosystems. This study was conducted to document input parameters for BIOME-BGC for major natural tropical forests in the Congo basin. Based on available literature and field measurements updated values for turnover and mortality, allometry, carbon to nitrogen ratios, allocation of plant material to labile, cellulose, and lignin pools, tree morphology and other relevant factors were assigned. Daily climate input data for the model applications were generated using the statistical weather generator MarkSim. The forest was inventoried at various sites and soil samples of corresponding stands across Gabon were collected. Carbon and nitrogen in the collected soil samples were determined from soil analysis. The observed tree volume, soil carbon and soil nitrogen were then compared with the simulated model outputs to evaluate the model performance. Furthermore, the simulation using Congo Basin specific parameters and generalised BIOME BGC parameters for tropical evergreen broadleaved tree species were also

Forest Management_MCD Issue2 2007

African Journals Online (AJOL)

for biodiversity on Earth, and this biodiversity is found mainly in Madagascar's .... Standardized models are appropriate .... this had little effect on its forest management policy until very recently. ... In the mid - 1980s, Madagascar's political climate began to change as ..... A selection correction for cloud cover in satellite images.

Mapping Clearances in Tropical Dry Forests Using Breakpoints, Trend, and Seasonal Components from MODIS Time Series: Does Forest Type Matter?

NARCIS (Netherlands)

Grogan, Kenneth; Pflugmacher, Dirk; Hostert, Patrick; Verbesselt, Jan; Fensholt, Rasmus

2016-01-01

Tropical environments present a unique challenge for optical time series analysis, primarily owing to fragmented data availability, persistent cloud cover and atmospheric aerosols. Additionally, little is known of whether the performance of time series change detection is affected by diverse forest

Seasonal photosynthetic activity in evergreen conifer leaves monitored with spectral reflectance

Science.gov (United States)

Wong, C. Y.; Gamon, J. A.

2013-12-01

Boreal evergreen conifers must maintain photosynthetic systems in environments where temperatures vary greatly across seasons from high temperatures in the summer to freezing levels in the winter. This involves seasonal downregulation and photoprotection during periods of extreme temperatures. To better understand this downregulation, seasonal dynamics of photosynthesis of lodgepole (Pinus contorta D.) and ponderosa pine (Pinus ponderosa D.) were monitored in Edmonton, Canada over two years. Spectral reflectance at the leaf and stand scales was measured weekly and the Photochemical Reflectance Index (PRI), often used as a proxy for chlorophyll and carotenoid pigment levels and photosynthetic light-use efficiency (LUE), was used to track the seasonal dynamics of photosynthetic activity. Additional physiological measurements included leaf pigment content, chlorophyll fluorescence, and gas exchange. All the metrics indicate large seasonal changes in photosynthetic activity, with a sharp transition from winter downregulation to active photosynthesis in the spring and a more gradual fall transition into winter. The PRI was a good indicator of several other variables including seasonally changing photosynthetic activity, chlorophyll fluorescence, photosynthetic LUE, and pigment pool sizes. Over the two-year cycle, PRI was primarily driven by changes in constitutive (chlorophyll:carotenoid) pigment levels correlated with seasonal photosynthetic activity, with a much smaller variation caused by diurnal changes in xanthophyll cycle activity (conversion between violaxanthin & zeaxanthin). Leaf and canopy scale PRI measurements exhibited parallel responses during the winter-spring transition. Together, our findings indicate that evergreen conifers photosynthetic system possesses a remarkable degree of resilience in response to large temperature changes across seasons, and that optical remote sensing can be used to observe the seasonal effects on photosynthesis and

Paleoenvironmental informa-tion recorded by pollen in B-3GC gravity core in Okinawa Trough

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

Based on pollen records in B-3GC gravity core, environmental change since 9500 aBP of Okinawa Trough and its adjacent islands was derived. The result showed that the most time during this period was in a warm temperate climate except in middle Holocene (6800-4400 aBP) that was under subtropical climate control. During 9500-8300 aBP and 3100-2000 aBP periods, it appeared colder and drier than the rest time. The original area of pollen sources surrounding Okinawa Trough was covered by evergreen and deciduous broadleaf forest alternatively with mixed broad-leaf-conifer forest distributed in high mountainous areas. Usually, these three kinds of forests existed at the same time with difference in altitude. Pollen from subtropical and tropical plants increased obviously in about 5000-6000 aBP, reflecting a great lifting of vegetation zone and expansion of evergreen broad-leaf forest in the study area. However, there was a slight descending of plant zone and shrinking of evergreen broadleaf forest during 9500-8300 aBP and 3000-2000 aBP. During the remaining periods vegetation zone was higher than the present but in a limited range.

The role of clouds in the surface energy balance over the Amazon forest

International Nuclear Information System (INIS)

Eltahir, E.A.B.; Humphries, E.J. Jr.

1998-01-01

Deforestation in the Amazon region will initially impact the energy balance at the land surface through changes in land cover and surface hydrology. However, continuation of this human activity will eventually lead to atmospheric feedbacks, including changes in cloudiness which may play an important role in the final equilibrium of solar and terrestrial radiation at the surface. In this study, the different components of surface radiation over an undisturbed forest in the Amazon region are computed using data from the Amazon region micrometerological experiment (ARME). Several measures of cloudiness are defined: two estimated from the terrestrial radiation measurements, and one from the solar radiation measurements. The sensitivity of the surface fluxes of solar and terrestrial radiation to natural variability in cloudiness is investigated to infer the potential role of the cloudiness feedback in the surface energy balance. The results of this analysis indicate that a 1% decrease in cloudiness would increase net solar radiation by ca. 1.6 W/m 2 . However, the overall magnitude of this feedback, due to total deforestation of the Amazon forest, is likely to be of the same order as the magnitude of the decrease in net solar radiation due to the observed increase in surface albedo following deforestation. Hence, the total change in net solar radiation is likely to have a negligible magnitude. In contrast to this conclusion, we find that terrestrial radiation is likely to be more strongly affected; reduced cloudiness will decrease net terrestrial radiation; a 1% decrease in cloudiness induces a reduction in net terrestrial radiation of ca. 0.7 W/m 2 ; this process augments the similar effects of the predicted warming and drying in the boundary layer. Due to the cloudiness feedback, the most significant effect of large-scale deforestation on the surface energy balance is likely to be in the modification of the terrestrial radiation field rather than the classical albedo

Fluxes of energy, H2O, and CO2 between the atmosphere and the monsoon tropical forest in Southern Vietnam.

Science.gov (United States)

Kurbatova, Yu A; Kuricheva, O A; Avilov, V K; Dinh, Ba Duy; Kuznetsov, A N

2015-01-01

The 2.5-year dynamics of heat, water and carbon dioxide fluxes in the tropical monsoon semi-evergreen forest in Southern Vietnam obtained by means of continuous eddy covariance observations using standard procedures of FLUXNET global network are analyzed. The features of wet seasons during the measurement period were close to long-term average ones, but dry seasons had a great heterogeneity. The maximal duration of the period with little precipitation was 4 months. The annual radiation balance in the south of Vietnam exceeded the balance at all stations of FLUXNET in tropical forests, except one. Annual evapotranspiration in monsoon forest of south of Vietnam is approximately equal to the evaporation of the rain forests of Central Amazonia. During the wet season evapotranspiration spent 80% of the radiation balance, and in the driest months this value decreased to 50%. In the dry season reduction of evapotranspiration and gross primary production was relatively small due to photosynthesizing trees of 2-4 canopy sub-layers. For the first time a large net sink of carbon dioxide from the atmosphere in the monsoon forest ecosystem was identified.

Global quantification of contrasting leaf life span strategies for deciduous and evergreen species in response to environmental conditions.

NARCIS (Netherlands)

van Ommen Kloeke, A.E.E.; Douma, J.C.; Ordonez Barragan, J.C.; Reick, P.B.; van Bodegom, P.M.

2012-01-01

Aim Species with deciduous and evergreen leaf habits typically differ in leaf life span (LLS). Yet quantification of the response of LLS, within each habit, to key environmental conditions is surprisingly lacking. The aim of this study is to quantify LLS strategies of the two leaf habits under

Seasonal dynamics of water use efficiency of typical forest and grassland ecosystems in China

CERN Document Server

Zhu, Xianjin; Wang, Qiufeng; Hu, Zhongmin; Han, Shijie; Yan, Junhua; Wang, Yanfen; Zhao, Liang

2014-01-01

We selected four sites of ChinaFLUX representing four major ecosystem types in China-Changbaishan temperate broad-leaved Korean pine mixed forest (CBS), Dinghushan subtropical evergreen broadleaved forest (DHS), Inner Mongolia temperate steppe (NM), and Haibei alpine shrub-meadow (HBGC)-to study the seasonal dynamics of ecosystem water use efficiency (WUE = GPP/ET, where GPP is gross primary productivity and ET is evapotranspiration) and factors affecting it. Our seasonal dynamics results indicated single-peak variation of WUE in CBS, NM, and HBGC, which were affected by air temperature (Ta) and leaf area index (LAI), through their effects on the partitioning of evapotranspiration (ET) into transpiration (T) (i.e., T/ET). In DHS, WUE was higher at the beginning and the end of the year, and minimum in summer. Ta and soil water content affected the seasonal dynamics of WUE through their effects on GPP/T. Our results indicate that seasonal dynamics of WUE were different because factors affecting the seasonal dyn...

Drivers of methane uptake by montane forest soils in the Peruvian Andes

Science.gov (United States)

Jones, Sam; Diem, Torsten; Huaraca Quispe, Lidia; Cahuana, Adan; Meir, Patrick; Teh, Yit

2016-04-01

The exchange of methane between the soils of humid tropical forests and the atmosphere is relatively poorly documented. This is particularly true of montane settings where variations between uptake and emission of atmospheric methane have been observed. Whilst most of these ecosystems appear to function as net sinks for atmospheric methane, some act as considerable sources. In regions like the Andes, humid montane forests are extensive and a better understanding of the magnitude and controls on soil-atmosphere methane exchange is required. We report methane fluxes from upper montane cloud forest (2811 - 2962 m asl), lower montane cloud forest (1532 - 1786 m asl), and premontane forest (1070 - 1088 m asl) soils in south-eastern Peru. Between 1000 and 3000 m asl, mean annual air temperature and total annual precipitation decrease from 24 ° C and 5000 mm to 12 ° C and 1700 mm. The study region experiences a pronounced wet season between October and April. Monthly measurements of soil-atmosphere gas exchange, soil moisture, soil temperature, soil oxygen concentration, available ammonium and available nitrate were made from February 2011 in the upper and lower montane cloud forests and July 2011 in the premontane forest to June 2013. These soils acted as sinks for atmospheric methane with mean net fluxes for wet and dry season, respectively, of -2.1 (0.2) and -1.5 (0.1) mg CH4 m-2 d-1 in the upper montane forest; -1.5 (0.2) and -1.4 (0.1) mg CH4 m-2 d-1in the lower montane forest; and -0.3 (0.2) and -0.2 (0.2) mg CH4 m-2 d-1 in the premontane forest. Spatial variations among forest types were related to available nitrate and water-filled pore space suggesting that nitrate inhibition of oxidation or constraints on the diffusional supply of methane to methanotrophic communities may be important controls on methane cycling in these soils. Seasonality in methane exchange, with weaker uptake related to increased water-filled pore space and soil temperature during the wet

The effects of future nationwide forest transition to discharge in the 21st century with regard to general circulation model climate change scenarios.

Science.gov (United States)

Mouri, Goro; Nakano, Katsuhiro; Tsuyama, Ikutaro; Tanaka, Nobuyuki

2016-08-01

Forest disturbance (or land-cover change) and climatic variability are commonly recognised as two major drivers interactively influencing hydrology in forested watersheds. Future climate changes and corresponding changes in forest type and distribution are expected to generate changes in rainfall runoff that pose a threat to river catchments. It is therefore important to understand how future climate changes will effect average rainfall distribution and temperature and what effect this will have upon forest types across Japan. Recent deforestation of the present-day coniferous forest and expected increases in evergreen forest are shown to influence runoff processes and, therefore, to influence future runoff conditions. We strongly recommend that variations in forest type be considered in future plans to ameliorate projected climate changes. This will help to improve water retention and storage capacities, enhance the flood protection function of forests, and improve human health. We qualitatively assessed future changes in runoff including the effects of variation in forest type across Japan. Four general circulation models (GCMs) were selected from the Coupled Model Intercomparison Project Phase 5 (CMIP5) ensemble to provide the driving fields: the Model for Interdisciplinary Research on Climate (MIROC), the Meteorological Research Institute Atmospheric General Circulation Model (MRI-GCM), the Hadley Centre Global Environment Model (HadGEM), and the Geophysical Fluid Dynamics Laboratory (GFDL) climate model. The simulations consisted of an ensemble including multiple physics configurations and different reference concentration pathways (RCP2.6, 4.5, and 8.5), the results of which have produced monthly data sets for the whole of Japan. The impacts of future climate changes on forest type in Japan are based on the balance amongst changes in rainfall distribution, temperature and hydrological factors. Methods for assessing the impact of such changes include the

Cloud Infrastructure & Applications - CloudIA

Science.gov (United States)

Sulistio, Anthony; Reich, Christoph; Doelitzscher, Frank

The idea behind Cloud Computing is to deliver Infrastructure-as-a-Services and Software-as-a-Service over the Internet on an easy pay-per-use business model. To harness the potentials of Cloud Computing for e-Learning and research purposes, and to small- and medium-sized enterprises, the Hochschule Furtwangen University establishes a new project, called Cloud Infrastructure & Applications (CloudIA). The CloudIA project is a market-oriented cloud infrastructure that leverages different virtualization technologies, by supporting Service-Level Agreements for various service offerings. This paper describes the CloudIA project in details and mentions our early experiences in building a private cloud using an existing infrastructure.

The influence of clouds and diffuse radiation on ecosystem-atmosphere CO2 and CO18O exhanges

Energy Technology Data Exchange (ETDEWEB)

Still, C.J.; Riley, W.J.; Biraud, S.C.; Noone, D.C.; Buenning, N.H.; Randerson, J.T.; Torn, M.S.; Welker, J.; White, J.W.C.; Vachon, R.; Farquhar, G.D.; Berry, J.A.

2009-05-01

This study evaluates the potential impact of clouds on ecosystem CO{sub 2} and CO{sub 2} isotope fluxes ('isofluxes') in two contrasting ecosystems (a broadleaf deciduous forest and a C{sub 4} grassland), in a region for which cloud cover, meteorological, and isotope data are available for driving the isotope-enabled land surface model, ISOLSM. Our model results indicate a large impact of clouds on ecosystem CO{sub 2} fluxes and isofluxes. Despite lower irradiance on partly cloudy and cloudy days, predicted forest canopy photosynthesis was substantially higher than on clear, sunny days, and the highest carbon uptake was achieved on the cloudiest day. This effect was driven by a large increase in light-limited shade leaf photosynthesis following an increase in the diffuse fraction of irradiance. Photosynthetic isofluxes, by contrast, were largest on partly cloudy days, as leaf water isotopic composition was only slightly depleted and photosynthesis was enhanced, as compared to adjacent clear sky days. On the cloudiest day, the forest exhibited intermediate isofluxes: although photosynthesis was highest on this day, leaf-to-atmosphere isofluxes were reduced from a feedback of transpiration on canopy relative humidity and leaf water. Photosynthesis and isofluxes were both reduced in the C{sub 4} grass canopy with increasing cloud cover and diffuse fraction as a result of near-constant light limitation of photosynthesis. These results suggest that some of the unexplained variation in global mean {delta}{sup 18}O of CO{sub 2} may be driven by large-scale changes in clouds and aerosols and their impacts on diffuse radiation, photosynthesis, and relative humidity.

Forest biomass, productivity and carbon cycling along a rainfall gradient in West Africa.

Science.gov (United States)

Moore, Sam; Adu-Bredu, Stephen; Duah-Gyamfi, Akwasi; Addo-Danso, Shalom D; Ibrahim, Forzia; Mbou, Armel T; de Grandcourt, Agnès; Valentini, Riccardo; Nicolini, Giacomo; Djagbletey, Gloria; Owusu-Afriyie, Kennedy; Gvozdevaite, Agne; Oliveras, Imma; Ruiz-Jaen, Maria C; Malhi, Yadvinder

2018-02-01

Net Primary Productivity (NPP) is one of the most important parameters in describing the functioning of any ecosystem and yet it arguably remains a poorly quantified and understood component of carbon cycling in tropical forests, especially outside of the Americas. We provide the first comprehensive analysis of NPP and its carbon allocation to woody, canopy and root growth components at contrasting lowland West African forests spanning a rainfall gradient. Using a standardized methodology to study evergreen (EF), semi-deciduous (SDF), dry forests (DF) and woody savanna (WS), we find that (i) climate is more closely related with above and belowground C stocks than with NPP (ii) total NPP is highest in the SDF site, then the EF followed by the DF and WS and that (iii) different forest types have distinct carbon allocation patterns whereby SDF allocate in excess of 50% to canopy production and the DF and WS sites allocate 40%-50% to woody production. Furthermore, we find that (iv) compared with canopy and root growth rates the woody growth rate of these forests is a poor proxy for their overall productivity and that (v) residence time is the primary driver in the productivity-allocation-turnover chain for the observed spatial differences in woody, leaf and root biomass across the rainfall gradient. Through a systematic assessment of forest productivity we demonstrate the importance of directly measuring the main components of above and belowground NPP and encourage the establishment of more permanent carbon intensive monitoring plots across the tropics. © 2017 John Wiley & Sons Ltd.

Exploratory Water Budget Analysis of A Transitional Premontane Cloud Forest in Costa Rica Through Undergraduate Research

Science.gov (United States)

Washington-Allen, R. A.; Buckwalter, E. H.; Moore, G. W.; Burns, J. N.; Dennis, A. R.; Dodge, O.; Guffin, E. C.; Morris, E. R.; Oien, R. P.; Orozco, G.; Peterson, A.; Teale, N. G.; Shibley, N. C.; Tourtellotte, N.; Houser, C.; Brooks, S. D.; Brumbelow, J. K.; Cahill, A. T.; Frauenfeld, O. W.; Gonzalez, E.; Hallmark, C. T.; McInnes, K. J.; Miller, G. R.; Morgan, C.; Quiring, S. M.; Rapp, A. D.; Roark, E.; Delgado, A.; Ackerson, J. P.; Arnott, R.

2012-12-01

The ecohydrology of transitional premontane cloud forests is not well understood. This problem is being addressed by a NSF Research Experience for Undergraduates (REU) study at the Texas A&M University Soltis Center for Research & Education in Costa Rica. Exploratory analysis of the water budget within a 20-ha watershed was used to connect three faculty-mentored research areas in ecohydrology, climate, and soil sciences and highlight the roles of 12 undergraduate researchers from 12 different universities. The water budget model is Q = Pn - E - T + ΔG + ΔS where Q = runoff, Pn = net precipitation, E = evaporation, T = transpiration, and ΔG and ΔS are change in groundwater soil water storage, respectively. Additionally, Pn = Pg - I = Tf + Sf + D, where Pg = gross precipitation, I/ΔI = canopy interception or storage, Tf = throughfall, Sf = stemflow, and D = canopy drip. The following terms were well understood Pg (satellite = 34-mm and tower = 38.1-mm) and Q from a recently constructed v-notch weir. We moderately understand Tf + D (30.9-mm from an array of forest rain gages), ΔI (7.2-mm) related to Sf, and T (10.4-mm measured with sapflow sensors). We found that soils were clay loam to silty loam textured Andisols on saprolitic tuft with a mean potential ΔS of 398 mm H2O under laboratory conditions, but in the field the following terms are almost completely unknown and require further field studies including E, ΔG, and ΔS. Recent installation of piezometers will address ΔG. Temporal scaling of measurements to a 1-week period was a challenge as well as the construction, deployment and calibration of instruments. However, this exploration allowed us to determine measurement uncertainties in the water budget, e.g., E, and to set future areas of research to address these uncertainties.

Xylem traits, leaf longevity and growth phenology predict growth and mortality response to defoliation in northern temperate forests.

Science.gov (United States)

Foster, Jane R

2017-09-01

Defoliation outbreaks are biological disturbances that alter tree growth and mortality in temperate forests. Trees respond to defoliation in many ways; some recover rapidly, while others decline gradually or die. Functional traits such as xylem anatomy, growth phenology or non-structural carbohydrate (NSC) storage could explain these responses, but idiosyncratic measures used by defoliation studies have frustrated efforts to generalize among species. Here, I test for functional differences with published growth and mortality data from 37 studies, including 24 tree species and 11 defoliators from North America and Eurasia. I synthesized data into standardized variables suitable for numerical models and used linear mixed-effects models to test the hypotheses that responses to defoliation vary among species and functional groups. Standardized data show that defoliation responses vary in shape and degree. Growth decreased linearly or curvilinearly, least in ring-porous Quercus and deciduous conifers (by 10-40% per 100% defoliation), whereas growth of diffuse-porous hardwoods and evergreen conifers declined by 40-100%. Mortality increased exponentially with defoliation, most rapidly for evergreen conifers, then diffuse-porous, then ring-porous species and deciduous conifers (Larix). Goodness-of-fit for functional-group models was strong (R2c = 0.61-0.88), if lower than species-specific mixed-models (R2c = 0.77-0.93), providing useful alternatives when species data are lacking. These responses are consistent with functional differences in leaf longevity, wood growth phenology and NSC storage. When defoliator activity lags behind wood-growth, either because xylem-growth precedes budburst (Quercus) or defoliator activity peaks later (sawflies on Larix), impacts on annual wood-growth will always be lower. Wood-growth phenology of diffuse-porous species and evergreen conifers coincides with defoliation and responds more drastically, and lower axial NSC storage makes them

The butterflies of Turquino National Park, Sierra Maestra, Cuba (Lepidoptera, Papilionoidea

Directory of Open Access Journals (Sweden)

Núñez, R.

2012-01-01

Full Text Available Between February and November 2011, we conducted a species inventory, created a natural history database and a made a first approach to the composition and structure of the butterfly communities present at several vegetation types in the Turquino National Park. The inventory included 83 species, 29 of them endemic. We recorded 57 species (18 endemic in transects along main vegetation pathways. In disturbed vegetation, species richness was higher (48 and abundance was better distributed, but the proportion of endemism was lower (23%. Species richness decreased and the dominance and proportion of endemism increased with altitude. Numbers of species and the proportions of endemism at natural habitats sampled were: 19 and 58% for evergreen forest, 10 and 60% for rainforest, eight and 100% for cloud forest, and four and 100% for the elfin thicket. Flowers of 27 plants were recorded as nectar sources for 30 butterfly species, and host plants were recorded for nine species.

Phenological characteristics of the main vegetation types on the Tibetan Plateau based on vegetation and water indices

International Nuclear Information System (INIS)

Peng, D L; Huang, W J; Zhou, B; Li, C J; Wu, Y P; Yang, X H

2014-01-01

Plant phenology is considered one of the most sensitive and easily observable natural indicators of climate change, though few studies have focused on the heterogeneities of phenology across the different vegetation types. In this study, we tried to find the phenological characteristics of the main vegetation types on the Tibetan Plateau. MCD12Q1 images over the Tibetan Plateau from 2001 to 2010 were used to extract the main vegetation types. The Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), and Land Surface Water Index (LSWI) were calculated using surface reflectance values from the blue, red, near-infrared, short-wave infrared (SWIR) 6 (for LSIW6), and SWIR7 (for LSIW7) bands derived from MOD09A1 and used to explore the phenological characteristics of the main vegetation types on the Tibetan Plateau. The results showed that there were eight constant vegetation types on the Tibetan Plateau from 2001 to 2010 demonstrating multiple phenological characteristics. Evergreen needleleaf forest, evergreen broadleaf forest, and permanent wetland had the minimum NDVI values during the summer season, while open shrubland and grassland had the maximum NDVI/EVI values during this period. NDVI and EVI of cropland/natural vegetation had two peaks for their seasonal variations. EVI showed a more significant correlation with LSWI6/LSWI7 than NDVI. Compared to LSWI7, larger EVI values occurred in evergreen needleleaf forest, evergreen broadleaf forest, mixed forest, and permanent wetland, while smaller values occurred in shrubland and barren or sparsely vegetated cover, and nearly equal values occurred in grassland and cropland

Within-twig leaf distribution patterns differ among plant life-forms in a subtropical Chinese forest.

Science.gov (United States)

Meng, Fengqun; Cao, Rui; Yang, Dongmei; Niklas, Karl J; Sun, Shucun

2013-07-01

In theory, plants can alter the distribution of leaves along the lengths of their twigs (i.e., within-twig leaf distribution patterns) to optimize light interception in the context of the architectures of their leaves, branches and canopies. We hypothesized that (i) among canopy tree species sharing similar light environments, deciduous trees will have more evenly spaced within-twig leaf distribution patterns compared with evergreen trees (because deciduous species tend to higher metabolic demands than evergreen species and hence require more light), and that (ii) shade-adapted evergreen species will have more evenly spaced patterns compared with sun-adapted evergreen ones (because shade-adapted species are generally light-limited). We tested these hypotheses by measuring morphological traits (i.e., internode length, leaf area, lamina mass per area, LMA; and leaf and twig inclination angles to the horizontal) and physiological traits (i.e., light-saturated net photosynthetic rates, Amax; light saturation points, LSP; and light compensation points, LCP), and calculated the 'evenness' of within-twig leaf distribution patterns as the coefficient of variation (CV; the higher the CV, the less evenly spaced leaves) of within-twig internode length for 9 deciduous canopy tree species, 15 evergreen canopy tree species, 8 shade-adapted evergreen shrub species and 12 sun-adapted evergreen shrub species in a subtropical broad-leaved rainforest in eastern China. Coefficient of variation was positively correlated with large LMA and large leaf and twig inclination angles, which collectively specify a typical trait combination adaptive to low light interception, as indicated by both ordinary regression and phylogenetic generalized least squares analyses. These relationships were also valid within the evergreen tree species group (which had the largest sample size). Consistent with our hypothesis, in the canopy layer, deciduous species (which were characterized by high LCP, LSP and

Formation of Massive Molecular Cloud Cores by Cloud-cloud Collision

OpenAIRE

Inoue, Tsuyoshi; Fukui, Yasuo

2013-01-01

Recent observations of molecular clouds around rich massive star clusters including NGC3603, Westerlund 2, and M20 revealed that the formation of massive stars could be triggered by a cloud-cloud collision. By using three-dimensional, isothermal, magnetohydrodynamics simulations with the effect of self-gravity, we demonstrate that massive, gravitationally unstable, molecular cloud cores are formed behind the strong shock waves induced by the cloud-cloud collision. We find that the massive mol...

Arthropod prey of Wilson's Warblers in the understory of Douglas-fir forests

Science.gov (United States)

Hagar, J.C.; Dugger, K.M.; Starkey, E.E.

2007-01-01

Availability of food resources is an important factor in avian habitat selection. Food resources for terrestrial birds often are closely related to vegetation structure and composition. Identification of plant species important in supporting food resources may facilitate vegetation management to achieve objectives for providing bird habitat. We used fecal analysis to describe the diet of adult Wilson's Warblers (Wilsonia pusilla) that foraged in the understory of Douglas-fir (Pseudotsuga menziesii) forests in western Oregon during the breeding season. We sampled arthropods at the same sites where diet data were collected, and compared abundance and biomass of prey among seven common shrub species. Wilson's Warblers ate more caterpillars (Lepidoptera larvae), flies (Diptera), beetles (Coleoptera), and Homoptera than expected based on availability. Deciduous shrubs supported higher abundances of arthropod taxa and size classes used as prey by Wilson's Warblers than did evergreen shrubs. The development and maintenance of deciduous understory vegetation in conifer forests of the Pacific Northwest may be fundamental for conservation of food webs that support breeding Wilson's Warblers and other shrub-associated, insectivorous songbirds.

Do seasonal profiles of foliar pigments improve species discrimination of evergreen coastal tree species in KwaZulu- Natal, South Africa?

CSIR Research Space (South Africa)

Van Deventer, Heidi

2013-04-01

Full Text Available of seven evergreen tree species in a sub-tropical region of South Africa, over four seasons during 2011-12. Parametric ANOVA classification was compared to similarity measures of shape (spectral angle mapper; SAM) and magnitude (sum of Euclidean Distance...

Classificação fitogeográfica das florestas do Alto Rio Xingu Phytogeographical classification of the Upper Xingu River forest

Directory of Open Access Journals (Sweden)

Natália Macedo Ivanauskas

2008-01-01

Full Text Available Este trabalho propõe a inclusão da categoria Floresta Estacional Perenifólia no sistema oficial de classificação da vegetação brasileira, devido às particularidades florísticas e fisionômicas da floresta da borda sul-amazônica, que atinge maior amplitude geográfica na região do Alto Rio Xingu. Para justificar essa inclusão são apresentadas as características ambientais (clima, solo, hidrologia e diferenças fisionômicas e florísticas entre as florestas do Alto Xingu e demais florestas ombrófilas da Bacia do Amazonas e estacionais do Planalto Central.This paper proposes the inclusion of the "Evergreen Seasonal Forest" category in the official system used to classify Brazilian forests. This proposal is based upon the floristic and physiognomic particularities of the Southern Amazonian forest, which reach a greater magnitude around the Upper Xingu River. In order to justify the inclusion, the paper reports environmental characteristics (climate, soil and hydrology as well as floristic and physiognomic differences between the Upper Xingu River forest and both the Ombrophilous Forest from the Amazon Basin and the Seasonal Forest of the Central Plateau.

Solar Physics at Evergreen: Solar Dynamo and Chromospheric MHD

Science.gov (United States)

Zita, E. J.; Maxwell, J.; Song, N.; Dikpati, M.

2006-12-01

We describe our five year old solar physics research program at The Evergreen State College. Famed for its cloudy skies, the Pacific Northwest is an ideal location for theoretical and remote solar physics research activities. Why does the Sun's magnetic field flip polarity every 11 years or so? How does this contribute to the magnetic storms Earth experiences when the Sun's field reverses? Why is the temperature in the Sun's upper atmosphere millions of degrees higher than the Sun's surface temperature? How do magnetic waves transport energy in the Sun’s chromosphere and the Earth’s atmosphere? How does solar variability affect climate change? Faculty and undergraduates investigate questions such as these in collaboration with the High Altitude Observatory (HAO) at the National Center for Atmospheric Research (NCAR) in Boulder. We will describe successful student research projects, logistics of remote computing, and our current physics investigations into (1) the solar dynamo and (2) chromospheric magnetohydrodynamics.

Evergreening, patent challenges, and effective market life in pharmaceuticals.

Science.gov (United States)

Hemphill, C Scott; Sampat, Bhaven N

2012-03-01

Observers worry that generic patent challenges are on the rise and reduce the effective market life of drugs. A related concern is that challenges disproportionately target high-sales drugs, reducing market life for these "blockbusters." To study these questions, we examine new data on generic entry over the past decade. We show that challenges are more common for higher sales drugs. We also demonstrate a slight increase in challenges over this period, and a sharper increase for early challenges. Despite this, effective market life is stable across drug sales categories, and has hardly changed over the decade. To better understand these results, we examine which patents are challenged on each drug, and show that lower quality and later expiring patents disproportionately draw challenges. Overall, this evidence suggests that challenges serve to maintain, not reduce, the historical baseline of effective market life, thereby limiting the effectiveness of "evergreening" by branded firms. Copyright © 2012 Elsevier B.V. All rights reserved.

In vitro foliage susceptibility of canary islands laurel forests: a model for better understanding the ecology of Phytophthora ramorum

Science.gov (United States)

Eduardo Moralejo; Enrique Descals

2008-01-01

The tree species that dominate the cloud-zone forests of Macaronesia, the coastal redwoods of California, the Valdivian forests of Chile, the Atlantic forests of Brazil and the podocarp forests of New Zealand are all examples of paleoendemic species that once had a much wider distribution. They appear to owe their survival to the particular environmental conditions...

Water-use dynamics of a peat swamp forest and a dune forest in Maputaland, South Africa

Directory of Open Access Journals (Sweden)

A. D. Clulow

2013-05-01

Full Text Available Peat swamp forests are the second rarest forest type found in South Africa while dune forests have been under severe threat through mining and agriculture. Both forest types exist in the conservation area, and World Heritage site, known as the iSimangaliso Wetland Park on the East coast of South Africa. The area is prone to severe droughts (Taylor et al., 2006 and recent attempts to understand the local water balance revealed that there was insufficient information on the water use of the indigenous forests of the area. The peat swamp forest and dune forest sites studied in this research were located within close proximity to each other, yet, are characterised by different landscape positions in terms of water availability. The coastal dune forest soil profile was generally dry and sandy and the tree roots did not have access to the water table. In contrast the peat swamp forest is located in an interdunal wetland where the trees have permanent access to water. The climate at both sites is subtropical with a mean annual precipitation of 1200 mm yr−1. However, over 20 months of measurement, the first summer (October 2009 to March 2010 was drier (424 versus 735 mm than the second summer (October 2010 to March 2011 emphasising the variability of the rainfall in the area and providing a wide range of conditions measured. The sap flow of an evergreen, overstory Syzygium cordatum and a semi-deciduous, understory Shirakiopsis elliptica were measured in the peat swamp forest using the heat ratio method. The Syzygium cordatum water use was not highly seasonal and the daily maximum water use ranged from approximately 30 L d−1 in winter to 45 L d−1 in summer whereas the extit{Shirakiopsis elliptica} water use was more seasonal at 2 L d−1 in winter and 12 L d−1 in summer. The water use of the Syzygium cordatum was not influenced by seasonal rainfall variations and was actually higher in the drier summer (October 2009 to March 2010. Three trees of

Photosynthesis and photosynthetic electron flow in the alpine evergreen species Quercus guyavifolia in winter

Directory of Open Access Journals (Sweden)

Wei Huang

2016-10-01

Full Text Available Alpine evergreen broadleaf tree species must regularly cope with low night temperatures in winter. However, the effects of low night temperatures on photosynthesis in alpine evergreen broadleaf tree species are unclear. We measured the diurnal photosynthetic parameters before and after cold snap for leaves of Quercus guyavifolia growing in its native habitat at 3290 m. On 11 and 12 December 2013 (before cold snap, stomatal and mesophyll conductances (gs and gm, CO2 assimilation rate (An, and total electron flow through PSII (JPSII at daytime were maintained at high levels. The major action of alternative electron flow was to provide extra ATP for primary metabolisms. On 20 December 2013 (after cold snap, the diurnal values of gs, gm, An and JPSII at daytime largely decreased, mainly due to the large decrease in night air temperature. Meanwhile, the ratio of photorespiration and alternative electron flow to JPSII largely increased on 20 December. Furthermore, the high levels of alternative electron flow were accompanied with low rates of extra ATP production. A quantitative limitation analysis reveals that the gm limitation increased on 20 December with decreased night air temperature. Therefore, the night air temperature was an important determinant of stomatal/mesophyll conductance and photosynthesis. When photosynthesis is inhibited following freezing night temperatures, photorespiration and alternative electron flow are important electron sinks, which support the role of photorespiration and alternative electron flow in photoportection for alpine plants under low temperatures.

Photosynthesis and carbon isotope discrimination in boreal forest ecosystems: A comparison of functional characteristics in plants from three mature forest types

Science.gov (United States)

Flanagan, Lawrence B.; Brooks, J. Renee; Ehleringer, James R.

1997-12-01

seasonal changes in ecosystem discrimination for aspen forests, while the evergreen conifer forests exhibited relatively constant discrimination values throughout the active growing season.

Spatial and Temporal Changes of Sundarbans Reserve Forest in Bangladesh

Directory of Open Access Journals (Sweden)

Sanaul Haque Mondal

2017-03-01

Full Text Available Sundarbans, the largest mangrove chunk of the world is shared between Bangladesh (62% and India (38%. The objective of this paper was to examine the spatial and temporal changes in land cover (forest cover area of Sundarbans from 1973 to 2010 using remote sensing and geographic information system (GIS tool. Normal¬ized difference vegetation index (NDVI was applied to calculate the density of vegetation of Sundarbans reserved forest (SRF. This study found that there were no major changes in total areas of SRF in the last 37 years (from 1973 to 2010 albeit changes were detected within the four land cover categories-water body, mudflat, barren land and vegetated land. During 1973 to 2010, water bodies, mudflats and barren lands increased by 0.45%, 19.69% and 14.81%, respectively, while vegetated land decreased by 4.01% during the same period. This indicated that the density of evergreen vegetation and its canopy closure decreased in Sundarbans. It was thus recommended that GIS and remote sensing based real time monitoring system be developed to identify spatial and temporal changes of land cover classes of SRF.

Preliminary Response of Soil Fauna to Simulated N Deposition in Three Typical Subtropical Forests

Institute of Scientific and Technical Information of China (English)

XU Guo-Liang; MO Jiang-Ming; ZHOU Guo-Yi; FU Sheng-Lei

2006-01-01

A field-scale experiment arranged in a complete randomized block design with three N addition treatments including a control (no addition of N), a low N (5 g m-2 year-1), and a medium N (10 g m-2 year-1) was performed in each of the three typical forests, a pine (Pinus massoniana Lamb.) forest (PF), a pine-broadleaf mixed forest (MF) and a mature monsoon evergreen broadleaf forest (MEBF), of the Dinghushan Biosphere Reserve in subtropical China to study the response of soil fauna community to additions of N. Higher NH4+ and NO3- concentrations and a lower soil pH occurred in the medium N treatment of MEBF, whereas the NO3- concentration was the lowest in PF after the additions of N. The response of the density, group abundance and diversity index of soil fauna to addition of N varied with the forest type,and all these variables decreased with increasing N under MEBF but the trend was opposite under PF. The N treatments had no significant effects on these variables under MF. Compared with the control plots, the medium N treatment had significant negative effect on soil fauna under MEBF. The group abundance of soil fauna increased significantly with additions of higher N rates under PF. These results suggested that the response of soil fauna to N deposition varied with the forest type and N deposition rate, and soil N status is one of the important factors affecting the response of soil fauna to N deposition.

Relationship between cloud radiative forcing, cloud fraction and cloud albedo, and new surface-based approach for determining cloud albedo

OpenAIRE

Y. Liu; W. Wu; M. P. Jensen; T. Toto

2011-01-01

This paper focuses on three interconnected topics: (1) quantitative relationship between surface shortwave cloud radiative forcing, cloud fraction, and cloud albedo; (2) surfaced-based approach for measuring cloud albedo; (3) multiscale (diurnal, annual and inter-annual) variations and covariations of surface shortwave cloud radiative forcing, cloud fraction, and cloud albedo. An analytical expression is first derived to quantify the relationship between cloud radiative forcing, cloud fractio...

Faunal diversity in a semi-evergreen forest of Bornadi-Khalingduar Complex of Assam, India