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Sample records for unit leaf area

  1. Leaf vein length per unit area is not intrinsically dependent on image magnification: avoiding measurement artifacts for accuracy and precision.

    NARCIS (Netherlands)

    Sack, L.; Caringella, M.; Scoffoni, C.; Rawls, M.; Markesteijn, L.; Poorter, L.

    2014-01-01

    Leaf vein length per unit leaf area (VLA; also known as vein density) is an important determinant of water and sugar transport, photosynthetic function, and biomechanical support. A range of software methods are in use to visualize and measure vein systems in cleared leaf images; typically, users lo

  2. Characterizing Leaf Area Index (LAI and Vertical Foliage Profile (VFP over the United States

    Directory of Open Access Journals (Sweden)

    H. Tang

    2015-08-01

    Full Text Available Leaf area index (LAI and vertical foliage profile (VFP are among the important canopy structural variables. Recent advances in lidar remote sensing technology have demonstrated the capability of accurately mapping LAI and VFP over large areas. The primary objective of this study was to derive and validate a LAI and VFP product over the contiguous United States using spaceborne waveform lidar data. This product was derived at the footprint level from the Geoscience Laser Altimeter System (GLAS using a biophysical model. We validated GLAS derived LAI and VFP across major forest biomes using airborne waveform lidar. The comparison results showed that GLAS retrievals of total LAI were generally accurate with little bias (r2 = 0.67, bias = −0.13, RMSE = 0.75. The derivations of GLAS retrievals of VFP within layers was not as accurate overall (r2 = 0.36, bias = −0.04, RMSE = 0.26, and these varied as a function of height, increasing from understory to overstory −0 to 5 m layer: r2 = 0.04, bias = 0.09, RMSE = 0.31; 10 to 15 m layer: r2 = 0.53, bias = −0.08, RMSE = 0.22; and 15 to 20 m layer: r2 = 0.66, bias =−0.05, RMSE = 0.20. Significant relationships were also found between GLAS LAI products and different environmental factors, in particular elevation and annual precipitation. In summary, our results provide a unique insight into vertical canopy structure distribution across North American ecosystems. This data set is a first step towards a baseline of canopy structure needed for evaluating climate and land use induced forest changes at continental scale in the future and should help deepen our understanding of the role of vertical canopy structure on terrestrial ecosystem processes across varying scales.

  3. Characterizing leaf area index (LAI) and vertical foliage profile (VFP) over the United States

    Science.gov (United States)

    Tang, H.; Ganguly, S.; Zhang, G.; Hofton, M. A.; Nelson, R. F.; Dubayah, R.

    2016-01-01

    Leaf area index (LAI) and vertical foliage profile (VFP) are among the important canopy structural variables. Recent advances in lidar remote sensing technology have demonstrated the capability of accurately mapping LAI and VFP over large areas. The primary objective of this study was to derive and validate a LAI and VFP product over the contiguous United States (CONUS) using spaceborne waveform lidar data. This product was derived at the footprint level from the Geoscience Laser Altimeter System (GLAS) using a biophysical model. We validated GLAS-derived LAI and VFP across major forest biomes using airborne waveform lidar. The comparison results showed that GLAS retrievals of total LAI were generally accurate with little bias (r2 = 0.67, bias = -0.13, RMSE = 0.75). The derivations of GLAS retrievals of VFP within layers were not as accurate overall (r2 = 0.36, bias = -0.04, RMSE = 0.26), and these varied as a function of height, increasing from understory to overstory - 0 to 5 m layer: r2 = 0.04, bias = 0.09, RMSE = 0.31; 10 to 15 m layer: r2 = 0.53, bias = -0.08, RMSE = 0.22; and 15 to 20 m layer: r2 = 0.66, bias = -0.05, RMSE = 0.20. Significant relationships were also found between GLAS LAI products and different environmental factors, in particular elevation and annual precipitation. In summary, our results provide a unique insight into vertical canopy structure distribution across North American ecosystems. This data set is a first step towards a baseline of canopy structure needed for evaluating climate and land use induced forest changes at the continental scale in the future, and should help deepen our understanding of the role of vertical canopy structure in terrestrial ecosystem processes across varying scales.

  4. Variation in chlorophyll content per unit leaf area in spring wheat and implications for selection in segregating material.

    Directory of Open Access Journals (Sweden)

    John Hamblin

    Full Text Available Reduced levels of leaf chlorophyll content per unit leaf area in crops may be of advantage in the search for higher yields. Possible reasons include better light distribution in the crop canopy and less photochemical damage to leaves absorbing more light energy than required for maximum photosynthesis. Reduced chlorophyll may also reduce the heat load at the top of canopy, reducing water requirements to cool leaves. Chloroplasts are nutrient rich and reducing their number may increase available nutrients for growth and development. To determine whether this hypothesis has any validity in spring wheat requires an understanding of genotypic differences in leaf chlorophyll content per unit area in diverse germplasm. This was measured with a SPAD 502 as SPAD units. The study was conducted in series of environments involving up to 28 genotypes, mainly spring wheat. In general, substantial and repeatable genotypic variation was observed. Consistent SPAD readings were recorded for different sampling positions on leaves, between different leaves on single plant, between different plants of the same genotype, and between different genotypes grown in the same or different environments. Plant nutrition affected SPAD units in nutrient poor environments. Wheat genotypes DBW 10 and Transfer were identified as having consistent and contrasting high and low average SPAD readings of 52 and 32 units, respectively, and a methodology to allow selection in segregating populations has been developed.

  5. Leaf vein length per unit area is not intrinsically dependent on image magnification: avoiding measurement artifacts for accuracy and precision.

    Science.gov (United States)

    Sack, Lawren; Caringella, Marissa; Scoffoni, Christine; Mason, Chase; Rawls, Michael; Markesteijn, Lars; Poorter, Lourens

    2014-10-01

    Leaf vein length per unit leaf area (VLA; also known as vein density) is an important determinant of water and sugar transport, photosynthetic function, and biomechanical support. A range of software methods are in use to visualize and measure vein systems in cleared leaf images; typically, users locate veins by digital tracing, but recent articles introduced software by which users can locate veins using thresholding (i.e. based on the contrasting of veins in the image). Based on the use of this method, a recent study argued against the existence of a fixed VLA value for a given leaf, proposing instead that VLA increases with the magnification of the image due to intrinsic properties of the vein system, and recommended that future measurements use a common, low image magnification for measurements. We tested these claims with new measurements using the software LEAFGUI in comparison with digital tracing using ImageJ software. We found that the apparent increase of VLA with magnification was an artifact of (1) using low-quality and low-magnification images and (2) errors in the algorithms of LEAFGUI. Given the use of images of sufficient magnification and quality, and analysis with error-free software, the VLA can be measured precisely and accurately. These findings point to important principles for improving the quantity and quality of important information gathered from leaf vein systems.

  6. Estimation of leaf area in tropical maize

    NARCIS (Netherlands)

    Elings, A.

    2000-01-01

    Leaf area development of six tropical maize cultivars grown in 1995 and 1996 in several tropical environments in Mexico (both favourable and moisture-and N-limited) was observed and analysed. First, the validity of a bell-shaped curve describing the area of individual leaves as a function of leaf nu

  7. Effect of Plant Growth Regulators on Leaf Number, Leaf Area and Leaf Dry Matter in Grape

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    Zahoor Ahmad BHAT

    2011-03-01

    Full Text Available Influence of phenylureas (CPPU and brassinosteriod (BR along with GA (gibberellic acid were studied on seedless grape vegetative characteristics like leaf number, leaf area and leaf dry matter. Growth regulators were sprayed on the vines either once (7 days after fruit set or 15 days after fruit set or twice (7+15 days after fruit set. CPPU 2 ppm+BR 0.4 ppm+GA 25 ppm produced maximum number of leaves (18.78 while as untreated vines produced least leaf number (16.22 per shoot. Maximum leaf area (129.70 cm2 and dry matter content (26.51% was obtained with higher CPPU (3 ppm and BR (0.4 ppm combination along with GA 25 ppm. Plant growth regulators whether naturally derived or synthetic are used to improve the productivity and quality of grapes. The relatively high value of grapes justifies more expensive inputs. A relatively small improvement in yield or fruit quality can justify the field application of a very costly product. Application of new generation growth regulators like brassinosteroids and phenylureas like CPPU have been reported to increase the leaf number as well as leaf area and dry matter thereby indirectly influencing the fruit yield and quality in grapes.

  8. Effects of CO/sub 2/ enrichment on internal leaf surface area in soybeans

    Energy Technology Data Exchange (ETDEWEB)

    Leadley, P.W.; Reynolds, J.A.; Thomas, J.F.; Reynolds, J.F.

    1987-06-01

    Internal cell surface areas were measured on fully expanded leaves of soybean seedlings that had been continuously exposed to 348 or 645 ppm CO/sub 2/ environments. Plants grown in the high CO/sub 2/ treatment had thicker leaves but less palisade cell surface area per unit of leaf area. Surface area of the mesophyll per unit leaf area was unaffected by CO/sub 2/. The potential ramifications of these CO/sub 2/-induced changes in leaf anatomy on photosynthesis and water-use efficiency are explored.

  9. Simulation of Leaf Area Development Based on Dry Matter Partitioning and Specific Leaf Area for Cut Chrysanthemum

    NARCIS (Netherlands)

    Lee, J.H.; Heuvelink, E.

    2003-01-01

    This work aims to predict time courses of leaf area index (LAI) based on dry matter partitioning into the leaves and on specific leaf area of newly formed leaf biomass (SLA(n)) for year-round cut chrysanthemum crops. In five glasshouse experiments, each consisting of several plant densities and plan

  10. LEAF AREA ESTIMATION IN LITCHI BY MEANS OF ALLOMETRIC RELATIONSHIPS

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    PABLO SOUTO OLIVEIRA

    Full Text Available ABSTRACT Obtaining leaf area is critical in several agronomic studies, being one of the important instruments to assess plant growth. The aim of this study was to estimate equations and select the most appropriate in determining leaf area in litchi (Litchi chinensis Sonn.. From the linear dimensions of length (L and maximum width (W of leaf limb, equations were estimated using linear, quadratic, potential and exponential models. The linear regression equation using the product of the length by maximum width, given by Y = 0.2885 + 0.662 (L.W is the one that best expresses the leaf area estimation of litchi tree.

  11. Effects of leaf area of downy oak (Quercus pubescens Willd ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-08-18

    Aug 18, 2009 ... gravity meter with sensitivity of 0.01 g and by means of formula 1. The 1st and 2nd age ... multiplying these values the area of a leaf (l.a, mm2) is calculated. 4. ..... Considering obtained data from this study of effects of leaf area ...

  12. Estimation of leaf area with an integrating sphere.

    Science.gov (United States)

    Serrano, Lydia; Gamon, J. A.; Berry, J.

    1997-01-01

    Relative absorptance of intact branches measured with an integrating sphere was compared to leaf area estimated by conventional methods (volume displacement and scanning area meter) for three conifer species: Picea mariana (Mill.) BSP, Pinus banksiana (Lamb.) and Pseudotsuga menziesii (Mirb.) Franco. A consistent relationship between relative absorptance and surface area emerged for the three species. The ability to predict leaf area from absorptance was further explored by measuring branches of Pseudotsuga menziesii grown in varying light and nutrient regimes. When a single equation was used to predict leaf area under all growth conditions, errors were as large as 40% primarily because of variation in leaf absorptivity, with the largest errors associated with extremely nutrient-deficient foliage. When separate empirical equations were developed for each growth treatment, predicted leaf surface area agreed to within 5% of the area determined by the volume displacement method. Leaf surface area estimated from theoretical principles was also in good agreement with total surface area estimated independently by conventional methods. With proper accounting for needle absorptivity, which varied with growth conditions, leaf area estimates obtained by the integrating sphere method were of similar accuracy to those obtained by conventional methods, with the added advantage that the method allowed intact foliage to be sampled nondestructively in the field. Because the integrating sphere method preserves branch structure during measurement, it could provide a useful measure of needle area for photosynthetic or developmental studies requiring repeated sampling of the same branch.

  13. Development of leaf area and leaf number of micropropagated potato plants

    NARCIS (Netherlands)

    Tadesse, M.; Lommen, W.J.M.; Putten, van der P.E.L.; Struik, P.C.

    2001-01-01

    Aboveground leaf area and leaf number development of in vitro produced potato plantlets was studied over three growth phases. In vitro plantlets were produced at 17 or 23°C (normalisation phase, 3 weeks), planted in soil at 18/12 or 26/20°C (transplant production phase, 2 weeks), and later transplan

  14. A non-destructive method for estimating onion leaf area

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    Córcoles J.I.

    2015-06-01

    Full Text Available Leaf area is one of the most important parameters for characterizing crop growth and development, and its measurement is useful for examining the effects of agronomic management on crop production. It is related to interception of radiation, photosynthesis, biomass accumulation, transpiration and gas exchange in crop canopies. Several direct and indirect methods have been developed for determining leaf area. The aim of this study is to develop an indirect method, based on the use of a mathematical model, to compute leaf area in an onion crop using non-destructive measurements with the condition that the model must be practical and useful as a Decision Support System tool to improve crop management. A field experiment was conducted in a 4.75 ha commercial onion plot irrigated with a centre pivot system in Aguas Nuevas (Albacete, Spain, during the 2010 irrigation season. To determine onion crop leaf area in the laboratory, the crop was sampled on four occasions between 15 June and 15 September. At each sampling event, eight experimental plots of 1 m2 were used and the leaf area for individual leaves was computed using two indirect methods, one based on the use of an automated infrared imaging system, LI-COR-3100C, and the other using a digital scanner EPSON GT-8000, obtaining several images that were processed using Image J v 1.43 software. A total of 1146 leaves were used. Before measuring the leaf area, 25 parameters related to leaf length and width were determined for each leaf. The combined application of principal components analysis and cluster analysis for grouping leaf parameters was used to reduce the number of variables from 25 to 12. The parameter derived from the product of the total leaf length (L and the leaf diameter at a distance of 25% of the total leaf length (A25 gave the best results for estimating leaf area using a simple linear regression model. The model obtained was useful for computing leaf area using a non

  15. Evolutionarily Stable Leaf Area Production in Plant Populations

    NARCIS (Netherlands)

    Anten, N.P.R.

    2002-01-01

    Using an analytical model, it was shown that for a given amount of nitrogen in the canopy of a stand (N-T), there exists an evolutionarily stable leaf area index (ES-LAI), and therefore an evolutionarily stable average leaf nitrogen content (n(anu)(ES); n(anu)(ES) = N-T/ES - LAI), at which no indivi

  16. Barley Leaf Area and Leaf Growth Rates Are Maximized during the Pre-Anthesis Phase

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    Ahmad M. Alqudah

    2015-04-01

    Full Text Available Leaf developmental traits are an important component of crop breeding in small-grain cereals. Surprisingly, little is known about the genetic basis for the differences in barley (Hordeum vulgare L. leaf development. The two barley row-type classes, i.e., two- and six-rowed, show clear-cut differences in leaf development. To quantify these differences and to measure the genetic component of the phenotypic variance for the leaf developmental differences in both row-type classes we investigated 32 representative spring barley accessions (14 two- and 18 six-rowed accessions under three independent growth conditions. Leaf mass area is lower in plants grown under greenhouse (GH conditions due to fewer, smaller, and lighter leaf blades per main culm compared to pot- and soil-grown field plants. Larger and heavier leaf blades of six-rowed barley correlate with higher main culm spike grain yield, spike dry weight, and harvest index; however, smaller leaf area (LA in two-rowed barley can be attributed to more spikes, tillers, and biological yield (aboveground parts. In general, leaf growth rate was significantly higher between awn primordium and tipping stages. Moderate to very high broad-sense heritabilities (0.67–0.90 were found under all growth conditions, indicating that these traits are predominantly genetically controlled. In addition, our data suggests that GH conditions are suitable for studying leaf developmental traits. Our results also demonstrated that LA impacts single plant yield and can be reconsidered in future breeding programs. Six-rowed spike 1 (Vrs1 is the major determinate of barley row-types, the differences in leaf development between two- and six-rowed barleys may be attributed to the regulation of Vrs1 in these two classes, which needs further testing.

  17. Leaf-age effects on seasonal variability in photosynthetic parameters and its relationships with leaf mass per area and leaf nitrogen concentration within a Pinus densiflora crown.

    Science.gov (United States)

    Han, Qingmin; Kawasaki, Tatsuro; Nakano, Takashi; Chiba, Yukihiro

    2008-04-01

    In the temperate zone of Japan, Pinus densiflora Sieb. et Zucc. bears needles of up to three age classes in the upper crown and up to five age classes in the lower crown. To elucidate the effects of leaf age on photosynthetic parameters and its relationships with leaf mass per unit area (LMA) and leaf nitrogen (N(l)) concentration on an area (N(a)) and mass (N(m)) basis, we measured seasonal variations in LMA, N(l), light-saturated photosynthetic rate (A(max)), stomatal conductance (g(s)), maximum rate of carboxylation (V(cmax)) and maximum rate of electron transport (J(max)) in leaves of all age classes in the upper and lower crown. Leaf mass per unit area increased by 27% with increasing leaf age in the lower crown, but LMA did not depend on age in the upper crown. Leaf age had a significant effect on N(m) but not on N(a) in both crown positions, indicating that decreases in N(m) resulted from dilution. Photosynthetic parameters decreased significantly with leaf age in the lower crown (39% for A(max) and 43% for V(cmax)), but the effect of leaf age was not as great in the upper crown, although these parameters exhibited seasonal variation in both crown positions. Regression analysis indicated a close relationship between LMA and N(a), regardless of age class or when each age class was pooled (r(2) = 0.57-0.86). Relationships between LMA and N(a) and among A(max), V(cmax) and J(max) were weak or not significant when all age classes were examined by regression analysis. However, compared with older leaves, relationships among LMA, N(a) and A(max) were stronger in younger leaves. These results indicate that changes in LMA and N(l) mainly reflect light acclimation during leaf development, but they are only slightly affected by irradiance in mature leaves. In conclusion, LMA and N(l) are useful parameters for estimating photosynthetic capacity, but age-related effects need to be taken into account, especially in evergreen conifers.

  18. Leaf Area Adjustment As an Optimal Drought-Adaptation Strategy

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    Manzoni, S.; Beyer, F.; Thompson, S. E.; Vico, G.; Weih, M.

    2014-12-01

    Leaf phenology plays a major role in land-atmosphere mass and energy exchanges. Much work has focused on phenological responses to light and temperature, but less to leaf area changes during dry periods. Because the duration of droughts is expected to increase under future climates in seasonally-dry as well as mesic environments, it is crucial to (i) predict drought-related phenological changes and (ii) to develop physiologically-sound models of leaf area dynamics during dry periods. Several optimization criteria have been proposed to model leaf area adjustment as soil moisture decreases. Some theories are based on the plant carbon (C) balance, hypothesizing that leaf area will decline when instantaneous net photosynthetic rates become negative (equivalent to maximization of cumulative C gain). Other theories draw on hydraulic principles, suggesting that leaf area should adjust to either maintain a constant leaf water potential (isohydric behavior) or to avoid leaf water potentials with negative impacts on photosynthesis (i.e., minimization of water stress). Evergreen leaf phenology is considered as a control case. Merging these theories into a unified framework, we quantify the effect of phenological strategy and climate forcing on the net C gain over the entire growing season. By accounting for the C costs of leaf flushing and the gains stemming from leaf photosynthesis, this metric assesses the effectiveness of different phenological strategies, under different climatic scenarios. Evergreen species are favored only when the dry period is relatively short, as they can exploit most of the growing season, and only incur leaf maintenance costs during the short dry period. In contrast, deciduous species that lower maintenance costs by losing leaves are advantaged under drier climates. Moreover, among drought-deciduous species, isohydric behavior leads to lowest C gains. Losing leaves gradually so as to maintain a net C uptake equal to zero during the driest period in

  19. Photosynthetic leaf area modulates tiller bud outgrowth in sorghum.

    Science.gov (United States)

    Kebrom, Tesfamichael H; Mullet, John E

    2015-08-01

    Shoot branches or tillers develop from axillary buds. The dormancy versus outgrowth fates of buds depends on genetic, environmental and hormonal signals. Defoliation inhibits bud outgrowth indicating the role of leaf-derived metabolic factors such as sucrose in bud outgrowth. In this study, the sensitivity of bud outgrowth to selective defoliation was investigated. At 6 d after planting (6 DAP), the first two leaves of sorghum were fully expanded and the third was partially emerged. Therefore, the leaves were selectively defoliated at 6 DAP and the length of the bud in the first leaf axil was measured at 8 DAP. Bud outgrowth was inhibited by defoliation of only 2 cm from the tip of the second leaf blade. The expression of dormancy and sucrose-starvation marker genes was up-regulated and cell cycle and sucrose-inducible genes was down-regulated during the first 24 h post-defoliation of the second leaf. At 48 h, the expression of these genes was similar to controls as the defoliated plant recovers. Our results demonstrate that small changes in photosynthetic leaf area affect the propensity of tiller buds for outgrowth. Therefore, variation in leaf area and photosynthetic activity should be included when integrating sucrose into models of shoot branching.

  20. Leaf area estimation of cassava from linear dimensions

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    SAMARA ZANETTI

    2017-08-01

    Full Text Available ABSTRACT The objective of this study was to determine predictor models of leaf area of cassava from linear leaf measurements. The experiment was carried out in greenhouse in the municipality of Botucatu, São Paulo state, Brazil. The stem cuttings with 5-7 nodes of the cultivar IAC 576-70 were planted in boxes filled with about 320 liters of soil, keeping soil moisture at field capacity, monitored by puncturing tensiometers. At 80 days after planting, 140 leaves were randomly collected from the top, middle third and base of cassava plants. We evaluated the length and width of the central lobe of leaves, number of lobes and leaf area. The measurements of leaf areas were correlated with the length and width of the central lobe and the number of lobes of the leaves, and adjusted to polynomial and multiple regression models. The linear function that used the length of the central lobe LA = -69.91114 + 15.06462L and linear multiple functions LA = -69.9188 + 15.5102L + 0.0197726K - 0.0768998J or LA = -69.9346 + 15.0106L + 0.188931K - 0.0264323H are suitable models to estimate leaf area of cassava cultivar IAC 576-70.

  1. Causes and consequences of variation in leaf mass per area (LMA): a meta-analysis

    NARCIS (Netherlands)

    Poorter, H.; Niinemets, U.; Poorter, L.; Wright, I.J.; Villar, H.

    2009-01-01

    Here, we analysed a wide range of literature data on the leaf dry mass per unit area (LMA). In nature, LMA varies more than 100-fold among species. Part of this variation (c. 35%) can be ascribed to differences between functional groups, with evergreen species having the highest LMA, but most of the

  2. METHODS OF BIOMONITORING IN URBAN ENVIRONMENT: LEAF AREA AND FRACTAL DIMENSION

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    Nicoleta IANOVICI

    2015-12-01

    Full Text Available In urban conditions, we investigated several leaf traits (leaf area, specific leaf area, fractal dimension and specific leaf weight on Taraxacum officinale, Tilia tomentosa, Aesculus hippocastanum and Ambrosia artemisiifolia. The analyzed organs were mature leaves, on the first indications of senescence. This study used an exact, inexpensive and efficient in terms of costs alternative methods for determining the leaf parameters. On the other hand, this paper presents an application of the leaf area and fractal dimension in the analysis of leaf shape. Our results show that leaf area and fractal dimension are sensitive parameters that can be effectively used in biomonitoring.

  3. Rapid, high-resolution measurement of leaf area and leaf orientation using terrestrial LiDAR scanning data

    Science.gov (United States)

    Bailey, Brian N.; Mahaffee, Walter F.

    2017-06-01

    The rapid evolution of high performance computing technology has allowed for the development of extremely detailed models of the urban and natural environment. Although models can now represent sub-meter-scale variability in environmental geometry, model users are often unable to specify the geometry of real domains at this scale given available measurements. An emerging technology in this field has been the use of terrestrial LiDAR scanning data to rapidly measure the three-dimensional geometry of trees, such as the distribution of leaf area. However, current LiDAR methods suffer from the limitation that they require detailed knowledge of leaf orientation in order to translate projected leaf area into actual leaf area. Common methods for measuring leaf orientation are often tedious or inaccurate, which places constraints on the LiDAR measurement technique. This work presents a new method to simultaneously measure leaf orientation and leaf area within an arbitrarily defined volume using terrestrial LiDAR data. The novelty of the method lies in the direct measurement of the fraction of projected leaf area G from the LiDAR data which is required to relate projected leaf area to total leaf area, and in the new way in which radiation transfer theory is used to calculate leaf area from the LiDAR data. The method was validated by comparing LiDAR-measured leaf area to (1) ‘synthetic’ or computer-generated LiDAR data where the exact area was known, and (2) direct measurements of leaf area in the field using destructive sampling. Overall, agreement between the LiDAR and reference measurements was very good, showing a normalized root-mean-squared-error of about 15% for the synthetic tests, and 13% in the field.

  4. Estimation of stand-level leaf area for boreal bryophytes.

    Science.gov (United States)

    Bond-Lamberty, Ben; Gower, Stith T

    2007-04-01

    Bryophytes dominate the carbon and nitrogen cycling of many poorly drained terrestrial ecosystems and are important in the vegetation-atmosphere exchange of carbon and water, yet few studies have estimated their leaf area at the stand scale. This study quantified the bryophyte-specific leaf area (SLA) and leaf area index (LAI) in a group of different-aged boreal forest stands in well and poorly drained soils. Species-specific SLA (for three feather mosses, four Sphagnum spp. and Aulacomnium palustre mixed with Tomentypnum nitens) was assessed by determining the projected area using a flatbed scanner and cross-sectional geometry using a dissecting microscope. The hemisurface leaf area was computed as the product of SLA and live biomass and was scaled by coverage data collected at all stands. Pleurozium schreberi dominated the spatial coverage, biomass and leaf area in the well-drained stands, particularly the oldest, while S. fuscum and A. palustre were important in the poorly drained stands. Live moss biomass ranged from 47 to 230 g m(-2) in the well-drained stands dominated by feather mosses and from 102 to 228 g m(-2) in the poorly drained stands. Bryophyte SLA varied between 135 and 473 cm(2) g(-1), for A. palustre and S. capillifolium, respectively. SLA was strongly and significantly affected by bryophyte species, but did not vary between stands; in general, there was no significant difference between the SLA of non-Sphagnum mosses. Bryophyte LAI increased with stand age, peaking at 3.1 and 3.7 in the well and poorly drained stands, respectively; this represented approximately 40% of the overstory LAI in the well-drained stands and 100-1,000% in the poorly drained stands, underscoring the important role bryophytes play in the water and carbon budgets of these boreal forests.

  5. Inferring Amazon leaf demography from satellite observations of leaf area index

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    S. Caldararu

    2011-10-01

    Full Text Available Seasonal and year-to-year variations in leaf cover imprint significant spatial and temporal variability on biogeochemical cycles, and affect land-surface properties related to climate. We develop a demographic model of leaf phenology based on the hypothesis that trees seek an optimal Leaf Area Index (LAI as a function of available light and soil water, and fitted it to spaceborne observations of LAI over the Amazon Basin, 2001–2005. We find the model reproduces the spatial and temporal LAI distribution whilst also predicting geographic variation in leaf age from the basin center (2.1 ± 0.2 yr, through to the lowest values over the deciduous Eastern Amazon (6 ± 2 months. The model explains the observed increase in LAI during the dry season as a net addition of leaves in response to increased solar radiation. We anticipate our work to be a starting point from which to develop better descriptions of leaf phenology to incorporate into more sophisticated earth system models.

  6. Inferring Amazon leaf demography from satellite observations of leaf area index

    Directory of Open Access Journals (Sweden)

    S. Caldararu

    2012-04-01

    Full Text Available Seasonal and year-to-year variations in leaf cover imprint significant spatial and temporal variability on biogeochemical cycles, and affect land-surface properties related to climate. We develop a demographic model of leaf phenology based on the hypothesis that trees seek an optimal leaf area index (LAI as a function of available light and soil water, and fit it to spaceborne observations of LAI over the Amazon basin, 2001–2005. We find the model reproduces the spatial and temporal LAI distribution whilst also predicting geographic variation in leaf age from the basin centre (2.1 ± 0.2 years, through to the lowest values over the deciduous eastern and southern Amazon (6 ± 2 months. The model explains the observed increase in LAI during the dry season as a net addition of leaves in response to increased solar radiation. We anticipate our work to be a starting point from which to develop better descriptions of leaf phenology to incorporate into more sophisticated earth system models.

  7. The Design and Implementation of the Leaf Area Index Sensor

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    Xiuhong Li

    2015-03-01

    Full Text Available The quick and accurate acquisition of crop growth parameters on a large scale is important for agricultural management and food security. The combination of photographic and wireless sensor network (WSN techniques can be used to collect agricultural information, such as leaf area index (LAI, over long distances and in real time. Such acquisition not only provides farmers with photographs of crops and suggestions for farmland management, but also the collected quantitative parameters, such as LAI, can be used to support large scale research in ecology, hydrology, remote sensing, etc. The present research developed a Leaf Area Index Sensor (LAIS to continuously monitor the growth of crops in several sampling points, and applied 3G/WIFI communication technology to remotely collect (and remotely setup and upgrade crop photos in real-time. Then the crop photos are automatically processed and LAI is estimated based on the improved leaf area index of Lang and Xiang (LAILX algorithm in LAIS. The research also constructed a database of images and other information relating to crop management. The leaf length and width method (LAILLW can accurately measure LAI through direct field harvest. The LAIS has been tested in several exemplary applications, and validation with LAI from LAILLW. The LAI acquired by LAIS had been proved reliable.

  8. The design and implementation of the leaf area index sensor.

    Science.gov (United States)

    Li, Xiuhong; Liu, Qiang; Yang, Rongjin; Zhang, Haijing; Zhang, Jialin; Cai, Erli

    2015-03-13

    The quick and accurate acquisition of crop growth parameters on a large scale is important for agricultural management and food security. The combination of photographic and wireless sensor network (WSN) techniques can be used to collect agricultural information, such as leaf area index (LAI), over long distances and in real time. Such acquisition not only provides farmers with photographs of crops and suggestions for farmland management, but also the collected quantitative parameters, such as LAI, can be used to support large scale research in ecology, hydrology, remote sensing, etc. The present research developed a Leaf Area Index Sensor (LAIS) to continuously monitor the growth of crops in several sampling points, and applied 3G/WIFI communication technology to remotely collect (and remotely setup and upgrade) crop photos in real-time. Then the crop photos are automatically processed and LAI is estimated based on the improved leaf area index of Lang and Xiang (LAILX) algorithm in LAIS. The research also constructed a database of images and other information relating to crop management. The leaf length and width method (LAILLW) can accurately measure LAI through direct field harvest. The LAIS has been tested in several exemplary applications, and validation with LAI from LAILLW. The LAI acquired by LAIS had been proved reliable.

  9. An evolutionary attractor model for sapwood cross section in relation to leaf area.

    Science.gov (United States)

    Westoby, Mark; Cornwell, William K; Falster, Daniel S

    2012-06-21

    Sapwood cross-sectional area per unit leaf area (SA:LA) is an influential trait that plants coordinate with physical environment and with other traits. We develop theory for SA:LA and also for root surface area per leaf area (RA:LA) on the premise that plants maximizing the surplus of revenue over costs should have competitive advantage. SA:LA is predicted to increase in water-relations environments that reduce photosynthetic revenue, including low soil water potential, high water vapor pressure deficit (VPD), and low atmospheric CO(2). Because sapwood has costs, SA:LA adjustment does not completely offset difficult water relations. Where sapwood costs are large, as in tall plants, optimal SA:LA may actually decline with (say) high VPD. Large soil-to-root resistance caps the benefits that can be obtained from increasing SA:LA. Where a plant can adjust water-absorbing surface area of root per leaf area (RA:LA) as well as SA:LA, optimal RA:SA is not affected by VPD, CO(2) or plant height. If selection favours increased height more so than increased revenue-minus-cost, then height is predicted to rise substantially under improved water-relations environments such as high-CO(2) atmospheres. Evolutionary-attractor theory for SA:LA and RA:LA complements models that take whole-plant conductivity per leaf area as a parameter. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. [The analysis of the causes of variability of the relationship between leaf dry mass and area in plants].

    Science.gov (United States)

    Vasfilov, S P

    2011-01-01

    The lamina dry mass: area ratio (LMA - Leaf Mass per Area) is a quite variable trait. Leaf dry mass consists of symplast mass (a set of all leaf protoplasts) and apoplast mass (a set of all cell walls in a leaf). The ratio between symplast and apoplast masses is positively related to any functional trait of leaf calculated per unit of dry mass. The value of this ratio is defined by cells size and their number per unit of leaf area, number of mesophyll cells layers and their differentiation between palisade and spongy ones, and also by density of cells packing. The LMA value is defined by leaf thickness and density. The extent and direction of variability in both leaf traits define the extent and direction of variability in LMA. Negative correlation between leaf thickness and density reduces the level of LMA variability. As a consequence of this correlation the following pattern emerges: the thinner a leaf, the denser it is. Changes in the traits that define the LMA value take place both within a species under the influence of environmental factors and between species that differ in leaf structure and functions. Light is the most powerful environmental factor that influences the LMA, increase in illumination leading to increase in LMA. This effect occurs during leaf growth at the expense of structural changes associated with the reduction of symplast/apoplast mass ratio. Under conditions of intense illumination, LMA may increase due to accumulation of starch. With regard to the majority of leaf functions, the mass of starch may be ascribed to apoplast. Starch accumulation in leaves is observed also under conditions of elevated CO2 concentration in the air. Under high illumination, however, LMA increases also due to increased apoplast contribution to leaf dry mass. Scarce mineral nutrition leads to LMA increase due to lowering of growth zones demands for phothosyntates and, therefore, to increase in starch content of leaves. High level of mineral nutrition during

  11. Use of remotely sensed precipitation and leaf area index in a distributed hydrological model

    DEFF Research Database (Denmark)

    Andersen, Jens; Dybkjær, Gorm Ibsen; Jensen, Karsten Høgh

    2002-01-01

    distributed hydrological modelling, remote sensing, precipitation, leaf area index, NOAA AVHRR, cold cloud duration......distributed hydrological modelling, remote sensing, precipitation, leaf area index, NOAA AVHRR, cold cloud duration...

  12. Georeferenced Scanning System to Estimate the Leaf Wall Area in Tree Crops

    Directory of Open Access Journals (Sweden)

    Ignacio del-Moral-Martínez

    2015-04-01

    Full Text Available This paper presents the use of a terrestrial light detection and ranging (LiDAR system to scan the vegetation of tree crops to estimate the so-called pixelated leaf wall area (PLWA. Scanning rows laterally and considering only the half-canopy vegetation to the line of the trunks, PLWA refers to the vertical projected area without gaps detected by LiDAR. As defined, PLWA may be different depending on the side from which the LiDAR is applied. The system is completed by a real-time kinematic global positioning system (RTK-GPS sensor and an inertial measurement unit (IMU sensor for positioning. At the end, a total leaf wall area (LWA is computed and assigned to the X, Y position of each vertical scan. The final value of the area depends on the distance between two consecutive scans (or horizontal resolution, as well as the number of intercepted points within each scan, since PLWA is only computed when the laser beam detects vegetation. To verify system performance, tests were conducted related to the georeferencing task and synchronization problems between GPS time and central processing unit (CPU time. Despite this, the overall accuracy of the system is generally acceptable. The Leaf Area Index (LAI can then be estimated using PLWA as an explanatory variable in appropriate linear regression models.

  13. Georeferenced scanning system to estimate the leaf wall area in tree crops.

    Science.gov (United States)

    del-Moral-Martínez, Ignacio; Arnó, Jaume; Escolà, Alexandre; Sanz, Ricardo; Masip-Vilalta, Joan; Company-Messa, Joaquim; Rosell-Polo, Joan R

    2015-04-10

    This paper presents the use of a terrestrial light detection and ranging (LiDAR) system to scan the vegetation of tree crops to estimate the so-called pixelated leaf wall area (PLWA). Scanning rows laterally and considering only the half-canopy vegetation to the line of the trunks, PLWA refers to the vertical projected area without gaps detected by LiDAR. As defined, PLWA may be different depending on the side from which the LiDAR is applied. The system is completed by a real-time kinematic global positioning system (RTK-GPS) sensor and an inertial measurement unit (IMU) sensor for positioning. At the end, a total leaf wall area (LWA) is computed and assigned to the X, Y position of each vertical scan. The final value of the area depends on the distance between two consecutive scans (or horizontal resolution), as well as the number of intercepted points within each scan, since PLWA is only computed when the laser beam detects vegetation. To verify system performance, tests were conducted related to the georeferencing task and synchronization problems between GPS time and central processing unit (CPU) time. Despite this, the overall accuracy of the system is generally acceptable. The Leaf Area Index (LAI) can then be estimated using PLWA as an explanatory variable in appropriate linear regression models.

  14. Leaf area compounds height-related hydraulic costs of water transport in Oregon White Oak trees.

    Science.gov (United States)

    N. Phillips; B. J. Bond; N. G. McDowell; Michael G. Ryan; A. Schauer

    2003-01-01

    The ratio of leaf to sapwood area generally decreases with tree size, presumably to moderate hydraulic costs of tree height. This study assessed consequences of tree size and leaf area on water flux in Quercus garryana Dougl. ex. Hook (Oregon White Oak), a species in which leaf to sapwood area ratio increases with tree size. We tested hypotheses that...

  15. Linear measurements of the leaf blade in xaraes and massai grasses for estimation of the leaf area

    Directory of Open Access Journals (Sweden)

    Wilton Ladeira da Silva

    2013-09-01

    Full Text Available Knowledge on the leaf area of foraging grasses is essential, since it’s one of the most important variables in the evaluation of plant growth. Thus, one aimed at determining equations which allow, through simple measurements of leaf length, as well as average and maximum width, to quickly and accurately estimate the actual leaf area of Brachiaria brizantha cv. Xaraes and Panicum maximum cv. Massai. One measured with millimeter rulers the length along the main vein (L, the maximum width perpendicular to the main vein (Wmax, and the average width (Wave of leaf blades in both species. For determining the actual leaf areas (ALA, one used the Li-Cor®, model LI 3000. Regression and correlation studies were performed between ALA and the leaf area estimated through the linear or exponential equations for choosing the best equations. For xaraes grass the equation with the best accuracy for estimating ALA was the linear 0.53+0.98 LWave and for massai grass the best options were the linear 1.30+0.92 LWave and the exponential 8.86e0.04LWmax and 10.30e0.03LWave. Estimates of the leaf area of xaraes grass and massai grass through simple measurements of leaf length and width have proved to be effective and accurate.

  16. Simulation of leaf area index and biomass at landscape scale

    Institute of Scientific and Technical Information of China (English)

    ZHANGNa; YUGuirui; YUZhenliang; ZHAOShidong

    2003-01-01

    The method for simulating the temporal and spatial distribution patterns of leaf area index (LAI) and biomass at landscape scale using remote sensing images and surface data was discussed in this paper,The procedure was:(1) annual maximum normalized difference vegetation index (NDVI) over the landscape was calculated from TM images;(2) the relationship model between NDVI and LAI was built and annual maximum LAI over the landscape was simulated;(3) the relationship models between LAI and biomass were built and annual branch ,stem ,root and maximum leaf biomass over the landscape were simulated;(4) spatial distribution patterns of leaf biomass and LAI in different periods all the year round were obtained.The simulation was based on spatial analysis module GRID in ArcoInfo software ,The method is laso a kind of scaling method from patch scale to landscape scale ,A case study of Changbai Mountain Nature Reserve was dissertated ,Aalysis and primary validation were carried out to the simulated LAI and biomass for the major vegetation types in the Changbai Mountain in 1995.

  17. Plant morphology, environment, and leaf area growth in wheat and maize

    NARCIS (Netherlands)

    Bos, H.J.

    1999-01-01

    Leaf area expansion of wheat (Triticum aestivum L.) and maize (Zea mays L.) plants, as contrasting representatives of the Gramineae family, was analysed. Seven variables were identified that together completely determine leaf area expansion of the plant: leaf appearance rate per tiller, specific sit

  18. Leaf area expansion and assimilate production in sunflower (Helianthus annuus L.) growing under low phosphorus conditions.

    NARCIS (Netherlands)

    Rodriguez, D.; Zubillaga, M.M.; Ploschuk, E.L.; Keltjens, W.G.; Goudriaan, J.; Lavado, R.S.

    1998-01-01

    Reductions in leaf area and plant growth as a consequence of phosphorus (P) limitations have been attributed both to direct effects of P shortage on leaf expansion rate and to a reduced production of assimilates required for growth. Canopy assimilation and leaf area expansion are closely interrelate

  19. Leaf thickness controls variation in leaf mass per area (LMA) among grazing-adapted grasses in Serengeti.

    Science.gov (United States)

    Griffith, Daniel M; Quigley, Kathleen M; Anderson, T Michael

    2016-08-01

    Leaf mass per area (LMA) is a primary plant functional trait that represents the cost of constructing a leaf. Ultimately, plants modify LMA by altering leaf thickness (LT), leaf dry matter content (LDMC), or both. While LMA can be modified through both of these constituents, studies of LMA have found that there is variation in whether LT or LDMC changes are responsible for LMA-and the relationships change depending on the species or functional groups being compared. In this study, we used a phylogenetic framework to determine that evolutionary shifts in LMA are driven by LT, and not LDMC, among 45 Serengeti grass species. We considered two alternative hypotheses that could result in evolutionary correlation of LMA on LT but not LDMC: either (1) LT is more labile than LDMC-and is therefore a less costly means to change LMA or (2) LDMC is tightly coupled to a different dimension of leaf variation (e.g., leaf hydraulics), leaving LT as the source of variation in LMA. LT was not more labile than LDMC, leading us to conclude that the evolution of LMA has been shaped by LT because LDMC is responding to other demands on leaf physiology. We speculate that leaf hydraulics provide this constraint on LDMC. The decoupling of LDMC from LT may allow plants to better optimize resource allocation in ecosystems where gradients in light competition, herbivory, and aridity place competing demands on leaf economics.

  20. INFLUENCE OF LEAF AREA INDEX (LAI ON SLOPE STABILITY

    Directory of Open Access Journals (Sweden)

    Tymoteusz Adam Zydroń

    2016-09-01

    Full Text Available Determination of effect of the leaf area ratio on the results of slope stability calculation of one of the landslide's prone slope of in the Pogórze Wiśnickie was presented in the paper. The calculations were carried out in modules Vadose/W and SLOPE/W of package GeoStudio 2012. The calculations involved the integration of rainfall infiltration process and slope stability calculations. As a result, the calculations allow to determinate precipitation conditions (time and accumulated precipitation height causing slope failure (i.e. rainfall threshold. The calculation results showed significant impact of LAI on the results of modeling. It was revealed, that LAI values in range 1-3, corresponding to the grass vegetation, contribute in long-term to accumulation of precipitation within slope, which limits its retention ability when intense rainfalls occur. In turn, the leaf are index LAI = 5, corresponding to the coverage of trees, increase the retentive capacity of the soil, which resulting in delayed response of slope on rainfall with in comparison to an area covered with grass plants. It was also found significant impact of moisture content conditions on rainfall threshold. It was revealed that in case of analyzed slope threshold rainfall can be comprised from 90 mm to over 700 mm.

  1. Estimation of Tropical Forest Leaf Area Index Using Medium-Footprint Lidar

    Science.gov (United States)

    Sheldon, S. L.; Dubayah, R. O.; Clark, D. B.; Hofton, M. A.; Blair, J. B.

    2008-12-01

    As an important descriptor of forest canopy structure and productivity, leaf surface area strongly relates to respiration, photosynthesis, canopy dynamics, and other biophysical processes. Leaf Area Index (LAI), the amount of one sided leaf area per unit of ground area, has been an important parameter in a variety of ecosystem models. We explore the use of medium-footprint airborne scanning lidar to estimate the spatial distribution of LAI at a landscape scale. Direct estimates of LAI were collected on vertical transects at 71 sites stratified across a tropical wet forest landscape at La Selva Biological Station in Costa Rica. Vertical canopy structure information was collected by the Laser Vegetation Imaging Sensor (LVIS) over La Selva in March of 2005. We analyze the relationship between field-derived LAI estimates and three-dimensional lidar-derived canopy structure information, specifically waveforms and waveform-derived metrics. We also assess the potential of lidar data to scale local estimates of LAI to the landscape level.

  2. Joint leaf chlorophyll and leaf area index retrieval using a regularized canopy reflectance model inversion system

    Science.gov (United States)

    Houborg, R.; McCabe, M. F.; Gitelson, A. A.

    2013-12-01

    Leaf area index (LAI) and leaf chlorophyll (Chl) represent key biophysical and biochemical controls on water, energy and carbon exchange processes in the terrestrial biosphere. In combination LAI and Chl provide critical information on vegetation density and phenology, the vitality of vegetation and photosynthetic functioning, and joint satellite-based retrievals can be used to inform land surface models and reduce uncertainties of model predicted ecosystem fluxes in space and time. Simultaneous retrieval of LAI and Chl from space observations is however extremely challenging as the interference of atmospheric effects, canopy characteristics and background reflectance may confound the detection of relatively subtle differences in canopy reflectance resulting from changes in Chl. Regularization strategies are therefore required to increase robustness and accuracy of retrieved properties and more reliably separate soil, leaf and canopy variables. Here we describe recent refinements to the REGularized canopy reFLECtance model (REGFLEC) retrieval system, which includes enhanced regularization techniques for exploiting ancillary LAI and temporal information derived from multiple satellite scenes over a given growing season. REGFLEC is applied to Landsat time-series data and retrieval results evaluated against in-situ LAI and Chl collected over maize and soybean sites in central Nebraska over a 5-year period (2001-2005). While REGFLEC may provide useful information on the density and vitality of vegetation, the results reflect the challenges associated with accurately extracting the relatively small leaf-level chlorophyll signal from the total satellite signal when using a few standard broad bands available operationally (i.e. blue, green, red and near-infrared) as input to a homogeneous canopy reflectance model. A noteworthy and novel aspect of the REGFLEC approach is the fact that no site-specific data were used to calibrate the model that may be run in a completely

  3. Estimation of papaya leaf area using the central vein length

    Directory of Open Access Journals (Sweden)

    Campostrini Eliemar

    2001-01-01

    Full Text Available Four genotypes of papaya (Carica papaya L. two from the 'Solo' group (Sunrise Solo and Improved Sunrise Solo line 72/12 and two from the 'Formosa' group (Tainung 02 and Known-You 01, grown in Macaé, RJ, Brazil (lat. 22(0 24' S, long. 41(0 42' W, were used in this study. Twenty-five mature leaves from each genotype were sampled four and five months after seedling transplant to the field to determine the length of the leaf central vein (LLCV and the leaf area (LA. According to covariance analyses there were no significant differences in the slope and intercept of the mathematical models calculated for each genotype. Thus, a single mathematical model (Log LA = 0.315 + 1.85 Log LLCV, R²=0.898 was adjusted to estimate the LA using the length of LLCV for the four genotypes. An unique model can be applied to estimate the LA for the four papaya genotypes using LLCV in the range from 0.25 to 0.60 m, and for papaya trees 150 to 180 days after transplanting.

  4. An analysis of the growth of leaf area of oil palms in Indonesia

    NARCIS (Netherlands)

    Gerritsma, W.; Soebagyo, F.X.

    1999-01-01

    In two cultivar × density trials for oil palms (Elaeis guineensis) planted in Indonesia, single leaf area, number of green leaves per tree, leaf opening rate per year and rachis length of leaves were followed over fourteen years. The data were analysed to determine the time course of canopy leaf

  5. COEFFICIENTS FOR DETERMINATION OF THE LEAF AREA IN THREE BURLEY TOBACCO VARIETIES

    Directory of Open Access Journals (Sweden)

    RADKA PETROVA BOZHINOVA

    2006-10-01

    Full Text Available In relation to determination of leaf area through linear measurements of leaf blade and mathematical coeffi cients in Burley tobacco individual values of correction coeffi cients have been determined by variety and in dependence of the leaf position.

  6. Spectral estimation of green leaf area index of oats

    Science.gov (United States)

    Best, R. G.; Harlan, J. C.

    1985-01-01

    Green leaf area index (LAI) is a measure of vegetative growth and development and is frequently used as an input parameter in yield estimation and evapotranspiration models. Extensive destructive sampling is usually required to achieve accurate estimates of green LAI in natural situations. In this investigation, a statistical modeling approach was used to predict the green LAI of oats from bidirectional reflectance data collected with multiband radiometers. Stepwise multiple regression models based on two sets of spectral reflectance factors accounted for 73 percent and 65 percent of the variance in green LAI of oats. Exponential models of spectral data transformations of greenness, normalized difference, and near-infrared/red ratio accounted for more of the variance in green LAI than the multiple regression models.

  7. Spectral estimation of green leaf area index of oats

    Science.gov (United States)

    Best, R. G.; Harlan, J. C.

    1985-01-01

    Green leaf area index (LAI) is a measure of vegetative growth and development and is frequently used as an input parameter in yield estimation and evapotranspiration models. Extensive destructive sampling is usually required to achieve accurate estimates of green LAI in natural situations. In this investigation, a statistical modeling approach was used to predict the green LAI of oats from bidirectional reflectance data collected with multiband radiometers. Stepwise multiple regression models based on two sets of spectral reflectance factors accounted for 73 percent and 65 percent of the variance in green LAI of oats. Exponential models of spectral data transformations of greenness, normalized difference, and near-infrared/red ratio accounted for more of the variance in green LAI than the multiple regression models.

  8. Relationship of 2 100-2 300 nm Spectral Characteristics of Wheat Canopy to Leaf Area Index and Leaf N as Affected by Leaf Water Content

    Institute of Scientific and Technical Information of China (English)

    ZHAO Chun-Jiang; WANG Ji-Hua; LIU Liang-Yun; HUANG Wen-Jiang; ZHOU Qi-Fa

    2006-01-01

    The effects of leaf water status in a wheat canopy on the accuracy of estimating leaf area index (LAI) and N were determined in this study using extracted spectral characteristics in the 2 000-2 300 nm region of the short wave infrared (SWI) band. A newly defined spectral index, relative adsorptive index in the 2 000-2 300 nm region (RAI2000-2300), which can be calculated by RAI2000-2300 = (R2224 - R2054) (R2224 + R2054)-1 with R being the reflectance at 2 224 or2 054 nm, was utilized. This spectral index, RAI2000-2300, was significantly correlated (P < 0.01) with green LAI and leaf N concentration and proved to be potentially valuable for monitoring plant green LAI and leaf N at the field canopy scale. Moreover, plant LAI could be monitored more easily and more successfully than plant leaf N. The study also showed that leaf water had a strong masking effect on the 2 000-2 300 nm spectral characteristics and both the coefficient between RAI2000-2300 and green LAI and that between RAI2000-2300 and leaf N content decreased as leaf water content increased.

  9. Estimating the total leaf area of the green dwarf coconut tree (Cocos nucifera L.

    Directory of Open Access Journals (Sweden)

    Sousa Elias Fernandes de

    2005-01-01

    Full Text Available Leaf area has significant effect on tree transpiration, and its measurement is important to many study areas. This work aimed at developing a non-destructive, practical, and empirical method to estimate the total leaf area of green dwarf coconut palms (Cocos nucifera L. in plantations located at the northern region of Rio de Janeiro state, Brazil. A mathematical model was developed to estimate total leaf area values (TLA as function of the average lengths of the last three leaf raquis (LR3, and of the number of leaves in the canopy (NL. The model has satisfactory degree of accuracy for agricultural engineering purposes.

  10. Estimation of Leaf Area Index Using IRS Satellite Images

    Directory of Open Access Journals (Sweden)

    A Faridhosseini

    2012-12-01

    Full Text Available Estimation of vegetation cover attributes, such as the Leaf Area Index (LAI, is an important step in identifying the amount of water use for some plants. The goal of this study is to investigate the feasibility of using IRS LISS-III data to retrieve LAI. To get a LAI retrieval model based on reflectance and vegetation index, detailed field data were collected in the study area of eastern Iran. In this study, atmospheric corrected IRS LISS-III imagery was used to calculate Normalized Difference Vegetation Index (NDVI. Data of 50 samples of LAI were measured by Sun Scan System – SS1 in the study area. In situ measurements of LAI were related to widely use spectral vegetation indices (NDVI. The best model through analyzing the results was LAI = 19.305×NDVI+5.514 using the method of linear-regression analysis. The results showed that the correlation coefficient R2 was 0.534 and RMSE was 0.67. Thereby, suggesting that, when using remote sensing NDVI for LAI estimation, not only is the choice of NDVI of importance but also prior knowledge of plant architecture and soil background. Hence, some kind of landscape stratification is required before using multi- spectral imagery for large-scale mapping of vegetation biophysical variables.

  11. Responses of leaf nitrogen concentration and leaf area of Populus sibirica seedlings to nitrogen fertilization in a semi-arid area, Mongolia

    Science.gov (United States)

    Chang, H.; Han, S. H.; Son, Y.

    2016-12-01

    We investigate the effects of three rates of nitrogen fertilization on Populus sibirica seedlings in a semi-arid area, Elsentasarkhai, Mongolia. In May 2015, 2-year-old P. sibirica seedlings were planted in the control and three fertilized plots. Urea was applied to each seedling with 5 g (N1), 15 g (N2) and 30 g (N3) in May 2015 and 2016. Leaf nitrogen concentration, total chlorophyll content, leaf area and specific leaf area (SLA) were measured in July 2016 and the differences were analyzed using one-way ANOVA (PSLA, however, leaf area in the N2 plot (3109.9 cm2) was significantly higher than that in the control (494.0 cm2). The N3 treatment significantly increased leaf nitrogen concentration and total chlorophyll content, however, it did not change leaf area. The N2 treatment seems to be suitable for leaf growth of P. sibirica seedlings in the study site. To determine the optimal rate of nitrogen fertilization, the growth and biomass of seedlings after treatments also need to be examined. * This study was supported by Korea Forest Service (S211216L030120).

  12. Causes and consequences of variation in leaf mass per area (LMA): a meta-analysis.

    Science.gov (United States)

    Poorter, Hendrik; Niinemets, Ulo; Poorter, Lourens; Wright, Ian J; Villar, Rafael

    2009-01-01

    Here, we analysed a wide range of literature data on the leaf dry mass per unit area (LMA). In nature, LMA varies more than 100-fold among species. Part of this variation (c. 35%) can be ascribed to differences between functional groups, with evergreen species having the highest LMA, but most of the variation is within groups or biomes. When grown in the same controlled environment, leaf succulents and woody evergreen, perennial or slow-growing species have inherently high LMA. Within most of the functional groups studied, high-LMA species show higher leaf tissue densities. However, differences between evergreen and deciduous species result from larger volumes per area (thickness). Response curves constructed from experiments under controlled conditions showed that LMA varied strongly with light, temperature and submergence, moderately with CO2 concentration and nutrient and water stress, and marginally under most other conditions. Functional groups differed in the plasticity of LMA to these gradients. The physiological regulation is still unclear, but the consequences of variation in LMA and the suite of traits interconnected with it are strong. This trait complex is an important factor determining the fitness of species in their environment and affects various ecosystem processes.

  13. Viewing forests from below: fine root mass declines relative to leaf area in aging lodgepole pine stands.

    Science.gov (United States)

    Schoonmaker, A S; Lieffers, V J; Landhäusser, S M

    2016-07-01

    In the continued quest to explain the decline in productivity and vigor with aging forest stands, the most poorly studied area relates to root system change in time. This paper measures the wood production, root and leaf area (and mass) in a chronosequence of fire-origin lodgepole pine (Pinus contorta Loudon) stands consisting of four age classes (12, 21, 53, and ≥100 years), each replicated ~ five times. Wood productivity was greatest in the 53-year-old stands and then declined in the ≥100-year-old stands. Growth efficiency, the quantity of wood produced per unit leaf mass, steadily declined with age. Leaf mass and fine root mass plateaued between the 53- and ≥100-year-old stands, but leaf area index actually increased in the older stands. An increase in the leaf area index:fine root area ratio supports the idea that older stand are potentially limited by soil resources. Other factors contributing to slower growth in older stands might be lower soil temperatures and increased self-shading due to the clumped nature of crowns. Collectively, the proportionally greater reduction in fine roots in older stands might be the variable that predisposes these forests to be at a potentially greater risk of stress-induced mortality.

  14. Characteristics of leaf areas of plantations in semiarid hills and gully loess regions

    Institute of Scientific and Technical Information of China (English)

    Jing YIN; Fan HE; Guoyu QIU; Kangning HE; Jinghui TIAN; Weiqiang ZHANG; Yujiu XIONG; Shaohua ZHAO; Jianxin LIU

    2009-01-01

    The objectives of our study were to explore the relationship of leaf area and stand density and to find a convenient way to measure stand leaf areas. During the 2004 growing season, from May to October, we used direct and indirect methods to measure the seasonal variation of the leaf areas of tree and shrub species. The trees were from Robinia pseudoacacia stands of four densities (3333 plants/hm2, 1666 plants/hm2, 1111 plants/hm2, and 833 plants/hm2) and Platycladus orientalis stands of three densities (3333 plants/hm2, 1666 plants/hm2, and 1111 plants/hm2). The shrub species were Caragana korshinskii, Hippophae rhamnoides, and Amorpha fruticosa. Based on our survey data, empirical formulas for calculating leaf area were obtained by correlating leaf fresh weight, diameter of base branches, and leaf areas. Our results show the following: 1) in September, the leaf area and leaf area index (LAI) of trees (R. pseudoacacia and P orientalis) reached their maximum values, with LAI peak values of 10.5 and 3.2, respectively. In August, the leaf area and LAI of shrubs (C. korshinskii, H. rhamnoides, and A. fruticosa) reached their maximum values, with LAI peak values of 1.195, 1.123, and 1.882, respectively. 2) There is a statistically significant power relation between leaf area and leaf fresh weight for R. pseudoacacia. There are significant linear relationships between leaf area and leaf fresh weight for P. orientalis, C. korshinskii, H. rhamnoides, and A. fruticosa. Moreover, there is also a significant power relation between leaf area and diameter of base branches for C. korshinskii. There are significant linear relations between leaf area and diameter of base branches of H. rhamnoides and A. fruticosa. 3) In the hills and gully regions of the Loess Plateau, the LAIs of R. pseudoacacia stand at different densities converged after the planted stands entered their fast growth stage. Their LAI do not seem to be affected by its initial and current density. The same is true

  15. The Microclimate and Leaf Area Index of Yam Plant in the Guinea ...

    African Journals Online (AJOL)

    The Microclimate and Leaf Area Index of Yam Plant in the Guinea Savanna Ecological Zone of Nigeria. ... and hence plant production is mainly the function of its leaf area index (LAI). ... mulching yam beds to reduce the scorching effect of sun.

  16. Non-destructive automatic leaf area measurements by combining stereo and time-of-flight images

    NARCIS (Netherlands)

    Song, Y.; Glasbey, C.A.; Polder, G.; Heijden, van der G.W.A.M.

    2014-01-01

    Leaf area measurements are commonly obtained by destructive and laborious practice. This study shows how stereo and time-of-flight (ToF) images can be combined for non-destructive automatic leaf area measurements. The authors focus on some challenging plant images captured in a greenhouse environmen

  17. Water use of tree lines: importance of leaf area and micrometeorology in sub-humid Kenya

    NARCIS (Netherlands)

    Radersma, S.; Ong, C.K.; Coe, R.

    2006-01-01

    In this research the relative importance of leaf area and microclimatic factors in determining water use of tree lines was examined in sub-humid Western Kenya. Measurements of tree water-use by a heat-balance technique, leaf area, bulk air saturation deficit, daily radiation, and soil water content

  18. Estimation of leaf area for large scale phenotyping and modeling of rose genotypes

    NARCIS (Netherlands)

    Gao, M.; Heijden, van der G.W.A.M.; Vos, J.; Eveleens, B.A.; Marcelis, L.F.M.

    2012-01-01

    Leaf area is a major parameter in many physiological and plant modeling studies. When we want to use physiological models in plant breeding, we need to measure the leaf area for a large number of genotypes. This requires a fast and non-destructive method. In this study, we investigated whether for c

  19. Non-destructive leaf area measurement in maize (Zea mays L.).

    Science.gov (United States)

    Sezer, Ismail; Oner, Fatih; Mut, Zeki

    2009-09-01

    In this research, leaf area prediction model was developed for some leaf-used maize (Zea mays L.) cultivars namely Coluna, Luce, Maveric, Ranchero, TTM-813, Zamora and RX-788 grown in Black Sea region of Turkey. Lamina width, length and leaf area were measured without destroying the leaf to develop the models. The actual leaf areas of the plants were measured by PLACOM Digital Planimeter and multiple regression analysis with Excel 2003 computer package program was performed for the plants separately. The produced leaf area prediction models in the present study were formulized as LA = a - (b x W2) + [c x (W x L)] where LA is leaf area, W is leaf width, L is leaf length and a, b, c are coefficiencies. R2 values for maize cultivars tested varied with species from 0.95 in Luce to 0.98 in Maveric. All R2 values and standard errors were found to be significant at the p < 0.001 level.

  20. Leaf Area Index Retrieved from Thermal Hyperspectral Data

    Science.gov (United States)

    Neinavaz, Elnaz; Skidmore, Andrew K.; Darvishzadeh, Roshanak; Groen, Thomas A.

    2016-06-01

    Leaf area index (LAI) is an important essential biodiversity variable due to its role in many terrestrial ecosystem processes such as evapotranspiration, energy balance, and gas exchanges as well as plant growth potential. A novel approach presented here is the retrieval of LAI using thermal infrared (8-14 μm, TIR) measurements. Here, we evaluate LAI retrieval using TIR hyperspectral data. Canopy emissivity spectral measurements were recorded under controlled laboratory conditions using a MIDAC (M4401-F) illuminator Fourier Transform Infrared spectrometer for two plant species during which LAI was destructively measured. The accuracy of retrieval for LAI was then assessed using partial least square regression (PLSR) and narrow band index calculated in the form of normalized difference index from all possible combinations of wavebands. The obtained accuracy from the PLSR for LAI retrieval was relatively higher than narrow-band vegetation index (0.54 data. The study highlights the potential of hyperspectral thermal data for retrieval of vegetation biophysical variables at the canopy level for the first time.

  1. Retrieving leaf area index from SPOT4 satellite data

    Directory of Open Access Journals (Sweden)

    M. Aboelghar

    2010-12-01

    Full Text Available A research project was conducted as collaboration between the National Authority for Remote Sensing and Space Sciences (NARSS in Egypt and the Institute of Remote Sensing Applications (IRSA, Chinese Academy of Sciences. The objective of this study is to generate normalized difference vegetation index (NDVI–leaf area index (LAI statistical inversion models for three rice varieties planted in Egypt (Giza-178, Sakha-102, and Sakha-104 using the data of two rice growing seasons. Field observations were carried out to collect LAI field measurements during 2008 and 2009 rice seasons. The SPOT4 satellite data acquired in rice season of 2008 and 2009 conjunction with field observations dates were used to calculate the vegetation indices values. Statistical analyses were performed to confirm the assumptions of inversion modeling for plant variables and to get reliable models that fit the inversion relationship between LAI and NDVI. The inversion process resulted in three NDVI–LAI models adequate to predict LAI with 95% confidence for the three different rice varieties. The accuracy of the generated models ranged between 50% in the case of Sakha-104 and 82% in the case of Giza-178. LAI maps were produced from NDVI imageries based on the generated models.

  2. The Stimulating Effects of Rewatering on Leaf Area of Winter Wheat Suffering Water Stress

    Institute of Scientific and Technical Information of China (English)

    LIU Xiao-ying; LUO Yuan-pei; SHI Yuan-chun

    2002-01-01

    After water stress at various levels and durations at different growth stages, rewatering could greatly stimulate the leaf area development of winter wheat. The results showed that the stimulation effect changed with water stress time, degree and duration. Rewatering under earlier stress had greater stimulation effect on leaf area than that under later stress. Higher stimulation effect was observed under severe water stress than that under moderate stress. Longer duration of stress resulted in low stimulation effect. In spite of the greater stimulation effect under severe and longer stress, the final leaf area in these situations was lower than that under moderate stress and shorter duration. Whenever the stress occurred, the stimulating effect was due to the increase of the leaf area of the tillers. Once the leaf on the main stem emerged during stress period,rewatering had no effect on its size, and consequently its leaf area. The stimulation of rewateirng on leaf area contributed to the final grain yield by 45% under moderate stress, and 67% under severe stress. Although the stimulation partly compensated for the loss during stress, the final leaf area and the grain yield could not reach the level without water stress.

  3. Leaf Area Index Retrieval Using High Resolution Remote Sensing Data

    Directory of Open Access Journals (Sweden)

    Michele Rinaldi

    2010-06-01

    Full Text Available Vegetation indices obtained from remote sensed data can be used to characterize crop canopy on a large scale using a non-destructive method. With the recent launch of the IKONOS satellite, very high spatial resolution (1 meter images are available for the detailed monitoring of ecosystems as well as for precision agriculture. The aim of this study is to evaluate the accuracy of leaf area index (LAI retrieval over agricultural area that can be obtained by empirical relationships between different spectral vegetation indices (VI and LAI measured on three different dates over the spring-summer period of 2008, in the Capitanata plain (Southern Italy. All the VIs used (NDVI, RDVI, WDVI, MSAVI and GEMI were related to the LAI through exponential regression functions, either global or crop-dependent. In the first case, LAI was estimated with comparable accuracies for all VIs employed, with a slightly higher accuracy for GEMI, which determination coefficient achieved the value of 0.697. Whereas the LAI regression functions were calculated separately for each crop, the WDVI, GEMI and RDVI vegetation indices provided the highest determination coefficients with values close to 0.90 for wheat and sugar beet, and with values close to 0.70 for tomatoes. A validation of the models was carried out with a selection of independent sampling data. The validation confirmed that WDVI and GEMI were the VIs that provided the highest LAI retrieval accuracies, with RMSE values of about to 1.1 m2 m-2. The exponential functions, calibrated and validated to calculate LAI from GEMI, were used to derive LAI maps from IKONOS high-resolution remote sensing images with good accuracy. These maps can be used as input variables for crop growth models, obtaining relevant information that can be useful in agricultural management strategies (in particular irrigation and fertilization, as well as in the application of precision farming.

  4. Simple models for predicting leaf area of mango (Mangifera indica L.

    Directory of Open Access Journals (Sweden)

    Maryam Ghoreishi

    2012-01-01

    Full Text Available Mango (Mangifera indica L., one of the most popular tropical fruits, is cultivated in a considerable part of southern Iran. Leaf area is a valuable parameter in mango research, especially plant physiological and nutrition field. Most of available methods for estimating plant leaf area are difficult to apply, expensive and destructive which could in turn destroy the canopy and consequently make it difficult to perform further tests on the same plant. Therefore, a non-destructive method which is simple, inexpensive, and could yield an accurate estimation of leaf area will be a great benefit to researchers. A regression analysis was performed in order to determine the relationship between the leaf area and leaf width, leaf length, dry and fresh weight. For this purpose 50 mango seedlings of local selections were randomly took from a nursery in the Hormozgan province, and different parts of plants were separated in laboratory. Leaf area was measured by different method included leaf area meter, planimeter, ruler (length and width and the fresh and dry weight of leaves were also measured. The best regression models were statistically selected using Determination Coefficient, Maximum Error, Model Efficiency, Root Mean Square Error and Coefficient of Residual Mass. Overall, based on regression equation, a satisfactory estimation of leaf area was obtained by measuring the non-destructive parameters, i.e. number of leaf per seedling, length of the longest and width of widest leaf (R2 = 0.88 and also destructive parameters, i.e. dry weight (R2 = 0.94 and fresh weight (R2= 0.94 of leaves.

  5. Investigating the Alometric Relationships between Leaf Area and Some of Vegetative Characteristics in SC704 Corn Hybrid

    Directory of Open Access Journals (Sweden)

    E Zeinali

    2016-10-01

    in 2012. The experiment was carried out in a randomized complete block design as factorial with three replications. The experimental factors and their levels were, including plant density (4, 6, 8, 10 and 12 plants per square meter and planting date (May 30 and June 30. Each plot was including 6 rows with 76 cm inter-row spacing and 6 m length. Corn hybrid SC704, a common hybrid in Iran and Gorgan region, was used in this study. Plant sampling was carried out once every 10 days from 15 days after planting to physiological maturity to measure leaf dry weight, plant green leaf area, the leaf (node number per stem, dry weight of total vegetative plant parts and plant height. Green leaf area was measured using leaf area meter in laboratory. Plant samples were placed in an oven with 70 oC for 48 hours. To obtain allometric relationships various mathematical equations fitted to green leaf area against mentioned traits data. Fitting the functions to data and examining them was carried out in three steps: 1 Fitting function to each of the plant density in each planting date, 2 Fitting a function to all plant densities in each of two planting dates, separately, and 3 Fitting a function to all data. At each step, after fitting the functions and analysis of coefficients, if the differences were not significant, the next step was used. Statistical analysis was done using the software SAS and the graphs drew using Excel software. Results and Discussion The results showed that a non-linear segmented model can be used to describe the relationships between the number of leaves per stem with cumulative thermal units (R2= 0.94, RMSE =5.59%, and leaf area per plant with leaf dry weight per plant (R2= 0.98, RMSE =6.54% and plant dry weight (R2= 0.95, RMSE =11.25% in all plant densities and planting dates. Moreover, the results revealed that the effect of planting date and plant density on the phyllochron, time between the appearance of successive leaves on a shoot was not significant

  6. BIOMONITORING OF URBAN AREA BY ANATOMICAL LEAF CHANGES

    Directory of Open Access Journals (Sweden)

    Elena IRIZA

    2012-01-01

    Full Text Available Plants play a vital role as indicators of pollution. The automobile emissions are high particularly at the traffic intersections. Plants growing under the stress of air pollution show differences in leaf surface characteristics. Light microscopic studies of leaf surface revealed an increase in the number of stomata and trichomes of polluted populations in comparison to control populations of Plantago major and Plantago lanceolata. These changes can be considered as indicators of environmental stress.

  7. Seasonal patterns of tropical forest leaf area index and CO2 exchange

    Science.gov (United States)

    Doughty, Christopher E.; Goulden, Michael L.

    2008-03-01

    We used in situ and satellite measurements to investigate the seasonal patterns of leaf area index (LAI) and gross ecosystem CO2 exchange (GEE) by an evergreen tropical forest. The forest experienced a dry season from June through November. The rates of light-saturated CO2 uptake (GEE) were comparatively high from December through March and low from May through July. In situ measurements showed that LAI varied seasonally, with a minimum from May through September. Leaf production and leaf abscission were reduced from December through April. Leaf abscission increased in May, which reduced LAI. High rates of leaf abscission and production occurred from July through September associated with leaf turnover. Leaf abscission decreased abruptly in October, while production continued, which rapidly increased LAI. Leaf phenology was not directly correlated with changes in soil water. The seasonal cycle of in situ LAI differed markedly from the seasonal cycles of in situ normalized difference vegetation index (NDVI) and the Moderate Resolution Imaging Spectroradiometer (MODIS) MOD15 LAI product. We hypothesize that the NDVI and MOD15 seasonality at the site is driven partly by seasonal changes in leaf age and leaf reflectance. We developed three simple models to investigate the causes of GEE seasonality. The first two models showed that the seasonal changes in LAI alone, and the effects of leaf age on leaf-level photosynthesis alone, could not account for the observed GEE seasonality. The third model showed that the combined effect of seasonal changes in LAI and seasonal changes in leaf age and leaf photosynthesis was sufficient to account for the observed GEE seasonality.

  8. Quantity of plant leaf area on three major public squares in Kunming City, China

    Institute of Scientific and Technical Information of China (English)

    DONGYan; ZHAOLin-sen; ZHAOYu-xiang

    2004-01-01

    Regressive formulae to calculate the quantity of plant leaf area for 13 species of ornamental plants were set up based on investigation data of 30 species on 3 major public squares (Dongfeng square, Shengli square and Guandu square) in Kunruing City, China, which were applied to calculate quantities of plant leaf area of these 13 species. The quantities of plant leaf area for the other 17 ornamental plant species on these squares were directly measured, and the total quantity of plant leaf area of each studied square was obtained individually. The results showed that the quantity of plant leaf area on Shengli square with ornamental plants structure composed of arbor tree species, shrub tree species and turf grass was highest among the three squares. It is believed that the design model of multi-storied vertical structure and proper tending of plant community could not only increase the quantity of plant leaf area, but also play an important role in generating ecological and landscaping benefits.Some corresponding suggestions were put forward on the basis of comprehensive analyses on the plant leaf area quantity of the three representative squares in Kunming urban area.

  9. Varietal Difference in Leaf Nitrogen Content and Leaf Area and Their Effects to Ripening Rate During Mature Period of japonica Rice

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Employing the pot experiment of the complete random block design with 6 replications,four varieties of japonica rice (Fujisaka 5,Honenwase,Akitakomachi and Taichung 65) were used to study the varietal differ- ences in leaf nitrogen content (LNC) and leaf area during mature period,their relation and effects to the ripen ing rate. The results showed that(1) thee were varietal differences in LNC at the heading stage and the LNC decrease rate during the matue period,the high LNC at the heading stage was related to the rapid LNC de- crease. (2) There were two phases of the leaf area changing process during the mature period,first was the stable,and second was the decreased phase. There was varietal difference in the critical time of phase 1 and phase 2. The hign leaf area in the phase 1 was in relation to the rapid leaf area decrease in the phase 2. It was not found that there was relation between the leaf quality and quantity. (3)It wa unfavorable to the ripening rate for the high leaf area at the heading stage and the rapid decrease of the leaf area during the mature peri- od. (4)It was put forward that the super high yield rice variety should possess the not very high leaf area and high LNC at the heading stage,slow senescence in the leaf area during the mature period.

  10. Varietal Difference in Leaf Nitrogen Content and Leaf Area and Their Effects to Ripening Rate During Mature Period of japonica Rice

    Institute of Scientific and Technical Information of China (English)

    LiRong-tian; KojimaNobuyoshi; 等

    1999-01-01

    Employing the pot experiment of the complete random block design with 6 replications,four varieties of japonica rice (Fujisaka 5,Honenwase,Akitakomachi and Taichung 65) were used to study the varietal differences in leaf nitrogen content (LNC) and leaf area during mature period,their relation and effects to the ripening rate.The results showed that (1) thee were varietal differences in LNC at the heading stage and the LNC decrease rate during the matur period,the high LNC at the heading stage was related to the rapid LNC decrease.(2) There were two phases of the leaf area changing process during the mature period,first was the stable,and second was the decreased phase.There was varietal difference in the critical time of phase 1 and phase 2.The hign leaf area in the phase 1 was in relation to the rapid leaf area decrease in the phase 2.It was not found that there was relation between the leaf quality and quantity.(2)It wa unfavorable to the ripening rate for the high leaf area at the heading stage and the rapid decrease of the leaf area during the mature period.(4)It was put forward that the super high yield rice variety should possess the not very high leaf area and high LNC at the heading stage,slow senescence in the leaf area during the mature period.

  11. Taxonomy and remote sensing of leaf mass per area (LMA) in humid tropical forests

    Science.gov (United States)

    Gregory P. Asner; Roberta E. Martin; Raul Tupayachi; Ruth Emerson; Paola Martinez; Felipe Sinca; George V.N. Powell; S. Joseph Wright; Ariel E. Lugo

    2011-01-01

    Leaf mass per area (LMA) is a trait of central importance to plant physiology and ecosystem function, but LMA patterns in the upper canopies of humid tropical forests have proved elusive due to tall species and high diversity. We collected top-of-canopy leaf samples from 2873 individuals in 57 sites spread across the Neotropics, Australasia, and Caribbean and Pacific...

  12. Controls on and consequences of specific leaf area variation with permafrost depth in a boreal forest

    Science.gov (United States)

    Anderson, C.; Bond-Lamberty, B. P.; Huang, M.; Xu, Y.; Stegen, J.

    2016-12-01

    Specific leaf area (SLA, leaf area per unit dry mass) is an index of plant carbon captured by photosynthesis and an important input into many terrestrial process models. However, the controls on and consequences of SLA variation are poorly understood, especially in high latitude, climatically-sensitive permafrost regions. To address this, we measured SLA along with soil and topographic properties across a boreal forest permafrost transition, in which forest composition changed as permafrost deepened from 54 to >150 cm. Using replicated transects, we characterized both linear and threshold relationships between topographic and edaphic variables and SLA, and evaluated and expanded upon a conceptual model of environmental factors and vegetation patterns. We found that the depth of the soil active layer above permafrost (ALD) was highly correlated with SLA, for both coniferous and deciduous boreal tree species. Across a permafrost transition, intraspecific SLA variation was associated with a fivefold increase in NPP, suggesting that changes in ALD due to permafrost thaw could heavily influence ecosystem carbon accumulation. High levels of intraspecific trait variation suggest the need for flexible trait representation across plant functional types in Earth System Models. We thus incorporated our empirical environment-SLA relationships into spatially explicit spin-ups of the Community Land Model (CLM v4.5) in an effort to constrain model uncertainty. Dynamic representation of plant traits can improve our representation of intraspecific trait variability and its functional relationship with environmental gradients in models predicting ecosystem responses to ongoing climate change.

  13. Worldwide Historical Estimates of Leaf Area Index, 1932-2000

    Energy Technology Data Exchange (ETDEWEB)

    Scurlock, JMO

    2002-02-06

    Approximately 1000 published estimates of leaf area index (LAI) from nearly 400 unique field sites, covering the period 1932-2000, have been compiled into a single data set. LA1 is a key parameter for global and regional models of biosphere/atmosphere exchange of carbon dioxide, water vapor, and other materials. It also plays an integral role in determining the energy balance of the land surface. This data set provides a benchmark of typical values and ranges of LA1 for a variety of biomes and land cover types, in support of model development and validation of satellite-derived remote sensing estimates of LA1 and other vegetation parameters. The LA1 data are linked to a bibliography of over 300 original source references. These historic LA1 data are mostly from natural and seminatural (managed) ecosystems, although some agricultural estimates are also included. Although methodologies for determining LA1 have changed over the decades, it is useful to represent the inconsistencies (e.g., in maximum value reported for a particular biome) that are actually found in the scientific literature. Needleleaf (coniferous) forests are by far the most commonly measured biome/land cover types in this compilation, with 22% of the measurements from temperate evergreen needleleaf forests, and boreal evergreen needleleaf forests and crops the next most common (about 9% each). About 40% of the records in the data set were published in the past 10 years (1991-2000), with a further 20% collected between 1981 and 1990. Mean LAI ({+-} standard deviation), distributed between 15 biome/land cover classes, ranged from 1.31 {+-} 0.85 for deserts to 8.72 {+-} 4.32 for tree plantations, with evergreen forests (needleleaf and broadleaf) displaying the highest LA1 among the natural terrestrial vegetation classes. We have identified statistical outliers in this data set, both globally and according to the different biome/land cover classes, but despite some decreases in mean LA1 values reported

  14. Leaf Area Index in Earth System Models: evaluation and projections

    Directory of Open Access Journals (Sweden)

    N. Mahowald

    2015-04-01

    Full Text Available The amount of leaves in a plant canopy (measured as leaf area index, LAI modulates key land–atmosphere interactions, including the exchange of energy, moisture, carbon dioxide (CO2, and other trace gases, and is therefore an essential variable in predicting terrestrial carbon, water, and energy fluxes. The latest generation of Earth system models (ESMs simulate LAI, as well as provide projections of LAI in the future to improve simulations of biophysical and biogeochemical processes, and for use in climate impact studies. Here we use satellite measurements of LAI to answer the following questions: (1 are the models accurately simulating the mean LAI spatial distribution? (2 Are the models accurately simulating the seasonal cycle in LAI? (3 Are the models correctly simulating the processes driving interannual variability in the current climate? And finally based on this analysis, (4 can we reduce the uncertainty in future projections of LAI by using each model's skill in the current climate? Overall, models are able to capture some of the main characteristics of the LAI mean and seasonal cycle, but all of the models can be improved in one or more regions. Comparison of the modeled and observed interannual variability in the current climate suggested that in high latitudes the models may overpredict increases in LAI based on warming temperature, while in the tropics the models may overpredict the negative impacts of warming temperature on LAI. We expect, however, larger uncertainties in observational estimates of interannual LAI compared to estimates of seasonal or mean LAI. Future projections of LAI by the ESMs are largely optimistic, with only limited regions seeing reductions in LAI. Future projections of LAI in the models are quite different, and are sensitive to climate model projections of precipitation. They also strongly depend on the amount of carbon dioxide fertilization in high latitudes. Based on comparisons between model simulated

  15. AfSIS MODIS Collection: Leaf Area Index - FPAR, 2012 Release

    Data.gov (United States)

    Center for International Earth Science Information Network, Columbia University — The Africa Soil Information Service (AfSIS) Moderate Resolution Imaging Spectroradiometer (MODIS) Collection Leaf Area Index (LAI) and Photosynthetically Active...

  16. Rest Areas in the Western United States

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Rest areas in the western United States. Data was collected from various data sources including georeferenced locations obtained from other agencies, digitizied...

  17. A Novel Approach for Retrieving Tree Leaf Area from Ground-Based LiDAR

    Directory of Open Access Journals (Sweden)

    Ting Yun

    2016-11-01

    Full Text Available Leaf area is an important plant canopy structure parameter with important ecological significance. Light detection and ranging technology (LiDAR with the application of a terrestrial laser scanner (TLS is an appealing method for accurately estimating leaf area; however, the actual utility of this scanner depends largely on the efficacy of point cloud data (PCD analysis. In this paper, we present a novel method for quantifying total leaf area within each tree canopy from PCD. Firstly, the shape, normal vector distribution and structure tensor of PCD features were combined with the semi-supervised support vector machine (SVM method to separate various tree organs, i.e., branches and leaves. In addition, the moving least squares (MLS method was adopted to remove ghost points caused by the shaking of leaves in the wind during the scanning process. Secondly, each target tree was scanned using two patterns, i.e., one scan and three scans around the canopy, to reduce the occlusion effect. Specific layer subdivision strategies according to the acquisition ranges of the scanners were designed to separate the canopy into several layers. Thirdly, 10% of the PCD was randomly chosen as an analytic dataset (ADS. For the ADS, an innovative triangulation algorithm with an assembly threshold was designed to transform these discrete scanning points into leaf surfaces and estimate the fractions of each foliage surface covered by the laser pulses. Then, a novel ratio of the point number to leaf area in each layer was defined and combined with the total number of scanned points to retrieve the total area of the leaves in the canopy. The quantified total leaf area of each tree was validated using laborious measurements with a LAI-2200 Plant Canopy Analyser and an LI-3000C Portable Area Meter. The results showed that the individual tree leaf area was accurately reproduced using our method from three registered scans, with a relative deviation of less than 10

  18. Interannual variation in leaf photosynthetic capacity during summer in relation to nitrogen, leaf mass per area and climate within a Fagus crenata crown on Naeba Mountain, Japan.

    Science.gov (United States)

    Iio, Atsuhiro; Yokoyama, Akira; Takano, Masamitsu; Nakamura, Tetsurou; Fukasawa, Hisakazu; Nose, Yachiho; Kakubari, Yoshitaka

    2008-09-01

    During the summers (July and August) of 2002-2005, we measured interannual variation in maximum carboxylation rate (V(cmax)) within a Fagus crenata Blume crown in relation to climate variables such as air temperature, daytime vapor pressure deficit (VPD) and daily photosynthetic photon flux, leaf nitrogen per unit area (N(a)) and leaf mass per unit area (LMA). Climatic conditions in the summers of 2002-2004 differed markedly, with warm and dry atmospheric conditions in 2002, cool, humid and cloudy conditions in 2003, and warm clear conditions in 2004. Conditions in summer 2005 were intermediate between those of summers 2002 and 2003, and similar to recent (8-year) means. In July, marked interannual variation in V(cmax) was mainly observed in leaves in the high-light environment (relative photon flux > 50%) within the crown. At the crown top, V(cmax) was about twofold higher in 2002 than in 2003, and V(cmax) values in 2004 and 2005 were intermediate between those in 2002 and 2003. In August, although interannual variation in V(cmax) among the years 2003, 2004 and 2005 was less, marked variation between 2002 and the other study years was evident. Multiple regression analysis of V(cmax) against the climate variables revealed that VPD of the previous 10-30 days had a significant influence on variability in V(cmax). Neither N(a), LMA nor leaf CO(2) conductance from the stomata to the carboxylation site explained the variability in V(cmax). Our results indicate that the long-term climatic response of V(cmax) should be considered when estimating forest carbon gain across the year.

  19. Seasonal variability of leaf area index and foliar nitrogen in contrasting dry-mesic tundras

    DEFF Research Database (Denmark)

    Campioli, Matteo; Michelsen, Anders; Lemeur, Raoul;

    2009-01-01

    Assimilation and exchange of carbon for arctic ecosystems depend strongly on leaf area index (LAI) and total foliar nitrogen (TFN). For dry-mesic tundras, the seasonality of these characteristics is unexplored. We addressed this knowledge gap by measuring variations of LAI and TFN at five...... contrasting subarctic heaths during the growing season 2007, from about 2 weeks after bud burst until about 2 weeks before senescence. The communities generally showed an early season LAI and TFN increase, owing to leaf development of deciduous shrubs, and limited variations later on, owing to concurrent leaf...

  20. Model-simulated and Satellite-derived Leaf Area Index (LAI) Comparisons Across Multiple Spatial Scales

    Science.gov (United States)

    Iiames, J. S., Jr.; Cooter, E. J.

    2016-12-01

    Leaf Area Index (LAI) is an important parameter in assessing vegetation structure for characterizing forest canopies over large areas at broad spatial scales using satellite remote sensing data. However, satellite-derived LAI products can be limited by obstructed atmospheric conditions yielding sub-optimal values, or complete non-returns. The United States Environmental Protection Agency's Exposure Methods and Measurements and Computational Exposure Divisions are investigating the viability of supplemental modelled LAI inputs into satellite-derived data streams to support various regional and local scale air quality models for retrospective and future climate assessments. In this present study, one-year (2002) of plot level stand characteristics at four study sites located in Virginia and North Carolina (USA) are used to calibrate species-specific plant parameters in a semi-empirical biogeochemical model. The Environmental Policy Integrated Climate (EPIC) model was designed primarily for managed agricultural field crop ecosystems, but also includes managed woody species that span both xeric and mesic sites (e.g., mesquite, pine, oak, etc.). LAI was simulated using EPIC at a 4 km2 and 12 km2 grid coincident with the regional Community Multiscale Air Quality Model (CMAQ) grid. LAI comparisons were made between model-simulated and MODIS-derived LAI. Field/satellite-upscaled LAI was also compared to the corresponding MODIS LAI value. Preliminary results show field/satellite-upscaled LAI (1 km2) was 1.5 to 3 times smaller than that with the corresponding 1 km2 MODIS LAI for all four sites across all dates, with the largest discrepancies occurring at leaf-out and leaf senescence periods. Simulated LAI/MODIS LAI comparison results will be presented at the conference. Disclaimer: This work is done in support of EPA's Sustainable Healthy Communities Research Program. The U.S. Environmental Protection Agency funded and conducted the research described in this paper. Although

  1. PREDICTION OF THE LEAF AREA IN ZUCCHINI FRUIT: A NON DESTRUCTIVE, EXACT, SIMPLE, FAST AND PRACTICAL METHOD

    Directory of Open Access Journals (Sweden)

    Gustavo Sessa Fialho1

    2011-12-01

    Full Text Available Non destructive methods aiming the estimation of the leaf area, fast, easily executed, with acceptable levels of accuracy are useful to the study of plants growing under field conditions. This way, the leaf area of zucchini fruit plants was estimated, through regression models. The leaf areas, measured by a leaf integrator were distributed according to the leaf dimension (length-C, wideness-L and of the product-CL of the original leaves. Several estimators were generated, however, only the three most relevant were studied, among which, the best, statistically, was elected for validation analysis. We concluded that the leaf area of the zucchini fruit, grown in field, can be predicted, based on the leaf wideness (L, by the following estimator: , that, by its turn, was shown accurate, exact, simple, fast and practical, being reliable to predict this important agronomic variable.

  2. Joint leaf chlorophyll content and leaf area index retrieval from Landsat data using a regularized model inversion system (REGFLEC)

    KAUST Repository

    Houborg, Rasmus

    2015-01-19

    Leaf area index (LAI) and leaf chlorophyll content (Chll) represent key biophysical and biochemical controls on water, energy and carbon exchange processes in the terrestrial biosphere. In combination, LAI and Chll provide critical information on vegetation density, vitality and photosynthetic potentials. However, simultaneous retrieval of LAI and Chll from space observations is extremely challenging. Regularization strategies are required to increase the robustness and accuracy of retrieved properties and enable more reliable separation of soil, leaf and canopy parameters. To address these challenges, the REGularized canopy reFLECtance model (REGFLEC) inversion system was refined to incorporate enhanced techniques for exploiting ancillary LAI and temporal information derived from multiple satellite scenes. In this current analysis, REGFLEC is applied to a time-series of Landsat data.A novel aspect of the REGFLEC approach is the fact that no site-specific data are required to calibrate the model, which may be run in a largely automated fashion using information extracted entirely from image-based and other widely available datasets. Validation results, based upon in-situ LAI and Chll observations collected over maize and soybean fields in central Nebraska for the period 2001-2005, demonstrate Chll retrieval with a relative root-mean-square-deviation (RMSD) on the order of 19% (RMSD=8.42μgcm-2). While Chll retrievals were clearly influenced by the version of the leaf optical properties model used (PROSPECT), the application of spatio-temporal regularization constraints was shown to be critical for estimating Chll with sufficient accuracy. REGFLEC also reproduced the dynamics of in-situ measured LAI well (r2 =0.85), but estimates were biased low, particularly over maize (LAI was underestimated by ~36 %). This disparity may be attributed to differences between effective and true LAI caused by significant foliage clumping not being properly accounted for in the canopy

  3. Remote sensing of the leaf area index of temperate coniferous forests

    Science.gov (United States)

    Spanner, M. A.; Acevedo, W.; Teuber, K. W.; Running, S. W.; Peterson, D. L.; Card, D. H.; Mouat, D. A.

    1984-01-01

    To estimate the one-sided leaf area index (LAI) of temperate coniferous forests using data acquired from the Daedalus Airborne Thematic Mapper, an empirical model is developed. The study area follows an environmental gradient across west-central Oregon, where leaf development varies in response to temperature and moisture. The relationship between the ratio of thematic-mapper simulator channels four and three and the leaf area index for selected closed canopy or fully stocked forest stands along the gradient is analyzed. Results show that a good relationship exists between the LAI and the IR/red ratio for conifers and that a conifer species-independent asymptotic relationship is observed between LAI and near IR/red reflectance, with near radiometric saturation occurring at an LAI of about 7-8.

  4. Mapping Vineyard Leaf Area Using Mobile Terrestrial Laser Scanners: Should Rows be Scanned On-the-Go or Discontinuously Sampled?

    Directory of Open Access Journals (Sweden)

    Ignacio del-Moral-Martínez

    2016-01-01

    Full Text Available The leaf area index (LAI is defined as the one-side leaf area per unit ground area, and is probably the most widely used index to characterize grapevine vigor. However, LAI varies spatially within vineyard plots. Mapping and quantifying this variability is very important for improving management decisions and agricultural practices. In this study, a mobile terrestrial laser scanner (MTLS was used to map the LAI of a vineyard, and then to examine how different scanning methods (on-the-go or discontinuous systematic sampling may affect the reliability of the resulting raster maps. The use of the MTLS allows calculating the enveloping vegetative area of the canopy, which is the sum of the leaf wall areas for both sides of the row (excluding gaps and the projected upper area. Obtaining the enveloping areas requires scanning from both sides one meter length section along the row at each systematic sampling point. By converting the enveloping areas into LAI values, a raster map of the latter can be obtained by spatial interpolation (kriging. However, the user can opt for scanning on-the-go in a continuous way and compute 1-m LAI values along the rows, or instead, perform the scanning at discontinuous systematic sampling within the plot. An analysis of correlation between maps indicated that MTLS can be used discontinuously in specific sampling sections separated by up to 15 m along the rows. This capability significantly reduces the amount of data to be acquired at field level, the data storage capacity and the processing power of computers.

  5. Correlation between relative growth rate and specific leaf area requires associations of specific leaf area with nitrogen absorption rate of roots.

    Science.gov (United States)

    Osone, Yoko; Ishida, Atsushi; Tateno, Masaki

    2008-07-01

    Close correlations between specific leaf area (SLA) and relative growth rate (RGR) have been reported in many studies. However, theoretically, SLA by itself has small net positive effect on RGR because any increase in SLA inevitably causes a decrease in area-based leaf nitrogen concentration (LNCa), another RGR component. It was hypothesized that, for a correlation between SLA and RGR, SLA needs to be associated with specific nitrogen absorption rate of roots (SAR), which counteracts the negative effect of SLA on LNCa. Five trees and six herbs were grown under optimal conditions and relationships between SAR and RGR components were analyzed using a model based on balanced growth hypothesis. SLA varied 1.9-fold between species. Simulations predicted that, if SAR is not associated with SLA, this variation in SLA would cause a47% decrease in LNCa along the SLA gradient, leading to a marginal net positive effect on RGR. In reality, SAR was positively related to SLA, showing a 3.9-fold variation, which largely compensated for the negative effect of SLA on LNCa. Consequently, LNCa values were almost constant across species and a positive SLA-RGR relationship was achieved. These results highlight the importance of leaf-root interactions in understanding interspecific differences in RGR.

  6. Is whole-plant photosynthetic rate proportional to leaf area? A test of scalings and a logistic equation by leaf demography census.

    Science.gov (United States)

    Koyama, Kohei; Kikuzawa, Kihachiro

    2009-05-01

    Allometric scalings and a logistic equation assume that whole-plant photosynthetic rate under resource-unlimited conditions is proportional to leaf area. We tested this proportionality for the herb Helianthus tuberosus. During growth, we repeatedly measured the percentage of leaves with high, medium, and low photosynthetic capacity to estimate the whole-plant sum of photosynthetic capacity. We found that the whole-plant sum of the light-saturated photosynthetic rate of leaves is proportional to the whole-plant leaf area, disregarding the dynamics of the leaf population. We also found that the daily photosynthesis of each leaf appeared as a linear function of the light-saturated photosynthetic rate of that leaf, as predicted by the optimization theory. Using those results, we expressed whole-plant photosynthetic rate as a product of the light-saturated whole-plant photosynthetic rate and an efficiency index that reflects resource limitation as in the logistic equation. This efficiency decreased with increasing leaf area, reflecting light limitation. Therefore, realized whole-plant photosynthetic rate is not proportional to leaf area. These "diminishing returns" are well explained by a simple saturating curve, such as the logistic equation.

  7. Canopy cover and leaf area index relationships for wheat, triticale, and corn

    Science.gov (United States)

    The AquaCrop model requires canopy cover (CC) measurements to define crop growth and development. Some previously collected data sets that would be useful for calibrating and validating AquaCrop contain only leaf area index (LAI) data, but could be used if relationships were available relating LAI t...

  8. Measurement methods and variability assessment of the Norway spruce total leaf area: Implications for remote sensing

    NARCIS (Netherlands)

    Homolova, L.; Lukes, P.; Malenovsky, Z.; Lhotakova, Z.; Kaplan, V.; Hanus, J.

    2013-01-01

    Estimation of total leaf area (LAT) is important to express biochemical properties in plant ecology and remote sensing studies. A measurement of LAT is easy in broadleaf species, but it remains challenging in coniferous canopies. We proposed a new geometrical model to estimate Norway spruce LAT and

  9. Estimation of leaf area index in cereal crops using red-green images

    DEFF Research Database (Denmark)

    Kirk, Kristian; Andersen, Hans Jørgen; Thomsen, Anton G;

    2009-01-01

    A new method for estimating the leaf area index (LAI) in cereal crops based on red-green images taken from above the crop canopy is introduced. The proposed method labels pixels into vegetation and soil classes using a combination of greenness and intensity derived from the red and green colour...

  10. Upscaling leaf area index in an Arctic landscape through multiscale observations

    NARCIS (Netherlands)

    Williams, M.; Bell, R.; Spadavecchia, L.; Street, L.E.; Wijk, van M.T.

    2008-01-01

    Monitoring and understanding global change requires a detailed focus on upscaling, the process for extrapolating from the site-specific scale to the smallest scale resolved in regional or global models or earth observing systems. Leaf area index (LAI) is one of the most sensitive determinants of pla

  11. Discrete return lidar-based prediction of leaf area index in two conifer forests

    Science.gov (United States)

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

    2008-01-01

    Leaf area index (LAI) is a key forest structural characteristic that serves as a primary control for exchanges of mass and energy within a vegetated ecosystem. Most previous attempts to estimate LAI from remotely sensed data have relied on empirical relationships between field-measured observations and various spectral vegetation indices (SVIs) derived from optical...

  12. Forest Productivity, Leaf Area, and Terrain in Southern Appalachian Deciduous Forests

    Science.gov (United States)

    Paul V. Bolstad; James M. Vose; Steven G. McNulty

    2000-01-01

    Leaf area index (LAI) is an important structural characteristic of forest ecosystems which has been shown to be strongly related to forest mass and energy cycles and forest productivity. LAI is more easily measured than forest productivity, and so a strong relationship between LAI and productivity would be a valuable tool in forest management. While a linear...

  13. Upscaling leaf area index in an Arctic landscape through multiscale observations

    NARCIS (Netherlands)

    Williams, M.; Bell, R.; Spadavecchia, L.; Street, L.E.; Wijk, van M.T.

    2008-01-01

    Monitoring and understanding global change requires a detailed focus on upscaling, the process for extrapolating from the site-specific scale to the smallest scale resolved in regional or global models or earth observing systems. Leaf area index (LAI) is one of the most sensitive determinants of pla

  14. Low temperature leaf photosynthesis of a Miscanthus germplasm collection correlates positively to shoot growth rate and specific leaf area

    DEFF Research Database (Denmark)

    Jiao, Xiurong; Sørensen, Kirsten Kørup; Andersen, Mathias Neumann

    2016-01-01

    were selected and grown under warm (24 °C) and cold (14 °C) conditions in a controlled environment. Dark-adapted chlorophyll fluorescence, specific leaf area (SLA) and net photosynthetic rate at a photosynthetically active radiation (PAR) of 1000 μmol m–2 s–1 (A1000) were measured. Photosynthetic light...... and CO2 response curves were obtained from 11 of the genotypes, and shoot growth rate was measured under field conditions. Key Results A positive linear relationship was found between SLA and light-saturated photosynthesis (Asat) across genotypes, and also between shoot growth rate under cool field...... interspecies hybrids with improved traits for temperate climates. Two easily measured variables, SLA and shoot growth rate, may be useful for genotype screening of productivity and cold tolerance....

  15. Marsh canopy leaf area and orientation calculated for improved marsh structure mapping

    Science.gov (United States)

    Ramsey III, Elijah W.; Rangoonwala, Amina; Jones, Cathleen E.; Bannister, Terri

    2015-01-01

    An approach is presented for producing the spatiotemporal estimation of leaf area index (LAI) of a highly heterogeneous coastal marsh without reliance on user estimates of marsh leaf-stem orientation. The canopy LAI profile derivation used three years of field measured photosynthetically active radiation (PAR) vertical profiles at seven S. alterniflora marsh sites and iterative transform of those PAR attenuation profiles to best-fit light extinction coefficients (KM). KM sun zenith dependency was removed obtaining the leaf angle distribution (LAD) representing the average marsh orientation and the LAD used to calculate the LAI canopy profile. LAI and LAD reproduced measured PAR profiles with 99% accuracy and corresponded to field documented structures. LAI and LAD better reflect marsh structure and results substantiate the need to account for marsh orientation. The structure indexes are directly amenable to remote sensing spatiotemporal mapping and offer a more meaningful representation of wetland systems promoting biophysical function understanding.

  16. Comparison of the New LEAF Area INDEX (LAI 3G) with the Kazahstan-Wide LEAF Area INDEX DATA SET (GGRS-LAI) over Central ASIA

    Science.gov (United States)

    Kappas, M.; Propastin, P.; Degener, J.; Renchin, T.

    2014-12-01

    Long-term global data sets of Leaf Area Index (LAI) are important for monitoring global vegetation dynamics. LAI indicating phenological development of vegetation is an important state variable for modeling land surface processes. The comparison of long-term data sets is based on two recently available data sets both derived from AVHRR time series. The LAI 3g data set introduced by Zaichun Zhu et al. (2013) is developed from the new improved third generation Global Inventory Modeling and Mapping Studies (GIMMS) Normalized Difference Vegetation Index (NDVI3g) and best-quality MODIS LAI data. The second long-term data set is based on the 8 km spatial resolution GIMMS-AVHRR data (GGRS-data set by Propastin et al. 2012). The GGRS-LAI product uses a three-dimensional physical radiative transfer model which establishes relationship between LAI, vegetation fractional cover and given patterns of surface reflectance, view-illumination conditions and optical properties of vegetation. The model incorporates a number of site/region specific parameters, including the vegetation architecture variables such as leaf angle distribution, clumping index, and light extinction coefficient. For the application of the model to Kazakhstan, the vegetation architecture variables were computed at the local (pixel) level based on extensive field surveys of the biophysical properties of vegetation in representative grassland areas of Kazakhstan. The comparison of both long-term data sets will be used to interpret their quality for scientific research in other disciplines. References:Propastin, P., Kappas, M. (2012). Retrieval of coarse-resolution leaf area index over the Republic of Kazakhstan using NOAA AVHRR satellite data and ground measurements," Remote Sensing, vol. 4, no. 1, pp. 220-246. Zaichun Zhu, Jian Bi, Yaozhong Pan, Sangram Ganguly, Alessandro Anav, Liang Xu, Arindam Samanta, Shilong Piao, Ramakrishna R. Nemani and Ranga B. Myneni (2013). Global Data Sets of Vegetation Leaf Area

  17. The effect of the original leaf area on growth of softwood cuttings and planting material of rose

    NARCIS (Netherlands)

    Costa, J.M.; Challa, H.

    2002-01-01

    Leaf area influences root formation and growth of single node softwood stem cuttings of rose. However, a complete assessment of the quantitative effect of the area of the original leaf on growth of cuttings and of derived planting material (rooted cuttings) is still lacking. Therefore, it was our ai

  18. Prediction of the competitive effects of weeds on crop yields based on the relative leaf area of weeds

    DEFF Research Database (Denmark)

    Lotz, L. A. P.; Christensen, Svend; Cloutier, D.

    1996-01-01

    L.) and in 11 experiments in spring wheat (Triticum aestivum L.). Most data sets were heller described by a model based on the relative leaf area of the weed than by a hyperbolic model based on weed density. This leaf area model accounted for (part of) the effect of different emerging times of the S....... alba whereas the density model did not. A parameter that allows the maximum yield loss to be smaller than 100% was mostly not needed to describe the effects of weed competition. The parameter that denotes the competitiveness of the weed species with respect to the crop decreased the later the relative...... leaf area of the mustard was determined. This decrease could be estimated from the differences in relative growth rate of the leaf area of crop and S. alba. However, the accuracy of this estimation was poor. The parameter value of the leaf area model varied considerably between sites and years...

  19. Effect of brushwood transposition on the leaf litter arthropod fauna in a cerrado area

    Directory of Open Access Journals (Sweden)

    Paula Cristina Benetton Vergílio

    2013-10-01

    Full Text Available The results of ecological restoration techniques can be monitored through biological indicators of soil quality such as the leaf litter arthropod fauna. This study aimed to determine the immediate effect of brushwood transposition transferred from an area of native vegetation to a disturbed area, on the leaf litter arthropod fauna in a degraded cerrado area. The arthropod fauna of four areas was compared: a degraded area with signal grass, two experimental brushwood transposition areas, with and without castor oil plants, and an area of native cerrado. In total, 7,660 individuals belonging to 23 taxa were sampled. Acari and Collembola were the most abundant taxa in all studied areas, followed by Coleoptera, Diptera, Hemiptera, Hymenoptera, and Symphyla. The brushwood transposition area without castor oil plants had the lowest abundance and dominance and the highest diversity of all areas, providing evidence of changes in the soil community. Conversely, the results showed that the presence of castor oil plants hampered early succession, negatively affecting ecological restoration in this area.

  20. Rootstock-mediated changes in xylem ionic and hormonal status are correlated with delayed leaf senescence, and increased leaf area and crop productivity in salinized tomato.

    Science.gov (United States)

    Albacete, Alfonso; Martínez-Andújar, Cristina; Ghanem, Michel Edmond; Acosta, Manuel; Sánchez-Bravo, José; Asins, María J; Cuartero, Jesús; Lutts, Stanley; Dodd, Ian C; Pérez-Alfocea, Francisco

    2009-07-01

    Tomato crop productivity under salinity can be improved by grafting cultivars onto salt-tolerant wild relatives, thus mediating the supply of root-derived ionic and hormonal factors that regulate leaf area and senescence. A tomato cultivar was grafted onto rootstocks from a population of recombinant inbred lines (RILs) derived from a Solanum lycopersicum x Solanum cheesmaniae cross and cultivated under moderate salinity (75 mM NaCl). Concentrations of Na(+), K(+) and several phytohormones [abscisic acid (ABA); the cytokinins (CKs) zeatin, Z; zeatin riboside, ZR; and the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC)] were analysed in leaf xylem sap in graft combinations of contrasting vigour. Scion leaf area correlated with photosystem II (PSII) efficiency (F(v)/F(m)) and determined fruit productivity. Xylem K(+) (but not Na(+)), K(+)/Na(+), the active CK Z, the ratio with its storage form Z/ZR and especially the ratio between CKs and ACC (Z/ACC and Z + ZR/ACC) were positively loaded into the first principal component (PC) determining both leaf growth and PSII efficiency. In contrast, the ratio ACC/ABA was negatively correlated with leaf biomass. Although the underlying physiological mechanisms by which rootstocks mediate leaf area or chlorophyll fluorescence (and thus influence tomato salt tolerance) seem complex, a putative potassium-CK interaction involved in regulating both processes merits further attention.

  1. Regression models for estimating leaf area of seedlings and adult individuals of Neotropical rainforest tree species

    Directory of Open Access Journals (Sweden)

    E. Brito-Rocha

    Full Text Available Abstract Individual leaf area (LA is a key variable in studies of tree ecophysiology because it directly influences light interception, photosynthesis and evapotranspiration of adult trees and seedlings. We analyzed the leaf dimensions (length – L and width – W of seedlings and adults of seven Neotropical rainforest tree species (Brosimum rubescens, Manilkara maxima, Pouteria caimito, Pouteria torta, Psidium cattleyanum, Symphonia globulifera and Tabebuia stenocalyx with the objective to test the feasibility of single regression models to estimate LA of both adults and seedlings. In southern Bahia, Brazil, a first set of data was collected between March and October 2012. From the seven species analyzed, only two (P. cattleyanum and T. stenocalyx had very similar relationships between LW and LA in both ontogenetic stages. For these two species, a second set of data was collected in August 2014, in order to validate the single models encompassing adult and seedlings. Our results show the possibility of development of models for predicting individual leaf area encompassing different ontogenetic stages for tropical tree species. The development of these models was more dependent on the species than the differences in leaf size between seedlings and adults.

  2. Rapid, high-resolution measurement of leaf area and leaf orientation using terrestrial LiDAR scanning data

    Science.gov (United States)

    Leaf orientation plays a fundamental role in many transport processes in plant canopies. At the plant or stand level, leaf orientation is often highly anisotropic and heterogeneous, yet most analyses neglect such complexity. In many cases, this is due to the difficulty in measuring the spatial varia...

  3. Some quantitative relationships between leaf area index and canopy nitrogen content and distribution.

    Science.gov (United States)

    Yin, Xinyou; Lantinga, Egvert A; Schapendonk, Ad H C M; Zhong, Xuhua

    2003-06-01

    In a previous study (Yin et al. 2000. Annals of Botany 85: 579-585), a generic logarithmic equation for leaf area index (L) in relation to canopy nitrogen content (N) was developed: L=(1/ktn)1n(1+ktnN/nb). The equation has two parameters: the minimum leaf nitrogen required to support photosynthesis (nb), and the leaf nitrogen extinction coefficient (ktn). Relative to nb, there is less information in the literature regarding the variation of ktn. We therefore derived an equation to theoretically estimate the value of ktn. The predicted profile of leaf nitrogen in a canopy using this theoretically estimated value of ktn is slightly more uniform than the profile predicted by the optimum nitrogen distribution that maximizes canopy photosynthesis. Relative to the optimum profile, the predicted profile is somewhat closer to the observed one. Based on the L-N logarithmic equation and the theoretical ktn value, we further quantified early leaf area development of a canopy in relation to nitrogen using simulation analysis. In general, there are two types of relations between L and N, which hold for canopies at different developmental phases. For a fully developed canopy where the lowest leaves are senescing due to nitrogen shortage, the relationship between L and N is described well by the logarithmic model above. For a young, unclosed canopy (i.e. L < 1.0), the relation between L and N is nearly linear. This linearity is virtually the special case of the logarithmic model when applied to a young canopy where its total nitrogen content approaches zero and the amount of nitrogen in its lowest leaves is well above nb. The expected patterns of the L-N relationship are discussed for the phase of transition from young to fully developed canopies.

  4. Photosynthesis in relation to leaf nitrogen, phosphorus and specific leaf area of seedlings and saplings in tropical montane rain forests of Hainan Island, south China

    Institute of Scientific and Technical Information of China (English)

    Fude LIU; Ming ZHANG; Wenjin WANG; Shuning CHEN; Jianwei ZHENG; Wenjie YANG; Fengqin HU; Shuqing AN

    2009-01-01

    In order to make clear the relationships between photosynthesis and leaf N, leaf P and SLA of tropical trees, and test the differences in the relationships among life-form groups (trees, shrub-like trees and shrubs),seedlings and saplings of 101 species from a tropical montane rain forest, located in the Diaoluo Mountain of Hainan Island, were selected. The net photosynthesis based on area and mass (Aarea and Amass), leaf nitrogen content based on area and mass (Narea and Nmass), leaf phosphorus content based on area and mass (Parea and Pmass) and specific leaf area (SLA) were measured and/or calculated.The results showed that Aarea and Amass tended to follow the order of shrubs > trees > shrub-like trees. One-way ANOVA showed that the difference in Aarea between shrubs and shrub-like trees was significant (p 0.05). The relationship between Aarea and SLAwas highly significant in shrubs (p = 0.0006),trees (p 0.05). The relationships between Amass and leaf N and SLA were highly significant in all three life-form groups and for all species (p < 0.0001). For Amass and leaf P, there were significant correlations in tree groups (p =0.0377) and highly significant correlations in shrub groups (p = 0.0004), shrub-like tree groups (p = 0.0018) and for all species (p < 0.0001). Stepwise regression showed that predicted Amass values were closer to the observed values than those for predicted Aarea values. Thus, it can be concluded that the relationships obtained from seedling and sapling measurements are close to those from mature individuals; correlations between photosynthesis and Nmass, Pmass and SLA traits are significant and the relationships are stronger and more stable for A mass than for Aarea.

  5. ESTIMATION OF LEAF AREA INDEX IN OPEN-CANOPY PONDEROSA PINE FORESTS AT DIFFERENT SUCCESSIONAL STAGES AND MANAGEMENT REGIMES IN OREGON. (R828309)

    Science.gov (United States)

    AbstractLeaf area and its spatial distribution are key parameters in describing canopy characteristics. They determine radiation regimes and influence mass and energy exchange with the atmosphere. The evaluation of leaf area in conifer stands is particularly challengi...

  6. Tree mortality across biomes is promoted by drought intensity, lower wood density and higher specific leaf area.

    Science.gov (United States)

    Greenwood, Sarah; Ruiz-Benito, Paloma; Martínez-Vilalta, Jordi; Lloret, Francisco; Kitzberger, Thomas; Allen, Craig D; Fensham, Rod; Laughlin, Daniel C; Kattge, Jens; Bönisch, Gerhard; Kraft, Nathan J B; Jump, Alistair S

    2017-04-01

    Drought events are increasing globally, and reports of consequent forest mortality are widespread. However, due to a lack of a quantitative global synthesis, it is still not clear whether drought-induced mortality rates differ among global biomes and whether functional traits influence the risk of drought-induced mortality. To address these uncertainties, we performed a global meta-analysis of 58 studies of drought-induced forest mortality. Mortality rates were modelled as a function of drought, temperature, biomes, phylogenetic and functional groups and functional traits. We identified a consistent global-scale response, where mortality increased with drought severity [log mortality (trees trees(-1)  year(-1) ) increased 0.46 (95% CI = 0.2-0.7) with one SPEI unit drought intensity]. We found no significant differences in the magnitude of the response depending on forest biomes or between angiosperms and gymnosperms or evergreen and deciduous tree species. Functional traits explained some of the variation in drought responses between species (i.e. increased from 30 to 37% when wood density and specific leaf area were included). Tree species with denser wood and lower specific leaf area showed lower mortality responses. Our results illustrate the value of functional traits for understanding patterns of drought-induced tree mortality and suggest that mortality could become increasingly widespread in the future. © 2017 John Wiley & Sons Ltd/CNRS.

  7. Estimation of leaf area in coffee leaves (Coffea arabica L. of the Castillo® variety

    Directory of Open Access Journals (Sweden)

    Carlos Andrés Unigarro-Muñoz

    2015-01-01

    Full Text Available Allometric models based on measurements of single leaf dimensions or a combination there are useful tools for determining individual leaf area (LA because they are non-destructive, precise, simple and economical methods. The present study was carried out at the Central Station Naranjal of Cenicafé, located in the Department of Caldas (Colombia, four models were defined using the variables length (L and/or width (W to estimate LA in coffee leaves of the Castillo® variety (Coffea arabica L.. Estimation of regression coefficients was performed using information recorded from 6,441 leaves (group 1, and their validation was performed using records from another 992 leaves (group 2. Leaves were collected from all strata of the canopy and ranged from 0.76 to 140 cm2 in LA. In addition to exhibiting coefficients of variation differing from zero based on t-tests at 1%, the evaluated models possess coefficients of determination between 0.93 and 0.99. Four expressions have developed and adjusted to estimate leaf area in individual leaves, based on the measurement of simple variables and non-destructive.

  8. Evaporation and wetted area of single droplets on waxy and hairy leaf surfaces.

    Science.gov (United States)

    Zhu, H; Yu, Y; Ozkan, H E; Derksen, R C; Krause, C R

    2008-01-01

    Understanding the evaporation of pesticide droplets and wetting of Leaf surfaces can increase foliar application efficiency and reduce pesticide use. Evaporation time and wetted area of single pesticide droplets on hairy and waxy geranium leaf surfaces were measured under the controlled conditions for five droplet sizes and three relative humidities. The sprays used to form droplets included water, a nonionic colloidal polymer drift retardant, an alkyl polyoxyethylene surfactant, and an insecticide. Adding the surfactant into spray mixtures greatly increased droplet wetted area on the surfaces while droplet evaporation time was greatly reduced. Adding the drift retardant into spray mixture slightly increased the droplet evaporation time and the wetted area. Also, droplets had Longer evaporation times on waxy leaves than on hairy leaves for all droplet diameters and all relative humidity conditions. Increasing relative humidity could increase the droplet evaporation time greatly but did not change the the wetted area. The droplet evaporation time and wetted area increased exponentially as the droplet size increased. Therefore, droplet size, surface characteristics of the target, relative humidity, and chemical composition of the spray mixtures (water alone, pesticide, additives) should be included as important factors that affect the efficacy and efficiency of pesticide applications.

  9. NOAA Climate Data Record (CDR) of Leaf Area Index (LAI) and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR), Version 4

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains gridded daily Leaf Area Index (LAI) and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) derived from the NOAA Climate Data...

  10. Leaf morphological variability and intraspecific taxonomic units for pedunculate oak and grayish oak (genus Quercus L., series Pedunculatae Schwz.) in Southern Carpathian Region (Romania).

    Science.gov (United States)

    Apostol, Ecaterina Nicoleta; Curtu, Alexandru Lucian; Daia, Liviu Mihai; Apostol, Bogdan; Dinu, Cristiana Georgeta; Şofletea, Neculae

    2017-07-26

    Even though pedunculate oak (Quercus robur L.) and grayish oak (Quercus pedunculiflora K. Koch) have different ecological requirements, they have been considered as having low differentiation at the level of morphological traits and genetic variation. The leaf morphology for 862 trees has been assessed in 16 natural populations, seven of Q. robur, eight of Q. pedunculiflora and a mixed forest were both taxa coexist. In total, fifteen descriptors have been analysed by using discriminant analysis, while it was found that with only four out of the fifteen leaf traits (abaxial pubescence, abaxial colour of the leaf, petiole length and basal shape of lamina) the two taxa could be clearly differentiated. A dendrogram has been constructed on the basis of these traits, where the populations of each taxon have been clustered together. PU and CL traits of Q. pedunculiflora were discussed for their adaptive value for drought resistance in the steppe habitats occupied by this taxon. Using the leaves' morphological descriptors and data from the literature, intra-taxonomic units (varieties, forms and sub-forms) have been identified in all analysed populations. Eight intraspecific units for Q. robur and six for Q. pedunculiflora have been identified in the investigated area. An analysis of spatial distribution of the two taxa and of their intraspecific units has been performed using maps of ecoregions for the study area. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Leaf Mass per Area (LMA and Its Relationship with Leaf Structure and Anatomy in 34 Mediterranean Woody Species along a Water Availability Gradient.

    Directory of Open Access Journals (Sweden)

    Enrique G de la Riva

    Full Text Available Leaf mass per area (LMA is a morphological trait widely used as a good indicator of plant functioning (i.e. photosynthetic and respiratory rates, chemical composition, resistance to herbivory, etc.. The LMA can be broken down into the leaf density (LD and leaf volume to area ratio (LVA or thickness, which in turn are determined by anatomical tissues and chemical composition. The aim of this study is to understand the anatomical and chemical characteristics related to LMA variation in species growing in the field along a water availability gradient. We determined LMA and its components (LD, LVA and anatomical tissues for 34 Mediterranean (20 evergreen and 14 deciduous woody species. Variation in LMA was due to variation in both LD and LVA. For both deciduous and evergreen species LVA variation was strongly and positively related with mesophyll volume per area (VA or thickness, but for evergreen species positive relationships of LVA with the VA of epidermis, vascular plus sclerenchyma tissues and air spaces were found as well. The leaf carbon concentration was positively related with mesophyll VA in deciduous species, and with VA of vascular plus sclerenchymatic tissues in evergreens. Species occurring at the sites with lower water availability were generally characterised by a high LMA and LD.

  12. Leaf Mass per Area (LMA) and Its Relationship with Leaf Structure and Anatomy in 34 Mediterranean Woody Species along a Water Availability Gradient.

    Science.gov (United States)

    de la Riva, Enrique G; Olmo, Manuel; Poorter, Hendrik; Ubera, José Luis; Villar, Rafael

    2016-01-01

    Leaf mass per area (LMA) is a morphological trait widely used as a good indicator of plant functioning (i.e. photosynthetic and respiratory rates, chemical composition, resistance to herbivory, etc.). The LMA can be broken down into the leaf density (LD) and leaf volume to area ratio (LVA or thickness), which in turn are determined by anatomical tissues and chemical composition. The aim of this study is to understand the anatomical and chemical characteristics related to LMA variation in species growing in the field along a water availability gradient. We determined LMA and its components (LD, LVA and anatomical tissues) for 34 Mediterranean (20 evergreen and 14 deciduous) woody species. Variation in LMA was due to variation in both LD and LVA. For both deciduous and evergreen species LVA variation was strongly and positively related with mesophyll volume per area (VA or thickness), but for evergreen species positive relationships of LVA with the VA of epidermis, vascular plus sclerenchyma tissues and air spaces were found as well. The leaf carbon concentration was positively related with mesophyll VA in deciduous species, and with VA of vascular plus sclerenchymatic tissues in evergreens. Species occurring at the sites with lower water availability were generally characterised by a high LMA and LD.

  13. Retrieval of effective leaf area index (LAIe) and leaf area density (LAD) profile at individual tree level using high density multi-return airborne LiDAR

    Science.gov (United States)

    Lin, Yi; West, Geoff

    2016-08-01

    As an important canopy structure indicator, leaf area index (LAI) proved to be of considerable implications for forest ecosystem and ecological studies, and efficient techniques for accurate LAI acquisitions have long been highlighted. Airborne light detection and ranging (LiDAR), often termed as airborne laser scanning (ALS), once was extensively investigated for this task but showed limited performance due to its low sampling density. Now, ALS systems exhibit more competing capacities such as high density and multi-return sampling, and hence, people began to ask the questions like-"can ALS now work better on the task of LAI prediction?" As a re-examination, this study investigated the feasibility of LAI retrievals at the individual tree level based on high density and multi-return ALS, by directly considering the vertical distributions of laser points lying within each tree crown instead of by proposing feature variables such as quantiles involving laser point distribution modes at the plot level. The examination was operated in the case of four tree species (i.e. Picea abies, Pinus sylvestris, Populus tremula and Quercus robur) in a mixed forest, with their LAI-related reference data collected by using static terrestrial laser scanning (TLS). In light of the differences between ALS- and TLS-based LAI characterizations, the methods of voxelization of 3D scattered laser points, effective LAI (LAIe) that does not distinguish branches from canopies and unified cumulative LAI (ucLAI) that is often used to characterize the vertical profiles of crown leaf area densities (LADs) was used; then, the relationships between the ALS- and TLS-derived LAIes were determined, and so did ucLAIs. Tests indicated that the tree-level LAIes for the four tree species can be estimated based on the used airborne LiDAR (R2 = 0.07, 0.26, 0.43 and 0.21, respectively) and their ucLAIs can also be derived. Overall, this study has validated the usage of the contemporary high density multi

  14. A mathematical description of maize leaf area growth using a logistic curve

    Directory of Open Access Journals (Sweden)

    M. Seidler

    2013-12-01

    Full Text Available In this paper, an attempt is made to apply the Verhulst-Pearl and the Robertson logistic curves to the description of maize plant growth. The changes with time of the total leaf area were taken as the parameter expressing the growth kinetics. The constant coefficients in the Verhulst-Pearl and Robertson equations were calculated with the help of a logarithmic transformation and the least square method. On this basis, the growth kinetics of the studied maize lines and hybrid were compared. The applicability of logistic curves to the description of completed growth processes was demonstrated as was the fact that Robertson's equation is better suited for mathematical calculations.

  15. Leaf Area Index (LAI Estimation of Boreal Forest Using Wide Optics Airborne Winter Photos

    Directory of Open Access Journals (Sweden)

    Pauline Stenberg

    2009-12-01

    Full Text Available A new simple airborne method based on wide optics camera is developed for leaf area index (LAI estimation in coniferous forests. The measurements are carried out in winter, when the forest floor is completely snow covered and thus acts as a light background for the hemispherical analysis of the images. The photos are taken automatically and stored on a laptop during the flights. The R2 value of the linear regression of the airborne and ground based LAI measurements was 0.89.

  16. Study on Leaf Area Regression Equation for ‘Dajiubao’ Peach%大久保桃叶面积回归测算方法研究

    Institute of Scientific and Technical Information of China (English)

    张传来; 周瑞金; 宋秀丽

    2012-01-01

    Taking ' Dajiubao' peach leaf as tested materials,the relation of leaf length( x1) , leaf width(x2) and leaf length×leaf width with leaf area (LA, y) was studied. The results showed that there was a significantly positive correlation between leaf area and leaf length, leaf width and leaf length×leaf width, and the correlation coefficient was 0.9203, 0.9297 and 0.9764,respectively; the multiple correlation coefficient of leaf length added leaf width, leaf length added leaf length×leaf width, leaf width added leaf length×leaf width with leaf area was 0.9866, 0.9884 and 0.9884,respectively, and the difference was extremely significant. On the base of these analysis results, the simple linearity regression equation of leaf length, leaf width and leaf length×leaf width with leaf area was established. At the same time, the binary regression equation was established for leaf length added leaf width with leaf area, leaf length added leaf length×leaf width with leaf area, leaf width added leaf length×leaf width with leaf area. The leaf area of ' Dajiubao' peach could be calculated by these six regression equations. Among them, the computing result of binary regression equation (y = 490. 6048 -4. 9315x1 +0. 6816x1x2) and the binary regression equation (y=-213.244 +18. 6115x2 +0. 5527x1x2) were more precise. The regression equation could be chosen according to the requirement of accuracy and the workload of calculation during specific application.%以大久保成熟叶片为试材,研究了叶长(x1)、叶宽(x2)、叶长×叶宽与叶面积(LA,y)的关系.结果表明,叶长、叶宽、叶长×叶宽与LA均呈正相关关系,相关系数分别为0.9203、0.9297、0.9764;叶长和叶宽、叶长和叶长×叶宽、叶宽和叶长×叶宽与LA的复相关系数分别为0.9866、0.9884、0.9884,差异均达到了极显著水平.在此基础上建立了叶长与LA、叶宽与LA、叶长×叶宽与LA3个简单线性回归方程以及叶长和叶宽与LA、

  17. Application of 3D triangulations of airborne laser scanning data to estimate boreal forest leaf area index

    Science.gov (United States)

    Majasalmi, Titta; Korhonen, Lauri; Korpela, Ilkka; Vauhkonen, Jari

    2017-07-01

    We propose 3D triangulations of airborne Laser Scanning (ALS) point clouds as a new approach to derive 3D canopy structures and to estimate forest canopy effective LAI (LAIe). Computational geometry and topological connectivity were employed to filter the triangulations to yield a quasi-optimal relationship with the field measured LAIe. The optimal filtering parameters were predicted based on ALS height metrics, emulating the production of maps of LAIe and canopy volume for large areas. The LAIe from triangulations was validated with field measured LAIe and compared with a reference LAIe calculated from ALS data using logarithmic model based on Beer's law. Canopy transmittance was estimated using All Echo Cover Index (ACI), and the mean projection of unit foliage area (β) was obtained using no-intercept regression with field measured LAIe. We investigated the influence species and season on the triangulated LAIe and demonstrated the relationship between triangulated LAIe and canopy volume. Our data is from 115 forest plots located at the southern boreal forest area in Finland and for each plot three different ALS datasets were available to apply the triangulations. The triangulation approach was found applicable for both leaf-on and leaf-off datasets after initial calibration. Results showed the Root Mean Square Errors (RMSEs) between LAIe from triangulations and field measured values agreed the most using the highest pulse density data (RMSE = 0.63, the coefficient of determination (R2) = 0.53). Yet, the LAIe calculated using ACI-index agreed better with the field measured LAIe (RMSE = 0.53 and R2 = 0.70). The best models to predict the optimal alpha value contained the ACI-index, which indicates that within-crown transmittance is accounted by the triangulation approach. The cover indices may be recommended for retrieving LAIe only, but for applications which require more sophisticated information on canopy shape and volume, such as radiative transfer models, the

  18. Simulation Models of Leaf Area Index and Yield for Cotton Grown with Different Soil Conditioners.

    Directory of Open Access Journals (Sweden)

    Lijun Su

    Full Text Available Simulation models of leaf area index (LAI and yield for cotton can provide a theoretical foundation for predicting future variations in yield. This paper analyses the increase in LAI and the relationships between LAI, dry matter, and yield for cotton under three soil conditioners near Korla, Xinjiang, China. Dynamic changes in cotton LAI were evaluated using modified logistic, Gaussian, modified Gaussian, log normal, and cubic polynomial models. Universal models for simulating the relative leaf area index (RLAI were established in which the application rate of soil conditioner was used to estimate the maximum LAI (LAIm. In addition, the relationships between LAIm and dry matter mass, yield, and the harvest index were investigated, and a simulation model for yield is proposed. A feasibility analysis of the models indicated that the cubic polynomial and Gaussian models were less accurate than the other three models for simulating increases in RLAI. Despite significant differences in LAIs under the type and amount of soil conditioner applied, LAIm could be described by aboveground dry matter using Michaelis-Menten kinetics. Moreover, the simulation model for cotton yield based on LAIm and the harvest index presented in this work provided important theoretical insights for improving water use efficiency in cotton cultivation and for identifying optimal application rates of soil conditioners.

  19. Detection of chlorophyll and leaf area index dynamics from sub-weekly hyperspectral imagery

    Science.gov (United States)

    Houborg, Rasmus; McCabe, Matthew F.; Angel, Yoseline; Middleton, Elizabeth M.

    2016-10-01

    Temporally rich hyperspectral time-series can provide unique time critical information on within-field variations in vegetation health and distribution needed by farmers to effectively optimize crop production. In this study, a dense timeseries of images were acquired from the Earth Observing-1 (EO-1) Hyperion sensor over an intensive farming area in the center of Saudi Arabia. After correction for atmospheric effects, optimal links between carefully selected explanatory hyperspectral vegetation indices and target vegetation characteristics were established using a machine learning approach. A dataset of in-situ measured leaf chlorophyll (Chll) and leaf area index (LAI), collected during five intensive field campaigns over a variety of crop types, were used to train the rule-based predictive models. The ability of the narrow-band hyperspectral reflectance information to robustly assess and discriminate dynamics in foliar biochemistry and biomass through empirical relationships were investigated. This also involved evaluations of the generalization and reproducibility of the predictions beyond the conditions of the training dataset. The very high temporal resolution of the satellite retrievals constituted a specifically intriguing feature that facilitated detection of total canopy Chl and LAI dynamics down to sub-weekly intervals. The study advocates the benefits associated with the availability of optimum spectral and temporal resolution spaceborne observations for agricultural management purposes.

  20. Relationship of Thematic Mapper simulator data to leaf area index of temperate coniferous forests

    Science.gov (United States)

    Peterson, David L.; Spanner, Michael A.; Running, Steven W.; Teuber, Kurt B.

    1987-01-01

    Regional relationships between remote sensing data and the leaf area index (LAI) of coniferous forests were analyzed using data acquired by an Airborne Thematic Mapper. Eighteen coniferous forest stands with a range of projected leaf area index of 0.6-16.1 were sampled from an environmental gradient in moisture and temperature across west-central Oregon. Spectral radiance measurements to account for atmospheric effects were acquired above the canopies from a radiometer mounted on a helicopter. A strong positive relationship was observed between LAI of closed canopy forest stands and the ratio of near-infrared and red spectral bands. A linear regression based on LAI explained 83 percent of the variation in the ratio of the atmospherically corrected bands. A log-linear equation fit the asymptotic characteristic of the relationship better, explaining 91 percent of the variance. The positive relationship is explained by a strong asymptotic inverse relationship between LAI and red radiation and a relatively flat response between LAI and near-infrared radiation.

  1. Detection of chlorophyll and leaf area index dynamics from sub-weekly hyperspectral imagery

    KAUST Repository

    Houborg, Rasmus

    2016-10-25

    Temporally rich hyperspectral time-series can provide unique time critical information on within-field variations in vegetation health and distribution needed by farmers to effectively optimize crop production. In this study, a dense timeseries of images were acquired from the Earth Observing-1 (EO-1) Hyperion sensor over an intensive farming area in the center of Saudi Arabia. After correction for atmospheric effects, optimal links between carefully selected explanatory hyperspectral vegetation indices and target vegetation characteristics were established using a machine learning approach. A dataset of in-situ measured leaf chlorophyll (Chll) and leaf area index (LAI), collected during five intensive field campaigns over a variety of crop types, were used to train the rule-based predictive models. The ability of the narrow-band hyperspectral reflectance information to robustly assess and discriminate dynamics in foliar biochemistry and biomass through empirical relationships were investigated. This also involved evaluations of the generalization and reproducibility of the predictions beyond the conditions of the training dataset. The very high temporal resolution of the satellite retrievals constituted a specifically intriguing feature that facilitated detection of total canopy Chl and LAI dynamics down to sub-weekly intervals. The study advocates the benefits associated with the availability of optimum spectral and temporal resolution spaceborne observations for agricultural management purposes.

  2. Applicability of non-destructive substitutes for leaf area in different stands of Norway spruce (Picea abies L. Karst.) focusing on traditional forest crown measures.

    Science.gov (United States)

    Laubhann, Daniel; Eckmüllner, Otto; Sterba, Hubert

    2010-09-30

    Since individual tree leaf area is an important measure for productivity as well as for site occupancy, it is of high interest in many studies about forest growth. The exact determination of leaf area is nearly impossible. Thus, a common way to get information about leaf area is to use substitutes. These substitutes are often variables which are collected in a destructive way which is not feasible for long term studies. Therefore, this study aimed at testing the applicability of using substitutes for leaf area which could be collected in a non-destructive way, namely crown surface area and crown projection area. In 8 stands of Norway spruce (Picea abies L. Karst.), divided into three age classes and two thinning treatments, a total of 156 trees were felled in order to test the relationship between leaf area and crown surface area and crown projection area, respectively. Individual tree leaf area of the felled sample trees was estimated by 3P-branch sampling with an accuracy of ±10%. Crown projection area and crown surface area were compared with other, more commonly used, but destructive predictors of leaf area, namely sapwood area at different heights on the bole. Our investigations confirmed findings of several studies that sapwood area is the most precise measure for leaf area because of the high correlation between sapwood area and the leaf area. But behind sapwood area at crown base and sapwood area at three tenth of the tree height the predictive ability of crown surface area was ranked third and even better than that of sapwood area at breast height (R(2) = 0.656 compared with 0.600). Within the stands leaf area is proportional to crown surface area. Using the pooled data of all stands a mixed model approach showed that additionally to crown surface area dominant height and diameter at breast height (dbh) improved the leaf area estimates. Thus, taking dominant height and dbh into account, crown surface area can be recommended for estimating the leaf area

  3. Branch age and light conditions determine leaf-area-specific conductivity in current shoots of Scots pine.

    Science.gov (United States)

    Grönlund, Leila; Hölttä, Teemu; Mäkelä, Annikki

    2016-08-01

    Shoot size and other shoot properties more or less follow the availability of light, but there is also evidence that the topological position in a tree crown has an influence on shoot development. Whether the hydraulic properties of new shoots are more regulated by the light or the position affects the shoot acclimation to changing light conditions and thereby to changing evaporative demand. We investigated the leaf-area-specific conductivity (and its components sapwood-specific conductivity and Huber value) of the current-year shoots of Scots pine (Pinus sylvestris L.) in relation to light environment and topological position in three different tree classes. The light environment was quantified in terms of simulated transpiration and the topological position was quantified by parent branch age. Sample shoot measurements included length, basal and tip diameter, hydraulic conductivity of the shoot, tracheid area and density, and specific leaf area. In our results, the leaf-area-specific conductivity of new shoots declined with parent branch age and increased with simulated transpiration rate of the shoot. The relation to transpiration demand seemed more decisive, since it gave higher R(2) values than branch age and explained the differences between the tree classes. The trend of leaf-area-specific conductivity with simulated transpiration was closely related to Huber value, whereas the trend of leaf-area-specific conductivity with parent branch age was related to a similar trend in sapwood-specific conductivity.

  4. Selecting a spatial resolution for estimation of per-field green leaf area index

    Science.gov (United States)

    Curran, Paul J.; Williamson, H. Dawn

    1988-01-01

    For any application of multispectral scanner (MSS) data, a user is faced with a number of choices concerning the characteristics of the data; one of these is their spatial resolution. A pilot study was undertaken to determine the spatial resolution that would be optimal for the per-field estimation of green leaf area index (GLAI) in grassland. By reference to empirically-derived data from three areas of grassland, the suitable spatial resolution was hypothesized to lie in the lower portion of a 2-18 m range. To estimate per-field GLAI, airborne MSS data were collected at spatial resolutions of 2 m, 5 m and 10 m. The highest accuracies of per-field GLAI estimation were achieved using MSS data with spatial resolutions of 2 m and 5 m.

  5. Crop area and leaf area index simultaneous retrieval based on spatial scaling transformation

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Accurate estimation of crop yields is crucial for ensuring food security. However, crops are distributed so fragmentally in China that mixed pixels account for a large proportion in moderate and coarse resolution remote sensing images. As a result, unmixing of mixed pixel becomes a major problem to estimate crop yield by means of remote sensing method. Aimed at mixed pixels, we developed a new method to introduce additional information contained in the spatial scaling transformation equation to the canopy reflectance model. The crop area and LAI can be retrieved simultaneously. On the basis of a precise and simple canopy reflectance model, directional second derivative method was chosen to retrieve LAI from optimal bands of hyper-spectral data; this method can reduce the impact of the canopy non-isotropic features and soil background. To evaluate the performance of the method, Yingke Oasis, Zhangye City, Gansu Province, was chosen as the validation area. This area was covered mainly by maize and wheat. A Hyperion/EO-1 image with the 30 m spatial resolution was acquired on July 15, 2008. Images of 180 m and 1080 m resolutions were generated by linearly interpolating the original Hyperion image to coarser resolutions. Then a multi-scale image serial was obtained. Using the proposed method, we calculated crop area and the average LAI of every 1080 m pixel. A SPOT-5 classification figure serves as the validation data of crop area proportion. Results show that the pattern of crop distribution accords with the classification figure. The errors are restrained mainly to -0.1-0.1, and approximate a Normal Distribution. Meanwhile, 85 LAI values obtained using LAI-2000 Plant Canopy Analyzer, equipped with GPS, were taken as the ground reference. Results show that the standard deviation of the errors is 0.340. The method proposed in the paper is reliable.

  6. Is whole-plant photosynthetic rate proportional to leaf area? A test of scalings and a logistic equation by leaf demography census.

    OpenAIRE

    Koyama, Kohei; Kikuzawa, Kihachiro; 小山, 耕平

    2009-01-01

    Allometric scalings and a logistic equation assume that whole-plant photosynthetic rate under resource-unlimited conditions is proportional to leaf area. We tested this proportionality for the herb Helianthus tuberosus. During growth, we repeatedly measured the percentage of leaves with high, medium, and low photosynthetic capacity to estimate the whole-plant sum of photosynthetic capacity. We found that the whole-plant sum of the light-saturated photosynthetic rate of leaves is proportional ...

  7. Importance of crown architecture for leaf area index of different Populus genotypes in a high-density plantation.

    Science.gov (United States)

    Broeckx, L S; Verlinden, M S; Vangronsveld, J; Ceulemans, R

    2012-10-01

    Crown architecture is an important determinant of biomass production and yield of any bio-energy plantation since it determines leaf area display and hence light interception. Four Populus genotypes-of different species and hybrids and with contrasting productivity and leaf area-were examined in terms of their branch characteristics in relation to crown architecture during the first and second growing seasons after plantation establishment. The trees were planted at high density (8000 ha(-1)) on two different former land use types, cropland and pasture. We documented significant differences in branch architecture among the genotypes and for the first year among the former land use types. Land use effects only affected factors not related to canopy closure and wood production, and decreased after the first growing season. This suggested that both former land use types were equally suited for the establishment success of a poplar bio-energy plantation. Tree height and branch dimensions-branch diameter and branch length-were the most important determinants of wood production and maximum leaf area index. Despite the secondary importance of the number of sylleptic branches, these branches contributed significantly to the total leaf area in three out of the four studied genotypes. This indicated that enhanced syllepsis accelerates leaf area development and hence carbon assimilation, especially in the early stages of a high-density plantation with poplar.

  8. High resolution imaging of subcellular glutathione concentrations by quantitative immunoelectron microscopy in different leaf areas of Arabidopsis

    Science.gov (United States)

    Koffler, Barbara E.; Bloem, Elke; Zellnig, Günther; Zechmann, Bernd

    2013-01-01

    Glutathione is an important antioxidant and redox buffer in plants. It fulfills many important roles during plant development, defense and is essential for plant metabolism. Even though the compartment specific roles of glutathione during abiotic and biotic stress situations have been studied in detail there is still great lack of knowledge about subcellular glutathione concentrations within the different leaf areas at different stages of development. In this study a method is described that allows the calculation of compartment specific glutathione concentrations in all cell compartments simultaneously in one experiment by using quantitative immunogold electron microscopy combined with biochemical methods in different leaf areas of Arabidopsis thaliana Col-0 (center of the leaf, leaf apex, leaf base and leaf edge). The volume of subcellular compartments in the mesophyll of Arabidopsis was found to be similar to other plants. Vacuoles covered the largest volume within a mesophyll cell and increased with leaf age (up to 80% in the leaf apex of older leaves). Behind vacuoles, chloroplasts covered the second largest volume (up to 20% in the leaf edge of the younger leaves) followed by nuclei (up to 2.3% in the leaf edge of the younger leaves), mitochondria (up to 1.6% in the leaf apex of the younger leaves), and peroxisomes (up to 0.3% in the leaf apex of the younger leaves). These values together with volumes of the mesophyll determined by stereological methods from light and electron micrographs and global glutathione contents measured with biochemical methods enabled the determination of subcellular glutathione contents in mM. Even though biochemical investigations did not reveal differences in global glutathione contents, compartment specific differences could be observed in some cell compartments within the different leaf areas. Highest concentrations of glutathione were always found in mitochondria, where values in a range between 8.7 mM (in the apex of younger

  9. Litterfall and Leaf Area Index in the CONECOFOR Permanent Monitoring Plots

    Directory of Open Access Journals (Sweden)

    Andrea CUTINI

    2002-09-01

    Full Text Available Forest canopies are more sensitive and react more promptly to abiotic and biotic disturbances than other stand structural components. Monitoring crown and canopy characteristics is therefore a crucial issue for intensive and continuous monitoring programs of forest ecosystem status. These observations formed the basis for the measurement of annual litter production and leaf area index (LAI in the Italian permanent monitoring plots (CONECOFOR program established within the EC-UN/ECE program "Intensive Monitoring (Level II of Forest Ecosystems". Preliminary results after three years of observation are presented. The low value of within plot mean relative standard deviation (20.8 ± 1.9% of litter production, which in any case never exceeded 30%, accounted for the good sampling error and accuracy of the chosen method, which seems to be accurate enough to detect changes in litter production through the years. The higher inconsistency of the amount of woody and fruits fractions over the years demonstrated the greater reliability of leaf fraction or, on the other hand, of LAI compared to total litter. Mean values of annual leaf-litter and total litter production and LAI were rather high in comparison with data reported in literature for similar stands, and reflected both a medium-high productivity and a juvenile phase in the development of the selected stands on average. Focusing on changes in litter production through the years, statistical analysis on a sub-sample of plots showed the existence of significant differences both in leaf litter and total litter production. These findings seem to attribute to the "year" factor a driving role in determining changes in litter production and LAI. Temporal intermittence in data collection, together with the shortness of the monitoring period, make it difficult to speculate or arrive at definitive conclusions on changes in litter production due to time-dependent factors. The importance of having a complete

  10. Large ontogenetic declines in intra-crown leaf area index in two temperate deciduous tree species.

    Science.gov (United States)

    Nock, C A; Caspersen, J P; Thomas, S C

    2008-03-01

    The widespread occurrence of age-related changes in leaf morphology and allocation suggests that the leaf area index of individual trees (intra-crown LAI) may decline late in ontogeny. We used direct, within-canopy measurements to quantify the LAI of canopy trees with exposed crowns of two temperate deciduous species. Intra-crown LAI declined from approximately 7 to 4 in Acer saccharum, and from approximately 9.5 to 6.5 in Betula alleghaniensis, as tree size increased (from 15 to 72 cm diameter at breast height [dbh]). For A. saccharum, age (which varied from 30 to 160 years) was a significantly better predictor of LAI decline than dbh. We also modeled the effect of ontogenetic declines in LAI on understory light availability and found that light transmission increases significantly as canopy trees grow and mature. Our results thus suggest that gradual declines in LAI with tree age may play an important and overlooked role in contributing to the heterogeneity of sub-canopy light regimes in mature forests.

  11. Taxonomy and remote sensing of leaf mass per area (LMA) in humid tropical forests.

    Science.gov (United States)

    Asner, Gregory P; Martin, Roberta E; Tupayachi, Raul; Emerson, Ruth; Martinez, Paola; Sinca, Felipe; Powell, George V N; Wright, S Joseph; Lugo, Ariel E

    2011-01-01

    Leaf mass per area (LMA) is a trait of central importance to plant physiology and ecosystem function, but LMA patterns in the upper canopies of humid tropical forests have proved elusive due to tall species and high diversity. We collected top-of-canopy leaf samples from 2873 individuals in 57 sites spread across the Neotropics, Australasia, and Caribbean and Pacific Islands to quantify environmental and taxonomic drivers of LMA variation, and to advance remote-sensing measures of LMA. We uncovered strong taxonomic organization of LMA, with species accounting for 70% of the global variance and up to 62% of the variation within a forest stand. Climate, growth habit, and site conditions are secondary contributors (1-23%) to the observed LMA patterns. Intraspecific variation in LMA averages 16%, which is a fraction of the variation observed between species. We then used spectroscopic remote sensing (400-2500 nm) to estimate LMA with an absolute uncertainty of 14-15 g/m2 (r2 = 0.85), or approximately 10% of the global mean. With radiative transfer modeling, we demonstrated the scalability of spectroscopic remote sensing of LMA to the canopy level. Our study indicates that remotely sensed patterns of LMA will be driven by taxonomic variation against a backdrop of environmental controls expressed at site and regional levels.

  12. Protected Areas Database of the United States (PAD-US)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The USGS Protected Areas Database of the United States (PAD-US) is the nation's inventory of protected areas, including public open space and voluntarily provided,...

  13. Influence of Leaf Area Index Prescriptions on Simulations of Heat, Moisture, and Carbon Fluxes

    Science.gov (United States)

    Kala, Jatin; Decker, Mark; Exbrayat, Jean-Francois; Pitman, Andy J.; Carouge, Claire; Evans, Jason P.; Abramowitz, Gab; Mocko, David

    2013-01-01

    Leaf-area index (LAI), the total one-sided surface area of leaf per ground surface area, is a key component of land surface models. We investigate the influence of differing, plausible LAI prescriptions on heat, moisture, and carbon fluxes simulated by the Community Atmosphere Biosphere Land Exchange (CABLEv1.4b) model over the Australian continent. A 15-member ensemble monthly LAI data-set is generated using the MODIS LAI product and gridded observations of temperature and precipitation. Offline simulations lasting 29 years (1980-2008) are carried out at 25 km resolution with the composite monthly means from the MODIS LAI product (control simulation) and compared with simulations using each of the 15-member ensemble monthly-varying LAI data-sets generated. The imposed changes in LAI did not strongly influence the sensible and latent fluxes but the carbon fluxes were more strongly affected. Croplands showed the largest sensitivity in gross primary production with differences ranging from -90 to 60 %. PFTs with high absolute LAI and low inter-annual variability, such as evergreen broadleaf trees, showed the least response to the different LAI prescriptions, whilst those with lower absolute LAI and higher inter-annual variability, such as croplands, were more sensitive. We show that reliance on a single LAI prescription may not accurately reflect the uncertainty in the simulation of the terrestrial carbon fluxes, especially for PFTs with high inter-annual variability. Our study highlights that the accurate representation of LAI in land surface models is key to the simulation of the terrestrial carbon cycle. Hence this will become critical in quantifying the uncertainty in future changes in primary production.

  14. Losses of leaf area owing to herbivory and early senescence in three tree species along a winter temperature gradient

    Science.gov (United States)

    González-Zurdo, P.; Escudero, A.; Nuñez, R.; Mediavilla, S.

    2016-11-01

    In temperate climates, evergreen leaves have to survive throughout low temperature winter periods. Freezing and chilling injuries can lead to accelerated senescence of part of the leaf surface, which contributes to a reduction of the lifespan of the photosynthetic machinery and of leaf lifetime carbon gain. Low temperatures are also associated with changes in foliar chemistry and morphology that affect consumption by herbivores. Therefore, the severity of foliar area losses caused by accelerated senescence and herbivory can change along winter temperature gradients. The aim of this study is to analyse such responses in the leaves of three evergreen species ( Quercus ilex, Q. suber and Pinus pinaster) along a climatic gradient. The leaves of all three species presented increased leaf mass per area (LMA) and higher concentrations of structural carbohydrates in cooler areas. Only the two oak species showed visible symptoms of damage caused by herbivory, this being less intense at the coldest sites. The leaves of all three species presented chlorotic and necrotic spots that increased in size with leaf age. The foliar surface affected by chlorosis and necrosis was larger at the sites with the coldest winters. Therefore, the effects of the winter cold on the lifespan of the photosynthetic machinery were contradictory: losses of leaf area due to accelerated senescence increased, but there was a decrease in losses caused by herbivory. The final consequences for carbon assimilation strongly depend on the exact timing of the appearance of the damage resulting from low temperature and grazing by herbivores.

  15. Developing Student's Notion of Measurement Unit for Area

    Science.gov (United States)

    Yuberta, Kurnia Rahmi; Zulkardi; Hartono, Yusuf; van Galen, Frans

    2011-01-01

    Many researchers found that students have difficulties in understanding area measurement. Students mostly focus on applying formula to find the area of certain shapes without knowing what the area is and why the formula works. It is important for the students to know what attribute being measured and to construct the unit for area measurement.…

  16. Use of remotely sensed precipitation and leaf area index in a distributed hydrological model

    DEFF Research Database (Denmark)

    Andersen, J.; Dybkjær, G.; Jensen, Karsten Høgh

    2002-01-01

    Remotely sensed precipitation from METEOSAT data and leaf area index (LAI) from NOAA AVHRR data is used as input data to the distributed hydrological modelling of three sub catchments (82.000 km(2)) in the Senegal River Basin. Further, root depths of annual vegetation are related to the temporal...... and spatial variation of LAI. The modelling results are compared with results based on conventional input of precipitation and vegetation characteristics. The introduction of remotely sensed LAI shows improvements in the simulated hydrographs, a marked change in the relative proportions of actual...... evapotranspiration comprising canopy evaporation, soil evaporation and transpiration. while no clear trend in the spatial pattern could be found, The remotely sensed precipitation resulted in similar model performances with respect to the simulated hydrographs as with the conventional raingauge input. A simple...

  17. Biomass, Leaf Area, and Resource Availability of Kudzu Dominated Plant Communities Following Herbicide Treatment

    Energy Technology Data Exchange (ETDEWEB)

    L.T. Rader

    2001-10-01

    Kudzu is an exotic vine that threatens the forests of the southern U.S. Five herbicides were tested with regard to their efficacy in controlling kudzu, community recover was monitored, and interactions with planted pines were studied. The sites selected were old farm sites dominated by kudzu.These were burned following herbicide treatment. The herbicides included triclopyr, clopyralid, metsulfuron, tebuthiuron, and picloram plus 2,4-D. Pine seedlings were planted the following year. Regression equations were developed for predicting biomass and leaf area. Four distinct plant communities resulted from the treatments. The untreated check continued to be kudzu dominated. Blackberry dominated the clopyradid treatment. Metsulfron, trychlopyr and picloram treated sites resulted in herbaceous dominated communities. The tebuthiuron treatment maintained all vegetation low.

  18. Assessing Leaf Area Index from High Resolution Satellite Datasets for Maize in Trans Nzoia County, Kenya

    Science.gov (United States)

    Bartolomew Thiongo, Kuria; Menz, Gunter; Thonfeld, Frank

    2016-08-01

    The Normalized Differenced Vegetation Index (NDVI) and the two band Enhanced vegetation Index (EVI2) derived from RapidEye and Landsat 8 satellite images were evaluated against the empirically derived terrestrial Leaf Area Index (LAI) acquired during the maize growth season April to November, 2015 and covering the phenological growth stages prescribed in the BBCH code. The results indicate a high correlation of the vegetation indices plotted over the entire maize season with R2 values of 88% and 83% for NDVI and EVI2 respectively. The maximum values were found to occur during the maize vegetative phase in the months of July and August. The correlation between the vegetation indices and the LAI had R2 values of 50% and 49% for NDVI and EVI2 respectively. Alternative methods of estimating and calculating the LAI values may improve the achieved results.

  19. Retrieving leaf area index for coniferous forest in Xingguo County, China with Landsat ETM+ images.

    Science.gov (United States)

    Tian, Q; Luo, Z; Chen, J M; Chen, M; Hui, F

    2007-11-01

    Spatial distributions of the leaf area index (LAI) needed for carbon cycle modeling in Xingguo County, China were estimated based on correlations between the field-measurements and vegetation indices (VIs). After making geometric and atmospheric corrections to two Landsat ETM+ images, one in January 2000 and the other in May 2003, three VIs (SR, NDVI, and RSR) were derived, and their separate correlations with ground LAI measurements were established. The correlation with RSR was the highest among the three VIs. The retrieved LAI values for January 2000 were lower than those for May 2003 because of a small seasonal variation in the coniferous forests (predominantly masson pine) and the decrease in the understorey vegetation during winter.

  20. Retrieval of leaf area index in different plant species using thermal hyperspectral data

    Science.gov (United States)

    Neinavaz, Elnaz; Skidmore, Andrew K.; Darvishzadeh, Roshanak; Groen, Thomas A.

    2016-09-01

    Leaf area index (LAI) is an important variable of terrestrial ecosystems because it is strongly correlated with many ecosystem processes (e.g., water balance and evapotranspiration) and directly related to the plant energy balance and gas exchanges. Although LAI has been accurately predicted using visible and short-wave infrared hyperspectral data (0.3-2.5 μm), LAI estimation using thermal infrared (TIR, 8-14 μm) measurements has not yet been addressed. The novel approach of this study is to evaluate the retrieval of LAI using TIR hyperspectral data. The leaf area indices were destructively acquired for four plant species: Azalea japonica, Buxussempervirens, Euonymus japonicus, and Ficus benjamina. Canopy emissivity spectral measurements were obtained under controlled laboratory conditions using a MIDAC (M4401-F) spectrometer. The LAI retrieval was assessed using a partial least squares regression (PLSR), artificial neural networks (ANNs), and narrow band indices calculated from all possible combinations of waveband pairs for three vegetation indices including simple difference, simple ratio, and normalized difference. ANNs retrieved LAI more accurately than PLSR and vegetation indices (0.67 retrieval did not differ significantly between the vegetation indices. The results revealed that wavebands from the 8-12 μm region contain relevant information for LAI estimation, irrespective of the chosen vegetation index. Moreover, they demonstrated that LAI may be successfully predicted from TIR hyperspectral data, even for higher values of LAI (LAI ⩾ 5.5). The study showed the significance of using PLSR and ANNs as multivariate methods compared to the univariate technique (e.g., narrow band vegetation indices) when hyperspectral thermal data is utilized. We thus demonstrated for the first time the potential of hyperspectral thermal data to accurately retrieve LAI.

  1. Leaf Collection Posting Log

    Data.gov (United States)

    Montgomery County of Maryland — This dataset contains leaf collection dates for area and subarea where leaf collection service is provided by Montgomery County Department of Transportation. Update...

  2. Leaf area index retrieval based on canopy reflectance and vegetation index in easternChina

    Institute of Scientific and Technical Information of China (English)

    JIANGJianjun; CHENSuozhong; CAOShunxian; WUHongan; ZHANGLi; ZHANGHailong

    2005-01-01

    The aim of this paper is to investigate the feasibility of using Landsat TM data to retrieve leaf area index (LAI). To get a LAI retrieval model based ground reflectance and vegetation index,detailed field data were collected in the study area of eastern China, dominated by bamboo, tea plant and greengage. Plant canopy reflectance of Landsat TM wavelength bands has been inversed using software of 6S. LAI is an important ecological parameter. In this paper, atmospheric corrected Landsat TM imagery was utilized to calculate different vegetation indices (Ⅵ), such as simple ratio vegetationin dex (SR), shortwave infrared modified simple ratio (MSR), and normalized difference vegetation index (NDⅥ). Data of 53 samples of LAI were measured by LAI-2000 (LI-COR) in the study area.LAI was modeled based on different reflectances of bands and different vegetation indices from Landsat TM and LAI samples data. There are certainly correlations between LAI and the reflectance of TM3, TM4, TM5 and TM7. The best model through analyzing the results is LAI = 1.2097*MSR+0.4741 using the method of regression analysis. The result shows that the correlation coefficient R2 is 0.5157, and average accuracy is 85.75%. However, whether the model of this paper is suitable for application in subtropics needs to be verified in the future.

  3. Hierarchical porous carbon with ultrahigh surface area from corn leaf for high-performance supercapacitors application

    Science.gov (United States)

    Yang, Xiaoqing; Li, Chengfei; Chen, Yue

    2017-02-01

    A new class of hierarchical porous carbon (HPC) with ultrahigh surface area is successfully fabricated by carefully selecting biomass carbon precursors and activation reagent, through which corn leaf (CL) with natural well-defined macropore channels is used as the carbon precursor, and H3PO4 is used as the active agent by virtue of its pore-widening effect. The as-prepared CL-based HPC (CLHPC) with a H3PO4/semi-carbonized CL mass ratio of 2 (CLHPC-2) demonstrates the highest specific surface area of 2507 m2 g-1 donated by 28.3% of micropore and 71.6% of mesopore, while maintaining the channel-like macroporous structure derived from the well-defined natural structure in CL. The combination of the hierarchical porous structure and ultrahigh surface area enables rapid electrolyte diffusion and sufficient active sites for charge accumulation. As a result, CLHPC-2 exhibits excellent electrochemical performance, such as high specific capacitance of 230 F g-1 at the current density of 0.1 A g-1, excellent high-rate capability (retention of 91% from 0.1 to 5 A g-1), and good cycling stability (99% capacitance retention after 10 000 cycles).

  4. Functional ratios among leaf, xylem and phloem areas in branches change with shade tolerance, but not with local light conditions, across temperate tree species

    NARCIS (Netherlands)

    Zhang, Lan; Copini, Paul; Weemstra, Monique; Sterck, Frank

    2016-01-01

    Leaf, xylem and phloem areas drive the water and carbon fluxes within branches and trees, but their mutual coordination is poorly understood. We test the hypothesis that xylem and phloem areas increase relative to leaf area when species are selected for, or branches are exposed to, higher levels

  5. Development of monitoring method of coffee leaf rust fungus (Hemileia vastatrix) infected area using satellite remote sensing

    Science.gov (United States)

    Katsuhama, N.; Ikeda, K.; Imai, M.; Watanabe, K.; Marpaung, F.; Yoshii, T.; Naruse, N.; Takahashi, Y.

    2016-12-01

    Since 2008, coffee leaf rust fungus (Hemileia vastatrix) has expanded its infection in Latin America, and early trimming and burning infected trees have been only effective countermeasures to prevent spreading infection. Although some researchers reported a case about the monitoring of coffee leaf rust using satellite remote sensing in 1970s, the spatial resolution was unsatisfied, and therefore, further technological development has been required. The purpose of this research is to develop effective method of discovering coffee leaf rust infected areas using satellite remote sensing. Annual changes of vegetation indices, i.e. Normalized Difference Vegetation Index (NDVI) and Modified Structure Insensitive Pigment Index (MSIPI), around Cuchumatanes Mountains, Republic of Guatemala, were analyzed by Landsat 7 images. Study fields in the research were limited by the coffee farm areas based on a previous paper about on site surveys in different damage areas. As the result of the analysis, the annual change of NDVI at the coffee farm areas with damages tended to be lower than those without damages. Moreover, the decline of NDVI appear from 2008 before the damage was reported. On the other hand, the change of MSIPI had no significant difference. NDVI and MSIPI are mainly related to the amount of chlorophyll and carotenoid in the leaves respectively. This means that the infected coffee leaves turned yellow without defoliation. This situation well matches the symptom of coffee leaf rust. The research concluded that the property of infected leaves turning yellow is effective to monitoring of infection areas by satellite remote sensing.

  6. Estimating leaf area index by inversion of reflectance model for semiarid natural grasslands

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The study developed an integrated reflectance model combining radiative transfer and geometric optical properties in order to inverse leaf area index(LAI) of semiarid natural grasslands.In order to better link remote sensing information with land plants,and facilitate regional and global climate change studies,the model introduced a simple but important geometrical similarity parameter related to plant crown shapes.The model revealed the influences of different plant crown shapes(such as spherical,cylindrical/cuboidal and conic crowns) on leaf/branch angle distribution frequencies,shadow ground coverage,shadowed or sunlit background fractions,canopy reflectance,and scene reflectance.The modeled reflectance data agreed with the measured ones in the three Leymus chinensis steppes with different degradation degrees,which validated the reflectance model.The lower the degradation degree was,the better the modeled data agreed with the measured data.After this reflectance model was coupled with the optimization inversion method,LAI over the entire study region was estimated once every eight days using the eight-day products of surface reflectance obtained by multi-spectral Moderate-Resolution Imaging Spectroradiometer(MODIS) during the growing seasons in 2002.The temporal and spatial patterns of inversed LAI for the steppes with different cover degrees,swamps,flood plains,and croplands agreed with the general laws and measurements very well.But for unused land cover types(sands,saline,and barren lands) and forestlands,totally accounting for about 10% of the study region,the reasonable LAI values were not derived by inversing,requiring further revising of the model or the development of a new model for them.

  7. Leaf Area Index Estimation Using Chinese GF-1 Wide Field View Data in an Agriculture Region.

    Science.gov (United States)

    Wei, Xiangqin; Gu, Xingfa; Meng, Qingyan; Yu, Tao; Zhou, Xiang; Wei, Zheng; Jia, Kun; Wang, Chunmei

    2017-07-08

    Leaf area index (LAI) is an important vegetation parameter that characterizes leaf density and canopy structure, and plays an important role in global change study, land surface process simulation and agriculture monitoring. The wide field view (WFV) sensor on board the Chinese GF-1 satellite can acquire multi-spectral data with decametric spatial resolution, high temporal resolution and wide coverage, which are valuable data sources for dynamic monitoring of LAI. Therefore, an automatic LAI estimation algorithm for GF-1 WFV data was developed based on the radiative transfer model and LAI estimation accuracy of the developed algorithm was assessed in an agriculture region with maize as the dominated crop type. The radiative transfer model was firstly used to simulate the physical relationship between canopy reflectance and LAI under different soil and vegetation conditions, and then the training sample dataset was formed. Then, neural networks (NNs) were used to develop the LAI estimation algorithm using the training sample dataset. Green, red and near-infrared band reflectances of GF-1 WFV data were used as the input variables of the NNs, as well as the corresponding LAI was the output variable. The validation results using field LAI measurements in the agriculture region indicated that the LAI estimation algorithm could achieve satisfactory results (such as R² = 0.818, RMSE = 0.50). In addition, the developed LAI estimation algorithm had potential to operationally generate LAI datasets using GF-1 WFV land surface reflectance data, which could provide high spatial and temporal resolution LAI data for agriculture, ecosystem and environmental management researches.

  8. Functional ratios among leaf, xylem and phloem areas in branches change with shade tolerance, but not with local light conditions, across temperate tree species.

    Science.gov (United States)

    Zhang, Lan; Copini, Paul; Weemstra, Monique; Sterck, Frank

    2016-03-01

    Leaf, xylem and phloem areas drive the water and carbon fluxes within branches and trees, but their mutual coordination is poorly understood. We test the hypothesis that xylem and phloem areas increase relative to leaf area when species are selected for, or branches are exposed to, higher levels of light intensity. Trees of 10 temperate, broadleaved and deciduous, tree species were selected. Fifty-centimetre-long branches were collected from shaded and exposed conditions at a height of 3-4 m. We measured the total leaf area, xylem area, phloem area and leaf traits, as well as the area of the constituent cell types, for a stem section at the branch base. Xylem area : leaf area and phloem area : leaf area ratios did not differ consistently between sun and shade branches, but, as expected, they decreased with species' shade tolerance. Similar trends were observed for conductive cell areas in xylem and phloem. Trees of light-demanding species maintain higher water loss and carbon gain rates per leaf area by producing more xylem area and phloem area than shade-tolerant species. We call for more comparative branch studies as they provide an integrated biological perspective on functional traits and their role in the ecology of tree species. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  9. Satellite remote sensing for estimating leaf area index, FPAR and primary production. A literature review

    Energy Technology Data Exchange (ETDEWEB)

    Boresjoe Bronge, Laine [SwedPower AB, Stockholm (Sweden)

    2004-03-01

    Land vegetation is a critical component of several biogeochemical cycles that have become the focus of concerted international research effort. Most ecosystem productivity models, carbon budget models, and global models of climate, hydrology and biogeochemistry require vegetation parameters to calculate land surface photosynthesis, evapotranspiration and net primary production. Therefore, accurate estimates of vegetation parameters are increasingly important in the carbon cycle, the energy balance and in environmental impact assessment studies. The possibility of quantitatively estimating vegetation parameters of importance in this context using satellite data has been explored by numerous papers dealing with the subject. This report gives a summary of the present status and applicability of satellite remote sensing for estimating vegetation productivity by using vegetation index for calculating leaf area index (LAI) and fraction of absorbed photosynthetically active radiation (FPAR). Some possible approaches for use of satellite data for estimating LAI, FPAR and net primary production (NPP) on a local scale are suggested. Recommendations for continued work in the Forsmark and Oskarshamn investigation areas, where vegetation data and NDVI-images based on satellite data have been produced, are also given.

  10. Scale effects of leaf area index inversion based on environmental and disaster monitoring satellite data

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The spatial distribution of sub-pixel components has an impact on retrieval accuracy,and should be accounted for when inverting a three-dimensional adiative transfer model to retrieve leaf area index(LAI).To investigate this effect,we constructed three realistic scenarios with the same LAI values and other properties,except that the simulated plants had different distributions.We implemented the radiosity method to subsequently produce synthetic bidirectional reflectance factor(BRF) datasets based upon these simulated scenes.The inversion was conducted using these data,which showed that spatial distribution affects retrieval accuracy.The inversion was also conducted for LAI based on charge-coupled device(CCD) data from the Environment and Disaster Monitor Satellite(HJ-1),which depicted both forest and drought-resistant crop land cover.This showed that heterogeneity in coarse-resolution remote sensing data is the main error source in LAI inversion.The spatial distribution of global fractal dimension index,which can be used to describe the area of sub-pixel components and their spatial distribution modes,shows good consistency with the coarse resolution LAI inversion error.

  11. Monitoring leaf area index at watershed level through NDVI from Landsat-7/ETM+ data

    Directory of Open Access Journals (Sweden)

    Xavier Alexandre Cândido

    2004-01-01

    Full Text Available Leaf area index (LAI is an important parameter of the vegetation canopy, and is used, for instance, to estimate evapotranspiration, an important component of the hydrological cycle. This work analyzed the relationship between LAI, measured in field, and NDVI from four dates (derived from Landsat-7/ETM+ data, and with such vegetation index, to generate and analyze LAI maps of the study area for the diverse dates. LAI data were collected monthly in the field with LAI-2000 equipment in stands of sugar cane, pasture, corn, eucalypt, and riparian forest. The relationships between LAI and NDVI were adjusted by a potential model; 57% to 72% of the NDVI variance were explained by the LAI. LAI maps generated by empirical relationships between LAI and NDVI showed reasonable precision (standard error of LAI estimate ranged from 0.42 to 0.87 m² m-2. The mean LAI value of each monthly LAI map was shown to be related to the total precipitation in the three previous months.

  12. Measuring Leaf Area in Soy Plants by HSI Color Model Filtering and Mathematical Morphology

    Science.gov (United States)

    Benalcázar, M.; Padín, J.; Brun, M.; Pastore, J.; Ballarin, V.; Peirone, L.; Pereyra, G.

    2011-12-01

    There has been lately a significant progress in automating tasks for the agricultural sector. One of the advances is the development of robots, based on computer vision, applied to care and management of soy crops. In this task, digital image processing plays an important role, but must solve some important problems, like the ones associated to the variations in lighting conditions during image acquisition. Such variations influence directly on the brightness level of the images to be processed. In this paper we propose an algorithm to segment and measure automatically the leaf area of soy plants. This information is used by the specialists to evaluate and compare the growth of different soy genotypes. This algorithm, based on color filtering using the HSI model, detects green objects from the image background. The segmentation of leaves (foliage) was made applying Mathematical Morphology. The foliage area was estimated counting the pixels that belong to the segmented leaves. From several experiments, consisting in applying the algorithm to measure the foliage of about fifty plants of various genotypes of soy, at different growth stages, we obtained successful results, despite the high brightness variations and shadows in the processed images.

  13. Sugarcane leaf area estimate obtained from the corrected Normalized Difference Vegetation Index (NDVI

    Directory of Open Access Journals (Sweden)

    Rodrigo Moura Pereira

    2016-06-01

    Full Text Available Large farmland areas and the knowledge on the interaction between solar radiation and vegetation canopies have increased the use of data from orbital remote sensors in sugarcane monitoring. However, the constituents of the atmosphere affect the reflectance values obtained by imaging sensors. This study aimed at improving a sugarcane Leaf Area Index (LAI estimation model, concerning the Normalized Difference Vegetation Index (NDVI subjected to atmospheric correction. The model generated by the NDVI with atmospheric correction showed the best results (R2 = 0.84; d = 0.95; MAE = 0.44; RMSE = 0.55, in relation to the other models compared. LAI estimation with this model, during the sugarcane plant cycle, reached a maximum of 4.8 at the vegetative growth phase and 2.3 at the end of the maturation phase. Thus, the use of atmospheric correction to estimate the sugarcane LAI is recommended, since this procedure increases the correlations between the LAI estimated by image and by plant parameters.

  14. Comparison of vertical resolved leaf area index measurements in an open canopy savannah-type forest

    Science.gov (United States)

    Piayda, Arndt; Cuntz, Matthias; Dubbert, Maren; Werner, Christiane; Pereira, Joao S.

    2013-04-01

    Leaf area index (LAI) is a very important vegetation parameter in soil-vegetation-atmosphere exchange modeling. To represent the structure of ecosystems in vertically distributed modeling, vertical resolved LAI distributions as well as vertically and angular gap fraction (Pgap) distributions are needed, but rarely available. Additionally, former studies neglect woody plant components when using light interception or digital photography based methods for LAI or Pgap observations. This can lead to significantly biased results, particularly in semi-arid savannah-type ecosystems with low LAI values. The objective of this study is to compare three non-destructive LAI measurement techniques in a sparse savannah-type cork oak canopy in central Portugal in order to derive vertically resolved LAI as well as vertically and angular resolved Pgap. Since established canopy analyzers, such as the LAI-2000, rely on diffuse light conditions, which are rarely realized in semi-arid regions, we also employed fast, digital cover photography (DCP) working independently from diffuse light conditions. We used vertical and angular distributed DCP and applied object-based image analysis techniques to exclude woody plant components from Pgap estimation and LAI determination. We compared the results with vertically distributed LAI-2000 measurements, and additionally with vertical estimates based on easily measurable forest canopy parameters. We employed bootstrap resampling methods to determine the accuracy of all measurements depending on sample size. Leaf inclination measurements indicate planophile leaf orientation. Thus LAI was calculated with Pgap and the leaf inclination information. This led to a spatial averaged LAI of 0.52 +- 0.06 for DCP while LAI-2000 measurements resulted in 0.67 +- 0.07. Uncertainty bounds of LAI converge much faster with increasing sample size for the DCP than for the LAI-2000. This allows a more efficient sampling design, which is of great importance in

  15. Global dependence of field-observed leaf area index in woody species on climate: a systematic review

    NARCIS (Netherlands)

    Iio, A.; Hikosaka, K.; Anten, N.P.R.; Nakagawa, Y.; Ito, A.

    2014-01-01

    Aim Leaf area index (LAI) is one of the key variables related to carbon, water and nutrient cycles in terrestrial ecosystems, but its global distribution patterns remain poorly understood.We evaluated the dependence of LAI on mean annual temperature (MAT) and wetness index (WI; a ratio of annual pre

  16. Global dependence of field-observed leaf area index in woody species on climate: a systematic review

    NARCIS (Netherlands)

    Iio, A.; Hikosaka, K.; Anten, N.P.R.; Nakagawa, Y.; Ito, A.

    2014-01-01

    Aim Leaf area index (LAI) is one of the key variables related to carbon, water and nutrient cycles in terrestrial ecosystems, but its global distribution patterns remain poorly understood.We evaluated the dependence of LAI on mean annual temperature (MAT) and wetness index (WI; a ratio of annual pre

  17. Estimating Yellow Starthistle (Centaurea solstitialis) Leaf Area Index and Aboveground Biomass with the Use of Hyperspectral Data

    Science.gov (United States)

    Hyperspectral remote-sensed data were obtained via a Compact Airborne Spectrographic Imager-II (CASI-II) and used to estimate leaf-area index (LAI) and aboveground biomass of a highly invasive weed species, yellow starthistle (YST). In parallel, 34 ground-based field plots were used to measure abov...

  18. Assimilating a synthetic Kalman filter leaf area index series into the WOFOST model to improve regional winter wheat yield estimation

    Science.gov (United States)

    The scale mismatch between remotely sensed observations and crop growth models simulated state variables decreases the reliability of crop yield estimates. To overcome this problem, we used a two-step data assimilation phases: first we generated a complete leaf area index (LAI) time series by combin...

  19. Leaf area index estimation with MODIS reflectance time series and model inversion during full rotations of Eucalyptus plantations

    NARCIS (Netherlands)

    Maire, Le G.; Marsden, C.; Verhoef, W.; Ponzoni, F.J.; Seen, Lo D.; Bégué, A.; Stape, J.L.; Nouvellon, Y.

    2011-01-01

    The leaf area index (LAI) of fast-growing Eucalyptus plantations is highly dynamic both seasonally and inter-annually, and is spatially variable depending on pedo-climatic conditions. LAI is very important in determining the carbon and water balance of a stand, but is difficult to measure during a

  20. Benchmarking sensitivity of biophysical processes to leaf area changes in land surface models

    Science.gov (United States)

    Forzieri, Giovanni; Duveiller, Gregory; Georgievski, Goran; Li, Wei; Robestson, Eddy; Kautz, Markus; Lawrence, Peter; Ciais, Philippe; Pongratz, Julia; Sitch, Stephen; Wiltshire, Andy; Arneth, Almut; Cescatti, Alessandro

    2017-04-01

    Land surface models (LSM) are widely applied as supporting tools for policy-relevant assessment of climate change and its impact on terrestrial ecosystems, yet knowledge of their performance skills in representing the sensitivity of biophysical processes to changes in vegetation density is still limited. This is particularly relevant in light of the substantial impacts on regional climate associated with the changes in leaf area index (LAI) following the observed global greening. Benchmarking LSMs on the sensitivity of the simulated processes to vegetation density is essential to reduce their uncertainty and improve the representation of these effects. Here we present a novel benchmark system to assess model capacity in reproducing land surface-atmosphere energy exchanges modulated by vegetation density. Through a collaborative effort of different modeling groups, a consistent set of land surface energy fluxes and LAI dynamics has been generated from multiple LSMs, including JSBACH, JULES, ORCHIDEE, CLM4.5 and LPJ-GUESS. Relationships of interannual variations of modeled surface fluxes to LAI changes have been analyzed at global scale across different climatological gradients and compared with satellite-based products. A set of scoring metrics has been used to assess the overall model performances and a detailed analysis in the climate space has been provided to diagnose possible model errors associated to background conditions. Results have enabled us to identify model-specific strengths and deficiencies. An overall best performing model does not emerge from the analyses. However, the comparison with other models that work better under certain metrics and conditions indicates that improvements are expected to be potentially achievable. A general amplification of the biophysical processes mediated by vegetation is found across the different land surface schemes. Grasslands are characterized by an underestimated year-to-year variability of LAI in cold climates

  1. IMPACT OF TEHNICAL SPRAYING FACTORS ON LEAF AREA COVERAGE IN PERMANENT CROPS

    Directory of Open Access Journals (Sweden)

    Vjekoslav Tadić

    2013-12-01

    Full Text Available Researches are conducted in vineyard and apple orchard with two different types of mist blowers, axial (Hardi Zaturn and radial (Hardi Arrow. The influence of major technical spraying factors (type of nozzle, working speed and spray volume were observed on coverage of the treated area, average droplet diameter, number of droplets per cm2 and drift. The working speed of sprayer was set at 6 and 8 km/h, and spray volume on 250, 325 and 400 l/ha for apple orchard and 250, 300 and 350 l/ha for vineyard. Researchers used Lechler blue (TR 8003, yellow (TR 8002 and green (TR 80015 nozzles. The research was set as three - factorial field experiment with 18 treatments in 4 repetitions, for different type of sprayer and permanent crops. We used 60 water sensitive papers for that treatment, which were processed with digital image analysis and ImageJ software. In addition to the main features of the research, research showed leaf area index and density, speed and flow of air current, working pressure, orientation of the nozzles and weather conditions, which were monitored during the study. Before the research, mist blowers are tested according to the European standard 13790. By decreasing the ISO number of nozzles and by increasing the working speed and spray volume, we found increase of area coverage, number of droplets per cm2and drift, and decrease of average droplet diameter. Also, by comparing the results of research exploitation by axial and radial mist blower in the vineyards and apple orchards, better results are achieved with radial mist blower (Hardi Arrow in both cases. The best relationship of area coverage and liquid drift in vineyard were achieved with 64.22% area coverage and 17.11% of liquid drift (green nozzle, working speed of 6 km/h, spray volume of 350 l/ha, and working pressure of 10.99 bar. In apple orchard the best relationship of area coverage and liquid drift were achieved with 59.55% area coverage and 21.10% of liquid drift (green

  2. Grapevine Yield and Leaf Area Estimation Using Supervised Classification Methodology on RGB Images Taken under Field Conditions

    Science.gov (United States)

    Diago, Maria-Paz; Correa, Christian; Millán, Borja; Barreiro, Pilar; Valero, Constantino; Tardaguila, Javier

    2012-01-01

    The aim of this research was to implement a methodology through the generation of a supervised classifier based on the Mahalanobis distance to characterize the grapevine canopy and assess leaf area and yield using RGB images. The method automatically processes sets of images, and calculates the areas (number of pixels) corresponding to seven different classes (Grapes, Wood, Background, and four classes of Leaf, of increasing leaf age). Each one is initialized by the user, who selects a set of representative pixels for every class in order to induce the clustering around them. The proposed methodology was evaluated with 70 grapevine (V. vinifera L. cv. Tempranillo) images, acquired in a commercial vineyard located in La Rioja (Spain), after several defoliation and de-fruiting events on 10 vines, with a conventional RGB camera and no artificial illumination. The segmentation results showed a performance of 92% for leaves and 98% for clusters, and allowed to assess the grapevine’s leaf area and yield with R2 values of 0.81 (p < 0.001) and 0.73 (p = 0.002), respectively. This methodology, which operates with a simple image acquisition setup and guarantees the right number and kind of pixel classes, has shown to be suitable and robust enough to provide valuable information for vineyard management. PMID:23235443

  3. Changes in leaf area, nitrogen content and canopy photosynthesis in soybean exposed to an ozone concentration gradient.

    Science.gov (United States)

    Oikawa, Shimpei; Ainsworth, Elizabeth A

    2016-08-01

    Influences of ozone (O3) on light-saturated rates of photosynthesis in crop leaves have been well documented. To increase our understanding of O3 effects on individual- or stand level productivity, a mechanistic understanding of factors determining canopy photosynthesis is necessary. We used a canopy model to scale photosynthesis from leaf to canopy, and analyzed the importance of canopy structural and leaf ecophysiological characteristics in determining canopy photosynthesis in soybean stands exposed to 9 concentrations of [O3] (37-116 ppb; 9-h mean). Light intensity and N content peaked in upper canopy layers, and sharply decreased through the lower canopy. Plant leaf area decreased with increasing [O3] allowing for greater light intensity to reach lower canopy levels. At the leaf level, light-saturated photosynthesis decreased and dark respiration increased with increasing [O3]. These data were used to calculate daily net canopy photosynthesis (Pc). Pc decreased with increasing [O3] with an average decrease of 10% for an increase in [O3] of 10 ppb, and which was similar to changes in above-ground dry mass production of the stands. Absolute daily net photosynthesis of lower layers was very low and thus the decrease in photosynthesis in the lower canopy caused by elevated [O3] had only minor significance for total canopy photosynthesis. Sensitivity analyses revealed that the decrease in Pc was associated with changes in leaf ecophysiology but not with decrease in leaf area. The soybean stands were very crowded, the leaves were highly mutually shaded, and sufficient light for positive carbon balance did not penetrate to lower canopy leaves, even under elevated [O3].

  4. Measuring the response of canopy emissivity spectra to leaf area index variation using thermal hyperspectral data

    Science.gov (United States)

    Neinavaz, Elnaz; Darvishzadeh, Roshanak; Skidmore, Andrew K.; Groen, Thomas A.

    2016-12-01

    One of the plant biophysical factors affecting the canopy spectral reflectance of plants in the optical domain to receive research attention in recent decades is leaf area index (LAI). Although it is expected that the value of LAI affects the emission of radiation, it not known how. To our knowledge, the effect of LAI on plant canopy emissivity spectra has not yet been investigated in the thermal infrared region (TIR 8-14 μm). The overall aim of this study was to demonstrate the effect of LAI on canopy emissivity spectra of different species at the nadir position. The 279 spectral wavebands in the TIR domain were measured under controlled laboratory condition using a MIDAC spectrometer for four plant species. The corresponding LAI of each measurement was destructively calculated. We found a positive correlation between canopy emissivity spectra at various LAI values, indicating that emissivity increases concomitantly with LAI value. The canopy emissivity spectra of the four species were found to be statistically different at various wavebands even when the LAI values of the species were similar. It seems that other biophysical or biochemical factors also contribute to canopy emissivity spectra: this merits further investigation. We not only quantify the role of LAI on canopy emissivity spectra for the first time, but also demonstrate the potential of using hyperspectral thermal data to estimate LAI of plant species.

  5. Optimising view angles for the estimation of leaf area index via entropy-difference analysis

    Indian Academy of Sciences (India)

    Yanjuan Yao; Qiang Liu; Qinhuo Liu; Yanhua Gao

    2012-06-01

    It is important to evaluate the information content of remote sensing data in order to synthetically use multi-source remote sensing data to improve the accuracy and consistency of land surface parameter retrieval. This paper presents a technique for information content evaluation of multi-spectral/angular remote sensing data for the leaf area index (LAI) inversion, the method of entropy-difference analysis.The proposed method is based on a numerical evaluation of the entropy of the observed dataset to learn how much variation in observation is caused by the variation in LAI. The relationship between remote sensing information and the LAI inversion accuracy is validated based on the model-simulated canopy reflectance data and the experiment data. We make the following observation: the larger the entropydifference for canopy reflectance data, the higher the LAI inversion accuracy. That is, choosing a good combination of observation angles is sometimes more important than simply increasing the number of observations. The presented technique may be useful in designing and evaluating quantitative remote sensing algorithms and products.

  6. Modifying Geometric-Optical Bidirectional Reflectance Model for Direct Inversion of Forest Canopy Leaf Area Index

    Directory of Open Access Journals (Sweden)

    Congrong Li

    2015-08-01

    Full Text Available Forest canopy leaf area index (LAI inversion based on remote sensing data is an important method to obtain LAI. Currently, the most widely-used model to achieve forest canopy structure parameters is the Li-Strahler geometric-optical bidirectional reflectance model, by considering the effect of crown shape and mutual shadowing, which is referred to as the GOMS model. However, it is difficult to retrieve LAI through the GOMS model directly because LAI is not a fundamental parameter of the model. In this study, a gap probability model was used to obtain the relationship between the canopy structure parameter nR2 and LAI. Thus, LAI was introduced into the GOMS model as an independent variable by replacing nR2 The modified GOMS (MGOMS model was validated by application to Dayekou in the Heihe River Basin of China. The LAI retrieved using the MGOMS model with optical multi-angle remote sensing data, high spatial resolution images and field-measured data was in good agreement with the field-measured LAI, with an R-square (R2 of 0.64, and an RMSE of 0.67. The results demonstrate that the MGOMS model obtained by replacing the canopy structure parameter nR2 of the GOMS model with LAI can be used to invert LAI directly and precisely.

  7. Leaf area index measurements at the middle reaches of Heihe River forest sites

    Science.gov (United States)

    Zou, Jie; Yan, Guang-jian; Zhang, Wu-ming; Zhu, Ling; Chen, Ling

    2008-12-01

    Leaf area index (LAI) is one of the most important parameters of canopy structure as it related to many biophysical and physiological processes, including photosynthesis, respiration, transpiration, carbon cycling, rain intercepting, net primary productivity, energy exchanging etc. Rapid, accurate and reliable estimations of LAI are required in these studies above. There are two main categories of procedures to estimate LAI: direct and indirect methods. The objective of this study is to evaluate LAI estimations obtained by different methods in HeiHe River forest sites. These methods include the LAI-2000 plant canopy analyzer, HemiView, fifty-seven degree photography method, fisheye photography method, the tracing radiation and architecture of canopies (TRAC), and Multi-Purpose Canopy Observation System (MCOS). HemiView shows a large variation on gap fraction measurements compared to LAI-2000, fifty-seven degree photography method is the superior choice to provide initial LAI values compared to other methods. To determine the non-photosynthesis elements and foliage clumping effects for optical methods, a new device named MCOS (Multi- Purpose Canopy Observation System) and TRAC were used. Finally, the results show that with the combination of MCOS or TRAC and LAI-2000 or hemispherical photography can provide accurate and efficient LAI values.

  8. Conventional digital cameras as a tool for assessing leaf area index and biomass for cereal breeding

    Institute of Scientific and Technical Information of China (English)

    Jaume Casadesús; Dolors Villegas

    2014-01-01

    Affordable and easy-to-use methods for assessing biomass and leaf area index (LAI) would be of interest in most breeding programs. Here, we describe the evaluation of a protocol for photographic sampling and image analysis aimed at providing low-labor yet robust indicators of biomass and LAI. In this trial, two genotypes of triticale, two of bread wheat, and four of tritordeum were studied. At six dates during the growing cycle, biomass and LAI were measured destructively, and digital photography was taken on the same dates. Several vegetation indices were calculated from each image. The results showed that repeatable and consistent values of the indices were obtained in consecutive photographic samplings on the same plots. The photographic indices were highly correlated with the destructive measure-ments, though the magnitude of the correlation was lower after anthesis. This work shows that photographic assess-ment of biomass and LAI can be fast, affordable, have good repeatability, and can be used under bright and overcast skies. A practical vegetation index derived from pictures is the fraction of green pixels over the total pixels of the image, and as it shows good correlations with all biomass variables, is the most robust to lighting conditions and has easy interpretation.

  9. Ecological strategies in california chaparral: Interacting effects of soils, climate, and fire on specific leaf area

    Science.gov (United States)

    Anacker, Brian; Rajakaruna, Nishanta; Ackerly, David; Harrison, Susan; Keeley, Jon E.; Vasey, Michael

    2011-01-01

    Background: High values of specific leaf area (SLA) are generally associated with high maximal growth rates in resource-rich conditions, such as mesic climates and fertile soils. However, fire may complicate this relationship since its frequency varies with both climate and soil fertility, and fire frequency selects for regeneration strategies (resprouting versus seeding) that are not independent of resource-acquisition strategies. Shared ancestry is also expected to affect the distribution of resource-use and regeneration traits.Aims: We examined climate, soil, and fire as drivers of community-level variation in a key functional trait, SLA, in chaparral in California.Methods: We quantified the phylogenetic, functional, and environmental non-independence of key traits for 87 species in 115 plots.Results: Among species, SLA was higher in resprouters than seeders, although not after phylogeny correction. Among communities, mean SLA was lower in harsh interior climates, but in these climates it was higher on more fertile soils and on more recently burned sites; in mesic coastal climates, mean SLA was uniformly high despite variation in soil fertility and fire history.Conclusions: We conclude that because important correlations exist among both species traits and environmental filters, interpreting the functional and phylogenetic structure of communities may require an understanding of complex interactive effects.

  10. Measurements and simulation of forest leaf area index and net primary productivity in Northern China.

    Science.gov (United States)

    Wang, P; Sun, R; Hu, J; Zhu, Q; Zhou, Y; Li, L; Chen, J M

    2007-11-01

    Large scale process-based modeling is a useful approach to estimate distributions of global net primary productivity (NPP). In this paper, in order to validate an existing NPP model with observed data at site level, field experiments were conducted at three sites in northern China. One site is located in Qilian Mountain in Gansu Province, and the other two sites are in Changbaishan Natural Reserve and Dunhua County in Jilin Province. Detailed field experiments are discussed and field data are used to validate the simulated NPP. Remotely sensed images including Landsat Enhanced Thematic Mapper plus (ETM+, 30 m spatial resolution in visible and near infrared bands) and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER, 15m spatial resolution in visible and near infrared bands) are used to derive maps of land cover, leaf area index, and biomass. Based on these maps, field measured data, soil texture and daily meteorological data, NPP of these sites are simulated for year 2001 with the boreal ecosystem productivity simulator (BEPS). The NPP in these sites ranges from 80 to 800 gCm(-2)a(-1). The observed NPP agrees well with the modeled NPP. This study suggests that BEPS can be used to estimate NPP in northern China if remotely sensed images of high spatial resolution are available.

  11. Relationships of Leaf Area Index and NDVI for 12 Brassica Cultivars in Northeastern Montana

    Science.gov (United States)

    Jabro, Jay; Allen, Brett; Long, Dan; Isbell, Terry; Gesch, Russ; Brown, Jack; Hatfield, Jerry; Archer, David; Oblath, Emily; Vigil, Merle; Kiniry, Jim; Hunter, Kimberly; Shonnard, David

    2017-04-01

    To our knowledge, there is limited information on the relationship of the normalized difference vegetation index (NDVI) and leaf area index (LAI) in spring Brassica oilseed crops. The 2014 results of NDVI and LAI of 12 spring varieties of oilseed crops were measured in a field study conducted in Sidney, Montana, USA under dryland conditions. These 12 varieties were grouped under six species (B. napus, B. rapa, B. juncea, B. carinata, Sinapis alba, and Camelina sativa). The NDVI and LAI were measured weekly throughout the growing season. The NDVI was continually measured at one sample per second across the whole plot using a Crop Circle ACS-470 active crop canopy sensor. The LAI was measured at two locations at 12 samples per plot using an AccuPar model LP-80 Ceptometer. Treatments were replicated four times in a randomized complete block design in plots of 3 m×9 m. Temporal dynamics of NDVI and LAI in various growth stages of 12 varieties were evaluated throughout the growing season. Significant relationships and models between NDVI and LAI were obtained when 12 varieties were grouped under six species.

  12. Geostatistics for Mapping Leaf Area Index over a Cropland Landscape: Efficiency Sampling Assessment

    Directory of Open Access Journals (Sweden)

    Javier Garcia-Haro

    2010-11-01

    Full Text Available This paper evaluates the performance of spatial methods to estimate leaf area index (LAI fields from ground-based measurements at high-spatial resolution over a cropland landscape. Three geostatistical model variants of the kriging technique, the ordinary kriging (OK, the collocated cokriging (CKC and kriging with an external drift (KED are used. The study focused on the influence of the spatial sampling protocol, auxiliary information, and spatial resolution in the estimates. The main advantage of these models lies in the possibility of considering the spatial dependence of the data and, in the case of the KED and CKC, the auxiliary information for each location used for prediction purposes. A high-resolution NDVI image computed from SPOT TOA reflectance data is used as an auxiliary variable in LAI predictions. The CKC and KED predictions have proven the relevance of the auxiliary information to reproduce the spatial pattern at local scales, proving the KED model to be the best estimator when a non-stationary trend is observed. Advantages and limitations of the methods in LAI field predictions for two systematic and two stratified spatial samplings are discussed for high (20 m, medium (300 m and coarse (1 km spatial scales. The KED has exhibited the best observed local accuracy for all the spatial samplings. Meanwhile, the OK model provides comparable results when a well stratified sampling scheme is considered by land cover.

  13. Variational assimilation to retrieve leaf area index from MODIS time series data

    Science.gov (United States)

    Xiao, Zhiqiang

    2009-10-01

    Currently, how to effectively utilize assimilation technique to retrieve biophysical parameters from time series remote sensing dada has attracted special concern. The assimilation technique is based on a reasonable consideration of the dynamical change rules of biophysical parameters and the time series observational quantities, thereby improving the quality of the retrieved profiles. In this paper, a variational assimilation procedure for retrieving leaf area index from time seires remote sensing data is investigated. The procedure is based on the formulation of an objective function, and SCE-UA optimization method is used to estimate LAI from the MODIS reflectance data with a higher quality in a given time window. A preliminary analysis using MODIS surface reflectance data at some sites was performed to validate this method. And the results show that the algorithm is able to produce temporally continuous LAI product efficiently, and the accuracy of the retrieved LAI has been significantly improved over the MODIS LAI product compared to the field measured LAI data.

  14. [Spatiotemporal variations of aboveground biomass and leaf area index of typical grassland in tower flux footprint].

    Science.gov (United States)

    Wang, Meng; Li, Gui-cai; Wang, Jun-bang

    2011-03-01

    By using cyclic sampling method, the aboveground biomass and leaf area index (LAI) of typical grassland in tower flux footprint were measured at three growth stages, i.e., early July (July 2-7), late July (July 20-26), and late August (Aug. 25-30), with their spatial patterns analyzed by geostatistics. At the three stages, the aboveground biomass of the grassland kept rising, while the LAI decreased after an initial increase. Both the two variables had good spatial autocorrelation, with similar spatial pattern and temporal evolution trend, and changed from stripe to patch. From early July to late August, the C0/(C0+C) of the aboveground biomass and LAI all decreased significantly, indicating that the spatial autocorrelation of the two variables changed from medium to high. The change ranges of the two variables gradually decreased, presenting the decrease of spatial continuity. The fractal dimension (D) also decreased gradually, suggesting the increase of spatial dependence. Topography and field management were the main factors affecting the spatial distribution of aboveground biomass and LAI, which induced the spatial variability of water and heat, and further, affected the grass growth.

  15. Estimating Leaf Area Index (LAI) in Vineyards Using the PocketLAI Smart-App.

    Science.gov (United States)

    Orlando, Francesca; Movedi, Ermes; Coduto, Davide; Parisi, Simone; Brancadoro, Lucio; Pagani, Valentina; Guarneri, Tommaso; Confalonieri, Roberto

    2016-11-26

    Estimating leaf area index (LAI) of Vitis vinifera using indirect methods involves some critical issues, related to its discontinuous and non-homogeneous canopy. This study evaluates the smart app PocketLAI and hemispherical photography in vineyards against destructive LAI measurements. Data were collected during six surveys in an experimental site characterized by a high level of heterogeneity among plants, allowing us to explore a wide range of LAI values. During the last survey, the possibility to combine remote sensing data and in-situ PocketLAI estimates (smart scouting) was evaluated. Results showed a good agreement between PocketLAI data and direct measurements, especially for LAI ranging from 0.13 to 1.41 (R² = 0.94, RRMSE = 17.27%), whereas the accuracy decreased when an outlying value (vineyard LAI = 2.84) was included (R² = 0.77, RRMSE = 43.00%), due to the saturation effect in case of very dense canopies arising from lack of green pruning. The hemispherical photography showed very high values of R², even in presence of the outlying value (R² = 0.94), although it showed a marked and quite constant overestimation error (RRMSE = 99.46%), suggesting the need to introduce a correction factor specific for vineyards. During the smart scouting, PocketLAI showed its reliability to monitor the spatial-temporal variability of vine vigor in cordon-trained systems, and showed a potential for a wide range of applications, also in combination with remote sensing.

  16. Optimal waveband identification for estimation of leaf area index of paddy rice

    Institute of Scientific and Technical Information of China (English)

    Fu-min WANG; Jing-feng HUANG; Qi-fa ZHOU; Xiu-zhen WANG

    2008-01-01

    The objectives of the study were to select suitable wavebands for rice leaf area index (LAI) estimation using the data acquired over a whole growing season, and to test the efficiency of the selected wavebands by comparing them with feature positions of rice canopy spectra. In this study, the field experiment in 2002 growing season was conducted at the experimental farm of Zhejiang University, Hangzhou, China. Measurements of hyperspectral reflectance (350-2500 nm) and corresponding LAI were made for a paddy rice canopy throughout the growing season. And three methods were employed to identify the optimal wavebands for paddy rice LAI estimation: correlation coefficient-based method, vegetation index-based method, and stepwise regression method. This research selected 15 wavebands in the region of 350-2500 nm, which appeared to be the optimal wavebands for the paddy rice LAI estimation. Of the selected wavebands, the most frequently occurring wavebands were centered around 554, 675, 723, and 1633 nm. They were followed by 444, 524, 576, 594, 804, 849, 974, 1074, 1219, 1510, and 2194 nm. Most of them made physical sense and had their counterparts in spectral known feature positions, which indicates the promising potential of the 15 selected wavebands for the retrieval of paddy rice LAI.

  17. Researches of Optimum Leaf Area Index Dynamicmodels for Rape(brassica Napus L.)

    Science.gov (United States)

    Cao, Hongxin; Zhang, Chunlei; Li, Guangming; Zhang, Baojun; Zhao, Suolao; Wang, Baoqing; Jin, Zhiqing; Zhu, Dawei; Zhu, Juanjuan; Wei, Xiufang

    The objectives of developing optimum leaf area index dynamic models for rape (OLAIDM) was to develop Rape Cultivation Simulation-Optimization- Decision Making System(Rape-CSODS) , to design its planting , to regulate and control its growth and development, and to fulfill its high yield, good quality, high benefits and standard production eventually. The OLAIDM were developed based on field experiments with 3 cultivars, 6 sowing dates, 2 types of plant pattern and 4 sites from 2002 to 2007 in middle and lower valley of Yangtze river in China and relative data from references of rape researches, employed ideas of R/WCSODS (Rice/Wheat Cultivation Simulation- Optimization-Decision Making System), and in the same time, the OLAIMR and its parameters also were assessed, calibrated and tested. The average absolute deviation(de), correlation coefficients(r) and the standard errors of their absolute deviation(Sde) of between the observed and simulated values for LAI of two cultivars in Wuhan and Nanjing were -0.03~0.1533, 0.9707~0.9997 and0.1332~0.4032, respectively. 1:1 line of them were in Fig. 1 to 4. Multi-factors such as the ramification types, cultivars, and light et al. were taken into account in this study, therefore, the OLAIDM with general adaptability, clear yield aim, mechanism, and dynamic characteristic can simulate optimum LAI dynamic for rape under different sites, cultivars and ramification types, and yielding levels.

  18. Innovative LIDAR 3D Dynamic Measurement System to estimate fruit-tree leaf area.

    Science.gov (United States)

    Sanz-Cortiella, Ricardo; Llorens-Calveras, Jordi; Escolà, Alexandre; Arnó-Satorra, Jaume; Ribes-Dasi, Manel; Masip-Vilalta, Joan; Camp, Ferran; Gràcia-Aguilá, Felip; Solanelles-Batlle, Francesc; Planas-DeMartí, Santiago; Pallejà-Cabré, Tomàs; Palacin-Roca, Jordi; Gregorio-Lopez, Eduard; Del-Moral-Martínez, Ignacio; Rosell-Polo, Joan R

    2011-01-01

    In this work, a LIDAR-based 3D Dynamic Measurement System is presented and evaluated for the geometric characterization of tree crops. Using this measurement system, trees were scanned from two opposing sides to obtain two three-dimensional point clouds. After registration of the point clouds, a simple and easily obtainable parameter is the number of impacts received by the scanned vegetation. The work in this study is based on the hypothesis of the existence of a linear relationship between the number of impacts of the LIDAR sensor laser beam on the vegetation and the tree leaf area. Tests performed under laboratory conditions using an ornamental tree and, subsequently, in a pear tree orchard demonstrate the correct operation of the measurement system presented in this paper. The results from both the laboratory and field tests confirm the initial hypothesis and the 3D Dynamic Measurement System is validated in field operation. This opens the door to new lines of research centred on the geometric characterization of tree crops in the field of agriculture and, more specifically, in precision fruit growing.

  19. Retrieving crop leaf area index by assimilation of MODIS data into a crop growth model

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Leaf area index (LAI) is an important parameter in monitoring crop growth. One of the methods for retrieving LAI from remotely sensed observations is through inversion of canopy reflectance models. Many model inversion methods fail to account for variable LAI values at different crop growth stages. In this research, we use the crop growth model to describe the LAI changes with crop growth, and consider a priori LAI values at different crop growth stages as constraint information. The key approach of this research is to assimilate multiple canopy reflectance values observed at different growth stages and a priori LAI values into a coupled crop growth and radiative transfer model sequentially using a variational data assimilation algorithm. Adjoint method is used to minimize the cost function. Any other information source can be easily incorporated into the inversion cost function. The validation results show that the time series of MODIS canopy reflectance can greatly reduce the uncertainty of the inverted LAI values. Compared with MODIS LAI product at Changping and Shunyi Counties of Beijing, this method has significantly improved the estimated LAI temporal profile.

  20. Innovative LIDAR 3D Dynamic Measurement System to Estimate Fruit-Tree Leaf Area

    Directory of Open Access Journals (Sweden)

    Ignacio Del-Moral-Martínez

    2011-05-01

    Full Text Available In this work, a LIDAR-based 3D Dynamic Measurement System is presented and evaluated for the geometric characterization of tree crops. Using this measurement system, trees were scanned from two opposing sides to obtain two three-dimensional point clouds. After registration of the point clouds, a simple and easily obtainable parameter is the number of impacts received by the scanned vegetation. The work in this study is based on the hypothesis of the existence of a linear relationship between the number of impacts of the LIDAR sensor laser beam on the vegetation and the tree leaf area. Tests performed under laboratory conditions using an ornamental tree and, subsequently, in a pear tree orchard demonstrate the correct operation of the measurement system presented in this paper. The results from both the laboratory and field tests confirm the initial hypothesis and the 3D Dynamic Measurement System is validated in field operation. This opens the door to new lines of research centred on the geometric characterization of tree crops in the field of agriculture and, more specifically, in precision fruit growing.

  1. Using SPOT data and leaf area index for rice yield estimation in Egyptian Nile delta

    Directory of Open Access Journals (Sweden)

    M. Aboelghar

    2011-12-01

    Full Text Available The objective of the current work is to generate statistical empirical rice yield estimation models under the local conditions of the Egyptian Nile delta. The methodology is based on regressing measured yield with satellite derived spectral information or leaf area index (LAI. LAI field measurements and spectral information from SPOT data collected during two crop seasons are examined against measured yield to generate the yield models. Near-infrared and red bands, six vegetation indices and LAI of 100 points are used as the main inputs for the modeling process while 20 points of the same are used for validation process. Nine models are generated and tested against the observed yield. Comparing the generated models show relatively higher superiority of (LAI-yield and (infrared-yield models over the rest of the models with (0.061 and (0.090 as a standard error of estimate and (0.945 and (0.883 as coefficient of determinations between modeled and observed yield. The models are applicable a month before harvest for similar regions with same conditions.

  2. An Observing System Simulation Experiment of assimilating leaf area index and soil moisture over cropland

    Science.gov (United States)

    Lafont, Sebastien; Barbu, Alina; Calvet, Jean-Christophe

    2013-04-01

    A Land Data Assimilation System (LDAS) is an off-line data assimilation system featuring uncoupled land surface model which is driven by observation-based atmospheric forcing. In this study the experiments were conducted with a surface externalized (SURFEX) modelling platform developed at Météo-France. It encompasses the land surface model ISBA-A-gs that simulates photosynthesis and plant growth. The photosynthetic activity depends on the vegetation types. The input soil and vegetation parameters are provided by the ECOCLIMAP II global database which assigns the ecosystem classes in several plant functional types as grassland, crops, deciduous forest and coniferous forest. New versions of the model have been recently developed in order to better describe the agricultural plant functional types. We present a set of observing system simulation experiments (OSSE) which asses leaf area index (LAI) and soil moisture assimilation for improving the land surface estimates in a controlled synthetic environment. Synthetic data were assimilated into ISBA-A-gs using an Extended Kalman Filter (EKF). This allows for an understanding of model responses to an augmentation of the number of crop types and different parameters associated to this modification. In addition, the interactions between uncertainties in the model and in the observations were investigated. This study represents the first step of a process that envisages the extension of LDAS to the new versions of the ISBA-A-gs model in order to assimilate remote sensing observations.

  3. Spatial and Temporal Dynamics of the Leaf Area Index of the Caatinga Biome

    Science.gov (United States)

    Alves Rodrigues Pinheiro, Everton; de Jong van Lier, Quirijn; Metselaar, Klaas

    2015-04-01

    Leaf Area Index (LAI) is an important characteristic of ecosystems with a prominent role in processes such as transpiration, photosynthesis and interception. The Caatinga biome is a unique semiarid ecosystem ocurring in a specific region of Brazil. An important main feature of this biome is the leaf shedding and regenerative capacity of its species. The aim of this study was to quantify both spatial and temporal dynamics of the LAI of the Caatinga biome in the Aiuaba Experimental Basin, an integrally-preserved Caatinga reserve, coordinates 6°42'S; 40°17'W. The research site (12 km2) was divided into three main Soil and Vegatation Associations (SVA). For each SVA the soil type and root depth are respectively, Acrisol -0.8 m, Luvisol - 0.6 m and Regosol - 0.4 m. The LAI was estimated by SEBAL algorithm applied to eleven satellite images from Landsat 5. The values of LAI estimated by SEBAL were correlated to the mean soil water content of the 15 days previous to the satellite image date. Eight images were used to generate a simple regression model, yielding a range of coefficient of determination from 0.89 to 0.92. Three other images were used to validate the equations. The Nash-Sutcliffe efficiency coefficient ranged from 0.76 to 0.94. Using the validated correlations, the LAI was calculated over the time for each of the three SVA, from 2004 to 2012. For SVA1, SVA2 and SVA3, the avarage values of LAI during the rainy season were 0.97, 1.12 and 1.07, respectively. During the dry season, the mean values were 0.15 for SVA1 and 0.11 for SVA2 and SVA3. The vegetation showed abrupt LAI changes, and the average previous 15 days soil water content was a good indicator for this. The study has shown that the maximum LAI was relatively stable over the years, occurring between March and April. The spatial behavior of LAI appeared to be similar, independently of the soil type and root depth.

  4. Evaluation of seasonal variations of remotely sensed leaf area index over five evergreen coniferous forests

    Science.gov (United States)

    Wang, Rong; Chen, Jing M.; Liu, Zhili; Arain, Altaf

    2017-08-01

    Seasonal variations of leaf area index (LAI) have crucial controls on the interactions between the land surface and the atmosphere. Over the past decades, a number of remote sensing (RS) LAI products have been developed at both global and regional scales for various applications. These products are so far only validated using ground LAI data acquired mostly in the middle of the growing season. The accuracy of the seasonal LAI variation in these products remains unknown and there are few ground data available for this purpose. We performed regular LAI measurements over a whole year at five coniferous sites using two methods: (1) an optical method with LAI-2000 and TRAC; (2) a direct method through needle elongation monitoring and litterfall collection. We compared seasonal trajectory of LAI from remote sensing (RS LAI) with that from a direct method (direct LAI). RS LAI agrees very well with direct LAI from the onset of needle growth to the seasonal peak (R2 = 0.94, RMSE = 0.44), whereas RS LAI declines earlier and faster than direct LAI from the seasonal peak to the completion of needle fall. To investigate the possible reasons for the discrepancy, the MERIS Terrestrial Chlorophyll Index (MTCI) was compared with RS LAI. Meanwhile, phenological metrics, i.e. the start of growing season (SOS) and the end of growing season (EOS), were extracted from direct LAI, RS LAI and MTCI time series. SOS from RS LAI is later than that from direct LAI by 9.3 ± 4.0 days but earlier than that from MTCI by 2.6 ± 1.9 days. On the contrary, for EOS, RS LAI is later than MTCI by 3.3 ± 8.4 days and much earlier than direct LAI by 30.8 ± 7.2 days. Our results suggest that the seasonal trajectory of RS LAI well captures canopy structural information from the onset of needle growth to the seasonal peak, but is greatly influenced by the decrease in leaf chlorophyll content, as indicated by MTCI, from the seasonal peak to the completion of needle fall. These findings have significant

  5. Urban Areas of the United States - Direct Download

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set includes a selection of urban areas in the United States derived from the urban areas layer of the Digital Chart of the World (DCW). This is a revised...

  6. Mapping Spatial and Temporal Variations of Leaf Area Index for Winter Wheat in North China

    Institute of Scientific and Technical Information of China (English)

    YANG Peng; WU Wen-bin; TANG Hua-jun; ZHOU Qing-bo; ZOU Jin-qiu; ZHANG Li

    2007-01-01

    Leaf area index(LAI)is an important parameter in a number of models related to ecosystem functioning,carbon budgets,climate,hydrology,and crop growth simulation.Mapping and monitoring the spatial and temporal variations of LAI are necessary for understanding crop growth and development at regional level.In this study.the relationships between LAI of winter wheat and Landsat TM spectral vegetation indices(SVIs)were analyzed by using the curve estimation procedure in North China Plain.The series of LAI maps retrieved by the best regression model were used to assess the spatial and temporal Variations of winter wheat LAI.The results indicated that the general relationships between LAI and SVIs were curvilinear,and that the exponential model gave a better fit than the linear model or other nonlinear models for most SVIs.The best regression model was constructed using an exponential model between surface-reflectance-derived difference vegetation index(DVI)and LAI,with the adjusted R2(0.82)and the RMSE(0.77).The TM LAI maps retrieved from DVILAI model showed the significant spatial and temporal variations.The mean TMLAI value(30m)for winter wheat of the study area increased from 1.29(March 7,2004)to 3.43(April 8,2004),with standard deviations of 0.22 and 1.17,respectively.In conclusion,spectral vegetation indices from multi-temporal Landsat TM images can be used to produce fine-resolution LAI maps for winter wheat in North China Plain.

  7. Detection of the Coupling between Vegetation Leaf Area and Climate in a Multifunctional Watershed, Northwestern China

    Directory of Open Access Journals (Sweden)

    Lu Hao

    2016-12-01

    Full Text Available Accurate detection and quantification of vegetation dynamics and drivers of observed climatic and anthropogenic change in space and time is fundamental for our understanding of the atmosphere–biosphere interactions at local and global scales. This case study examined the coupled spatial patterns of vegetation dynamics and climatic variabilities during the past three decades in the Upper Heihe River Basin (UHRB, a complex multiple use watershed in arid northwestern China. We apply empirical orthogonal function (EOF and singular value decomposition (SVD analysis to isolate and identify the spatial patterns of satellite-derived leaf area index (LAI and their close relationship with the variability of an aridity index (AI = Precipitation/Potential Evapotranspiration. Results show that UHRB has become increasingly warm and wet during the past three decades. In general, the rise of air temperature and precipitation had a positive impact on mean LAI at the annual scale. At the monthly scale, LAI variations had a lagged response to climate. Two major coupled spatial change patterns explained 29% and 41% of the LAI dynamics during 1983–2000 and 2001–2010, respectively. The strongest connections between climate and LAI were found in the southwest part of the basin prior to 2000, but they shifted towards the north central area afterwards, suggesting that the sensitivity of LAI to climate varied over time, and that human disturbances might play an important role in altering LAI patterns. At the basin level, the positive effects of regional climate warming and precipitation increase as well as local ecological restoration efforts overwhelmed the negative effects of overgrazing. The study results offer insights about the coupled effects of climatic variability and grazing on ecosystem structure and functions at a watershed scale. Findings from this study are useful for land managers and policy makers to make better decisions in response to climate

  8. Developing Student’s Notion of Measurement Unit For Area

    Directory of Open Access Journals (Sweden)

    Kurnia Rahmi Yuberta

    2011-07-01

    Full Text Available Many researchers found that students have difficulties in understanding area measurement. Students mostly focus on applying formula to find the area of certain shapes without knowing what the area is and why the formula works. It is important for the students to know what attribute being measured and to construct the unit for area measurement. Therefore, the aim of this research is to develop activities that support students to know the attribute of area and the notion of measurement unit in learning area measurement. For this purpose, design research is chosen for achieving the research goal. Realistic Mathematics Education (RME underlies the design of context and activities. A teacher and students in grade 3 in elementary school (SDN 21 in Palembang Indonesia will be involved in this research.

  9. Comparing modelled and remotely sensed leaf area dynamics in an Aleppo pine semiarid forest

    Science.gov (United States)

    Pasquato, Marta; Medici, Chiara; Friend, Andrew D.; Francés, Félix

    2013-04-01

    Much of the Earth's terrestrial surface is subject to arid climatic water stress. In these regions, plant ecosystems are controlled by water availability, inducing a tight interconnection between the hydrological cycle and the vegetation dynamics. For this reason, and to fully reproduce water-controlled ecosystems' behaviour, it is essential to jointly model vegetation and the hydrological cycle. In this work, the performance of a parsimonious dynamic vegetation model, suitable for the inclusion in a conceptual ecohydrological model, is tested in a semi-arid Aleppo Pine forest area in the south-east of Spain. The model simulates gross primary production (GPP) as a function of absorbed photosynthetically active radiation (APAR) and the light use efficiency (LUE). Net primary production (NPP) is then calculated taking into account maintenance respiration. The modelling is focused particularly on simulating foliar biomass, which is obtained from NPP through an allocation equation based on the maximum LAI sustainable by the system, and considering turnover. An analysis of the information offered by MODIS EVI, NDVI, and LAI products was performed in order to investigate vegetation dynamics in the study site and to select the best indices to be used to evaluate the ecohydrological model's performance. EVI is reported in literature (Huete et al., 2002) to be sensitive to canopy structure, particularly to leaf area index (LAI). In accordance with the phenological cycle timing described for the Aleppo pine in similar climates (Muñoz et al., 2003), the EVI showed maximum values in spring and minimum values in winter. Similar results were found applying the aforementioned vegetation model to the study area. Contrasting simulated LAI with the EVI series, a correlation coefficient r = 0.57 was found. Concerning NDVI, its own definition links this index to the "greenness" of the target, so that it appears highly linked to chlorophyll content and vegetation condition, but only

  10. Multiscale Estimation of Leaf Area Index from Satellite Observations Based on an Ensemble Multiscale Filter

    Directory of Open Access Journals (Sweden)

    Jingyi Jiang

    2016-03-01

    Full Text Available Currently, multiple leaf area index (LAI products retrieved from remote sensing data are widely used in crop growth monitoring, land-surface process simulation and studies of climate change. However, most LAI products are only retrieved from individual satellite observations, which may result in spatial-temporal discontinuities and low accuracy in these products. In this paper, a new method was developed to simultaneously retrieve multiscale LAI data from satellite observations with different spatial resolutions based on an ensemble multiscale filter (EnMsF. The LAI average values corresponding to the date of satellite observations were calculated from the multi-year Moderate Resolution Imaging Spectroradiometer (MODIS LAI product and were used as a priori knowledge for LAI in order to construct an initial ensemble multiscale tree (EnMsT. Satellite observations obtained at different spatial resolutions were then applied to update the LAI values at each node of the EnMsT using a two-sweep filtering procedure. Next, the retrieved LAI values at the finest scale were used as a priori knowledge for LAI for the new round of construction and updating of the EnMsT, until the sum of the difference of LAI values at each node of the EnMsT between two adjacent updates is less than a given threshold. The method was tested using Thematic Mapper (TM or Enhanced Thematic Mapper Plus (ETM+ surface reflectance data and MODIS surface reflectance data from five sites that have different vegetation types. The results demonstrate that the retrieved LAI values for each spatial resolution were in good agreement with the aggregated LAI reference map values for the corresponding spatial resolution. The retrieved LAI values at the coarsest scale provided better accuracy with the aggregated LAI reference map values (root mean square error (RMSE = 0.45 compared with that obtained from the MODIS LAI values (RMSE = 1.30.

  11. Estimating Leaf Area Index (LAI in Vineyards Using the PocketLAI Smart-App

    Directory of Open Access Journals (Sweden)

    Francesca Orlando

    2016-11-01

    Full Text Available Estimating leaf area index (LAI of Vitis vinifera using indirect methods involves some critical issues, related to its discontinuous and non-homogeneous canopy. This study evaluates the smart app PocketLAI and hemispherical photography in vineyards against destructive LAI measurements. Data were collected during six surveys in an experimental site characterized by a high level of heterogeneity among plants, allowing us to explore a wide range of LAI values. During the last survey, the possibility to combine remote sensing data and in-situ PocketLAI estimates (smart scouting was evaluated. Results showed a good agreement between PocketLAI data and direct measurements, especially for LAI ranging from 0.13 to 1.41 (R2 = 0.94, RRMSE = 17.27%, whereas the accuracy decreased when an outlying value (vineyard LAI = 2.84 was included (R2 = 0.77, RRMSE = 43.00%, due to the saturation effect in case of very dense canopies arising from lack of green pruning. The hemispherical photography showed very high values of R2, even in presence of the outlying value (R2 = 0.94, although it showed a marked and quite constant overestimation error (RRMSE = 99.46%, suggesting the need to introduce a correction factor specific for vineyards. During the smart scouting, PocketLAI showed its reliability to monitor the spatial-temporal variability of vine vigor in cordon-trained systems, and showed a potential for a wide range of applications, also in combination with remote sensing.

  12. Steady state estimation of soil organic carbon using satellite-derived canopy leaf area index

    Science.gov (United States)

    Fang, Yilin; Liu, Chongxuan; Huang, Maoyi; Li, Hongyi; Leung, L. Ruby

    2014-12-01

    Estimation of soil organic carbon (SOC) stock using models typically requires long term spin-up of the carbon-nitrogen (CN) models, which has become a bottleneck for global modeling. We report a new numerical approach to estimate global SOC stock that can alleviate long spin-up. The approach uses satellite-based canopy leaf area index (LAI) and takes advantage of a reaction-based biogeochemical module—Next Generation BioGeoChemical Module (NGBGC) that was recently developed and incorporated in version 4 of the Community Land Model (CLM4). Although NGBGC uses the same CN mechanisms as in CLM4CN, it can be easily configured to run prognostic or steady state simulations. The new approach was applied at point and global scales and compared with SOC derived from spin-up by running NGBGC in the prognostic mode, and SOC from the Harmonized World Soil Database (HWSD). The steady state solution is comparable to the spin-up value when the satellite LAI is close to that from the spin-up solution, and largely captured the global variability of the HWSD SOC across the different dominant plant functional types (PFTs). The correlation between the simulated and HWSD SOC was, however, weak at both point and global scales, suggesting the needs for improving the biogeochemical processes described in CLM4 and updating HWSD. Besides SOC, the steady state solution also includes all other state variables simulated by a spin-up run, which makes the tested approach a promising tool to efficiently estimate global SOC distribution and evaluate and compare multiple aspects simulated by different CN mechanisms in the model.

  13. New Vegetation Index and Its Application in Estimating Leaf Area Index of Rice

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Leaf area index (LAI) is an important characteristic of land surface vegetation system, and is also a key parameter for the models of global water balancing and carbon circulation. By using the reflectance values of Landsat-5 blue, green and red channels simulated from rice reflectance spectrum, the sensitivities of the bands to LAI were analyzed, and the response and capability to estimate LAI of various NDVIs (normalized difference vegetation indices), which were established by substituting the red band of general NDVI with all possible combinations of red, green and blue bands, were assessed. Finally,the conclusion was tested by rice data at different conditions. The sensitivities of red, green and blue bands to LAI were different under various conditions. When LAI was less than 3, red and blue bands were more sensitive to LAI. Though green band in the circumstances was less sensitive to LAI than red and blue bands, it was sensitive to LAI in a wider range. When the vegetation indices were constituted by all kinds of combinations of red, green and blue bands, the premise for making the sensitivity of these vegetation indices to LAI be meaningful was that the value of one of the combinations was greater than 0.024, i.e. visible reflectance (VIS)>0.024. Otherwise, the vegetation indices would be saturated, resulting in lower estimation accuracy of LAI. Comparison on the capabilities of the vegetation indices derived from all kinds of combinations of red, green and blue bands to LAI estimation showed that GNDVI (Green NDVI) and GBNDVI (Green-Blue NDVI) had the best relations with LAI. The capabilities of GNDVI and GBNDVI to LAI estimation were tested under different circumstances, and the same result was acquired. It suggested that GNDVI and GBNDVI performed better to predict LAI than the conventional NDVI.

  14. [Inversion of leaf area index during different growth stages in winter wheat].

    Science.gov (United States)

    Zhao, Juan; Huang, Wen-jiang; Zhang, Yao-hong; Jing, Yuan-shu

    2013-09-01

    Being orientated to the low prescion of crop leaf area index (LAI) inversion using the same spectral vegetation index during different crop growth stages, the present paper analyzed the precision of LAI inversion by employing NDVI(normalized difference vegetation index). Ten vegetation indices were chosen including six broad-band vegetation indices and four narrow-band vegetation indices responding to vegetation cover to inverse LAI in different growth stages. Several conclusions were drawn according to the analysis. The determinant coefficient (R2) and root mean square error (RMSE) between LAI inversion value and true value were 0.5585 and 0.3209 respectively during the whole growth duraton. The mSR (modified simple ratio index) index was appropriate to inverse of LAI during earlier growth stages (before jointing stage) in winter wheat. The R2 and RMSE between LAI inversion value and true value were 0.7287 and 0.2971 respectively. The SR (simple ratio index) index was suitable enough to inverse of LAI during medium growth stages (from joingting stagess to heading stages). The R2 and RMSE between LAI inversion value and true value were 0.6546 and 0.3061 respectively. The NDVI (normalized difference vegetation index) index was proven to be fine to inverse LAI during later growth stages(from heading stage to ripening stage). The R2 and RMSE between LAI inversion value and true value were 0.6794 and 0.3164 respectively. Therefore it was indicated that the results of LAI inversion was much better inverse of winter wheat LAI choosing different vegetation indices during differen growth stages for winter wheat according to the change of vegetation cover and canopy reflectance than merely with NDVI to inverse LAI in the whole growth stages. It was concluded that the precision of LAI inversion was significantly improved with segmented models based on different vegetation indices.

  15. Comparative analysis of different retrieval methods for mapping grassland leaf area index using airborne imaging spectroscopy

    Science.gov (United States)

    Atzberger, Clement; Darvishzadeh, Roshanak; Immitzer, Markus; Schlerf, Martin; Skidmore, Andrew; le Maire, Guerric

    2015-12-01

    Fine scale maps of vegetation biophysical variables are useful status indicators for monitoring and managing national parks and endangered habitats. Here, we assess in a comparative way four different retrieval methods for estimating leaf area index (LAI) in grassland: two radiative transfer model (RTM) inversion methods (one based on look-up-tables (LUT) and one based on predictive equations) and two statistical modelling methods (one partly, the other entirely based on in situ data). For prediction, spectral data were used that had been acquired over Majella National Park in Italy by the airborne hyperspectral HyMap instrument. To assess the performance of the four investigated models, the normalized root mean squared error (nRMSE) and coefficient of determination (R2) between estimates and in situ LAI measurements are reported (n = 41). Using a jackknife approach, we also quantified the accuracy and robustness of empirical models as a function of the size of the available calibration data set. The results of the study demonstrate that the LUT-based RTM inversion yields higher accuracies for LAI estimation (R2 = 0.91, nRMSE = 0.18) as compared to RTM inversions based on predictive equations (R2 = 0.79, nRMSE = 0.38). The two statistical methods yield accuracies similar to the LUT method. However, as expected, the accuracy and robustness of the statistical models decrease when the size of the calibration database is reduced to fewer samples. The results of this study are of interest for the remote sensing community developing improved inversion schemes for spaceborne hyperspectral sensors applicable to different vegetation types. The examples provided in this paper may also serve as illustrations for the drawbacks and advantages of physical and empirical models.

  16. Student housing unit in a floor area without corridors

    OpenAIRE

    Cekić Nikola; Vasov Miomir; Bjelić Igor

    2013-01-01

    This paper treats the issues of position and urbarchitectonic-functional organization of a housing unit in a floor area without corridors in a student hostel. The authors advocate a new, more rational and functional concept in which the student room is not in direct contact with the corridor communication, but belongs to the housing unit, student apartment for 4-6 users. In a more rational organized volume, the living of the students is more comfortable and has a different character. Th...

  17. Application of the Richards function to the description of leaf area growth in maize (Zea mays L.

    Directory of Open Access Journals (Sweden)

    Andrzej Grzegorczyk

    2014-02-01

    Full Text Available The leaf area growth in maize was approximated basing on the Richards function in the form of: y=A[l+b exp(-kt]1/(1-m . The constant coefficients of the Richards function were found by means of the Marquardt's method. The initial values of parameters were given basing on results of the preliminary approximation of the growth process by means of logistic function y = A[l+b exp(-kt]-1. The procedure of nonlinear regression was found to be useful (curvilinear determination coefficient R2 = 0.995. The Richards curve precisely describes the course of changes of the leaf area in maize since sprouting to a tassel flowering phase.

  18. Temporal dynamics and spatial variability in the enhancement of canopy leaf area under elevated atmospheric CO2

    Science.gov (United States)

    Heather R. McCarthy; Ram Oren; Adrien C. Finzi; David S. Ellsworth; Hyun-Seok Kim; Kurt H. Johnsen; Bonnie Millar

    2007-01-01

    Increased canopy leaf area (L) may lead to higher forest productivity and alter processes such as species dynamics and ecosystem mass and energy fluxes. Few CO2enrichment studies have been conducted in closed canopy forests and none have shown a sustained enhancement of L. We reconstructed 8 years (1996–2003) of L at Duke’s Free Air CO...

  19. Digital cover photography for estimating leaf area index (LAI) in apple trees using a variable light extinction coefficient.

    Science.gov (United States)

    Poblete-Echeverría, Carlos; Fuentes, Sigfredo; Ortega-Farias, Samuel; Gonzalez-Talice, Jaime; Yuri, Jose Antonio

    2015-01-28

    Leaf area index (LAI) is one of the key biophysical variables required for crop modeling. Direct LAI measurements are time consuming and difficult to obtain for experimental and commercial fruit orchards. Devices used to estimate LAI have shown considerable errors when compared to ground-truth or destructive measurements, requiring tedious site-specific calibrations. The objective of this study was to test the performance of a modified digital cover photography method to estimate LAI in apple trees using conventional digital photography and instantaneous measurements of incident radiation (Io) and transmitted radiation (I) through the canopy. Leaf area of 40 single apple trees were measured destructively to obtain real leaf area index (LAI(D)), which was compared with LAI estimated by the proposed digital photography method (LAI(M)). Results showed that the LAI(M) was able to estimate LAI(D) with an error of 25% using a constant light extinction coefficient (k = 0.68). However, when k was estimated using an exponential function based on the fraction of foliage cover (f(f)) derived from images, the error was reduced to 18%. Furthermore, when measurements of light intercepted by the canopy (Ic) were used as a proxy value for k, the method presented an error of only 9%. These results have shown that by using a proxy k value, estimated by Ic, helped to increase accuracy of LAI estimates using digital cover images for apple trees with different canopy sizes and under field conditions.

  20. First vs. second rotation of a poplar short rotation coppice: leaf area development, light interception and radiation use efficiency

    Directory of Open Access Journals (Sweden)

    Broeckx LS

    2015-10-01

    Full Text Available Given the high expectations for lignocellulosic biomass as one of the potential solutions for energy security and climate change mitigation, commercial scale studies over several rotations are crucial to assess the potential and the sustainability of short rotation coppice (SRC cultures for bioenergy. The first and the second rotation of the SRC poplar (Populus plantation of the present study differed significantly in biomass yield and in productivity determinants and their relationships. Coppicing enhanced leaf area development, radiation interception and woody biomass productivity. High total leaf area and radiation use efficiency (RUE equally contributed to the high biomass yield during the establishment rotation, while RUE became the most important determinant of biomass yield after coppice. The study confirmed the significant genotypic variation in biomass productivity and its underlying determinants, also among more recently selected poplar genotypes. The absence of a correlation between intercepted radiation and RUE suggests the potential of selecting for genotypes combining high total leaf area and photosynthetic carbon uptake in future breeding programs for yield maximization towards sustainable bioenergy cultivation.

  1. Digital Cover Photography for Estimating Leaf Area Index (LAI) in Apple Trees Using a Variable Light Extinction Coefficient

    Science.gov (United States)

    Poblete-Echeverría, Carlos; Fuentes, Sigfredo; Ortega-Farias, Samuel; Gonzalez-Talice, Jaime; Yuri, Jose Antonio

    2015-01-01

    Leaf area index (LAI) is one of the key biophysical variables required for crop modeling. Direct LAI measurements are time consuming and difficult to obtain for experimental and commercial fruit orchards. Devices used to estimate LAI have shown considerable errors when compared to ground-truth or destructive measurements, requiring tedious site-specific calibrations. The objective of this study was to test the performance of a modified digital cover photography method to estimate LAI in apple trees using conventional digital photography and instantaneous measurements of incident radiation (Io) and transmitted radiation (I) through the canopy. Leaf area of 40 single apple trees were measured destructively to obtain real leaf area index (LAID), which was compared with LAI estimated by the proposed digital photography method (LAIM). Results showed that the LAIM was able to estimate LAID with an error of 25% using a constant light extinction coefficient (k = 0.68). However, when k was estimated using an exponential function based on the fraction of foliage cover (ff) derived from images, the error was reduced to 18%. Furthermore, when measurements of light intercepted by the canopy (Ic) were used as a proxy value for k, the method presented an error of only 9%. These results have shown that by using a proxy k value, estimated by Ic, helped to increase accuracy of LAI estimates using digital cover images for apple trees with different canopy sizes and under field conditions. PMID:25635411

  2. Digital Cover Photography for Estimating Leaf Area Index (LAI in Apple Trees Using a Variable Light Extinction Coefficient

    Directory of Open Access Journals (Sweden)

    Carlos Poblete-Echeverría

    2015-01-01

    Full Text Available Leaf area index (LAI is one of the key biophysical variables required for crop modeling. Direct LAI measurements are time consuming and difficult to obtain for experimental and commercial fruit orchards. Devices used to estimate LAI have shown considerable errors when compared to ground-truth or destructive measurements, requiring tedious site-specific calibrations. The objective of this study was to test the performance of a modified digital cover photography method to estimate LAI in apple trees using conventional digital photography and instantaneous measurements of incident radiation (Io and transmitted radiation (I through the canopy. Leaf area of 40 single apple trees were measured destructively to obtain real leaf area index (LAID, which was compared with LAI estimated by the proposed digital photography method (LAIM. Results showed that the LAIM was able to estimate LAID with an error of 25% using a constant light extinction coefficient (k = 0.68. However, when k was estimated using an exponential function based on the fraction of foliage cover (ff derived from images, the error was reduced to 18%. Furthermore, when measurements of light intercepted by the canopy (Ic were used as a proxy value for k, the method presented an error of only 9%. These results have shown that by using a proxy k value, estimated by Ic, helped to increase accuracy of LAI estimates using digital cover images for apple trees with different canopy sizes and under field conditions.

  3. Implementation of the Leaching Environmental Assessment Framework (LEAF) in the United States

    Science.gov (United States)

    LEAF provides a uniform and integrated approach for evaluating leaching from solid materials (e.g., waste, treated wastes such as by solidification/stabilization, secondary materials such as blast furnace slags, energy residuals such as coal fly ash, soil, sediments, mining and m...

  4. Seasonal variation of photosynthetic model parameters and leaf area index from global Fluxnet eddy covariance data

    NARCIS (Netherlands)

    Groenendijk, M.; Dolman, A.J.; Ammann, C.; Arneth, A.; Cescatti, A.; Molen, van der M.K.; Moors, E.J.

    2011-01-01

    Global vegetation models require the photosynthetic parameters, maximum carboxylation capacity (Vcm), and quantum yield (a) to parameterize their plant functional types (PFTs). The purpose of this work is to determine how much the scaling of the parameters from leaf to ecosystem level through a seas

  5. Investigating Conceptual, Procedural, and Intuitive Aspects of Area Measurement with Non-Square Area Units

    Science.gov (United States)

    Miller, Amanda L.

    2013-01-01

    This dissertation reports the results of a qualitative research project on area measurement. The study utilized structured, task-based interviews with students to (a) investigate the ways students enumerate and structure two-dimensional space with a variety of area units; (b) identify conceptual, procedural, and intuitive aspects of area…

  6. Developing Student’s Notion of Measurement Unit For Area

    Directory of Open Access Journals (Sweden)

    Kurnia Rahmi Yuberta

    2011-07-01

    Full Text Available Many researchers found that students have difficulties in understandingarea measurement. Students mostly focus on applying formula to find the area of certain shapes without knowing what the area is and why theformula works. It is important for the students to know what attribute being measured and to construct the unit for area measurement. Therefore, the aim of this research is to develop activities that support students to know the attribute of area and  the notion of measurementunit in learning area measurement. For this purpose, design research is chosen for achieving the research goal. Realistic Mathematics Education (RME underlies the design of context and activities. A teacher and students in grade 3 in elementary school (SDN 21 in Palembang Indonesia will be involved in this research.Keywords: Area measurement, unit, design research, RME DOI: http://dx.doi.org/10.22342/jme.2.2.775.173-184

  7. MODIS/COMBINED MCD15A3H Leaf Area Index - Fraction of Photosynthetically Active Radiation 4-Day L4 Global 500 m Version 6

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 500-meter resolution....

  8. MODIS/AQUA MYD15A2H Leaf Area Index - Fraction of Photosynthetically Active Radiation 8-Day L4 Global 500 m Version 6

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 500-meter resolution....

  9. MODIS/COMBINED MCD15A2H Leaf Area Index - Fraction of Photosynthetically Active Radiation 8-Day L4 Global 500 m Version 6

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 500-meter resolution....

  10. MODIS/AQUA MYD15A2H Leaf Area Index - Fraction of Photosynthetically Active Radiation 8-Day L4 Global 500 m Version 6

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 500-meter...

  11. MODIS/COMBINED MCD15A3H Leaf Area Index - Fraction of Photosynthetically Active Radiation 4-Day L4 Global 500 m Version 6

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 500-meter...

  12. MODIS/COMBINED MCD15A2H Leaf Area Index - Fraction of Photosynthetically Active Radiation 8-Day L4 Global 500 m Version 6

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 500-meter...

  13. MODIS/TERRA MOD15A2 Leaf Area Index - Fraction of Photosynthetically Active Radiation 8-Day L4 Global 1km

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 1-kilometer...

  14. MODIS/COMBINED MCD15A2 Leaf Area Index - Fraction of Photosynthetically Active Radiation 8-Day L4 Global 1km

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 1-kilometer...

  15. MODIS/TERRA MOD15A2H Leaf Area Index - Fraction of Photosynthetically Active Radiation 8-Day L4 Global 500 m Version 6

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 500-meter resolution....

  16. MODIS/AQUA MYD15A2 Leaf Area Index - Fraction of Photosynthetically Active Radiation 8-Day L4 Global 1km

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 1-kilometer...

  17. Estimativa da área foliar de plantas daninhas: Solanum americanum Mill Leaf area determination of weeds: Solanum americanum Mill

    Directory of Open Access Journals (Sweden)

    Gustavo R. Tofoli

    1998-12-01

    Full Text Available A maria pretinha (Solanum americanum Mill é uma planta daninha infestante de diversas culturas e além da competição pode causar outros problemas. Nos estudos envolvendo a biologia e o controle de plantas daninhas, a área foliar é uma das mais importantes características a serem avaliadas, mas tem sido pouco estudada porque sua determinação exige equipamentos sofisticados ou utiliza técnicas destrutivas. Visando obter equações que permitissem a estimativa da área foliar desta planta daninha utilizando características lineares do limbo foliar, facilmente mensuráveis em plantas no campo, foram estudadas correlações entre a área foliar real e as seguintes características das folhas: comprimento ao longo da nervura principal (C, largura máxima do limbo (L e o produto (C x L. Para tanto, foram mensuradas 200 folhas coletadas de plantas sujeitas às mais diversas condições ecológicas em que a espécie sobrevive, considerando-se todas as folhas das plantas desde que não apresentassem deformações oriundas de fatores, tais como, pragas, moléstias e granizo. Todas as equações, lineares simples, geométricas e exponenciais, permitiram boa estimativa da área foliar (Af da maria pretinha. Do ponto de vista prático, sugere-se optar pela equação linear simples envolvendo o produto (C x L, a qual apresentou o menor QM Resíduo. Assim, a estimativa da área foliar de S. americanum pode ser efetuada pela equação AF = 0,5632 x (C x L, com coeficiente de determinação (R2 de valor igual a 0,9516.Solanum americanum is a very aggressive weed that, besides competition, can cause many other problems. Despite being one of the most important parameters to be analyzed, only few studies have been carried out concerning the leaf area mainly because its determination demands sophisticated equipment or destructive techniques. Aiming to develop equations that allow to estimate the leaf area of this weed using linear measure of the leaf

  18. Effects of arbuscular mycorrhizal fungi on leaf solutes and root absorption areas of trifoliate orange seedlings under water stress conditions

    Institute of Scientific and Technical Information of China (English)

    WU Qiangsheng; XIA Renxue

    2006-01-01

    The effects of the arbuscular mycorrhizal (AM)fungus Glomus mosseae on plant growth,leaf solutes and root absorption area of trifoliate orange (Poncirus trifoliata (L.) Raf.) seedlings were studied in potted culture under water stress conditions.Inoculation with G.mosseae increased plant height,stem diameter,leaf area,shoot dry weight,root dry weight and plant dry weight,when the soil water content was 20%,16% and 12%.AM inoculation also promoted the active and total absorption area of root system and absorption of phosphorus from the rhizosphere,enhanced the content of soluble sugar in leaves and roots,and reduced proline content in leaves.AM seedlings had higher plant water use efficiency and higher drought tolerance than non-AM seedlings.Effects of G.mosseae inoculation on trifoliate orange seedlings under 20% and 16% soil water content were more significant than under 12% soil water content.AM infection was severely restrained by 12% soil water content.Thus,effects of AM fungi on plants were probably positively related to the extent of root colonization by AM fungi.The mechanism of AM fungi in enhancing drought resistance of host plants ascribed to greater osmotic adjustment and greater absorption area of root system by AM colonization.

  19. Heterogeneity of competition at decameter scale: patches of high canopy leaf area in a shade-intolerant larch stand transpire less yet are more sensitive to drought.

    Science.gov (United States)

    Xiong, Wei; Oren, Ram; Wang, Yanhui; Yu, Pengtao; Liu, Hailong; Cao, Gongxiang; Xu, Lihong; Wang, Yunni; Zuo, Haijun

    2015-05-01

    Small differences in the sensitivity of stomatal conductance to light intensity on leaf surfaces may lead to large differences in total canopy transpiration (EC) with increasing canopy leaf area (L). Typically, the increase of L would more than compensate for the decrease of transpiration per unit of leaf area (EL), resulting in concurrent increase of EC. However, highly shade-intolerant species, such as Larix principis-rupprechtii Mayr., may be so sensitive to increased shading that such compensation is not complete. We hypothesized that in such a stand, windfall-induced spatial variation at a decameter scale would result in greatly reduced EL in patches of high L leading to lower EC than low competition patches of sparse canopy. We further hypothesized that quicker extraction of soil moisture in patches of lower competition will result in earlier onset of drought symptoms in these patches. Thus, patches of low L will transition from light to soil moisture as the factor dominating EL. This process should progressively homogenize EC in the stand even as the variation of soil moisture is increasing. We tested the hypotheses utilizing sap flux of nine trees, and associated environmental and stand variables. The results were consistent with only some of the expectations. Under non-limiting soil moisture, EL was very sensitive to the spatial variation of L, decreasing sharply with increasing L and associated decrease of mean light intensity on leaf surfaces. Thus, under the conditions of ample soil moisture maximum EC decreased with increasing patch-scale L. Annual EC and biomass production also decreased with L, albeit more weakly. Furthermore, variation of EC among patches decreased as average stand soil moisture declined between rain events. However, contrary to expectation, high L plots which transpired less showed a greater EL sensitivity to decreasing stand-scale soil moisture, suggesting a different mechanism than simple control by decreasing soil moisture. We

  20. The effect of leaf area reduction on the yield and quality of sugar beet (Beta vulgaris L. var. altissima Döll.

    Directory of Open Access Journals (Sweden)

    Radim Cerkal

    2007-01-01

    Full Text Available The yield of sugar beet is directly affected by LAI (leaf area index and values of LAD (leaf area duration. The integral leaf area plays, except for other factors, an important role during the damage or reduction of leaf apparatus. There are many sources of leaf damage: natural disasters (hailstorm, diseases, pests (including game browsing etc. The intensity of the root production and quality differs in relation to the growth stage of the damage plant. The aim of this study was to evaluate the extent of losses in the root yield and the quality of sugar beet upon gradual reduction of the leaf area. Two diploid varieties Monza and Compact were used in the small-plot trials conducted in years 2004 to 2006 (in the experimental station Žabčice – maize production region, zone K2, average altitude 184 m, soil type was classified as gley fluvisoil, soil is medium heavy to heavy, clay-loam to loam type. The leaf area was manually reduced by 25% and 50% at BBCH 18–19 growth phase (8–9 leaves unfolded. The results were statistically evaluated by analysis of variance and testing by Tukey test (at the significance level α = 5%. Reduction of the leaf area was reflected on the decrease of the root yield by 1 to 10% depending on the year of harvest. In addition, the stressful state of the plants after defoliation resulted in the decrease of the yield of polarization sugar per hectare, namely by 0.45 to 1.66 t.ha–1. In 2005, the leaf area reduction caused a rise of the α-amino nitrogen content. The rise in the potassium and sodium cations content caused by the leaf area reduction also increased the sugar content in the treacle (by 0.1 to 0.16%. The increasing leaf area reduction lead to decreasing of yield of polarization sugar. However, this descent was statistically significant in harvest year 2006 only.

  1. Variation of Leaf Area in Individual Tree for Poplar Shelterbelts%杨树农田防护林带单木叶面积的变化

    Institute of Scientific and Technical Information of China (English)

    赵东; 杨喜田; 樊巍; 高喜荣; 王齐瑞

    2011-01-01

    研究豫东平原5,7年生欧美杨107杨农田防护林带单木比叶面积、叶面积的变化,建立预侧林带单木叶面积的异速生长模型.结果表明:5,7年生单木比叶面积平均分别为136.6,138.2 cm2·g(-1),两者差异不显著;叶面积平均分别为45.4,85.8m2,两者差异显著.冠层位置对比叶面积、叶面积均有显著影响,从树冠的上层到下层,比叶面积显著增加;而叶面积在两林龄中垂直层次表现出差异性,在水平层次,由内层到外层,叶面积均显著增加.不同林龄林带具有不同级别的枝,各级别枝的叶面积间均有显著差异.异速生长关系表明:树高、胸径、冠长因子都能可靠地预测林带单木叶面积,相比而言,胸径和单木叶面积之间的异速生长模型在测算单木叶面积及其指数时较可靠、方便.%Leaf area (LA) as an essential part of crown structure affects both the growth of forests and protective effects of shelterbelt. The variation in specific leaf area (SLA) and leaf area with position in the crown was investigated for 5 -year-old and 7-year-old Populus × euramericana cv. “74/76” stand in Henan Eastern Plain. Allometric equations describing the leaf area of the entire crown were developed. The results showed that SLA on individual tree were 136. 6,138. 2 cm2 ·g-1 in 5-year-old and 7-year-old trees, respectively. However, leaf area on individual tree was significantly influenced by tree age, on average it were 45.4,85. 8 m2 in 5-year-old and 7-year-old trees, respectively. Specific leaf area and leaf area were significantly by the position in the crown. Specific leaf area increased significanfiy from the top to the bottom of the crown. Leaf area increased significanfiy from the top to the bottom of the crown for 5-year-old stand,however, it in the middle was significantly higher than that in the upper and the lower of the crown for 7-year-old stand,and both increased significantly from the interior to the exterior

  2. An Optimal Sampling Design for Observing and Validating Long-Term Leaf Area Index with Temporal Variations in Spatial Heterogeneities

    Directory of Open Access Journals (Sweden)

    Yelu Zeng

    2015-01-01

    Full Text Available A sampling strategy to define elementary sampling units (ESUs for an entire site at the kilometer scale is an important step in the validation process for moderate-resolution leaf area index (LAI products. Current LAI-sampling strategies are unable to consider the vegetation seasonal changes and are better suited for single-day LAI product validation, whereas the increasingly used wireless sensor network for LAI measurement (LAINet requires an optimal sampling strategy across both spatial and temporal scales. In this study, we developed an efficient and robust LAI Sampling strategy based on Multi-temporal Prior knowledge (SMP for long-term, fixed-position LAI observations. The SMP approach employed multi-temporal vegetation index (VI maps and the vegetation classification map as a priori knowledge. The SMP approach minimized the multi-temporal bias of the VI frequency histogram between the ESUs and the entire site and maximized the nearest-neighbor index to ensure that ESUs were dispersed in the geographical space. The SMP approach was compared with four sampling strategies including random sampling, systematic sampling, sampling based on the land-cover map and a sampling strategy based on vegetation index prior knowledge using the PROSAIL model-based simulation analysis in the Heihe River basin. The results indicate that the ESUs selected using the SMP method spread more evenly in both the multi-temporal feature space and geographical space over the vegetation cycle. By considering the temporal changes in heterogeneity, the average root-mean-square error (RMSE of the LAI reference maps can be reduced from 0.12 to 0.05, and the relative error can be reduced from 6.1% to 2.2%. The SMP technique was applied to assign the LAINet ESU locations at the Huailai Remote Sensing Experimental Station in Beijing, China, from 4 July to 28 August 2013, to validate three MODIS C5 LAI products. The results suggest that the average R2, RMSE, bias and relative

  3. Preliminary study on calculation method of leaf area and leaf biomass of Castanea crenata%日本栗叶面积与叶片生物量计算方法的初步研究

    Institute of Scientific and Technical Information of China (English)

    郑瑞杰; 王德永

    2011-01-01

    以6年生日本栗品种"辽栗10号"与"大峰"为试材,对其叶长、叶宽、单叶面积、单叶干重、冠幅、冠高、单株叶片生物量进行了测定。研究不同品种间叶片长宽比值和比叶面积的差异性,叶片长、叶宽和叶片长宽乘积与单叶面积的相关性以及冠幅、冠高与单株叶片生物量的相关性。结果表明:不同品种间叶片长宽比、比叶面积均无显著差异;对日本栗叶长、叶宽、叶片长宽乘积与单叶面积进行一元回归方程拟合,决定系数与修正决定系数均达极显著水平(P〈0.0001),其中以叶片长宽乘积与单叶面积的一元二次回归方程回归效果最好,决定系数达0.987 9,修正决定系数达0.987 7;单株叶片生物量与冠幅面积和冠高的二元线性回归关系达极显著水平(P〈0.0001),决定系数达0.997 2,修正决定系数达0.996 4。在生产上,可以通过测量冠幅面积、冠高计算出单株叶片生物量和叶面积指数,该方法操作简单,具有较高应用价值。%In this study,two cultivars of Castanea crenata,Liaoli No.10 and Dafeng were token as test materials.Based on the measurement of leaf length,leaf width,single leaf area,single leaf dry weight,crown width,crown height and the leaf biomass of individual plants,the reaches were carried out on the difference in leaf length-width ratio and specific leaf area of different cultivars,the relationship of leaf length,leaf width and the product of leaf length and width with leaf area,and the relationship of crown width and crown height with the leaf biomass of individual plants.The research results shown that there was no obvious difference in the leaf length-width ratio and specific leaf area of different cultivars;unitary regression equation fit on the leaf length,the leaf width and the product of the leaf length and width and the leaf area of Castanea crenata indicated that both determination coefficient and correction

  4. Validating and Linking the GIMMS Leaf Area Index (LAI3g with Environmental Controls in Tropical Africa

    Directory of Open Access Journals (Sweden)

    Marion Pfeifer

    2014-03-01

    Full Text Available The recent Global Inventory Modeling and Mapping Studies (GIMMS LAI3g product provides a 30-year global times-series of remotely sensed leaf area index (LAI, an essential variable in models of ecosystem process and productivity. In this study, we use a new dataset of field-based LAITrue to indirectly validate the GIMMS LAI3g product, LAIavhrr, in East Africa, comparing the distribution properties of LAIavhrr across biomes and environmental gradients with those properties derived for LAITrue. We show that the increase in LAI with vegetation height in natural biomes is captured by both LAIavhrr and LAITrue, but that LAIavhrr overestimates LAI for all biomes except shrubland and cropland. Non-linear responses of LAI to precipitation and moisture indices, whereby leaf area peaks at intermediate values and declines thereafter, are apparent in both LAITrue and LAIavhrr, although LAITrue reaches its maximum at lower values of the respective environmental driver. Socio-economic variables such as governance (protected areas and population affect both LAI responses, although cause and effect are not always obvious: a positive relationship with human population pressure was detected, but shown to be an artefact of both LAI and human settlement covarying with precipitation. Despite these complexities, targeted field measurements, stratified according to both environmental and socio-economic gradients, could provide crucial data for improving satellite-derived LAI estimates, especially in the human-modified landscapes of tropical Africa.

  5. Large-area landslide susceptibility with optimized slope-units

    Science.gov (United States)

    Alvioli, Massimiliano; Marchesini, Ivan; Reichenbach, Paola; Rossi, Mauro; Ardizzone, Francesca; Fiorucci, Federica; Guzzetti, Fausto

    2017-04-01

    A Slope-Unit (SU) is a type of morphological terrain unit bounded by drainage and divide lines that maximize the within-unit homogeneity and the between-unit heterogeneity across distinct physical and geographical boundaries [1]. Compared to other terrain subdivisions, SU are morphological terrain unit well related to the natural (i.e., geological, geomorphological, hydrological) processes that shape and characterize natural slopes. This makes SU easily recognizable in the field or in topographic base maps, and well suited for environmental and geomorphological analysis, in particular for landslide susceptibility (LS) modelling. An optimal subdivision of an area into a set of SU depends on multiple factors: size and complexity of the study area, quality and resolution of the available terrain elevation data, purpose of the terrain subdivision, scale and resolution of the phenomena for which SU are delineated. We use the recently developed r.slopeunits software [2,3] for the automatic, parametric delineation of SU within the open source GRASS GIS based on terrain elevation data and a small number of user-defined parameters. The software provides subdivisions consisting of SU with different shapes and sizes, as a function of the input parameters. In this work, we describe a procedure for the optimal selection of the user parameters through the production of a large number of realizations of the LS model. We tested the software and the optimization procedure in a 2,000 km2 area in Umbria, Central Italy. For LS zonation we adopt a logistic regression model implemented in an well-known software [4,5], using about 50 independent variables. To select the optimal SU partition for LS zonation, we want to define a metric which is able to quantify simultaneously: (i) slope-unit internal homogeneity (ii) slope-unit external heterogeneity (iii) landslide susceptibility model performance. To this end, we define a comprehensive objective function S, as the product of three

  6. Leaf Area Index (LAI) in different type of agroforestry systems based on hemispherical photographs in Cidanau Watershed

    Science.gov (United States)

    Nur Khairiah, Rahmi; Setiawan, Yudi; Budi Prasetyo, Lilik; Ayu Permatasari, Prita

    2017-01-01

    Ecological functions of agroforestry systems have perceived benefit to people around Cidanau Watershed, especially in the protection of water quality. The main causes of the problems encountered in the Cidanau Watershed are associated with the human factors, especially encroachment and conversion of forest into farmland. The encroachment has made most forest in Cidanau Watershed become bare land. To preserve the ecological function of agroforestry systems in Cidanau Watershed, monitoring of the condition of the vegetation canopy in agroforestry systems is really needed. High intensity thinning of crown density due to deforestation can change stand leaf area index dramatically. By knowing LAI, we can assess the condition of the vegetation canopy in agroforestry systems. LAI in this research was obtained from Hemispherical Photographs analysis using the threshold method in HemiView Canopy Analysis Software. Our research results indicate that there are six types of agroforestry in Cidanau Watershed i.e. Sengon Agroforestry, Clove Agroforestry, Melinjo Agroforestry, Chocolate Agroforestry, Coffee Agroforestry, and Complex Agroforestry. Several factors potentially contribute to variations in the value of LAI in different types of agroforestry. The simple assumptions about differences ranges of LAI values on six types of agroforestry is closely related to leaf area and plant population density.

  7. An application of plot-scale NDVI in predicting carbon dioxide exchange and leaf area index in heterogeneous subarctic tundra

    Energy Technology Data Exchange (ETDEWEB)

    Dagg, J.; Lafleur, P.

    2010-07-01

    This paper reported on a study that examined the flow of carbon into and out of tundra ecosystems. It is necessary to accurately predict carbon dioxide (CO{sub 2}) exchange in the Tundra because of the impacts of climate change on carbon stored in permafrost. Understanding the relationships between the normalized difference vegetation index (NDVI) and vegetation and CO{sub 2} exchange may explain how small-scale variation in vegetation community extends to remotely sensed estimates of landscape characteristics. In this study, CO{sub 2} fluxes were measured with a portable chamber in a range of Tundra vegetation communities. Biomass and leaf area were measured with destructive harvest, and NDVI was obtained using a hand-held infrared camera. There was a weak correlation between NDVI and leaf area index in some vegetation communities, but a significant correlation between NDVI and biomass, including mosses. NDVI was found to be strongly related to photosynthetic activity and net CO{sub 2} uptake in all vegetation groups. However, NDVI related to ecosystem respiration only in wet sedge. It was concluded that at plot scale, the ability of NDVI to predict ecosystem properties and CO{sub 2} exchange in heterogeneous Tundra vegetation is variable.

  8. Leaf area regression analysis of five Pyracantha species%五种火棘属植物的叶面积回归分析

    Institute of Scientific and Technical Information of China (English)

    王勇; 杜晓军; 招礼军; 焦志华; 安明态

    2013-01-01

    Leaf is an important plant organ for transpiration and photosynthesis.Accurate and non-destructive meth-ods for estimating leaf area are critical to many related studies.In order to get the accurate regression functions to es-timate leaf area of Pyracantha species,26401 mature leaf samples,from five species (Pyracantha fortuneana,P. densiflora,P.atalantioides,P.crenulata,P.angustifolia)in Guizhou,Yunnan,Guangxi,Hunan provinces in Chi-na,were collected in 2010 and 2011.Leaf analysis software of WinFOLIA was used to measure leaf indices such as leaf area (LA),leaf blade length (L),leaf horizontal width (W),leaf perimeter (LP),leaf vertical length (VL);then LW,L/W,LL and WW were also obtained.Regression analyses between LA and these leaf shape indices of these five species were carried out by using 1 1 models including power,cubic,quadratic,linear,logarithmic,inverse,compound, S,growth,exponential,logistic model.The results were as follows:leaf area can be modeled better with LW than other indices;leaf area can be modeled better with LW by power,cubic,quadratic and linear models,and power func-tion is the fittest model (R2>0.970);Power models for five Pyracantha species were LA=0.743(LW)0.936 ,LA=0.748(LW)0.936 ,LA=0.742(LW)0.955 ,LA=0.732(LW)0.952 and LA=0.766(LW)0.954 respectively.This study high-light that power model of leaf area based on L×W can be better used to non-destructively estimate leaf area of five Pyracantha species.%以采集于贵州、云南、广西、湖南等地的火棘、密花火棘、全缘火棘、细圆齿火棘和窄叶火棘共5种火棘属植物26401个成熟叶样为材料,利用WinFOLIA软件测量叶的多项形态指标并与叶面积进行11种模拟方程回归分析.结果表明:五种火棘属植物的叶面积(LA)与叶长×叶宽(LW)相关性最高,幂函数方程、三次方程、二次方程和线性方程能较好拟合其关系,且均以幂函数方程的解释程度最高(R2均大于0.970),5个物种

  9. A phenomics approach to the analysis of the influence of glutathione on leaf area and abiotic stress tolerance in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Daniel eSchnaubelt

    2013-11-01

    Full Text Available Reduced glutathione (GSH is an abundant low molecular weight plant thiol. It fulfils multiple functions in plant biology, many of which remain poorly characterised. A phenomics approach was therefore used to investigate the effects of glutathione homeostasis on growth and stress tolerance in Arabidopsis thaliana. Rosette leaf area was compared in mutants that are either defective in GSH synthesis (cad2, pad2 and rax1 or the export of γ-glutamyl cysteine and GSH from the chloroplast (clt and in wild type plants under standard growth conditions and following exposure to a range of abiotic stress treatments, including oxidative stress, water stress and high salt. In the absence of stress, the GSH synthesis mutants had a significantly lower leaf area than the wild type. Conversely, the clt mutant has a greater leaf area and a significantly reduced lateral root density than the wild type. These findings demonstrate that cellular glutathione homeostasis exerts an influence on root architecture and on rosette area. An impaired capacity to synthesise GSH or a specific depletion of the cytosolic GSH pool did not adversely affect leaf area in plants exposed to short term abiotic stress. However, the negative effects of long term exposure to oxidative stress and high salt on leaf area were less marked in the GSH synthesis mutants than the wild type. These findings demonstrate the importance of cellular glutathione homeostasis in the regulation of plant growth under optimal and stress conditions.

  10. Leaf and wood carbon isotope ratios, specific leaf areas and wood growth of Eucalyptus species across a rainfall gradient in Australia.

    Science.gov (United States)

    Schulze, Ernst-Detlef; Turner, Neil C; Nicolle, Dean; Schumacher, Jens

    2006-04-01

    Leaves and samples of recent wood of Eucalyptus species were collected along a rainfall gradient parallel to the coast of Western Australia between Perth in the north and Walpole in the south and along a southwest to northeast transect from Walpole in southwestern Australia, to near Mount Olga in central Australia. The collection included 65 species of Eucalyptus sampled at 73 sites and many of the species were collected at several sites along the rainfall gradient. Specific leaf area (SLA) and isotopic ratio of 13C to 12C (delta 13C) of leaves that grew in 2002, and tree ring growth and delta 13C of individual cell layers of the wood were measured. Rainfall data were obtained from the Australian Bureau of Meteorology for 29 locations that represented one or a few closely located collection sites. Site-averaged data and species-specific values of delta 13C decreased with decreasing annual rainfall between 1200 and 300 mm at a rate of 1.63 per thousand per 1000 mm decrease in rainfall. Responses became variable in the low rainfall region (rainfall, whereas delta 13C increased or remained constant in other species. The range of delta 13C values in the low rainfall region was as large as the range observed at sites receiving > 300 mm of annual rainfall. Specific leaf area varied between 2 and 6 m2 kg(-1) and tended to increase with decreasing annual rainfall in some species, but not all, whereas delta 13C decreased with SLA. The relationship between delta 13C and SLA was highly species and soil-type specific. Leaf-area-based nitrogen (N) content varied between 2 and almost 6 g m(-2) and decreased with rainfall. Thus, thicker leaves were associated with higher N content and this compensated for the effect of drought on delta 13C. Nitrogen content was also related to soil type and species identity. Based on a linear mixed model, statistical analysis of the whole data set showed that 27% of the variation in delta 13C was associated with changes in SLA, 16% with soil type

  11. The relationship between leaf area index and microclimate in tropical forest and oil palm plantation: Forest disturbance drives changes in microclimate.

    Science.gov (United States)

    Hardwick, Stephen R; Toumi, Ralf; Pfeifer, Marion; Turner, Edgar C; Nilus, Reuben; Ewers, Robert M

    2015-02-15

    Land use change is a major threat to biodiversity. One mechanism by which land use change influences biodiversity and ecological processes is through changes in the local climate. Here, the relationships between leaf area index and five climate variables - air temperature, relative humidity, vapour pressure deficit, specific humidity and soil temperature - are investigated across a range of land use types in Borneo, including primary tropical forest, logged forest and oil palm plantation. Strong correlations with the leaf area index are found for the mean daily maximum air and soil temperatures, the mean daily maximum vapour pressure deficit and the mean daily minimum relative humidity. Air beneath canopies with high leaf area index is cooler and has higher relative humidity during the day. Forest microclimate is also found to be less variable for sites with higher leaf area indices. Primary forest is found to be up to 2.5 °C cooler than logged forest and up to 6.5 °C cooler than oil palm plantations. Our results indicate that leaf area index is a useful parameter for predicting the effects of vegetation upon microclimate, which could be used to make small scale climate predictions based on remotely sensed data.

  12. Dynamics of leaf area index and canopy openness of three forest types in a warm temperate zone

    Institute of Scientific and Technical Information of China (English)

    Weiguo SANG; Sha CHEN; Guangqi LI

    2008-01-01

    Deciduous broad-leaved forests (DBF), Larix principis-rupprechtii (LF) and Pinus tabulaeformis planta-tions (PF) are three typical forest communities in the warm temperate zone of the Dongling Mountains. In this study, we used an indirect method, hemispheric pho-tography, to measure and analyze the dynamics of leaf area index (LAI) and canopy openness of the three forest communities. The results show that the LAI values of DBF and LF increased gradually with plant growth and development. The highest LAI value appeared in August, while canopy openness changed inversely with LAI. The lowest value appeared in November. DBF maintained a higher LAI in August and had a more open canopy in November compared with LF. For PF, we observed little changes in the LAI and canopy openness which was attributed to the leaf retention of this evergreen species. However, a similar relation between LAI and canopy openness was found for the three forest communities: canopy openness varied inversely with LAI. The relation is exponential and significant. Therefore, canopy open-ness is a good indicator of LAI in forests. This result can be used to test the validity of the LAI based on remote sensing and to provide a reference for the study of the canopy heterogeneity and its effect. This also benefits modeling for fluxes of carbon, water and energy from the level of the stand to landscape.

  13. Interspecific variation of photosynthesis and leaf characteristics in canopy trees of five species of Dipterocarpaceae in a tropical rain forest.

    Science.gov (United States)

    Kenzo, Tanaka; Ichie, Tomoaki; Yoneda, Reiji; Kitahashi, Yoshinori; Watanabe, Yoko; Ninomiya, Ikuo; Koike, Takayoshi

    2004-10-01

    Photosynthetic rate, nitrogen concentration and morphological properties of canopy leaves were studied in 18 trees, comprising five dipterocarp species, in a tropical rain forest in Sarawak, Malaysia. Photosynthetic rate at light saturation (Pmax) differed significantly across species, varying from 7 to 18 micro mol m(-2) s(-1). Leaf nitrogen concentration and morphological properties, such as leaf blade and palisade layer thickness, leaf mass per area (LMA) and surface area of mesophyll cells per unit leaf area (Ames/A), also varied significantly across species. Among the relationships with leaf characteristics, Pmax had the strongest correlation with leaf mesophyll parameters, such as palisade cell layer thickness (r2 = 0.76, P palisade layer, with up to five or more layers. We conclude that interspecific variation in photosynthetic capacity in tropical rain forest canopies is influenced more by leaf mesophyll structure than by leaf thickness, LMA or leaf nitrogen concentration.

  14. Estimativa da área foliar de Sida cordifolia e Sida rhombifolia usando dimensões lineares do limbo foliar Estimate of Sida cordifolia and Sida rhombifolia leaf area using leaf blade linear dimensions

    Directory of Open Access Journals (Sweden)

    S. Bianco

    2008-01-01

    Full Text Available A estimativa da área foliar pode auxiliar na compreensão de relações de interferência entre plantas daninhas e cultivadas. Com o objetivo de obter uma equação que, por meio de parâmetros lineares dimensionais das folhas, permita a estimativa da área foliar de Sida cordifolia e Sida rhombifolia, estudaram-se as correlações entre área foliar real (Af e parâmetros dimensionais do limbo foliar, como o comprimento (C ao longo da nervura principal e a largura máxima (L perpendicular à nervura principal. Foram analisados 200 limbos foliares de cada espécie, coletados em diferentes agroecossistemas na Universidade Estadual Paulista, campus de Jaboticabal. Os modelos estatísticos utilizados foram linear: Y = a + bx; linear simples: Y = bx; geométrico: Y = ax b; e exponencial: Y = ab x. Todos os modelos analisados podem ser empregados para estimação da área foliar de S. cordifolia e S. rhombifolia. Sugere-se optar pela equação linear simples, envolvendo o produto C*L, considerando-se o coeficiente linear igual a zero, em função da praticidade desta. Desse modo, a estimativa da área foliar de S. cordifolia pode ser obtida pela fórmula Af = 0,7878*(C*L, com coeficiente de determinação de 0,9307, enquanto para S. rhombifolia a estimativa da área foliar pode ser obtida pela fórmula Af = 0,6423*(C*L, com coeficiente de determinação de 0,9711.Leaf area estimate may contribute to understand the relationship of interference between weeds and crops. The objective of this research was to obtain a mathematical equation to estimate Sida cordifolia and Sida rhombifolia leaf area based on linear measures of leaf blade. Correlation studies were conducted between real leaf area (Af and dimensional leaf blade parameters such as leaf length (C and maximum leaf width (L. Around 200 leaf blades of each species were analyzed, collected from several agro-ecosystems at São Paulo State University, in Jaboticabal, SP, Brazil. The statistical

  15. EPIC-Simulated and MODIS-Derived Leaf Area Index (LAI) Comparisons Across mMltiple Spatial Scales RSAD Oral Poster based session

    Science.gov (United States)

    Leaf Area Index (LAI) is an important parameter in assessing vegetation structure for characterizing forest canopies over large areas at broad spatial scales using satellite remote sensing data. However, satellite-derived LAI products can be limited by obstructed atmospheric cond...

  16. Remote sensing based mapping of leaf nitrogen and leaf area index in European landscapes using the REGularized canopy reFLECtance (REGFLEC) model

    DEFF Research Database (Denmark)

    Boegh, E.; Houborg, R.; Bienkowski, J.

    2011-01-01

    index (LAI) are important determinants of the maximum CO2 Methods/Approach uptake by plants and trees. In the EU project NitroEurope, high spatial resolution (10-20 m) remote sensing data from the HRG and HRVIR sensors onboard the SPOT satellites were acquired to derive maps of leaf N and LAI for 5...

  17. Relationship between aerodynamic roughness length and bulk sedge leaf area index in a mixed-species boreal mire complex

    Science.gov (United States)

    Alekseychik, P. K.; Korrensalo, A.; Mammarella, I.; Vesala, T.; Tuittila, E.-S.

    2017-06-01

    Leaf area index (LAI) is an important parameter in natural ecosystems, representing the seasonal development of vegetation and photosynthetic potential. However, direct measurement techniques require labor-intensive field campaigns that are usually limited in time, while remote sensing approaches often do not yield reliable estimates. Here we propose that the bulk LAI of sedges (LAIs) can be estimated alternatively from a micrometeorological parameter, the aerodynamic roughness length for momentum (z0). z0 can be readily calculated from high-response turbulence and other meteorological data, typically measured continuously and routinely available at ecosystem research sites. The regressions of LAI versus z0 were obtained using the data from two Finnish natural sites representative of boreal fen and bog ecosystems. LAIs was found to be well correlated with z0 and sedge canopy height. Superior method performance was demonstrated in the fen ecosystem where the sedges make a bigger contribution to overall surface roughness than in bogs.

  18. Clonal Propagation of Khaya senegalensis: The Effects of Stem Length, Leaf Area, Auxins, Smoke Solution, and Stockplant Age

    Directory of Open Access Journals (Sweden)

    Catherine Ky-Dembele

    2011-01-01

    Full Text Available Khaya senegalensis is a multipurpose African timber species. The development of clonal propagation could improve plantation establishment, which is currently impeded by mahogany shoot borer. To examine its potential for clonal propagation, the effects of cutting length, leaf area, stockplant maturation, auxin, and smoke solution treatments were investigated. Leafy cuttings rooted well (up to 80% compared to leafless cuttings (0%. Cuttings taken from seedlings rooted well (at least 95%, but cuttings obtained from older trees rooted poorly (5% maximum. The rooting ability of cuttings collected from older trees was improved (16% maximum by pollarding. Auxin application enhanced root length and the number of roots while smoke solution did not improve cuttings' rooting ability. These results indicate that juvenile K. senegalensis is amenable to clonal propagation, but further work is required to improve the rooting of cuttings from mature trees.

  19. Assessment of actual transpiration rate in olive tree field combining sap-flow, leaf area index and scintillometer measurements

    Science.gov (United States)

    Agnese, C.; Cammalleri, C.; Ciraolo, G.; Minacapilli, M.; Provenzano, G.; Rallo, G.; de Bruin, H. A. R.

    2009-09-01

    Models to estimate the actual evapotranspiration (ET) in sparse vegetation area can be fundamental for agricultural water managements, especially when water availability is a limiting factor. Models validation must be carried out by considering in situ measurements referred to the field scale, which is the relevant scale of the modelled variables. Moreover, a particular relevance assumes to consider separately the components of plant transpiration (T) and soil evaporation (E), because only the first is actually related to the crop stress conditions. Objective of the paper was to assess a procedure aimed to estimate olive trees actual transpiration by combining sap flow measurements with the scintillometer technique at field scale. The study area, located in Western Sicily (Italy), is mainly cultivated with olive crop and is characterized by typical Mediterranean semi-arid climate. Measurements of sap flow and crop actual evapotranspiration rate were carried out during 2008 irrigation season. Crop transpiration fluxes, measured on some plants by means of sap flow sensors, were upscaled considering the leaf area index (LAI). The comparison between evapotranspiration values, derived by displaced-beam small-aperture scintillometer (DBSAS-SLS20, Scintec AG), with the transpiration fluxes obtained by the sap flow sensors, also allowed to evaluate the contribute of soil evaporation in an area characterized by low vegetation coverage.

  20. Adaptive phenotypic plasticity of Pseudoroegneria spicata: response of stomatal density, leaf area and biomass to changes in water supply and increased temperature

    Science.gov (United States)

    Fraser, Lauchlan H.; Greenall, Amber; Carlyle, Cameron; Turkington, Roy; Friedman, Cynthia Ross

    2009-01-01

    Background and Aims Changes in rainfall and temperature brought about through climate change may affect plant species distribution and community composition of grasslands. The primary objective of this study was to test how manipulation of water and temperature would influence the plasticity of stomatal density and leaf area of bluebunch wheatgrass, Pseudoroegneria spicata. It was hypothesized that: (1) an increased water supply will increase biomass and leaf area and decrease stomatal density, while a reduced water supply will cause the opposite effect; (2) an increase in temperature will reduce biomass and leaf area and increase stomatal density; and (3) the combinations of water and temperature treatments can be aligned along a stress gradient and that stomatal density will be highest at high stress. Methods The three water supply treatments were (1) ambient, (2) increased approx. 30 % more than ambient through weekly watering and (3) decreased approx. 30 % less than ambient by rain shades. The two temperature treatments were (1) ambient and (2) increased approx. 1–3 °C by using open-top chambers. At the end of the second experimental growing season, above-ground biomass was harvested, oven-dried and weighed, tillers from bluebunch wheatgrass plants sampled, and the abaxial stomatal density and leaf area of tillers were measured. Key Results The first hypothesis was partially supported – reducing water supply increased stomatal density, but increasing water supply reduced leaf area. The second hypothesis was rejected. Finally, the third hypothesis could not be fully supported – rather than a linear response there appears to be a parabolic stomatal density response to stress. Conclusions Overall, the abaxial stomatal density and leaf area of bluebunch wheatgrass were plastic in their response to water and temperature manipulations. Although bluebunch wheatgrass has the potential to adapt to changing climate, the grass is limited in its ability to respond

  1. Leaf Area Index, Biomass Carbon and Growth Rate of Radiata Pine Genetic Types and Relationships with LiDAR

    Directory of Open Access Journals (Sweden)

    Robert J. McGaughey

    2011-08-01

    Full Text Available Relationships between discrete-return light detection and ranging (LiDAR data and radiata pine leaf area index (LAI, stem volume, above ground carbon, and carbon sequestration were developed using 10 plots with directly measured biomass and leaf area data, and 36 plots with modelled carbon data. The plots included a range of genetic types established on north- and south-facing aspects. Modelled carbon was highly correlated with directly measured crown, stem, and above ground biomass data, with r = 0.92, 0.97 and 0.98, respectively. LiDAR canopy percentile height (P30 and cover, based on all returns above 0.5 m, explained 81, 88, and 93% of the variation in directly measured crown, stem, and above ground live carbon and 75, 89 and 88% of the modelled carbon, respectively. LAI (all surfaces ranged between 8.8–19.1 in the 10 plots measured at age 9 years. The difference in canopy percentile heights (P95–P30 and cover based on first returns explained 80% of the variation in total LAI. Periodic mean annual increments in stem volume, above ground live carbon, and total carbon between ages 9 and 13 years were significantly related to (P95–P30, with regression models explaining 56, 58, and 55%, respectively, of the variation in growth rate per plot. When plot aspect and genetic type were included with (P95–P30, the R2 of the regression models for stem volume, above ground live carbon, and total carbon increment increased to 90, 88, and 88%, respectively, which indicates that LiDAR regression equations for estimating stock changes can be substantially improved by incorporating supplementary site and crop data.

  2. Indirect estimations and spatial variation in leaf area index of coniferous, deciduous and mixed forest stands in Forsmark and Laxemar

    Energy Technology Data Exchange (ETDEWEB)

    Tagesson, Torbern [Dept. of Physical Geography and Ecosystem Analysis, Lund Univ., Lund (Sweden)

    2006-12-15

    Two sites in Sweden are investigated for a potential deep repository of the nuclear waste, the Laxemar investigation area (57 deg 5 min N, 16 deg 7 min E) and the Forsmark investigation area (60 deg 4 min N, 18 deg 2 min E). In the characterisation of these sites, development of site descriptive models is an important part. Leaves are the main surface were an exchange of matter and energy between the atmosphere and the biosphere takes place, and leaf area index (LAI) of the vegetation cover is an important variable correlated to a number of ecophysiological parameters and hereby an important parameter in ecosystem models. In the investigation areas, LAI of boreal and temperate ecosystems were therefore estimated indirectly through optical measurements using the LAI-2000 (LI-COR, Cambridge UK) and TRAC (Tracing Radiation and Architecture of Canopies). On average, measured maximum LAI was 3.40 in Laxemar and 3.43 in Forsmark; minimum LAI was 1.65 in Laxemar and 1.97 in Forsmark. Forest inventory data showed that LAI is positively correlated with basal area, stand height, stand volume and breast height tree diameter. For the coniferous stands, there was also a linearly negative relationship with age. In the Laxemar investigation area, there were no significant relationships for LAI with a satellite derived kNN (kNearest Neighbor) data set with stand height, stand volume and stand age. The kNN data set can therefore not be used to extrapolate measured LAI over the Laxemar investigation area. There were significant relationships between LAI and the normalized difference vegetation index (NDVI) for coniferous, deciduous and mixed forest stands in the Laxemar investigation area. A NDVI image could be used to extrapolate LAI over the entire investigation area. For the Forsmark investigation area, effective LAI for all stands were correlated to NDVI and this relationship could then be used for extrapolation. The effective LAI image was afterwards corrected for average

  3. Nonlinear variations of forest leaf area index over China during 1982-2010 based on EEMD method

    Science.gov (United States)

    Yin, Yunhe; Ma, Danyang; Wu, Shaohong; Dai, Erfu; Zhu, Zaichun; Myneni, Ranga B.

    2016-11-01

    Variations in leaf area index (LAI) are critical to research on forest ecosystem structure and function, especially carbon and water cycle, and their responses to climate change. Using the ensemble empirical mode decomposition (EEMD) method and global inventory modeling and mapping studies (GIMMS) LAI3g dataset from 1982 to 2010, we analyzed the nonlinear feature and spatial difference of forest LAI variability over China for the past 29 years in this paper. Results indicated that the national-averaged forest LAI was characterized by quasi-3- and quasi-7-year oscillations, which generally exhibited a rising trend with an increasing rate. When compared with 1982, forest LAI change by 2010 was more evident than that by 1990 and 2000. The largest increment of forest LAI occurred in Central and South China, while along the southeastern coastal areas LAI increased at the fastest pace. During the study period, forest LAI experienced from decrease to increase or vice versa across much of China and varied monotonically for only a few areas. Focusing on regional-averaged trend processes, almost all eco-geographical regions showed continuously increasing trends in forest LAI with different magnitudes and speeds, other than tropical humid region and temperate humid/subhumid region, where LAI decreased initially and increased afterwards.

  4. Decline of photosynthetic capacity with leaf age and position in two tropical pioneer tree species.

    Science.gov (United States)

    Kitajima, Kaoru; Mulkey, Stephen S; Samaniego, Mirna; Joseph Wright, S

    2002-12-01

    The effect of leaf age on photosynthetic capacity, a critical parameter in the theory of optimal leaf longevity, was studied for two tropical pioneer tree species, Cecropia longipes and Urera caracasana, in a seasonally dry forest in Panama. These species continuously produce short-lived leaves (74 and 93 d, respectively) during the rainy season (May-December) on orthotropic branches. However, they differ in leaf production rate, maximum number of leaves per branch, light environment experienced by the leaves, leaf mass per unit area, and nitrogen content. Light-saturated photosynthetic rates for marked leaves of known ages (±1 wk) were measured with two contrasting schemes (repeated measurements vs. chronosequence within branch), which overall produced similar results. In both species, photosynthetic rates and nitrogen use efficiency were negatively correlated with leaf age and positively correlated with light availability. Photosynthetic rates declined faster with leaf age in Cecropia than in Urera as predicted by the theory. The rate of decline was faster for leaves on branches with faster leaf turnover rates. Nitrogen per unit leaf area decreased with leaf age only for Urera. Leaf mass per unit area increased with leaf age, either partly (in Cecropia) or entirely (in Urera) due to ash accumulation.

  5. Understanding Spatial Variability and Point Classification Implications on Methods for Retrieval of Leaf Orientation for Effective Leaf Area Index from Terrestrial Laser Scanning.

    Science.gov (United States)

    Richardson, J. J.; Moskal, L. M.; Zheng, G.; Kato, A.

    2015-12-01

    Tree leaf orientation, including the distribution of the inclinational and azimuthal angles in the canopy, is an important attribute of forest canopy architecture and is critical in determining the within and below canopy solar radiation regimes. We demonstrate techniques for indirectly and nondestructively retrieves foliage elements' orientation and distribution from point cloud data (PCD) obtained using a terrestrial laser scanning (TLS) approach.An equation with a single parameter for characterizing the leaf angular distribution of crowns was developed. The TLS-based algorithm captures 97.4% (RMSE =1 .094 degrees, pmature tree crown, the TLS-based algorithm predicts 78.51% (RMSE =1 .225 degrees, pmodel captures 88.7% (rmse =0 .007, pdigital hemispherical photographs. Finally we demonstrate how scanner setup which includes lateral scans can reduce effects of occlusion in terrestrial laser data collection.

  6. 7 CFR 275.18 - Project area/management unit corrective action plan.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 4 2010-01-01 2010-01-01 false Project area/management unit corrective action plan... SYSTEM Corrective Action § 275.18 Project area/management unit corrective action plan. (a) The State agency shall ensure that corrective action plans are prepared at the project area/management unit level...

  7. Simulation on Leaf Area Index in Wheat%小麦叶面积指数的模拟模型研究

    Institute of Scientific and Technical Information of China (English)

    刘铁梅; 曹卫星; 罗卫红; 郭文善

    2001-01-01

    小麦叶面积指数计算为群体绿叶重与比叶面积的乘积,而绿叶重为其分配指数与地上部干重的乘积。建立了绿叶分配指数与生理发育时间之间的曲线关系。结果表明,模型能较好地模拟叶面积指数的变化动态,其平均相对误差小于10%。%Leaf area index (LAI) of wheat was calculated as the product of the green leaf weight by specific leaf area, and green leaf weight as the product of its partitioning index by top weight. The curvilinear relationship between partitioning index of green leaf and physiological development time was established. The simulation results showed that the relative errors of predicted LAI were less than ten percent.

  8. Estimativa da área foliar de plantas daninhas de ambiente aquático: Eichhornia crassipes Leaf area determination of aquatic weeds: waterhyacinth

    Directory of Open Access Journals (Sweden)

    S.R. Marchi

    2003-01-01

    Full Text Available O objetivo deste trabalho foi obter equações que, através de parâmetros lineares dimensionais do limbo e do pecíolo, permitam estimar a área foliar do limbo e a área externa do pulvino de Eichhornia crassipes. Para isso, estudaram-se correlações entre a área foliar real e os parâmetros dimensionais do limbo foliar, como o comprimento ao longo da nervura principal (C e a largura máxima (L perpendicular ao eixo principal, assim como correlações entre a área externa real e o comprimento máximo (CP e o maior diâmetro transversal (DP do pulvino. Todas as equações lineares simples, geométricas ou exponenciais permitiram boas estimativas da área foliar e área externa do pecíolo. Do ponto de vista prático, sugere-se optar pela equação linear simples envolvendo os respectivos produtos do comprimento pela largura máxima, considerando o coeficiente linear igual a zero. Desse modo, a estimativa da área foliar do limbo (AF de E. crassipes pode ser feita pela fórmula AF = 0,720 (C x L; e a área externa do pulvino (AP pode ser estimada pela fórmula AP = 2,378 (CP x DP, com coeficientes de determinação (R² de 0,9716 e 0,9268, respectivamente.The objective of this study was to obtain equations that allowed to estimate the leaf area and the float petiole outward area of Eichhornia crassipes, by studying the correlations between true leaf area and leaf dimensional parameters such as leaf length in the mid rib direction (C, and maximum leaf width (L, in the mid rib perpendicular direction, as well as the correlations between true float petiole outward area and maximum length (CP and the largest transversal diameter (DP of the float petiole. All the linear, geometric and exponential equations provided good leaf area and float petiole outward area estimates. It is suggested to opt for simple linear equations involving the respective C x L, considering zero as the linear coefficient. Thus, leaf area (AF of E. crassipes can be

  9. Mapping grassland leaf area index with airborne hyperspectral imagery : a comparison study of statistical approaches and inversion of radiative transfer models

    NARCIS (Netherlands)

    Darvishzadeh, R.; Atzberger, C.; Skidmore, A.K.; Schlerf, M.

    2011-01-01

    Statistical and physical models have seldom been compared in studying grasslands. In this paper, both modeling approaches are investigated for mapping leaf area index (LAI) in a Mediterranean grassland (Majella National Park, Italy) using HyMap airborne hyperspectral images. We compared inversion of

  10. Uncertainty Analysis in the Creation of a Fine-Resolution Leaf Area Index (LAI) Reference Map for Validation of Moderate Resolution LAI Products

    Science.gov (United States)

    The validation process for a moderate resolution leaf area index (LAI) product (i.e., MODIS) involves the creation of a high spatial resolution LAI reference map (Lai-RM), which when scaled to the moderate LAI resolution (i.e., >1 km) allows for comparison and analysis with this ...

  11. Examining variation in the leaf mass per area of dominant species across two contrasting tropical gradients in light of community assembly

    NARCIS (Netherlands)

    Neyret, Margot; Bentley, Lisa Patrick; Oliveras Menor, Imma; Marimon, Beatriz S.; Marimon-Junior, Ben Hur; Almeida de Oliveira, Edmar; Barbosa Passos, Fábio; Castro Ccoscco, Rosa; Santos, dos Josias; Matias Reis, Simone; Morandi, Paulo S.; Rayme Paucar, Gloria; Robles Cáceres, Arturo; Valdez Tejeira, Yolvi; Yllanes Choque, Yovana; Salinas, Norma; Shenkin, Alexander; Asner, Gregory P.; Díaz, Sandra; Enquist, Brian J.; Malhi, Yadvinder

    2016-01-01

    Understanding variation in key functional traits across gradients in high diversity systems and the ecology of community changes along gradients in these systems is crucial in light of conservation and climate change. We examined inter- and intraspecific variation in leaf mass per area (LMA) of s

  12. Leaf area development, dry weight accumulation and solar energy conversion efficiencies of Phaseolus vulgaris L. under different soil moisture levels near Nairobi, Kenya

    NARCIS (Netherlands)

    Muniafu, M.M.; Macharia, J.N.M.; Stigter, C.J.; Coulson, G.L.

    1999-01-01

    Leaf area development, dry weight accumulation and solar energy conversion efficiencies of Phaseolus vulgaris L. cv GLP-2 under two soil moisture levels in two contrasting seasons near Nairobi, Kenya were investigated. The experiment confirms that dry weights and yields of Phaseolus vulgaris are lim

  13. 7 CFR 29.2528 - Leaf.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.2528 Section 29.2528 Agriculture Regulations...-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2528 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall describe the divided unit of a whole leaf....

  14. 7 CFR 29.3033 - Leaf.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.3033 Section 29.3033 Agriculture Regulations... Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall describe the divided unit of a whole leaf....

  15. 7 CFR 29.3525 - Leaf.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.3525 Section 29.3525 Agriculture Regulations... Type 95) § 29.3525 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall describe the divided unit of a whole leaf....

  16. 7 CFR 29.1028 - Leaf.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.1028 Section 29.1028 Agriculture Regulations... Type 92) § 29.1028 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall describe the divided unit of a whole leaf....

  17. 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.

  18. Leaf-litter microfungal community on poor fen plant debris in Torfy Lake area (Central Poland

    Directory of Open Access Journals (Sweden)

    Mateusz Wilk

    2014-06-01

    Full Text Available The purpose of this study was to initially evaluate the species diversity of microfungi growing on litter of 15 plant species occurring on the poor fen and neighbouring area of the Torfy Lake, Masovian voivodeship, Poland. The lake is located near the planned road investment (construction of the Warsaw southern express ring road S2. The place is biologically valuable as there are rare plant communities from Rhynchosporion albae alliance protected under the Habitats Directive adopted by the European Union. On the examined plant debris 73 taxa of fungi were recorded (3 basidiomycetes, 13 ascomycetes, 2 zygomycetes, 43 anamorphic ascomycetes, 12 unidentified. Two of them, Dicranidion sp. and Wentiomyces sp. are presented here as new to Poland. Among the plant species examined, the litter of Rhododendron tomentosum harbored the highest number of fungal taxa (16. The highest percents of substrate-specific microfungi (i.e. recorded only on one plant species was noted on R. tomentosum (81.3 %, and Pteridium aquilinum (75%. It is emphasized that the lake area should be protected not only because of rare plant community but also because of the uniqueness and diversity of mycobiota.

  19. Monocot leaves are eaten less than dicot leaves in tropical lowland rain forests: correlations with toughness and leaf presentation

    DEFF Research Database (Denmark)

    Grubb, P.J.; Jackson, R.V.; Barberis, I.M.

    2008-01-01

    : At six sites on four continents, estimates were made of lamina area loss from the four most recently mature leaves of focal monocots and of the nearest dicot shoot. Measurements of leaf mass per unit area, and the concentrations of water and nitrogen were made for many of the species. In Panama...... of leaf mass per unit area, or concentrations of water or nitrogen. At only one site was the increase in loss from first to fourth mature leaf significant (also large and the same in monocots and dicots), but the losses sustained during expansion were much smaller in the monocots. In the leaf-cutter ant...... insects in tropical lowland rain forest, and that the relative importance varies widely with species. The difficulties of establishing unequivocally the roles of leaf toughness and leaf folding or rolling in a given case are discussed. Key words: anti-herbivore defences, dicots, herbivory, leaf folding...

  20. Integrated plant phenotypic responses to contrasting above- and below-ground resources: key roles of specific leaf area and root mass fraction.

    Science.gov (United States)

    Freschet, Grégoire T; Swart, Elferra M; Cornelissen, Johannes H C

    2015-06-01

    Plants adapt phenotypically to different conditions of light and nutrient supply, supposedly in order to achieve colimitation of these resources. Their key variable of adjustment is the ratio of leaf area to root length, which relies on plant biomass allocation and organ morphology. We recorded phenotypic differences in leaf and root mass fractions (LMF, RMF), specific leaf area (SLA) and specific root length (SRL) of 12 herbaceous species grown in factorial combinations of high/low irradiance and fertilization treatments. Leaf area and root length ratios, and their components, were influenced by nonadditive effects between light and nutrient supply, and differences in the strength of plant responses were partly explained by Ellenberg's species values representing ecological optima. Changes in allocation were critical in plant responses to nutrient availability, as the RMF contribution to changes in root length was 2.5× that of the SRL. Contrastingly, morphological adjustments (SLA rather than LMF) made up the bulk of plant response to light availability. Our results suggest largely predictable differences in responses of species and groups of species to environmental change. Nevertheless, they stress the critical need to account for adjustments in below-ground mass allocation to understand the assembly and responses of communities in changing environments.

  1. Deriving Leaf Area Index (LAI) from multiple lidar remote sensing systems

    Science.gov (United States)

    Tang, H.; Dubayah, R.; Zhao, F.

    2012-12-01

    LAI is an important biophysical variable linking biogeochemical cycles of earth systems. Observations with passive optical remote sensing are plagued by saturation and results from different passive and active sensors are often inconsistent. Recently lidar remote sensing has been applied to derive vertical canopy structure including LAI and its vertical profile. In this research we compare LAI retrievals from three different types of lidar sensors. The study areas include the La Selva Biological Station in Costa Rica and Sierra Nevada Forest in California. We first obtain independent LAI estimates from different lidar systems including airborne lidar (LVIS), spaceborne lidar (GLAS) and ground lidar (Echidna). LAI retrievals are then evaluated between sensors as a function of scale, land cover type and sensor characteristics. We also assess the accuracy of these LAI products against ground measurements. By providing a link between ground observations, ground lidar, aircraft and space-based lidar we hope to demonstrate a path for deriving more accurate estimates of LAI on a global basis, and to provide a more robust means of validating passive optical estimates of this important variable.

  2. Effects of different potting growing media for Petunia grandiflora and Nicotiana alata Link & Otto on photosynthetic capacity, leaf area, and flowering potential

    Directory of Open Access Journals (Sweden)

    Gheorghe Cristian Popescu

    2015-03-01

    Full Text Available Petunia grandiflora Juss. and Nicotiana alata Link & Otto are two of the most widely spread plants on the market for annual potted ornamental plants. In order to identify the most adequate substrate formula we analyzed the effects of different potting growing media used for P. hybrida grandiflora 'Bravo' and N. alata 'Dinamo' on their photosynthetic capacity, leaf area, and flowering potential. Optimization of growing media formula for petunia and ornamental tobacco was performed by preparing four growing media mixing fallow soil (FS, Biolan peat (BP, acid peat (AP, leaf compost (C, and perlite (P in different proportions. The physiological potential of petunia and ornamental tobacco was investigated by photosynthesis and respiration rate and chlorophyll pigments in leaves, while the vegetative and flowering phenological stages were evaluated by number of leaves per plant, leaf area, number of flowers per plant and leaf area/flowers ratio. These measurements were significantly influenced by the different potting growing media used in this study. In the flowering stage, the highest photosynthesis rates (8.612 μmol CO2 m-2 s-1 as well as leaf area (1.766 dm² of petunias were obtained on growing media with 60% biolan peat, 30% acid peat and 10% perlite (BP60-AP30-P10. Flowering responses to growing conditions vary greatly among plants and the biggest number of ornamental tobacco flowers (22 flowers plant-1 was registered as an effect of BP60-AP30-P10 media. Growing media with the BP60-AP30-P10 formula seem to be the most adequate growth substrate to develop profitable crops for petunias and ornamental tobacco with high decorative value.

  3. Effects of treated municipal wastewater on fluctuation trend of leaf area index and quality of maize (Zea mays).

    Science.gov (United States)

    Mousavi, Sayed Roholla; Galavi, Mohammad; Eskandari, Hamdollah

    2013-01-01

    The effect of primary-treated municipal wastewater (TMWW) on the leaf area index (LAI) and quality of maize (Zea mays) was studied in comparison to the clean irrigation water (control). The experiment was based on a randomized block design with four replicates, and it was conducted in a field experiment in Aligoudarz (Iran). Irrigation was applied with five different methods as treatments: T1: irrigation with clean water during whole growing period (control); T2: 75% clean water and 25% TMWW; T3: 50% clean water and 50% TMWW; T4: 25% clean water and 75% TMWW; T5: irrigation with TMWW during whole growing period. Results showed that irrigation with TMWW had a significant positive impact on all characters compared with the control. Maximum LAI was yielded on the 80th day after emergence in T4. Use of TMWW increased seed oil to 5.85%, which was 29.2% more than that in the control. Maximum values for percentage of protein, total dry matter and phosphorus concentration were obtained in T5. Maximum zinc concentration (15.93 mg kg(-1)) was obtained in T4; it was 8% more than the control. According to the results there was no significant difference in treatment T4 and T5.

  4. Estimation of leaf area index using ground-based remote sensed NDVI measurements: validation and comparison with two indirect techniques

    Energy Technology Data Exchange (ETDEWEB)

    Pontailler, J.-Y. [Univ. Paris-Sud XI, Dept. d' Ecophysiologie Vegetale, Orsay Cedex (France); Hymus, G.J.; Drake, B.G. [Smithsonian Environmental Research Center, Kennedy Space Center, Florida (United States)

    2003-06-01

    This study took place in an evergreen scrub oak ecosystem in Florida. Vegetation reflectance was measured in situ with a laboratory-made sensor in the red (640-665 nm) and near-infrared (750-950 nm) bands to calculate the normalized difference vegetation index (NDVI) and derive the leaf area index (LAI). LAI estimates from this technique were compared with two other nondestructive techniques, intercepted photosynthetically active radiation (PAR) and hemispherical photographs, in four contrasting 4 m{sup 2} plots in February 2000 and two 4m{sup 2} plots in June 2000. We used Beer's law to derive LAI from PAR interception and gap fraction distribution to derive LAI from photographs. The plots were harvested manually after the measurements to determine a 'true' LAI value and to calculate a light extinction coefficient (k). The technique based on Beer's law was affected by a large variation of the extinction coefficient, owing to the larger impact of branches in winter when LAI was low. Hemispherical photographs provided satisfactory estimates, slightly overestimated in winter because of the impact of branches or underestimated in summer because of foliage clumping. NDVI provided the best fit, showing only saturation in the densest plot (LAI = 3.5). We conclude that in situ measurement of NDVI is an accurate and simple technique to nondestructively assess LAI in experimental plots or in crops if saturation remains acceptable. (author)

  5. Performance Evaluation of Machine Learning Methods for Leaf Area Index Retrieval from Time-Series MODIS Reflectance Data

    Science.gov (United States)

    Wang, Tongtong; Xiao, Zhiqiang; Liu, Zhigang

    2017-01-01

    Leaf area index (LAI) is an important biophysical parameter and the retrieval of LAI from remote sensing data is the only feasible method for generating LAI products at regional and global scales. However, most LAI retrieval methods use satellite observations at a specific time to retrieve LAI. Because of the impacts of clouds and aerosols, the LAI products generated by these methods are spatially incomplete and temporally discontinuous, and thus they cannot meet the needs of practical applications. To generate high-quality LAI products, four machine learning algorithms, including back-propagation neutral network (BPNN), radial basis function networks (RBFNs), general regression neutral networks (GRNNs), and multi-output support vector regression (MSVR) are proposed to retrieve LAI from time-series Moderate Resolution Imaging Spectroradiometer (MODIS) reflectance data in this study and performance of these machine learning algorithms is evaluated. The results demonstrated that GRNNs, RBFNs, and MSVR exhibited low sensitivity to training sample size, whereas BPNN had high sensitivity. The four algorithms performed slightly better with red, near infrared (NIR), and short wave infrared (SWIR) bands than red and NIR bands, and the results were significantly better than those obtained using single band reflectance data (red or NIR). Regardless of band composition, GRNNs performed better than the other three methods. Among the four algorithms, BPNN required the least training time, whereas MSVR needed the most for any sample size. PMID:28045443

  6. Leaf Area Index Retrieval Combining HJ1/CCD and Landsat8/OLI Data in the Heihe River Basin, China

    Directory of Open Access Journals (Sweden)

    Jing Zhao

    2015-05-01

    Full Text Available The primary restriction on high resolution remote sensing data is the limit observation frequency. Using a network of multiple sensors is an efficient approach to increase the observations in a specific period. This study explores a leaf area index (LAI inversion method based on a 30 m multi-sensor dataset generated from HJ1/CCD and Landsat8/OLI, from June to August 2013 in the middle reach of the Heihe River Basin, China. The characteristics of the multi-sensor dataset, including the percentage of valid observations, the distribution of observation angles and the variation between different sensor observations, were analyzed. To reduce the possible discrepancy between different satellite sensors on LAI inversion, a quality control system for the observations was designed. LAI is retrieved from the high quality of single-sensor observations based on a look-up table constructed by a unified model. The averaged LAI inversion over a 10-day period is set as the synthetic LAI value. The percentage of valid LAI inversions increases significantly from 6.4% to 49.7% for single-sensors to 75.9% for multi-sensors. LAI retrieved from the multi-sensor dataset show good agreement with the field measurements. The correlation coefficient (R2 is 0.90, and the average root mean square error (RMSE is 0.42. The network of multiple sensors with 30 m spatial resolution can generate LAI products with reasonable accuracy and meaningful temporal resolution.

  7. Improving winter leaf area index estimation in coniferous forests and its significance in estimating the land surface albedo

    Science.gov (United States)

    Wang, Rong; Chen, Jing M.; Pavlic, Goran; Arain, Altaf

    2016-09-01

    Winter leaf area index (LAI) of evergreen coniferous forests exerts strong control on the interception of snow, snowmelt and energy balance. Simulation of winter LAI and associated winter processes in land surface models is challenging. Retrieving winter LAI from remote sensing data is difficult due to cloud contamination, poor illumination, lower solar elevation and higher radiation reflection by snow background. Underestimated winter LAI in evergreen coniferous forests is one of the major issues limiting the application of current remote sensing LAI products. It has not been fully addressed in past studies in the literature. In this study, we used needle lifespan to correct winter LAI in a remote sensing product developed by the University of Toronto. For the validation purpose, the corrected winter LAI was then used to calculate land surface albedo at five FLUXNET coniferous forests in Canada. The RMSE and bias values for estimated albedo were 0.05 and 0.011, respectively, for all sites. The albedo map over coniferous forests across Canada produced with corrected winter LAI showed much better agreement with the GLASS (Global LAnd Surface Satellites) albedo product than the one produced with uncorrected winter LAI. The results revealed that the corrected winter LAI yielded much greater accuracy in simulating land surface albedo, making the new LAI product an improvement over the original one. Our study will help to increase the usability of remote sensing LAI products in land surface energy budget modeling.

  8. Effects of controlled-release fertilizer on leaf area index and fruit yield in high-density soilless tomato culture using low node-order pinching.

    Directory of Open Access Journals (Sweden)

    Takafumi Kinoshita

    Full Text Available To further development of a simplified fertigation system using controlled-release fertilizers (CRF, we investigated the effects of differing levels of fertilizers and plant density on leaf area index (LAI, fruit yields, and nutrient use in soilless tomato cultures with low node-order pinching and high plant density during spring-summer (SS, summer-fall (SF, and fall-winter (FW seasons. Plants were treated with 1 of 3 levels of CRF in a closed system, or with liquid fertilizer (LF with constant electrical conductivity (EC in a drip-draining system. Two plant densities were examined for each fertilizer treatment. In CRF treatments, LAI at pinching increased linearly with increasing nutrient supply for all cropping seasons. In SS, both light interception by plant canopy at pinching and total marketable fruit yield increased linearly with increasing LAI up to 6 m(2 · m(-2; the maximization point was not reached for any of the treatments. In FW, both light interception and yield were maximized at an LAI of approximately 4. These results suggest that maximizing the LAI in SS and FW to the saturation point for light interception is important for increasing yield. In SF, however, the yield maximized at an LAI of approximately 3, although the light interception linearly increased with increasing LAI, up to 4.5. According to our results, the optimal LAI at pinching may be 6 in SS, 3 in SF, and 4 in FW. In comparing LAI values with similar fruit yield, we found that nutrient supply was 32-46% lower with the CRF method than with LF. In conclusion, CRF application in a closed system enables growers to achieve a desirable LAI to maximize fruit yield with a regulated amount of nutrient supply per unit area. Further, the CRF method greatly reduced nutrient use without decreasing fruit yield at similar LAIs, as compared to the LF method.

  9. Effects of controlled-release fertilizer on leaf area index and fruit yield in high-density soilless tomato culture using low node-order pinching.

    Science.gov (United States)

    Kinoshita, Takafumi; Yano, Takayoshi; Sugiura, Makoto; Nagasaki, Yuji

    2014-01-01

    To further development of a simplified fertigation system using controlled-release fertilizers (CRF), we investigated the effects of differing levels of fertilizers and plant density on leaf area index (LAI), fruit yields, and nutrient use in soilless tomato cultures with low node-order pinching and high plant density during spring-summer (SS), summer-fall (SF), and fall-winter (FW) seasons. Plants were treated with 1 of 3 levels of CRF in a closed system, or with liquid fertilizer (LF) with constant electrical conductivity (EC) in a drip-draining system. Two plant densities were examined for each fertilizer treatment. In CRF treatments, LAI at pinching increased linearly with increasing nutrient supply for all cropping seasons. In SS, both light interception by plant canopy at pinching and total marketable fruit yield increased linearly with increasing LAI up to 6 m(2) · m(-2); the maximization point was not reached for any of the treatments. In FW, both light interception and yield were maximized at an LAI of approximately 4. These results suggest that maximizing the LAI in SS and FW to the saturation point for light interception is important for increasing yield. In SF, however, the yield maximized at an LAI of approximately 3, although the light interception linearly increased with increasing LAI, up to 4.5. According to our results, the optimal LAI at pinching may be 6 in SS, 3 in SF, and 4 in FW. In comparing LAI values with similar fruit yield, we found that nutrient supply was 32-46% lower with the CRF method than with LF. In conclusion, CRF application in a closed system enables growers to achieve a desirable LAI to maximize fruit yield with a regulated amount of nutrient supply per unit area. Further, the CRF method greatly reduced nutrient use without decreasing fruit yield at similar LAIs, as compared to the LF method.

  10. EnviroAtlas - Potential Wetland Areas - Contiguous United States

    Data.gov (United States)

    U.S. Environmental Protection Agency — The EnviroAtlas Potential Wetland Areas (PWA) dataset shows potential wetland areas at 30-meter resolution. Beginning two centuries ago, many wetlands were turned...

  11. How Universal Is the Relationship between Remotely Sensed Vegetation Indices and Crop Leaf Area Index? A Global Assessment

    Directory of Open Access Journals (Sweden)

    Yanghui Kang

    2016-07-01

    Full Text Available Leaf Area Index (LAI is a key variable that bridges remote sensing observations to the quantification of agroecosystem processes. In this study, we assessed the universality of the relationships between crop LAI and remotely sensed Vegetation Indices (VIs. We first compiled a global dataset of 1459 in situ quality-controlled crop LAI measurements and collected Landsat satellite images to derive five different VIs including Simple Ratio (SR, Normalized Difference Vegetation Index (NDVI, two versions of the Enhanced Vegetation Index (EVI and EVI2, and Green Chlorophyll Index (CIGreen. Based on this dataset, we developed global LAI-VI relationships for each crop type and VI using symbolic regression and Theil-Sen (TS robust estimator. Results suggest that the global LAI-VI relationships are statistically significant, crop-specific, and mostly non-linear. These relationships explain more than half of the total variance in ground LAI observations (R2 > 0.5, and provide LAI estimates with RMSE below 1.2 m2/m2. Among the five VIs, EVI/EVI2 are the most effective, and the crop-specific LAI-EVI and LAI-EVI2 relationships constructed by TS, are robust when tested by three independent validation datasets of varied spatial scales. While the heterogeneity of agricultural landscapes leads to a diverse set of local LAI-VI relationships, the relationships provided here represent global universality on an average basis, allowing the generation of large-scale spatial-explicit LAI maps. This study contributes to the operationalization of large-area crop modeling and, by extension, has relevance to both fundamental and applied agroecosystem research.

  12. Stillwater Wildlife Management Area : Grasslands Management Plan : North Marsh Unit

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This plan is designed to serve as the initial Fish and Wildlife Service habitat management proposal for the North Marsh grazing unit of Stillwater National Wildlife...

  13. Classification of evapotranspiration units in major discharge areas of Death Valley regional

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The raster-based classification of evapotranspiration (ET) units is for nine major discharge areas in the Death Valley regional flow system. The ET units delineate...

  14. Modelos para estimativa da área foliar de Curcuma alismatifolia e Vurcuma zedoaria Leaf area prediction models for Curcuma alismatifolia and Curcuma zedoaria

    Directory of Open Access Journals (Sweden)

    Ana Christina Rossini Pinto

    2008-01-01

    Full Text Available O presente estudo determina modelos para estimativa da área foliar de Curcuma alismatifolia e de Curcuma zedoaria. Para utilização destas espécies como ornamentais, é necessário o estabelecimento de técnicas de produção adequadas. Assim, a determinação da área foliar é importante, pois é usada para avaliar a resposta da planta a fatores ambientais e técnicas culturais. O uso de modelos para estimar a área foliar é um método simples, de boa precisão e não destrutivo. No estádio de floração foram coletadas cem folhas de C.alismatifolia ('Pink' e 'White' e de C.zedoaria. Determinaram-se o comprimento (C e a largura (L máximos e a área foliar real (AFR, com auxílio de integrador de área foliar (LI-3100. Estudaram-se as relações entre a AFR e o C, L e CL (produto do comprimento pela largura da folha, por meio de modelos de regressão linear. Os modelos AFR = 0,59048 CL (C.alismatifolia 'Pink', AFR = 6,08410 + 0,52162 CL (C.alismatifolia 'White' e AFR = 0,70233 CL (C.zedoaria são estatisticamente adequados para estimar a área foliar real.The present work establishes regression models to estimate leaf area of Curcuma alismatifolia and Curcuma zedoaria. To use these of species as ornamental plants is necessary to establish adequate cultivation techniques. Thus, the determination of leaf area is very important, once it is used to evaluate plant response to environmental factors and crop techniques. The use of prediction models to estimate leaf area is a simple, accurate and nondestructive method. At the stage of flowering, a hundred leaves of C.alismatifolia ('Pink' and 'White' and C.zedoaria were collected for each species and cultivar. Maximum length (L, maximum width (W and real leaf area (RLA were measured with a leaf area meter (LI-3100. The relation between RLA and the L, W and the product of length by width (LW, was studied through linear regression models. The models RLA = 0.59048 LW (C.alismatifolia 'Pink', RLA = 6

  15. Estimação da área foliar do algodoeiro por meio de dimensões e massa das folhas Cotton leaf area estimates based on leaf dimensions and dry mass methods

    Directory of Open Access Journals (Sweden)

    José Eduardo B. A. Monteiro

    2005-01-01

    Full Text Available O objetivo deste trabalho foi avaliar dois métodos de estimação da área foliar do algodoeiro, por meio de suas dimensões e massa seca das folhas. Foram utilizadas as cultivares IAC 23 e Coodetec 401. No método que utilizou dimensões, as folhas do algodoeiro foram agrupadas em novas, cordiformes e maduras. Para cada tipo de folha, de cada cultivar, foi determinado um fator de forma (FF por meio de análise de regressão entre o produto do comprimento (C pela largura (L e a área das folhas. Avaliou-se a correlação entre a área foliar estimada pelo fator FF e sua medida direta, utilizando-se dados independentes. Testou-se, ainda, um fator único para cada cultivar, independente do estádio da cultura e, também, um fator geral para as duas cultivares. No método que utilizou a massa seca, as folhas foram agrupadas em novas e maduras. Determinou-se o fator de massa seca (FM por meio da análise de regressão entre a massa seca de folhas e respectivas áreas foliares. Em seguida, avaliou-se a correlação entre dados estimados por FM e dados medidos de forma direta, em nova amostra. O método das dimensões é viável para a estimação de área foliar do algodoeiro, por apresentar boa precisão e exatidão, com r² entre 0,71 e 0,98 e com coeficiente angular da regressão entre 0,87 e 0,95. No entanto, pelo método da massa seca, observaram-se precisão e exatidão maiores, com r² entre 0,94 e 0,98, e coeficiente angular da regressão entre 0,97 e 1,00, com a vantagem de ser menos trabalhoso.The objective of this study was to evaluate two different methods to estimate cotton leaf area (LA, based on leaf dimensions (length - L and width - W and leaf dry mass (DM. Two cultivars, IAC 23 and Coodetec 401, were used. For leaf dimensions method, leaves were classified by age: young, heart-shape, and mature. For each age class, a leaf shape factor (LSF was obtained by simple linear regression between L*W and LA. For leaf dry mass method, leaves

  16. Variation Character of Grain Yield per Unit Area in Main Grain-producing Area of Northeast China

    Institute of Scientific and Technical Information of China (English)

    CHENG Yeqing; ZHANG Pingyu; ZHANG Huimin

    2007-01-01

    Based on the surveys and the statistic data during 1980-2003, the variation character of grain yield per unit area in Northeast China and its main factors have been discussed by the methods of statistics and grey correlation analysis. The results show that: 1) the grain yield per unit area has been taking on an increasing trend in the recent 20 years. It increased from 2519.80kg/ha in 1980 to 4216.11 kg/ha in 2003, with an increasing rate of 67.32%; 2) the variation of grain yield per unit area is considerably prominent and its range is also very great, with the maximal increase rate of 42.59% and maximal decrease rate of 21.13%, respectively, which are far above the whole Chinese average level; 3) the variation of main crops' yield per unit area is remarkable, which takes on the character that the yield of corn is much higher than that of soybean and rice; and 4) the grey correlation analysis shows that the most important factors impacting the variation of grain yield per unit area are the total power of agricultural machinery, the consumption of chemical fertilizer and effective irrigated area. However, the influence of natural disaster and income level should not be ignored. Effective ways to improve grain yield per unit area are to construct farmland improvement groundwork, reclaim the middle- and low-yield farmland, etc.

  17. Dose per unit area - a study of elicitation of nickel allergy

    DEFF Research Database (Denmark)

    Fischer, Louise Arup; Menné, Torkil; Johansen, Jeanne Duus

    2007-01-01

    with a patch test and a repeated open application test (ROAT). Nickel was applied on small and large areas. The varying parameters were area, total dose and dose per unit area. RESULTS: In the patch test, at a low concentration [15 microg nickel (microg Ni)/cm(2)], there were significantly higher scores...... concentrations, even though the same dose per unit area is applied.......BACKGROUND: Experimental sensitization depends upon the amount of allergen per unit skin area and is largely independent of the area size. OBJECTIVES: This study aimed at testing if this also applies for elicitation of nickel allergy. PATIENTS/METHODS: 20 nickel allergic individuals were tested...

  18. Debris Control at Hydraulic Structures in Selected Areas of the United States and Europe

    Science.gov (United States)

    2007-11-02

    Selected Areas of the United States and Europe by N. Wallerstein , C. R. Thome, University of Nottingham S. R. Abt, Colorado State University Approved...December 1997 Debris Control at Hydraulic Structures in Selected Areas of the United States and Europe by N. Wallerstein , C. R. Thome Department... Wallerstein , N. Debris control at hydraulic structures in selected areas of the United States and Europe / by N. Wallerstein , C.R. Thome, S.R. Abt

  19. Specific leaf areas of the tank bromeliad Guzmania monostachia perform distinct functions in response to water shortage.

    Science.gov (United States)

    Freschi, Luciano; Takahashi, Cassia Ayumi; Cambui, Camila Aguetoni; Semprebom, Thais Ribeiro; Cruz, Aline Bertinatto; Mioto, Paulo Tamoso; de Melo Versieux, Leonardo; Calvente, Alice; Latansio-Aidar, Sabrina Ribeiro; Aidar, Marcos Pereira Marinho; Mercier, Helenice

    2010-05-01

    Leaves comprise most of the vegetative body of tank bromeliads and are usually subjected to strong longitudinal gradients. For instance, while the leaf base is in contact with the water accumulated in the tank, the more light-exposed middle and upper leaf sections have no direct access to this water reservoir. Therefore, the present study attempted to investigate whether different leaf portions of Guzmania monostachia, a tank-forming C(3)-CAM bromeliad, play distinct physiological roles in response to water shortage, which is a major abiotic constraint in the epiphytic habitat. Internal and external morphological features, relative water content, pigment composition and the degree of CAM expression were evaluated in basal, middle and apical leaf portions in order to allow the establishment of correlations between the structure and the functional importance of each leaf region. Results indicated that besides marked structural differences, a high level of functional specialization is also present along the leaves of this bromeliad. When the tank water was depleted, the abundant hydrenchyma of basal leaf portions was the main reservoir for maintaining a stable water status in the photosynthetic tissues of the apical region. In contrast, the CAM pathway was intensified specifically in the upper leaf section, which is in agreement with the presence of features more suitable for the occurrence of photosynthesis at this portion. Gas exchange data indicated that internal recycling of respiratory CO(2) accounted for virtually all nighttime acid accumulation, characterizing a typical CAM-idling pathway in the drought-exposed plants. Altogether, these data reveal a remarkable physiological complexity along the leaves of G. monostachia, which might be a key adaptation to the intermittent water supply of the epiphytic niche. Copyright 2009 Elsevier GmbH. All rights reserved.

  20. Do the energy fluxes and surface conductance of boreal coniferous forests in Europe scale with leaf area?

    Science.gov (United States)

    Launiainen, Samuli; Katul, Gabriel G; Kolari, Pasi; Lindroth, Anders; Lohila, Annalea; Aurela, Mika; Varlagin, Andrej; Grelle, Achim; Vesala, Timo

    2016-12-01

    Earth observing systems are now routinely used to infer leaf area index (LAI) given its significance in spatial aggregation of land surface fluxes. Whether LAI is an appropriate scaling parameter for daytime growing season energy budget, surface conductance (Gs ), water- and light-use efficiency and surface-atmosphere coupling of European boreal coniferous forests was explored using eddy-covariance (EC) energy and CO2 fluxes. The observed scaling relations were then explained using a biophysical multilayer soil-vegetation-atmosphere transfer model as well as by a bulk Gs representation. The LAI variations significantly alter radiation regime, within-canopy microclimate, sink/source distributions of CO2 , H2 O and heat, and forest floor fluxes. The contribution of forest floor to ecosystem-scale energy exchange is shown to decrease asymptotically with increased LAI, as expected. Compared with other energy budget components, dry-canopy evapotranspiration (ET) was reasonably 'conservative' over the studied LAI range 0.5-7.0 m(2) m(-2) . Both ET and Gs experienced a minimum in the LAI range 1-2 m(2) m(-2) caused by opposing nonproportional response of stomatally controlled transpiration and 'free' forest floor evaporation to changes in canopy density. The young forests had strongest coupling with the atmosphere while stomatal control of energy partitioning was strongest in relatively sparse (LAI ~2 m(2) m(-2) ) pine stands growing on mineral soils. The data analysis and model results suggest that LAI may be an effective scaling parameter for net radiation and its partitioning but only in sparse stands (LAI forests, any LAI dependency varies with physiological traits such as light-saturated water-use efficiency. The results suggest that incorporating species traits and site conditions are necessary when LAI is used in upscaling energy exchanges of boreal coniferous forests. © 2016 John Wiley & Sons Ltd.

  1. Retrieval of Leaf Area Index (LAI and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR from VIIRS Time-Series Data

    Directory of Open Access Journals (Sweden)

    Zhiqiang Xiao

    2016-04-01

    Full Text Available Long-term high-quality global leaf area index (LAI and fraction of absorbed photosynthetically active radiation (FAPAR products are urgently needed for the study of global change, climate modeling, and many other problems. As the successor of the Moderate Resolution Imaging Spectroradiometer (MODIS sensor, the Visible Infrared Imaging Radiometer Suite (VIIRS will continue to provide global environmental measurements. This paper aims to generate longer time series Global LAnd Surface Satellite (GLASS LAI and FAPAR products after the era of the MODIS sensor. To ensure spatial and temporal consistencies between GLASS LAI/FAPAR values retrieved from different satellite observations, the GLASS LAI/FAPAR retrieval algorithms were adapted in this study to retrieve LAI and FAPAR values from VIIRS surface reflectance time-series data. After reprocessing of the VIIRS surface reflectance to remove remaining effects of cloud contamination and other factors, a database generated from the GLASS LAI product and the reprocessed VIIRS surface reflectance for all Benchmark Land Multisite Analysis and Intercomparison of Products (BELMANIP sites was used to train general regression neural networks (GRNNs. The reprocessed VIIRS surface reflectance data from an entire year were entered into the trained GRNNs to estimate the one-year LAI values, which were then used to calculate FAPAR values. A cross-comparison indicates that the LAI and FAPAR values retrieved from VIIRS surface reflectance were generally consistent with the GLASS, MODIS and Geoland2/BioPar version 1 (GEOV1 LAI/FAPAR values in their spatial patterns. The LAI/FAPAR values retrieved from VIIRS surface reflectance achieved good agreement with the GLASS LAI/FAPAR values (R2 = 0.8972 and RMSE = 0.3054; and R2 = 0.9067 and RMSE = 0.0529, respectively. However, validation of the LAI and FAPAR values derived from VIIRS reflectance data is now limited by the scarcity of LAI/FAPAR ground measurements.

  2. Evaluation and Intercomparison of MODIS and GEOV1 Global Leaf Area Index Products over Four Sites in North China

    Directory of Open Access Journals (Sweden)

    Zhenwang Li

    2015-03-01

    Full Text Available This study investigated the performances of the Moderate Resolution Imaging Spectroradiometer (MODIS and GEOLAND2 Version 1 (GEOV1 Leaf Area Index (LAI products using ground measurements and LAI reference maps over four sites in North China for 2011–2013. The Terra + Aqua MODIS and Terra MODIS LAI retrieved by the main algorithm and GEOV1 LAI within the valid range were evaluated and intercompared using LAI reference maps to assess their uncertainty and seasonal variability The results showed that GEOV1 LAI is the most similar product with the LAI reference maps (R2 = 0.78 and RMSE = 0.59. The MODIS products performed well for biomes with low LAI values, but considerable uncertainty arose when the LAI was larger than 3. Terra + Aqua MODIS (R2 = 0.72 and RMSE = 0.68 was slightly more accurate than Terra MODIS (R2 = 0.57 and RMSE = 0.90 for producing slightly more successful observations. Both MODIS and GEOV1 products effectively followed the seasonal trajectory of the reference maps, and GEOV1 exhibited a smoother seasonal trajectory than MODIS. MODIS anomalies mainly occurred during summer and likely occurred because of surface reflectance uncertainty, shorter temporal resolutions and inconsistency between simulated and MODIS surface reflectances. This study suggests that further improvements of the MODIS LAI products should focus on finer algorithm inputs and improved seasonal variation modeling of MODIS observations. Future field work considering finer biome maps and better generation of LAI reference maps is still needed.

  3. Estimation of leaf area index using an angular vegetation index based on in situ measurements and CHRIS/PROBA data

    Science.gov (United States)

    Wang, Lijuan; Zhang, Guimin; Lin, Hui; Liang, Liang; Niu, Zheng

    2016-06-01

    The Normalized Difference Vegetation Index (NDVI) is widely used for Leaf Area Index (LAI) estimation. It is well documented that the NDVI is extremely subject to the saturation problem when LAI reaches a high value. A new multi-angular vegetation index, the Hotspot-darkspot Difference Vegetation Index (HDVI) is proposed to estimate the high density LAI. The HDVI, defined as the difference between the hot and dark spot NDVI, relative to the dark spot NDVI, was proposed based on the Analytical two-layer Canopy Reflectance Model (ACRM) model outputs. This index is validated using both in situ experimental data in wheat and data from the multi-angular optical Compact High-Resolution Imaging Spectrometer (CHRIS) satellite. Both indices, the Hotspot-Darkspot Index (HDS) and the NDVI were also selected to analyze the relationship with LAI, and were compared with new index HDVI. The results show that HDVI is an appropriate proxy of LAI with higher determination coefficients (R2) for both the data from the in situ experiment (R2=0.7342, RMSE=0.0205) and the CHRIS data (R2=0.7749, RMSE=0.1013). Our results demonstrate that HDVI can make better the occurrence of saturation limits with the information of multi-angular observation, and is more appropriate for estimating LAI than either HDS or NDVI at high LAI values. Although the new index needs further evaluation, it also has the potential under the condition of dense canopies. It provides the effective improvement to the NDVI and other vegetation indices that are based on the red and NIR spectral bands.

  4. Estimating winter wheat biomass by assimilating leaf area index derived from fusion of Landsat-8 and MODIS data

    Science.gov (United States)

    Dong, Taifeng; Liu, Jiangui; Qian, Budong; Zhao, Ting; Jing, Qi; Geng, Xiaoyuan; Wang, Jinfei; Huffman, Ted; Shang, Jiali

    2016-07-01

    A sufficient number of satellite acquisitions in a growing season are essential for deriving agronomic indicators, such as green leaf area index (GLAI), to be assimilated into crop models for crop productivity estimation. However, for most high resolution orbital optical satellites, it is often difficult to obtain images frequently due to their long revisit cycles and unfavorable weather conditions. Data fusion algorithms, such as the Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM) and the Enhanced STARFM (ESTARFM), have been developed to generate synthetic data with high spatial and temporal resolution to address this issue. In this study, we evaluated the approach of assimilating GLAI into the Simple Algorithm for Yield Estimation model (SAFY) for winter wheat biomass estimation. GLAI was estimated using the two-band Enhanced Vegetation Index (EVI2) derived from data acquired by the Operational Land Imager (OLI) onboard the Landsat-8 and a fusion dataset generated by blending the Moderate-Resolution Imaging Spectroradiometer (MODIS) data and the OLI data using the STARFM and ESTARFM models. The fusion dataset had the temporal resolution of the MODIS data and the spatial resolution of the OLI data. Key parameters of the SAFY model were optimised through assimilation of the estimated GLAI into the crop model using the Shuffled Complex Evolution-University of Arizona (SCE-UA) algorithm. A good agreement was achieved between the estimated and field measured biomass by assimilating the GLAI derived from the OLI data (GLAIL) alone (R2 = 0.77 and RMSE = 231 g m-2). Assimilation of GLAI derived from the fusion dataset (GLAIF) resulted in a R2 of 0.71 and RMSE of 193 g m-2 while assimilating the combination of GLAIL and GLAIF led to further improvements (R2 = 0.76 and RMSE = 176 g m-2). Our results demonstrated the potential of using the fusion algorithms to improve crop growth monitoring and crop productivity estimation when the number of high resolution

  5. Evaluation of a Phenology-Dependent Response Method for Estimating Leaf Area Index of Rice Across Climate Gradients

    Directory of Open Access Journals (Sweden)

    Bora Lee

    2016-12-01

    Full Text Available Accurate estimate of the seasonal leaf area index (LAI in croplands is required for understanding not only intra- and inter-annual crop development, but also crop management. Lack of consideration in different growth phases in the relationship between LAI and vegetation indices (VI often results in unsatisfactory estimation in the seasonal course of LAI. In this study, we partitioned the growing season into two phases separated by maximum VI ( VI max and applied the general regression model to the data gained from two phases. As an alternative method to capture the influence of seasonal phenological development on the LAI-VI relationship, we developed a consistent development curve method and compared its performance with the general regression approaches. We used the Normalized Difference VI (NDVI and the Enhanced VI (EVI from the rice paddy sites in Asia (South Korea and Japan and Europe (Spain to examine its applicability across different climate conditions and management cycles. When the general regression method was used, separating the season into two phases resulted in no better estimation than the estimation obtained with the entire season observation due to an abrupt change in seasonal LAI occurring during the transition between the before and after VI max . The consistent development curve method reproduced the seasonal patterns of LAI from both NDVI and EVI across all sites better than the general regression method. Despite less than satisfactory estimation of a local LAI max , the consistent development curve method demonstrates improvement in estimating the seasonal course of LAI. The method can aid in providing accurate seasonal LAI as an input into ecological process-based models.

  6. Total belowground carbon flux in subalpine forests is related to leaf area index, soil nitrogen, and tree height

    Science.gov (United States)

    Berryman, Erin Michele; Ryan, Michael G.; Bradford, John B.; Hawbaker, Todd J.; Birdsey, R.

    2016-01-01

    In forests, total belowground carbon (C) flux (TBCF) is a large component of the C budget and represents a critical pathway for delivery of plant C to soil. Reducing uncertainty around regional estimates of forest C cycling may be aided by incorporating knowledge of controls over soil respiration and TBCF. Photosynthesis, and presumably TBCF, declines with advancing tree size and age, and photosynthesis increases yet C partitioning to TBCF decreases in response to high soil fertility. We hypothesized that these causal relationships would result in predictable patterns of TBCF, and partitioning of C to TBCF, with natural variability in leaf area index (LAI), soil nitrogen (N), and tree height in subalpine forests in the Rocky Mountains, USA. Using three consecutive years of soil respiration data collected from 22 0.38-ha locations across three 1-km2 subalpine forested landscapes, we tested three hypotheses: (1) annual soil respiration and TBCF will show a hump-shaped relationship with LAI; (2) variability in TBCF unexplained by LAI will be related to soil nitrogen (N); and (3) partitioning of C to TBCF (relative to woody growth) will decline with increasing soil N and tree height. We found partial support for Hypothesis 1 and full support for Hypotheses 2 and 3. TBCF, but not soil respiration, was explained by LAI and soil N patterns (r2 = 0.49), and the ratio of annual TBCF to TBCF plus aboveground net primary productivity (ANPP) was related to soil N and tree height (r2 = 0.72). Thus, forest C partitioning to TBCF can vary even within the same forest type and region, and approaches that assume a constant fraction of TBCF relative to ANPP may be missing some of this variability. These relationships can aid with estimates of forest soil respiration and TBCF across landscapes, using spatially explicit forest data such as national inventories or remotely sensed data products.

  7. Dynamics of Leaf Mass, Leaf Area and Element Retranslocation Efficiency During Leaf Senescence in Phyllostachys pubescens%毛竹叶片衰老过程的叶重量、叶面积及元素内吸收率的动态

    Institute of Scientific and Technical Information of China (English)

    林益明; 彭在清; 林鹏

    2004-01-01

    Dynamics of leaf mass (LM), leaf area (LA) and element retranslocation efficiency during leaf senescence was investigated in Phyllostachys pubescens Mazel ex H. de Lehaie in Yongchun, Fujian,China. Comparison of differences in element retranslocation efficiencies (RE) based on per gram leaf dry weight, per leaf and per LA during leaf senescence was carried out. With leaf senescence, the mean decreases of LM, LA and specific leaf mass (SLM) were 19.55%, 15.16% and 5.07%, respectively. The seasonal changes in decrease percentage of LM and LA were similar, indicating that certain mass to area ratios occurred in P. pubescens leaves. On different bases, RE of N and K was positive, while RE of Ca was negative, suggesting that with leaf senescence, N and K were translocated out of senescing leaves to other parts of plant, while Ca accumulated in senescing leaves. For the mean RE of N, P, K, Ca and Mg on different bases, the rank order was RE2 (mg element/leaf)>RE3 (mg element/cm2 leaf)>RE1 (mg element/g), therefore, RE on the basis of leaf weight or LA would be underestimated.%对福建永春毛竹(Phyllostachyspubescens Mazel ex H.de Lehaie)叶片衰老过程的叶重量、叶面积及元素内吸收率的动态进行了研究,并对元素内吸收率RE1(以元素的干重含量为计算单位,mg/g)、RE2(以单位叶片的元素含量为计算单位,mg/leaf)以及RE3(以单位叶面积的元素含量为计算单位,mg/cm2)进行了比较.叶片衰老过程中,平均叶重量、叶面积及比叶重分别下降了19.55%、15.16%和5.07%.叶重量与叶面积下降百分率的季节变化趋势一致,说明毛竹叶片存在一定的重量与面积比率.在不同的元素内吸收率比较中,N和K的元素内吸收率均为正,Ca均为负,表明叶片衰老过程中N和K的元素含量从衰老叶片中转移至植株的其他部位,而Ca在老叶中累积.N、P、K、Ca和Mg5种元素平均的元素内吸收率高低顺序均为RE2>RE3>RE1,反映出以元素

  8. Multi-Spectral Imaging from an Unmanned Aerial Vehicle Enables the Assessment of Seasonal Leaf Area Dynamics of Sorghum Breeding Lines.

    Science.gov (United States)

    Potgieter, Andries B; George-Jaeggli, Barbara; Chapman, Scott C; Laws, Kenneth; Suárez Cadavid, Luz A; Wixted, Jemima; Watson, James; Eldridge, Mark; Jordan, David R; Hammer, Graeme L

    2017-01-01

    Genetic improvement in sorghum breeding programs requires the assessment of adaptation traits in small-plot breeding trials across multiple environments. Many of these phenotypic assessments are made by manual measurement or visual scoring, both of which are time consuming and expensive. This limits trial size and the potential for genetic gain. In addition, these methods are typically restricted to point estimates of particular traits, such as leaf senescence or flowering and do not capture the dynamic nature of crop growth. In water-limited environments in particular, information on leaf area development over time would provide valuable insight into water use and adaptation to water scarcity during specific phenological stages of crop development. Current methods to estimate plant leaf area index (LAI) involve destructive sampling and are not practical in breeding. Unmanned aerial vehicles (UAV) and proximal-sensing technologies open new opportunities to assess these traits multiple times in large small-plot trials. We analyzed vegetation-specific crop indices obtained from a narrowband multi-spectral camera on board a UAV platform flown over a small pilot trial with 30 plots (10 genotypes randomized within 3 blocks). Due to variable emergence we were able to assess the utility of these vegetation indices to estimate canopy cover and LAI over a large range of plant densities. We found good correlations between the Normalized Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index (EVI) with plant number per plot, canopy cover and LAI both during the vegetative growth phase (pre-anthesis) and at maximum canopy cover shortly after anthesis. We also analyzed the utility of time-sequence data to assess the senescence pattern of sorghum genotypes known as fast (senescent) or slow senescing (stay-green) types. The Normalized Difference Red Edge (NDRE) index which estimates leaf chlorophyll content was most useful in characterizing the leaf area dynamics

  9. Codes for the identification of aquifer names and geologic units in the United States and the Caribbean outlying areas

    Science.gov (United States)

    ,

    1988-01-01

    This standard provides codes to be used for the identification of aquifer names and geologic units in the United States, the Caribbean and other outlying areas. Outlying areas include Puerto Rico, the Virgin Islands, American Samoa, the Midway Islands, Trust Territories of the Pacific Islands, and miscellaneous Pacific Islands. Each code identifies an aquifer or rock-stratigraphic unit and its age designation. The codes provide a standardized base for use by organizations in the storage, retrieval, and exchange of ground-water data; the indexing and inventory of ground-water data and information; the cataloging of ground-water data acquisition activities; and a variety of other applications.

  10. Evaluating the effect of plant population densities and nitrogen application on the leaf area index of maize in a reclaimed wetland in Kenya

    Directory of Open Access Journals (Sweden)

    Njuguna Catherine Waithira

    2016-12-01

    Full Text Available Maize is the main staple food in Kenya with over 90% of Kenyans relying on it. While the annual national consumption is increasing, the production of this crop has been on the decline in the last two decades. Maize production in Kenya fell by 33.4% in 2013 with Nyeri among the counties said to be grappling with the production of this crop. Land pressure is one of the major causes of decreased availability of food as well as soil depletion and encroachment upon fragile ecosystems such as wetlands. Nitrogen is a key nutrient in the production of maize, and its deficiency is a major factor limiting its production. This study investigated the effect of N application at 120 kg N/ha and maize density on the Leaf Area Index in reclaimed wetland soils in an experimental set-up comprising a randomized complete block design with three replications. The research was carried out in Nyeri County, Kenya. Leaf Area Index (LAI was determined using the given SunScan formula. Measurements were done continuously until crop physiological maturity. Results indicated that the leaf area index increased with nitrogen application and reduced with spacing for most treatments. There were no significant differences between the two methods (Copy Method and SunScan. Leaf Area Index (LAI was high in treatments containing nitrogen and high plant density. It was concluded that high plant density gives high LAI. 50 cm * 12.5 cm (-N and 50 cm * 12.5 cm (+N are the recommended plant densities for the site.

  11. Defacto Marine Protected Areas of the United States

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data provide the spatial boundaries of DeFacto Marine Protected Areas in U.S. Waters. With nearly 1200 sites (for which GIS data are available), DFMPAs cover...

  12. Intercomparison and validation of MODIS and GLASS leaf area index (LAI) products over mountain areas: A case study in southwestern China

    Science.gov (United States)

    Jin, Huaan; Li, Ainong; Bian, Jinhu; Nan, Xi; Zhao, Wei; Zhang, Zhengjian; Yin, Gaofei

    2017-03-01

    The validation study of leaf area index (LAI) products over rugged surfaces not only gives additional insights into data quality of LAI products, but deepens understanding of uncertainties regarding land surface process models depended on LAI data over complex terrain. This study evaluated the performance of MODIS and GLASS LAI products using the intercomparison and direct validation methods over southwestern China. The spatio-temporal consistencies, such as the spatial distributions of LAI products and their statistical relationship as a function of topographic indices, time, and vegetation types, respectively, were investigated through intercomparison between MODIS and GLASS products during the period 2011-2013. The accuracies and change ranges of these two products were evaluated against available LAI reference maps over 10 sampling regions which standed for typical vegetation types and topographic gradients in southwestern China. The results show that GLASS LAI exhibits higher percentage of good quality data (i.e. successful retrievals) and smoother temporal profiles than MODIS LAI. The percentage of successful retrievals for MODIS and GLASS is vulnerable to topographic indices, especially to relief amplitude. Besides, the two products do not capture seasonal dynamics of crop, especially in spring over heterogeneously hilly regions. The yearly mean LAI differences between MODIS and GLASS are within ±0.5 for 64.70% of the total retrieval pixels over southwestern China. The spatial distribution of mean differences and temporal profiles of these two products are inclined to be dominated by vegetation types other than topographic indices. The spatial and temporal consistency of these two products is good over most area of grasses/cereal crops; however, it is poor for evergreen broadleaf forest. MODIS presents more reliable change range of LAI than GLASS through comparison with fine resolution reference maps over most of sampling regions. The accuracies of direct

  13. Scaling relationships among twig size, leaf size and leafing intensity in a successional series of subtropical forests.

    Science.gov (United States)

    Yan, En-Rong; Wang, Xi-Hua; Chang, Scott X; He, Fangliang

    2013-06-01

    Scaling relationships among twig size, leaf size and leafing intensity fundamentally influence the twig-leaf deployment pattern, a property that affects the architecture and functioning of plants. However, our understanding of how these relationships change within a species or between species as a function of forest succession is unclear. We determined log-log scaling relationships between twig cross-sectional area (twig size) and each of total and individual leaf area, and leafing intensity (the number of leaves per twig volume) for 78 woody species along a successional series in subtropical evergreen forests in eastern China. The series included four stages: secondary shrub (S1), young (S2), sub-climax (S3) and climax evergreen broadleaved forests (S4). The scaling slopes in each of the three relationships did not differ among the four stages. The y-intercept did not shift among the successional stages in the relationship between twig cross-sectional area and total leaf area; however, the y-intercept was greatest in S4, intermediate in S3 and lowest in S2 and S1 for the relationship between twig size and individual leaf area, while the opposite pattern was found for the twig size-leafing intensity relationship. This indicates that late successional trees have few but large leaves while early successional trees have more small leaves per unit twig size. For the relationship between twig cross-sectional area and total leaf area, there was no difference in the regression slope between recurrent (appear in more than one stages) and non-recurrent species (appear in only one stage) for each of the S1-S2, S2-S3 and S3-S4 pairs. A significant difference in the y-intercept was found in the S2-S3 pair only. In the relationship between twig cross-sectional area and individual leaf area, the regression slope between recurrent and non-recurrent species was homogeneous in the S1-S2 and S3-S4 pairs, but heterogeneous in the S2-S3 pair. We conclude that forest succession caused

  14. Gross primary production variability associated with meteorology, physiology, leaf area, and water supply in contrasting woodland and grassland semiarid riparian ecosystems

    Science.gov (United States)

    Jenerette, G. D.; Scott, R. L.; Barron-Gafford, G. A.; Huxman, T. E.

    2009-12-01

    Understanding ecosystem-atmosphere carbon exchanges in dryland environments has been more challenging than in mesic environments, likely due to more pronounced nonlinear responses of ecosystem processes to environmental variation. To better understand diurnal to interannual variation in gross primary productivity (GPP) variability, we coupled continuous eddy-covariance derived whole ecosystem gas exchange measurements with an ecophysiologic model based on fundamental principles of diffusion, mass balance, reaction kinetics, and biochemical regulation of photosynthesis. We evaluated the coupled data-model system to describe and understand the dynamics of 3 years of growing season GPP from a riparian grassland and woodland in southern Arizona. The data-model fusion procedure skillfully reproduced the majority of daily variation GPP throughout three growing seasons. While meteorology was similar between sites, the woodland site had consistently higher GPP rates and lower variability at daily and interannual timescales relative to the grassland site. We examined the causes of this variation using a new state factor model analysis that partitioned GPP variation into four factors: meteorology, physiology, leaf area, and water supply. The largest proportion of GPP variation was associated with physiological differences. The woodland showed a greater sensitivity than the grassland to water supply, while the grassland showed a greater sensitivity to leaf area. These differences are consistent with hypotheses of woody species using resistance mechanisms, stomatal regulation, and grassland species using resilience mechanisms, leaf area regulation, in avoiding water stress and have implications for future GPP sensitivity to climate variability following wood-grass transitions.

  15. Carbon benefits from protected areas in the conterminous United States

    Science.gov (United States)

    2013-01-01

    Background Conversion of forests to other land cover or land use releases the carbon stored in the forests and reduces carbon sequestration potential of the land. The rate of forest conversion could be reduced by establishing protected areas for biological diversity and other conservation goals. The purpose of this study is to quantify the efficiency and potential of forest land protection for mitigating GHG emissions. Results The analysis of related national-level datasets shows that during the period of 1992–2001 net forest losses in protected areas were small as compared to those in unprotected areas: -0.74% and −4.07%, respectively. If forest loss rates in protected and unprotected area had been similar, then forest losses in the protected forestlands would be larger by 870 km2/yr forests, that corresponds to release of 7 Tg C/yr (1 Tg=1012 g). Conversely, and continuing to assume no leakage effects or interactions of prices and harvest levels, about 1,200 km2/yr forests could have remained forest during the period of 1992–2001 if net area loss rate in the forestland outside protected areas was reduced by 20%. Not counting carbon in harvested wood products, this is equivalent to reducing fossil-fuel based carbon emissions by 10 Tg C/yr during this period. The South and West had much higher potentials to mitigate GHG emission from reducing loss rates in unprotected forests than that of North region. Spatially, rates of forest loss were higher across the coastal states in the southeastern US than would be expected from their population change, while interior states in the northern US experienced less forest area loss than would have been expected given their demographic characteristics. Conclusions The estimated carbon benefit from the reduced forest loss based on current protected areas is 7 Tg C/yr, equivalent to the average carbon benefit per year for a previously proposed ten-year $110 million per year tree planting program scenario in the US. If there

  16. Leaf nitrogen distribution in relation to crown architecture in the tall canopy species, Fagus crenata.

    Science.gov (United States)

    Osada, Noriyuki; Yasumura, Yuko; Ishida, Atsushi

    2014-08-01

    The theory of optimal leaf N distribution predicts that the C gain of plants is maximized when the N content per unit area (N(area)) scales with light availability, but most previous studies have demonstrated that the N distribution is not proportional to light availability. In tall trees, the leaves are often clustered on twigs (leaf cluster) and not evenly distributed within the crowns. Thus, we hypothesized that the suboptimal N distribution is partly caused by the limited capacity to translocate N between leaf clusters, and consequently, the relationship between light and N(area) differs for leaves in different clusters. We investigated the light availability and N content of all individual leaves within several leaf clusters on tall trees of a deciduous canopy species Fagus crenata in Japan. We observed that the within-cluster leaf N distribution patterns differed from the between-cluster patterns and the slopes of the relationships between light and N(area) were lower within clusters than between clusters. According to the detailed analysis of the N distribution within leaf clusters, N(area) was greater for current-year shoots with greater light availability or a larger total leaf area. The latter pattern was probably caused by the greater sink strength of the current-year shoots with a larger leaf area. These N distribution patterns suggest that leaf clusters are fairly independent with respect to their N use, and the productivity of real F. crenata crowns may be less than optimal.

  17. Estimative of Black Pepper leaf area with basis on the leaf blade linear dimension Estimativa da área foliar de pimenta do reino a partir de dimensões lineares do limbo foliar

    Directory of Open Access Journals (Sweden)

    Fábio Luiz Partelli

    2007-10-01

    Full Text Available This research was aimed at establishing regression equations to estimate black pepper (Piper nigrum leaf area based on linear leaf measures. Different black pepper varieties where growth on the field, four different size leaves were collected per plant with a total of 52 leaves to establish the regression equation and 28 to validate the equation for each variety (Bragantina, Laçará, Guajarina e Cingapura. Leaf midrib length (LML, maximum leaf broad width (MLBW and leaf area (LA were measured. Pearson's linear correlation coefficients were determined between observed and predicted measures with the observed LA, besides estimating the linear regression equation for each variety. The equations best-fitted to estimate LA based on circumscript rectangle were: 1 LA = 2.2689 + 0.6900 x LML x MLBW; 2 LA = 1.6402 + 0.6816 x LML x MLBW; 3 LA = 1.4942 + 0.6215 x LML x MLBW and 4 LA = 0.7467 + 0.6735 x LML x MLBW, for Bragantina, Laçará, Guajarina and Cingapura varieties respectively. For all equations predicted values had high correlation coefficient with observed values thus showing that these equations must be variety specific and that they are appropriate for black pepper leaf area estimative.O objetivo deste trabalho foi estabelecer equações de regressão para estimar a área foliar de diferentes variedades de pimenta-do-reino (Piper nigrum cultivadas no campo, a partir de medidas lineares de folhas. Foram coletadas quatro folhas por planta, de tamanhos diferentes, totalizando 52 folhas, para estabelecer a equação de regressão e 28 para validar a equação para cada variedade (Bragantina, Laçará, Guajarina e Cingapura. Procederam-se às medições do comprimento da nervura central (LML, da maior largura do limbo foliar (MLBW e da área foliar (LA. Determinaram-se os coeficientes de correlação linear de Pearson entre as medidas mensuráveis e preditas com a LA observada, além de estimarem-se as equações de regressão linear para cada

  18. Modelos de determinação não-destrutiva da área foliar em girassol Models for estimating leaf area in sunflower

    Directory of Open Access Journals (Sweden)

    Ivan Carlos Maldaner

    2009-08-01

    Full Text Available Os objetivos deste trabalho foram obter e testar modelos matemáticos de estimativa da área do limbo foliar em função das suas dimensões lineares para o girassol. Foram conduzidos dois experimentos na área experimental do departamento de Fitotecnia da Universidade Federal de Santa Maria. As plantas de girassol foram coletadas a partir dos 27 dias após emergência (DAE. A área foliar (AF foi determinada pelo método dos discos. Ajustaram-se modelos lineares, quadráticos, cúbicos e potenciais entre área foliar e comprimento ou largura e seus produtos (comprimento*largura, sendo eliminados os que apresentaram coeficiente de determinação menor do que 0,90. A estatística utilizada para avaliar o desempenho dos modelos foi a raiz do quadrado médio do erro (RQME. Os modelos que melhor se ajustaram aos dados foram: potência, quadrático e cúbico, considerando a largura como variável independente. A área foliar de girassol pode ser estimada com o modelo potência, por ser o mais preciso, e a largura da folha.The objective of this study was to obtain and to numerical models to estimate the leaf area in function leaves linear dimension in sunflower. Two experiments were conducted at the experimental area of the Plant Science Department of the Federal University of Santa Maria, Santa Maria, RS, Brazil. Plants of sunflower were collected starting 27 days after emergency (DAE. The disks method was used to determine the leaf area (LA. Leaves were dried in oven at 65°C until constant weight. Linear, quadratic, cubic and power models between leaf area and length or width, and the product (length * width, were fitted. Models that apresented coefficient of determination lower than 0.90 were not selected. The statistic used to evaluate the performance of the models was the root mean square error (RQME. Models that had the best fit were power, quadratic and cubic using blade width as the independent variable. Leaf area in sunflower can be

  19. Multiscale assessment of green leaf area in a semi-arid rangeland with a small unmanned aerial vehicle

    Science.gov (United States)

    Spatial variability in green leaf cover of a western rangeland was studied by comparing field measurements on 50 m crossed transects to aerial and satellite imagery. The normalized difference vegetation index was calculated for multiple 2 cm resolution images collected over the field transects with ...

  20. Extracting Leaf Area Index by Sunlit Foliage Component from Downward-Looking Digital Photography under Clear-Sky Conditions

    Directory of Open Access Journals (Sweden)

    Yelu Zeng

    2015-10-01

    Full Text Available The development of near-surface remote sensing requires the accurate extraction of leaf area index (LAI from networked digital cameras under all illumination conditions. The widely used directional gap fraction model is more suitable for overcast conditions due to the difficulty to discriminate the shaded foliage from the shadowed parts of images acquired on sunny days. In this study, a new LAI extraction method by the sunlit foliage component from downward-looking digital photography under clear-sky conditions is proposed. In this method, the sunlit foliage component was extracted by an automated image classification algorithm named LAB2, the clumping index was estimated by a path length distribution-based method, the LAD and G function were quantified by leveled digital images and, eventually, the LAI was obtained by introducing a geometric-optical (GO model which can quantify the sunlit foliage proportion. The proposed method was evaluated at the YJP site, Canada, by the 3D realistic structural scene constructed based on the field measurements. Results suggest that the LAB2 algorithm makes it possible for the automated image processing and the accurate sunlit foliage extraction with the minimum overall accuracy of 91.4%. The widely-used finite-length method tends to underestimate the clumping index, while the path length distribution-based method can reduce the relative error (RE from 7.8% to 6.6%. Using the directional gap fraction model under sunny conditions can lead to an underestimation of LAI by (1.61; 55.9%, which was significantly outside the accuracy requirement (0.5; 20% by the Global Climate Observation System (GCOS. The proposed LAI extraction method has an RMSE of 0.35 and an RE of 11.4% under sunny conditions, which can meet the accuracy requirement of the GCOS. This method relaxes the required diffuse illumination conditions for the digital photography, and can be applied to extract LAI from downward-looking webcam images

  1. [Comparison of precision in retrieving soybean leaf area index based on multi-source remote sensing data].

    Science.gov (United States)

    Gao, Lin; Li, Chang-chun; Wang, Bao-shan; Yang Gui-jun; Wang, Lei; Fu, Kui

    2016-01-01

    With the innovation of remote sensing technology, remote sensing data sources are more and more abundant. The main aim of this study was to analyze retrieval accuracy of soybean leaf area index (LAI) based on multi-source remote sensing data including ground hyperspectral, unmanned aerial vehicle (UAV) multispectral and the Gaofen-1 (GF-1) WFV data. Ratio vegetation index (RVI), normalized difference vegetation index (NDVI), soil-adjusted vegetation index (SAVI), difference vegetation index (DVI), and triangle vegetation index (TVI) were used to establish LAI retrieval models, respectively. The models with the highest calibration accuracy were used in the validation. The capability of these three kinds of remote sensing data for LAI retrieval was assessed according to the estimation accuracy of models. The experimental results showed that the models based on the ground hyperspectral and UAV multispectral data got better estimation accuracy (R² was more than 0.69 and RMSE was less than 0.4 at 0.01 significance level), compared with the model based on WFV data. The RVI logarithmic model based on ground hyperspectral data was little superior to the NDVI linear model based on UAV multispectral data (The difference in E(A), R² and RMSE were 0.3%, 0.04 and 0.006, respectively). The models based on WFV data got the lowest estimation accuracy with R2 less than 0.30 and RMSE more than 0.70. The effects of sensor spectral response characteristics, sensor geometric location and spatial resolution on the soybean LAI retrieval were discussed. The results demonstrated that ground hyperspectral data were advantageous but not prominent over traditional multispectral data in soybean LAI retrieval. WFV imagery with 16 m spatial resolution could not meet the requirements of crop growth monitoring at field scale. Under the condition of ensuring the high precision in retrieving soybean LAI and working efficiently, the approach to acquiring agricultural information by UAV remote

  2. Comparison of UAV and WorldView-2 imagery for mapping leaf area index of mangrove forest

    Science.gov (United States)

    Tian, Jinyan; Wang, Le; Li, Xiaojuan; Gong, Huili; Shi, Chen; Zhong, Ruofei; Liu, Xiaomeng

    2017-09-01

    Unmanned Aerial Vehicle (UAV) remote sensing has opened the door to new sources of data to effectively characterize vegetation metrics at very high spatial resolution and at flexible revisit frequencies. Successful estimation of the leaf area index (LAI) in precision agriculture with a UAV image has been reported in several studies. However, in most forests, the challenges associated with the interference from a complex background and a variety of vegetation species have hindered research using UAV images. To the best of our knowledge, very few studies have mapped the forest LAI with a UAV image. In addition, the drawbacks and advantages of estimating the forest LAI with UAV and satellite images at high spatial resolution remain a knowledge gap in existing literature. Therefore, this paper aims to map LAI in a mangrove forest with a complex background and a variety of vegetation species using a UAV image and compare it with a WorldView-2 image (WV2). In this study, three representative NDVIs, average NDVI (AvNDVI), vegetated specific NDVI (VsNDVI), and scaled NDVI (ScNDVI), were acquired with UAV and WV2 to predict the plot level (10 × 10 m) LAI. The results showed that AvNDVI achieved the highest accuracy for WV2 (R2 = 0.778, RMSE = 0.424), whereas ScNDVI obtained the optimal accuracy for UAV (R2 = 0.817, RMSE = 0.423). In addition, an overall comparison results of the WV2 and UAV derived LAIs indicated that UAV obtained a better accuracy than WV2 in the plots that were covered with homogeneous mangrove species or in the low LAI plots, which was because UAV can effectively eliminate the influence from the background and the vegetation species owing to its high spatial resolution. However, WV2 obtained a slightly higher accuracy than UAV in the plots covered with a variety of mangrove species, which was because the UAV sensor provides a negative spectral response function(SRF) than WV2 in terms of the mangrove LAI estimation.

  3. Assimilation of leaf area index and surface soil moisture satellite observations into the SIM hydrological model over France

    Science.gov (United States)

    Fairbairn, David; Calvet, Jean-Christophe; Mahfouf, Jean-Francois; Barbu, Alina

    2016-04-01

    Hydrological models have a variety of uses, including flood and drought prediction and water management. The SAFRAN-ISBA-MODCOU (SIM) hydrological model consists of three stages: An atmospheric analysis (SAFRAN) over France, which forces a land surface model (ISBA-A-gs), which then provides drainage and runoff inputs to a hydrological model (MODCOU). The river discharge from MODCOU is validated using observed river discharge over France. Data assimilation (DA) combines a short model forecast from the past with observations to improve the estimate of the model state. The ISBA-A-gs representation of soil moisture and its influence by vegetation can be improved by assimilating surface soil moisture (SSM) and leaf area index (LAI) observations respectively. The Advanced Scatterometer (ASCAT) on board the MetOP satellite measures a low-frequency microwave signal, which is used to retrieve daily SSM over France. The SPOT-VGT sensor observes LAI over France at a temporal frequency of about 10 days. The Simplified Extended Kalman (SEKF) filter combines the model and observed variables by weighting them according to their respective accuracies. Although the SEKF makes incorrect linear assumptions, past experiments have shown that it improves on the model estimates of SSM and LAI. However, due to nonlinearities in the land surface model, improvements in SSM and LAI do not imply improved soil moisture fluxes (drainage, runoff and evapotranspiration). This study indirectly examines the impact of the SEKF on the soil moisture fluxes using the MODCOU hydrological model. The ISBA-A-gs model appears to underestimate the LAI for grasslands in winter and spring, which results in an underestimation (overestimation) of evapotranspiration (drainage and runoff). The excess water flowing into the rivers and aquifers contributes to an overestimation of the MODCOU discharge. Assimilating LAI observations slightly increases the LAI analysis in winter and spring and therefore reduces the

  4. Retrieval of wheat leaf area index from AWiFS multispectral data using canopy radiative transfer simulation

    Science.gov (United States)

    Nigam, Rahul; Bhattacharya, Bimal K.; Vyas, Swapnil; Oza, Markand P.

    2014-10-01

    Accurate representation of leaf area index (LAI) from high resolution satellite observations is obligatory for various modelling exercises and predicting the precise farm productivity. Present study compared the two retrieval approach based on canopy radiative transfer (CRT) method and empirical method using four vegetation indices (VI) (e.g. NDVI, NDWI, RVI and GNDVI) to estimate the wheat LAI. Reflectance observations available at very high (56 m) spatial resolution from Advanced Wide-Field Sensor (AWiFS) sensor onboard Indian Remote Sensing (IRS) P6, Resourcesat-1 satellite was used in this study. This study was performed over two different wheat growing regions, situated in different agro-climatic settings/environments: Trans-Gangetic Plain Region (TGPR) and Central Plateau and Hill Region (CPHR). Forward simulation of canopy reflectances in four AWiFS bands viz. green (0.52-0.59 μm), red (0.62-0.68 μm), NIR (0.77-0.86 μm) and SWIR (1.55-1.70 μm) were carried out to generate the look up table (LUT) using CRT model PROSAIL from all combinations of canopy intrinsic variables. An inversion technique based on minimization of cost function was used to retrieve LAI from LUT and observed AWiFS surface reflectances. Two consecutive wheat growing seasons (November 2005-March 2006 and November 2006-March 2007) datasets were used in this study. The empirical models were developed from first season data and second growing season data used for validation. Among all the models, LAI-NDVI empirical model showed the least RMSE (root mean square error) of 0.54 and 0.51 in both agro-climatic regions respectively. The comparison of PROSAIL retrieved LAI with in situ measurements of 2006-2007 over the two agro-climatic regions produced substantially less RMSE of 0.34 and 0.41 having more R2 of 0.91 and 0.95 for TGPR and CPHR respectively in comparison to empirical models. Moreover, CRT retrieved LAI had less value of errors in all the LAI classes contrary to empirical estimates

  5. 31 CFR 585.524 - Humanitarian aid and trade in United Nations Protected Areas of Croatia and those areas of the...

    Science.gov (United States)

    2010-07-01

    ... Humanitarian aid and trade in United Nations Protected Areas of Croatia and those areas of the Republic of...-by-case basis to permit exportation to, or transshipment through, the United Nations Protected Areas... permit importation from, exportation to, or transshipment through the United Nations Protected Areas...

  6. A framework for consistent estimation of leaf area index, fraction of absorbed photosynthetically active radiation, and surface albedo from MODIS time-series data

    DEFF Research Database (Denmark)

    Xiao, Zhiqiang; Liang, Shunlin; Wang, Jindi

    2015-01-01

    -series MODerate Resolution Imaging Spectroradiometer (MODIS) surface reflectance data. If the reflectance data showed snow-free areas, an ensemble Kalman filter (EnKF) technique was used to estimate leaf area index (LAI) for a two-layer canopy reflectance model (ACRM) by combining predictions from a phenology......-surface parameter profiles from MODIS time-series reflectance data even if some of the reflectance data are contaminated by residual cloud or are missing and that the retrieved LAI, FAPAR, and surface albedo values are physically consistent. The root mean square errors of the retrieved LAI, FAPAR, and surface...

  7. Modelo para determinção da área foliar de Kalanchoe blossfeldiana Poelln Model for leaf area determination in Kalanchoe blossfeldiana Poelln

    Directory of Open Access Journals (Sweden)

    Marcia Xavier Peiter

    2006-12-01

    Full Text Available O presente trabalho teve por objetivo a verificação de um procedimento matemático que permita a descrição do crescimento foliar de Kalanchoe (Kalanchoe blossfeldiana Poelln. e possa prever a sua área foliar fotossinteticamente ativa a partir de medidas não destrutivas de folhas. As mudas de Kalanchoe Cv. "Gold Jewel" foram cultivadas para o procedimento experimental em vasos irrigados com doses recomendadas para a cultura. Semanalmente, foram retirados três vasos da estufa e as plantas tiveram suas folhas cortadas, identificadas e submetidas a tomadas de medidas de sua posição na planta, do máximo comprimento longitudinal e do máximo comprimento transversal. Foram realizadas um total de nove coletas semanalmente, desde 04/04/2003 até o início da floração. Em cada coleta, três plantas eram amostradas e a área foliar calculada com a utilização do método de Gauss (GARCIA & PIEDADE, 1944 implementado em Visual Basic especificamente para este objetivo. Foram amostradas um total de 979 folhas e a verificação da possibilidade de uso de um fator de correção médio (FCM para o cálculo da área de uma folha, independentemente de sua posição na planta ou fase do ciclo de crescimento, foi averiguada por análise de regressão entre os valores obtidos pelo método padrão (Gauss e os valores estimados pelo método do FCM. Os resultados experimentais indicam que o valor FCM=1,1134 pode ser utilizado para estimar a área foliar pela multiplicação pelos valores de comprimento e largura de folha em qualquer fase do cultivo e sem qualquer posição da folha na planta.This research was aimed at versifying a mathematical procedure that allows the description of leaf of Kalanchoe (Kalanchoe blossfeldiana Poelln. and the estimation of its photosynthetically active leaf area starting from a non destructive leaf determination. Seedlings of Kalanchoe cv Gold Jewel were cultivated in irrigated vases with recommended doses for the culture

  8. Landscape Soil Respiration Fluxes are Related to Leaf Area Index, Stand Height and Density, and Soil Nitrogen in Rocky Mountain Subalpine Forests

    Science.gov (United States)

    Berryman, E.; Bradford, J. B.; Hawbaker, T. J.; Birdsey, R.; Ryan, M. G.

    2015-12-01

    There is a recent multi-agency push for accurate assessments of terrestrial carbon stocks and fluxes in the United States. Assessing the state of the carbon cycle in the US requires estimates of stocks and fluxes at large spatial scales. Such assessments are difficult, especially for soil respiration, which dominates ecosystem respiration and is notoriously highly variable over space and time. Here, we report three consecutive years of measurement of soil respiration fluxes in three 1 km2 subalpine forest landscapes: Fraser Experimental Forest (Colorado), Glacier Lakes Ecosystems Experimental Site ("GLEES", Wyoming), and Niwot Ridge (Colorado). Plots were established following the protocol of the US Forest Service's Forest Inventory and Analysis (FIA) Program. Clusters of plots were distributed across the landscape in a 0.25 km grid pattern. From 2004 through 2006, measurements of soil respiration were made once monthly during the growing season and twice during snowpack coverage for each year. Annual cumulative soil respiration was 6.10 (+/- 0.21) Mg ha-1y-1 for Fraser, 6.55 (+/- 0.27) Mg ha-1y-1 for GLEES, and 6.97 (+/- 0.20) Mg ha-1y-1 for Niwot. Variability in annual cumulative soil respiration varied by less than 20% among the three subalpine forests, despite differences in terrain, climate, disturbance history and anthropogenic nitrogen deposition. We quantified the relationship between respiration fluxes and commonly-measured forest properties and found that soil respiration was nonlinearly related to leaf area index, peaking around 2.5 m2m-2 then slowly declining. Annual litterfall (FA) was subtracted from soil respiration (FR) to calculate total belowground carbon flux (TBCF), which declined with increasing tree height, density and soil nitrogen. This landscape analysis of soil respiration confirmed experimentally-derived principles governing carbon fluxes in forests: as trees age and get taller, and in high-fertility areas, carbon flux to roots declines

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

    Science.gov (United States)

    Köhler, P.; Huth, A.

    2010-05-01

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

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

    Directory of Open Access Journals (Sweden)

    P. Köhler

    2010-05-01

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

  11. Estimativa da área da folha da batateira utilizando medidas lineares Evaluation of the potato plant leaf area using linear measures

    Directory of Open Access Journals (Sweden)

    Marcelo CC Silva

    2008-03-01

    Full Text Available O objetivo deste experimento foi determinar o modelo mais apropriado para estimar a área da folha da batateira, utilizando-se medidas de comprimento e largura da folha. Foram coletadas 300 folhas de 300 plantas de batata, cultivar Monalisa, de forma aleatória, aos 21 e 56 dias após a emergência (DAE. Em laboratório, foram medidos o comprimento (C, a largura (L e a área de cada folha (AF. Os dados foram submetidos à análise de regressão com o valor da AF sendo considerado a variável dependente e os valores de comprimento e largura de folha as variáveis independentes. Foram testados três modelos estatísticos: linear, exponencial e logarítmico. A AF da batateira foi mais precisamente estimada (R² = 0,88, usando as medidas, L e C (AF = 0,2798**LC + 71,267. Para maior rapidez e praticidade, a AF da batateira, foi também apropriadamente estimada medindo-se apenas L ou C da folha e utilizando-se as equações AF = 0,0479**L + 10,777 (R² = 0,83 ou AF = 0,0659**C + 12,979 (R² = 0,82. A área foliar estimada 21 DAE, utilizando o modelo linear foi de 234,41 cm², sendo que o valor real medido, foi de 185,52 cm². Aos 56 DAE, a área foliar estimada pelo mesmo modelo foi de 175,60 cm², o valor real medido, foi de 176,01 cm². Com um dos modelos propostos, a área da folha pode ser estimada em tempo real, de forma rápida e sem a necessidade de coletar a folha.The objective of this experiment was to determine the most appropriate model to estimate potato leaf area through the leaf length and width. 300 leaves of 300 potato plants, cv. Monalisa were collected in an aleatory way, 21 and 56 days after the plant emergence (DAE. In laboratory, the length (C, width (L and area of each leaf (AF were measured. The data were submitted to the regression analysis with the AF value as a dependent variable and the leaf length and width values as the independent variables. Three statistical models were tested (linear, exponential and logarithmic. Potato

  12. 辽东栎冠层叶建成消耗与比叶面积的空间异质性%Spatial Heterogeneity of Specific Leaf Area and Leaf Construction Cost of Quercus liaotungensis Canopy

    Institute of Scientific and Technical Information of China (English)

    覃鑫浩

    2015-01-01

    Plant functional trait has been a hot topic of ecological research in recent years.Specific leaf ar-ea and leaf construction cost are important index factors in the research on harvest and expenditure of re-sources.The vertical and horizontal differences in the energy transmission and micrometeorological charac-teristics of forest canopy can lead to a considerable heterogeneity of functional traits.With Quercus liaotun-gensis,we studied the functional traits and their influence factors of different canopy positions.The results showed that CC on the top is higher than that at the bottom,but it is the other way around to SLA.Except the top and eastward parts,SLA in different canopy positions had significant differences;heat of combus-tion was the main influence factor for CC and SLA.%植物功能性状是目前生态学领域关注的热点问题之一,而比叶面积(Specific Leaf Area,SLA)和叶建成消耗(Leaf Construction Cost,LCC)则是功能性状中研究植物资源收获与支出的首选指标。树冠冠层结构与功能在方向上的不同可导致冠层功能性状空间分布的差异。以东灵山辽东栎为研究对象,分析了不同冠层不同方向部位叶片的功能性状以及影响因素。结果表明:在不同空间上,冠层上部的 CC 均高于冠层底部的,而 SLA 则相反;除上部与东向外,各方向叶片的比叶面积均有显著差异;热值则是影响二者的主要因素。冠层 CC 和 SLA 的空间异质性研究,对于在冠层水平上揭示植物资源利用具有重要意义。

  13. Desarrollo foliar y caulinar de las unidades de alargamiento de Nothofagus dombeyi (Nothofagaceae en condiciones de alta y baja luminosidad Leaf and stem development in extension units of Nothofagus dombeyi (Nothofagaceae under high and low light conditions

    Directory of Open Access Journals (Sweden)

    Cecilia Calabria

    2008-07-01

    Full Text Available Se analizaron el tamaño del tallo y las hojas que componen las unidades de alargamiento (UA del tronco, las ramas principales y las ramas cortas de ejemplares juveniles de Nothofagus dombeyi desarrollados en comunidades de áreas abiertas (bordes de camino y de sotobosque de Patagonia. Se evaluaron el área y la forma (ancho/longitud de las hojas a lo largo de las UA, el área foliar específica (AFE y las relaciones área foliar/volumen del tallo, longitud del tallo/peso del tallo y volumen del tallo/peso del tallo. Para igual posición en la UA, las hojas del tronco son mayores que las de las ramas principales y éstas mayores que las de las ramas cortas. En las UA del tronco el desarrollo caulinar es proporcionalmente mayor al de las hojas en comparación con las UA de las ramas principales y, en especial, de las ramas cortas. La restricción en el desarrollo caulinar y el aumento del AFE en ejemplares de N. dombeyi creciendo a la sombra permitiría su supervivencia pero con limitado desarrollo en altura y, en consecuencia, baja probabilidad de alcanzar el dosel.The size of stem and leaves was studied for trunk, main branch and short branch extension units (EU of young Nothofagus dombeyi trees growing in open areas (road verges and understory communities in Patagonia. The surface area and outline (width/length ratio of single leaves along EU, the specific leaf area, and the ratios leaf area/stem volume, stem length/stem mass and stem volume/stem mass were assessed. Trunk leaves were larger than main-branch leaves and main-branch leaves larger than short-branch leaves in similar positions on the EU. Stem developed proportionally more than leaves in trunk EU than in main-branch EU and, especially, short-branch EUs. Restrictions in stem development and increases in specific leaf area would allow N. dombeyi trees to survive under shaded conditions though limiting their height growth and, consequently, their chances to reach the canopy.

  14. Ozone in rural areas of the United States

    Science.gov (United States)

    Logan, Jennifer A.

    1989-06-01

    I present the results of an analysis of ozone data from rural locations in the United States. Ozone concentrations above 80 ppb are common in the east in spring and summer, but they are unusual in the west, and ozone shows considerably more day-to-day variability in the east. Variations in ozone levels are highly correlated over distances of several hundred kilometers in the east, indicating that high values are associated with episodes of large spatial scale, >600,000 km2. There were 10 and seven such episodes in 1978 and 1979 respectively, between the months of April and September; they persisted for 3-4 days, on average, with a range of 2-8 days, and were most common in June. Daily maximum ozone values exceeded 90 ppb at over half the sites during these episodes and were often greater than 120 ppb at one or more sites. An analysis of the meteorology for each episode shows that they occurred preferentially in the presence of weak, slow-moving, and persistent high-pressure systems. Two episodes that occurred outside the summer half of the year were associated with unseasonably warm weather; only one episode, in March 1978, appeared to reflect a major stratospheric intrusion. Concentrations of NOx at rural locations in the east are frequently high enough (>1 ppb) to permit significant photochemical formation of ozone. It is clear that rural ozone in the east in spring and summer is severely impacted by anthropogenic emissions of NOx and hydrocarbons, and that ozone episodes occur when the weather is particularly conducive to photochemical formation of ozone. Ozone episodes were present on 23% of days in May-August in the east in 1978-1979. The effect of these pollution episodes on vegetation cannot be assessed with current information on dose-response characteristics, which is based primarily on exposure of crops to a given level of ozone for 7 hours a day. The results presented here may be used to design studies that account for the periodic exposure of vegetation

  15. Spatial distribution of tree species governs the spatio-temporal interaction of leaf area index and soil moisture across a forested landscape.

    Directory of Open Access Journals (Sweden)

    Kusum J Naithani

    Full Text Available Quantifying coupled spatio-temporal dynamics of phenology and hydrology and understanding underlying processes is a fundamental challenge in ecohydrology. While variation in phenology and factors influencing it have attracted the attention of ecologists for a long time, the influence of biodiversity on coupled dynamics of phenology and hydrology across a landscape is largely untested. We measured leaf area index (L and volumetric soil water content (θ on a co-located spatial grid to characterize forest phenology and hydrology across a forested catchment in central Pennsylvania during 2010. We used hierarchical Bayesian modeling to quantify spatio-temporal patterns of L and θ. Our results suggest that the spatial distribution of tree species across the landscape created unique spatio-temporal patterns of L, which created patterns of water demand reflected in variable soil moisture across space and time. We found a lag of about 11 days between increase in L and decline in θ. Vegetation and soil moisture become increasingly homogenized and coupled from leaf-onset to maturity but heterogeneous and uncoupled from leaf maturity to senescence. Our results provide insight into spatio-temporal coupling between biodiversity and soil hydrology that is useful to enhance ecohydrological modeling in humid temperate forests.

  16. Spatial distribution of tree species governs the spatio-temporal interaction of leaf area index and soil moisture across a forested landscape.

    Science.gov (United States)

    Naithani, Kusum J; Baldwin, Doug C; Gaines, Katie P; Lin, Henry; Eissenstat, David M

    2013-01-01

    Quantifying coupled spatio-temporal dynamics of phenology and hydrology and understanding underlying processes is a fundamental challenge in ecohydrology. While variation in phenology and factors influencing it have attracted the attention of ecologists for a long time, the influence of biodiversity on coupled dynamics of phenology and hydrology across a landscape is largely untested. We measured leaf area index (L) and volumetric soil water content (θ) on a co-located spatial grid to characterize forest phenology and hydrology across a forested catchment in central Pennsylvania during 2010. We used hierarchical Bayesian modeling to quantify spatio-temporal patterns of L and θ. Our results suggest that the spatial distribution of tree species across the landscape created unique spatio-temporal patterns of L, which created patterns of water demand reflected in variable soil moisture across space and time. We found a lag of about 11 days between increase in L and decline in θ. Vegetation and soil moisture become increasingly homogenized and coupled from leaf-onset to maturity but heterogeneous and uncoupled from leaf maturity to senescence. Our results provide insight into spatio-temporal coupling between biodiversity and soil hydrology that is useful to enhance ecohydrological modeling in humid temperate forests.

  17. United States of America (country/area statements).

    Science.gov (United States)

    1985-09-01

    reconciled with the principle that all couples and individuals have the basic right to decide freely and responsably the number and spacing of their children and to have the information and means to do so. Voluntarism is an essential element in population programs because family planning touches the most intimate areas of the lives of couples, because longterm change in fertility behavior is achieved only when the choices reflect the free decisions of couples, because user-preferences and the motivation of providers to improve program acceptability are compromised by coercion, and because voluntarism is a basic human right.

  18. Housing growth in and near United States protected areas limits their conservation value

    Science.gov (United States)

    Radeloff, V.C.; Stewart, S.I.; Hawbaker, T.J.; Gimmi, U.; Pidgeon, A.M.; Flather, C.H.; Hammer, R.B.; Helmers, D.P.

    2010-01-01

    Protected areas are crucial for biodiversity conservation because they provide safe havens for species threatened by land-use change and resulting habitat loss. However, protected areas are only effective when they stop habitat loss within their boundaries, and are connected via corridors to other wild areas. The effectiveness of protected areas is threatened by development; however, the extent of this threat is unknown. We compiled spatially-detailed housing growth data from 1940 to 2030, and quantified growth for each wilderness area, national park, and national forest in the conterminous United States. Our findings show that housing development in the United States may severely limit the ability of protected areas to function as a modern "Noah's Ark." Between 1940 and 2000, 28 million housing units were built within 50 km of protected areas, and 940,000 were built within national forests. Housing growth rates during the 1990s within 1 km of protected areas (20% per decade) outpaced the national average (13%). If long-term trends continue, another 17 million housing units will be built within 50 km of protected areas by 2030 (1 million within 1 km), greatly diminishing their conservation value. US protected areas are increasingly isolated, housing development in their surroundings is decreasing their effective size, and national forests are even threatened by habitat loss within their administrative boundaries. Protected areas in the United States are thus threatened similarly to those in developing countries. However, housing growth poses the main threat to protected areas in the United States whereas deforestation is the main threat in developing countries.

  19. The effects of leaf area density variation on the collection efficiency of black carbon in the size range of ultrafine particles (UFP)

    Science.gov (United States)

    Huang, C.; Lin, M.; Khlystov, A.; Katul, G. G.

    2012-12-01

    Black carbon is mainly produced in the ultra-fine particle (UFP) size range of 10-100 nm from combustion processes and is now receiving significant attention given its role in global and regional climate change, cloud physics, human health and respiratory related diseases. Likewise, the role of vegetated surfaces in removing UFP is drawing increased attention, prompting interest in the relationship between leaf area density and UFP collection efficiency. Here, carbonaceous particles, mainly black carbon, were generated by burning candles during "sooting burn" to explore the effects of leaf area density (LAD) variation on the collection efficiency of black carbon in the UFP size range. Three scenarios were explored in a wind tunnel: (1) Juniperus Chinensis branches that are uniformly distributed within the test section; (2) LAD that is linearly increasing with downwind distance and (3) LAD that is decreasing with downwind distance. The total leaf area index (LAI) was maintained constant in all three cases. Particle concentrations were measured at multiple locations within the vegetated volume for a range of sizes of UFP (12.6-102 nm) using Scanning Mobility Particle Sizer (SMPS). The measured concentration can be used to evaluate the performance of a size-resolving model that couples the turbulent flow field and the collection efficiency for the variable LAD. The model assumes that (i) the mean longitudinal momentum balance is controlled only by the interplay between drag force and the pressure gradient, and (ii) the dominant collection mechanism for UFP is Brownian diffusion. Hence, other collection mechanisms such as inertial impaction, interception and phoretic effects are negligible. Good agreement was found between the model calculations of the UFP collection efficiency by the vegetation and the wind tunnel measurements for all three cases and across a wide range of wind speeds and particle size. It was shown that variations in leaf area density lead to a

  20. Protected Areas Database of the United States (PAD-US) - Combined: Version 1.3

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The Protected Areas Database of the United States (PAD-US) is a geodatabase, managed by U. S. Geological Survey Gap Analysis Program, that illustrates and describes...

  1. EnviroAtlas - Percent Large, Medium, and Small Natural Areas for the Conterminous United States

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset contains the percentage of small, medium, and large natural areas for each Watershed Boundary Dataset (WBD) 12-Digit Hydrologic Unit Code...

  2. Protected Areas Database of the United States (PADUS) - Combined: Version 1.3

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The Protected Areas Database of the United States (PAD-US) is a geodatabase, managed by U. S. Geological Survey Gap Analysis Program, that illustrates and describes...

  3. Tax Area Boundaries, Tax units, Published in unknown, Norton County Appraisal Office.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Tax Area Boundaries dataset, was produced all or in part from Hardcopy Maps information as of unknown. It is described as 'Tax units'. Data by this publisher...

  4. Determination of Leaf Area Index, Total Foliar N, and Normalized Difference Vegetation Index for Arctic Ecosystems Dominated by Cassiope tetragona

    DEFF Research Database (Denmark)

    Campioli, M; Street, LE; Michelsen, Anders

    2009-01-01

    have not been accurately quantified. We address this knowledge gap by (i) direct measurements of LAI and TFN for C. tetragona, and (ii) determining TFN-LAI and LAI–normalized difference vegetation index (NDVI) relationships for typical C. tetragona tundras in the subarctic (Sweden) and High Arctic...... leaf N and biomass. The LAI-NDVI and TFN-LAI relationships showed high correlation and can be used to estimate indirectly LAI and TFN. The LAI-NDVI relationship for C. tetragona vegetation differed from a generic LAI-NDVI relationship for arctic tundra, whereas the TFN-LAI relationship did not. Overall...

  5. Differences in leaf litter, ascospore production and infection of pear scab (Venturia pirina) in Dutch organic orchards

    NARCIS (Netherlands)

    Timmermans, B.G.H.; Jansonius, P.J.

    2012-01-01

    In 2010 and 2011 the amounts of leaf litter and ascospore production per unit of leaf litter area in 7 organic pear orchards throughout the Netherlands were measured. In one of the orchards, adapted managements strategies were implemented, being grass/clover that is grown as ground cover on the tree

  6. Spatial Heterogeneity of Leaf Area Index (LAI) and Its Temporal Course on Arable Land: Combining Field Measurements, Remote Sensing and Simulation in a Comprehensive Data Analysis Approach (CDAA).

    Science.gov (United States)

    Reichenau, Tim G; Korres, Wolfgang; Montzka, Carsten; Fiener, Peter; Wilken, Florian; Stadler, Anja; Waldhoff, Guido; Schneider, Karl

    2016-01-01

    The ratio of leaf area to ground area (leaf area index, LAI) is an important state variable in ecosystem studies since it influences fluxes of matter and energy between the land surface and the atmosphere. As a basis for generating temporally continuous and spatially distributed datasets of LAI, the current study contributes an analysis of its spatial variability and spatial structure. Soil-vegetation-atmosphere fluxes of water, carbon and energy are nonlinearly related to LAI. Therefore, its spatial heterogeneity, i.e., the combination of spatial variability and structure, has an effect on simulations of these fluxes. To assess LAI spatial heterogeneity, we apply a Comprehensive Data Analysis Approach that combines data from remote sensing (5 m resolution) and simulation (150 m resolution) with field measurements and a detailed land use map. Test area is the arable land in the fertile loess plain of the Rur catchment on the Germany-Belgium-Netherlands border. LAI from remote sensing and simulation compares well with field measurements. Based on the simulation results, we describe characteristic crop-specific temporal patterns of LAI spatial variability. By means of these patterns, we explain the complex multimodal frequency distributions of LAI in the remote sensing data. In the test area, variability between agricultural fields is higher than within fields. Therefore, spatial resolutions less than the 5 m of the remote sensing scenes are sufficient to infer LAI spatial variability. Frequency distributions from the simulation agree better with the multimodal distributions from remote sensing than normal distributions do. The spatial structure of LAI in the test area is dominated by a short distance referring to field sizes. Longer distances that refer to soil and weather can only be derived from remote sensing data. Therefore, simulations alone are not sufficient to characterize LAI spatial structure. It can be concluded that a comprehensive picture of LAI spatial

  7. Partial phenotypic reversion of ABA-deficient flacca tomato (Solanum lycopersicum) scions by a wild-type rootstock: normalizing shoot ethylene relations promotes leaf area but does not diminish whole plant transpiration rate.

    Science.gov (United States)

    Dodd, Ian C; Theobald, Julian C; Richer, Sarah K; Davies, William J

    2009-01-01

    To evaluate the role of root-synthesized ABA in regulating growth and stomatal behaviour under well-watered conditions, isogenic wild-type (WT) and ABA-deficient flacca (flc) tomato (Solanum lycopersicum) were reciprocally and self-grafted just below the cotyledonary node. Since flc scions had lower leaf water potentials due to higher transpiration rates, a subset of all graft combinations was grown under a shoot misting treatment to minimize differences in shoot water status. Misting did not alter the relative effects of the different graft combinations on leaf area. WT scions had the greatest leaf area and lowest whole plant transpiration rate irrespective of the rootstock, implying that shoot ABA biosynthesis was sufficient to account for a WT shoot phenotype. In WT scions, the rootstock had no effect on detached leaf ethylene evolution or xylem concentrations of ABA or the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC). In flc scions, although the WT rootstock suppressed stomatal conductance of individual leaves, there was no detectable effect on whole plant transpiration rate. However, leaf area of flc/WT (scion/rootstock) plants increased 1.6-fold compared to flc self-grafts. WT rootstocks increased xylem ABA concentration in flc scions (relative to flc self-grafts) up to 3-fold, and resulted in xylem ACC concentrations and detached leaf ethylene evolution similar to WT scions. Since the WT rootstock normalized shoot ethylene relations but only partially restored the leaf area of flc scions (relative to that of WT scions), shoot ABA biosynthesis can directly promote leaf area via an unknown, ethylene-independent, mechanism.

  8. Leaf beetle (Chrysomelidae: Coleoptera) assemblages in a mosaic of natural and altered areas in the Brazilian cerrado.

    Science.gov (United States)

    Pimenta, M; De Marco, P

    2015-06-01

    In landscape mosaics, species may use different vegetation types or be restricted to a single vegetation type or land-use feature highlighting the importance of the interaction of species requirements and environmental heterogeneity. In these systems, the determination of the overall pattern of β-diversity can indicate the importance of the environmental heterogeneity on diversity patterns. Here, we evaluate leaf beetles (Coleoptera: Chrysomelidae) as habitat quality bioindicators in a system with varying intensities of human impacts and different phyto-physiognomies (from open field to forests). We collected 1117 leaf beetles belonging to 245 species, of which 12 species and 5 genus were considered possible bioindicators based on IndVal measures. Higher species richness was observed in forests and regenerating fields, and habitats with lower species richness included pastures, mines, and veredas. Natural fields, regenerating fields, natural cerrado, and forest had higher values of β-diversity. Bioindicator systems that include not only species richness and abundance but also assemblage composition are needed to allow for a better understanding of Chrysomelidae response to environmental disturbance.

  9. 7 CFR 28.467 - Leaf Grade 7.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade 7. 28.467 Section 28.467 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.467 Leaf Grade 7. Leaf Grade 7 is leaf which is within the range represented...

  10. 7 CFR 28.465 - Leaf Grade 5.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade 5. 28.465 Section 28.465 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.465 Leaf Grade 5. Leaf Grade 5 is leaf which is within the range represented...

  11. 7 CFR 28.462 - Leaf Grade 2.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade 2. 28.462 Section 28.462 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.462 Leaf Grade 2. Leaf Grade 2 is leaf which is within the range represented...

  12. 7 CFR 28.463 - Leaf Grade 3.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade 3. 28.463 Section 28.463 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.463 Leaf Grade 3. Leaf Grade 3 is leaf which is within the range represented...

  13. 7 CFR 28.461 - Leaf Grade 1.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade 1. 28.461 Section 28.461 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.461 Leaf Grade 1. Leaf Grade 1 is leaf which is within the range represented...

  14. 7 CFR 28.466 - Leaf Grade 6.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade 6. 28.466 Section 28.466 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.466 Leaf Grade 6. Leaf Grade 6 is leaf which is within the range represented...

  15. 7 CFR 28.464 - Leaf Grade 4.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade 4. 28.464 Section 28.464 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Upland Cotton § 28.464 Leaf Grade 4. Leaf Grade 4 is leaf which is within the range represented...

  16. Measuring Effective Leaf Area Index, Foliage Profile, and Stand Height in New England Forest Stands Using a Full-Waveform Ground-Based Lidar

    Science.gov (United States)

    Zhao, Feng; Yang, Xiaoyuan; Schull, Mithcell A.; Roman-Colon, Miguel O.; Yao, Tian; Wang, Zhuosen; Zhang, Qingling; Jupp, David L. B.; Lovell, Jenny L.; Culvenor, Darius; Newnham, Glenn J.; Richardson, Andrew D.; Ni-Meister, Wenge; Schaaf, Crystal L.; Woodcock, Curtis E.; Strahler, Alan H.

    2011-01-01

    Effective leaf area index (LAI) retrievals from a scanning, ground-based, near-infrared (1064 nm) lidar that digitizes the full return waveform, the Echidna Validation Instrument (EVI), are in good agreement with those obtained from both hemispherical photography and the Li-Cor LAI-2000 Plant Canopy Analyzer. We conducted trials at 28 plots within six stands of hardwoods and conifers of varying height and stocking densities at Harvard Forest, Massachusetts, Bartlett Experimental Forest, New Hampshire, and Howland Experimental Forest, Maine, in July 2007. Effective LAI values retrieved by four methods, which ranged from 3.42 to 5.25 depending on the site and method, were not significantly different ( b0.1 among four methods). The LAI values also matched published values well. Foliage profiles (leaf area with height) retrieved from the lidar scans, although not independently validated, were consistent with stand structure as observed and as measured by conventional methods. Canopy mean top height, as determined from the foliage profiles, deviated from mean RH100 values obtained from the Lidar Vegetation Imaging Sensor (LVIS) airborne large-footprint lidar system at 27 plots by .0.91 m with RMSE=2.04 m, documenting the ability of the EVI to retrieve stand height. The Echidna Validation Instrument is the first realization of the Echidna lidar concept, devised by Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO), for measuring forest structure using full-waveform, ground-based, scanning lidar.

  17. 叶面积指数遥感反演算法研究%Research on Leaf Area Index Remote Sensing Inversion Algorithms

    Institute of Scientific and Technical Information of China (English)

    周洋; 米晓飞; 叶李灶

    2013-01-01

    叶面积指数是确定陆袁生态系统物质和能量交换大小的重要结构参数之一.本文基于NDVI、RVI的反演模型,结合GDAL影像库和C++语言设计实现相关算法,形成从影像数据到叶面积指数图的处理流程,提高了影像的利用率.经预处理的Hyperion数据测试,算法运行稳定且计算结果精确,为植物长势监测、粮食产量预测提供可靠数据源.%Leaf area index is one of the important structural parameters to ensure land surface ecosystem substances and the size of energy exchange, this algorithm is designed on NDVI, RVI inversion model, combine the GDAL image library and C++ language to realize. It has achieved the operational flow from image data to leaf area index map, which improve the utilization rate of image data. The algorithm runs stable and accurate by the test of pretreatment Hyperion data, and provides reliable data for plant growth monitoring, forecast the grain production.

  18. Measuring Effective Leaf Area Index, Foliage Profile, and Stand Height in New England Forest Stands Using a Full-Waveform Ground-Based Lidar

    Science.gov (United States)

    Zhao, Feng; Yang, Xiaoyuan; Schull, Mithcell A.; Roman-Colon, Miguel O.; Yao, Tian; Wang, Zhuosen; Zhang, Qingling; Jupp, David L. B.; Lovell, Jenny L.; Culvenor, Darius; hide

    2011-01-01

    Effective leaf area index (LAI) retrievals from a scanning, ground-based, near-infrared (1064 nm) lidar that digitizes the full return waveform, the Echidna Validation Instrument (EVI), are in good agreement with those obtained from both hemispherical photography and the Li-Cor LAI-2000 Plant Canopy Analyzer. We conducted trials at 28 plots within six stands of hardwoods and conifers of varying height and stocking densities at Harvard Forest, Massachusetts, Bartlett Experimental Forest, New Hampshire, and Howland Experimental Forest, Maine, in July 2007. Effective LAI values retrieved by four methods, which ranged from 3.42 to 5.25 depending on the site and method, were not significantly different ( b0.1 among four methods). The LAI values also matched published values well. Foliage profiles (leaf area with height) retrieved from the lidar scans, although not independently validated, were consistent with stand structure as observed and as measured by conventional methods. Canopy mean top height, as determined from the foliage profiles, deviated from mean RH100 values obtained from the Lidar Vegetation Imaging Sensor (LVIS) airborne large-footprint lidar system at 27 plots by .0.91 m with RMSE=2.04 m, documenting the ability of the EVI to retrieve stand height. The Echidna Validation Instrument is the first realization of the Echidna lidar concept, devised by Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO), for measuring forest structure using full-waveform, ground-based, scanning lidar.

  19. USGS 1:1,000,000-Scale Urban Areas of the United States 201504 Shapefile

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set includes urban areas in the United States, Puerto Rico, and the U.S. Virgin Islands. The data were derived from the 2010 TIGER/Line Urban Areas data...

  20. Corrective Action Plan for Corrective Action Unit 424: Area 3 Landfill Complex, Tonopah Test Range, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Bechtel Nevada

    1998-08-31

    This corrective action plan provides the closure implementation methods for the Area 3 Landfill Complex, Corrective Action Unit (CAU) 424, located at the Tonopah Test Range. The Area 3 Landfill Complex consists of 8 landfill sites, each designated as a separate corrective action site.

  1. 31 CFR 585.218 - Trade in United Nations Protected Areas of Croatia and those areas of the Republic of Bosnia and...

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Trade in United Nations Protected... HERZEGOVINA SANCTIONS REGULATIONS Prohibitions § 585.218 Trade in United Nations Protected Areas of Croatia... importation from, exportation to, or transshipment of goods through the United Nations Protected Areas in...

  2. Área foliar e número de flores de nastúrcio sob duas densidades de plantio Leaf area and flower number of nasturtium in two plant densities

    Directory of Open Access Journals (Sweden)

    Sidinei José Lopes

    2007-06-01

    Full Text Available Estimou-se a área foliar do nastúrcio (Tropaeolum majus L. por métodos não destrutivos e determinou-se a variação temporal da área foliar e do número de flores sob duas densidades de plantas em dois experimentos, em estufa plástica, na UFSM. No primeiro experimento calculou-se a área foliar a partir da análise de 50 folhas, provenientes de dez plantas, através de imagens digitais, relacionando-a à estimativa da área foliar feita a partir de discos foliares. Correlacionou-se também a área foliar à medida de quatro diagonais das folhas: medida sobre a nervura principal, perpendicular à nervura principal e duas medidas transversais à nervura principal. Obteve-se coeficiente de determinação (r² de 0,94 (p Two experiments were conducted in a plastic greenhouses in Santa Maria, Rio Grande do Sul State, Brazil, to estimate the nasturtium (Tropaeolum majus L. leaf area through non destructive methods, as well as to study the leaf area and flower number variation in time, in two planting densities. In the first experiment, leaf area was assessed using 50 leaves harvested out of ten plants through digital image. This calculated value was then compared to leaf area estimation obtained using leaf disks. In addition, leaf area was correlated to the following leaf diagonals: main rib, perpendicular to the main rib, and two transversal measures to the main rib. A determination coefficient (r² of 0,94 (p<0,05 was obtained for leaf area calculated through digital images and leaf disks. The leaf area formula 0,8906x², where x corresponds to the measure on the main rib, presented the largest determination coefficient (r² = 0,99; p<0,05 among the four tested diagonals. In the second experiment, two plant densities were tested: 0.60 x 0.50 m and 0.30 x 0.25 respectively between plants and rows. For each plant density, leaf area was estimated using the equation adjusted for the length of the main rib. Main rib was measured in all leaves

  3. Examining variation in the leaf mass per area of dominant species across two contrasting tropical gradients in light of community assembly.

    Science.gov (United States)

    Neyret, Margot; Bentley, Lisa Patrick; Oliveras, Imma; Marimon, Beatriz S; Marimon-Junior, Ben Hur; Almeida de Oliveira, Edmar; Barbosa Passos, Fábio; Castro Ccoscco, Rosa; Dos Santos, Josias; Matias Reis, Simone; Morandi, Paulo S; Rayme Paucar, Gloria; Robles Cáceres, Arturo; Valdez Tejeira, Yolvi; Yllanes Choque, Yovana; Salinas, Norma; Shenkin, Alexander; Asner, Gregory P; Díaz, Sandra; Enquist, Brian J; Malhi, Yadvinder

    2016-08-01

    Understanding variation in key functional traits across gradients in high diversity systems and the ecology of community changes along gradients in these systems is crucial in light of conservation and climate change. We examined inter- and intraspecific variation in leaf mass per area (LMA) of sun and shade leaves along a 3330-m elevation gradient in Peru, and in sun leaves across a forest-savanna vegetation gradient in Brazil. We also compared LMA variance ratios (T-statistics metrics) to null models to explore internal (i.e., abiotic) and environmental filtering on community structure along the gradients. Community-weighted LMA increased with decreasing forest cover in Brazil, likely due to increased light availability and water stress, and increased with elevation in Peru, consistent with the leaf economic spectrum strategy expected in colder, less productive environments. A very high species turnover was observed along both environmental gradients, and consequently, the first source of variation in LMA was species turnover. Variation in LMA at the genus or family levels was greater in Peru than in Brazil. Using dominant trees to examine possible filters on community assembly, we found that in Brazil, internal filtering was strongest in the forest, while environmental filtering was observed in the dry savanna. In Peru, internal filtering was observed along 80% of the gradient, perhaps due to variation in taxa or interspecific competition. Environmental filtering was observed at cloud zone edges and in lowlands, possibly due to water and nutrient availability, respectively. These results related to variation in LMA indicate that biodiversity in species rich tropical assemblages may be structured by differential niche-based processes. In the future, specific mechanisms generating these patterns of variation in leaf functional traits across tropical environmental gradients should be explored.

  4. High NDVI and Potential Canopy Photosynthesis of South American Subtropical Forests despite Seasonal Changes in Leaf Area Index and Air Temperature

    Directory of Open Access Journals (Sweden)

    Piedad M. Cristiano

    2014-02-01

    Full Text Available The canopy photosynthesis and carbon balance of the subtropical forests are not well studied compared to temperate and tropical forest ecosystems. The main objective of this study was to assess the seasonal dynamics of Normalized Difference Vegetation Index (NDVI and potential canopy photosynthesis in relation to seasonal changes in leaf area index (LAI, chlorophyll concentration, and air temperatures of NE Argentina subtropical forests throughout the year. We included in the analysis several tree plantations (Pinus, Eucalyptus and Araucaria species that are known to have high productivity. Field studies in native forests and tree plantations were conducted; stem growth rates, LAI and leaf chlorophyll concentration were measured. MODIS satellite-derived LAI (1 km SIN Grid and NDVI (250m SIN Grid from February 2000 to 2012 were used as a proxy of seasonal dynamics of potential photosynthetic activity at the stand level. The remote sensing LAI of the subtropical forests decreased every year from 6 to 5 during the cold season, similar to field LAI measurements, when temperatures were 10 °C lower than during the summer. The yearly maximum NDVI values were observed during a few months in autumn and spring (March through May and November, respectively because high and low air temperatures may have a small detrimental effect on photosynthetic activity during both the warm and the cold seasons. Leaf chlorophyll concentration was higher during the cold season than the warm season which may have a compensatory effect on the seasonal variation of the NDVI values. The NDVI of the subtropical forest stands remained high and fairly constant throughout the year (the intra-annual coefficient of variation was 1.9%, and were comparable to the values of high-yield tree plantations. These results suggest that the humid subtropical forests in NE Argentina potentially could maintain high canopy photosynthetic activity throughout the year and thus this ecosystem may

  5. 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.

  6. Engineering report on the Grayburg Cooperative and unit area, Eddy County, New Mexico

    Science.gov (United States)

    Barnett, John A.; Soyster, Merwin H.

    1945-01-01

    This report covers the area committed to the Grayburg Cooperative and Unit Agreement (I-Sec. 370) approved by the Assistant Secretary of the Interior on October 5, 1943, hereafter referred to as the "unit area", embracing 4,769.44 acres of public land in T. 17 S., Rs. 29 and 30 E., Eddy County, New Mexico. The area includes portions of the Anderson, Grayburg-Jackson, and Leonard oil fields as defined for proration purposes by the New Mexico Oil Conservation Commission. The unit area is covered by Federal oil and gas leases owned by the Grayburg Oil Company of New Mexico and the Western Production Company, Inc. The Grayburg Unit Association has been formed and designated to conduct and manage all operations in the unit area. As of December 31, 1943, there were forty-six producing oil wells within the unit area. The report has been prepared for the purpose of assisting the Grayburg Unit Association in determining the proper locations of gas-injection wells and the best methods for future operation of the pressure-maintenance system that is being installed for the purpose of retarding the reservoir pressure decline and increasing the ultimate recovery of oil from the Grayburg Zone defined in the above-mentioned agreement as formations not more than 3300 feet below the surface. Data used in the report were obtained from records on file in the Geological Survey office at Roswell, New Mexico, and from the records of the Western Production Company and the Grayburg Oil Company. All data were carefully checked as to accuracy with engineers and field representatives of both companies.

  7. Estimation of leaf area of dominant mangrove plants in Quanzhou Bay Estuarine wetland%泉州湾河口湿地主要红树植物叶面积测算

    Institute of Scientific and Technical Information of China (English)

    付为国; 汤涓涓; 吴沿友

    2012-01-01

    植物叶面积的测算对于评价生态系统初级生产力具有重要意义.本研究分别选用“最大叶长”、“最大叶宽”以及“最大叶长×最大叶宽”等指标,利用不同类型的线性或非线性回归方程,对泉州湾河口湿地主要红树植物秋茄、桐花树和白骨壤的叶面积进行测算,从而确定各自最佳拟合回归方程.结果表明:二元非线性回归方程Y=0.7297X10.8698 X2.11600、幂指数方程Y=0.9740X0.9634和Y=0.7773X 0.9954分别为秋茄、桐花树和白骨壤叶面积的最佳拟合回归方程.进一步的0-1回归检验和相对误差值分析显示,以上回归方程均能精确地估算各自的叶面积,其中,白骨壤叶面积测算更为精确.%Estimation of leaf area of plant was of great significance for the evaluation of the primary productivity of the , ecosystem. Leaf area of dominant mangrove plants, Kandelia candel, Aegiceras corniculatum, and Avicennia mari-nawere estimated with the indices of maximum leaf length, maximum leaf width, and maximum leaf length X maximum leaf width by using different types of linear or nonlinear regression equations. Then the best fitted regression e-quation for each mangrove plant was determined,respectively. The results showed that the binary non-linear regression equation Y=0. 7297X0.8598 1 X1.1600 2 was optimal fitted regression equation for estimation of leaf area of Kandelia candel.while the exponential equation Y=0. 9740X0.9634 and Y=0. 7773X0.9954 were very suitable for estimation of leaf area of Aegiceras corniculatum and Avicennia marina .respectively. Regression testing of 0 -1 and analysis of coefficient of variation showed that the above regression equation could accurately estimate their leaf areas,especially more accurate for estimation of leaf area of A. marina.

  8. Genetic control and combining ability of flag leaf area and relative water content traits of bread wheat cultivars under drought stress condition

    Directory of Open Access Journals (Sweden)

    Golparvar Ahmad Reza

    2013-01-01

    Full Text Available In order to compare mode of inheritance, combining ability, heterosis and gene action in genetic control of traits flag leaf area, relative water content and grain filling rate of bread wheat under drought stress, a study was conducted on 8 cultivars using of Griffing’s method2 in fixed model. Mean square of general combining ability was significant also for all traits and mean square of specific combining ability was significant also for all traits except relative water content of leaf which show importance of both additive and dominant effects of genes in heredity of these traits under stress. GCA to SCA mean square ratio was significant for none of traits. Results of this study showed that non additive effects of genes were more important than additive effect for all traits. According to results we can understand that genetic improvement of mentioned traits will have low genetic efficiency by selection from the best crosses of early generations. Then it is better to delay selection until advanced generations and increase in heritability of these traits.

  9. Corrective Action Plan for Corrective Action Unit 490: Station 44 Burn Area, Tonopah Test Range, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    K. B. Campbell

    2002-04-01

    Corrective Action Unit (CAU) 490, Station 44 Burn Area is located on the Tonopah Test Range (TTR). CAU 490 is listed in the Federal Facility Agreement and Consent Order (FFACO, 1996) and includes for Corrective Action Sites (CASs): (1) Fire Training Area (CAS 03-56-001-03BA); (2) Station 44 Burn Area (CAS RG-56-001-RGBA); (3) Sandia Service Yard (CAS 03-58-001-03FN); and (4) Gun Propellant Burn Area (CAS 09-54-001-09L2).

  10. Effects of age-related increases in sapwood area, leaf area, and xylem conductivity on height-related hydraulic costs in two contrasting coniferous species

    Science.gov (United States)

    Jean-Christophe Domec; Barbara Lachenbruch; Michele L. Pruyn; Rachel Spicer

    2012-01-01

    Introduction: Knowledge of vertical variation in hydraulic parameters would improve our understanding of individual trunk functioning and likely have important implications for modeling water movement to the leaves. Specifically, understanding how foliage area (Al), sapwood area (As), and hydraulic specific...

  11. 福州市常见植物比叶面积研究%Research on the Specific Leaf Area of Common Plants in Fuzhou City

    Institute of Scientific and Technical Information of China (English)

    程栋梁; 林娜

    2009-01-01

    [目的]研究不同植物的比叶面积与叶生物量的相关关系.[方法]以福州市24种常见绿化植物为试验对象,测定了其叶片干鲜重、叶面积及比叶面积并研究了不同物种的比叶面积对生物量增加的响应模式.[结果]回归分析表明,所有试验植物的叶面积(L_A)与叶生物量(L_M)均呈极显著正相关关系,6种植物在L_A与L_M之间的异速生长指数大于1.0,18种植物的异速生长指数小于1.0,24个植物物种异速生长指数的平均值为0.96.L_A与(L_M)0.94成正比.所有试验植物的叶片水分含量(M_W)与L_M均呈极显著正相关关系,8种植物在M_W与L_M之间的异速生长指数大于1.0,2种植物的异速生长指数为1.0,14种植物的异速生长指数小于1.0.M_W与(L_M)0.96成正比.[结论]不同物种的叶面积和叶生物量之间的异速生长指数和常数存在显著差异.%[Objective] The aim was to research the correlations between specific leaf area (SLA) and leaf biomass (L_M) of different plant species. [ Method] With the 24 common greening plant species in Fuzhou City as test objects,their dry and fresh leaf weights, leaf areas (L_A) and SLA were measured and the response models of SLA to biomass increasing of different species were researched. [ Result] The regression analysis showed that the L_A of all the tested plants showed extremely significantly positive correlation with their L_M; the allometry indexes between L_A, and LM of 6 plant species were bigger than 1.0 and that of 18 plant species were smaller than 1.0; the average allometry index of the 24 plant species was 0.96. L_A was proportional to (L_M) ~(0.94). The water content in leaf ( M_W ) of all the tested plants showed extremely significantly positive correlation with their L_M; the allometry indexes between M_W and L_M of S plant species were bigger than 1.0.that of 2 plant species were 1.0 and that of 14 plant species were smaller than 1.0 M_W was proportional to (L_M)~(0

  12. Área foliar de duas trepadeiras infestantes de cana-de-açúcar utilizando dimensões lineares de folhas Foliar area estimate of two sugarcane-infesting weeds using leaf blade linear dimensions

    Directory of Open Access Journals (Sweden)

    N.P. Cardozo

    2009-01-01

    Full Text Available Esta pesquisa teve como objetivo obter uma equação, por meio de medidas lineares dimensionais das folhas, que permitisse a estimativa da área foliar de Momordica charantia e Pyrostegia venusta. Entre maio e dezembro de 2007, foram estudadas as correlações entre a área folia real (Sf e as medidas dimensionais do limbo foliar, como o comprimento ao longo da nervura principal (C e a largura máxima (L perpendicular à nervura principal. Todas as equações, exponenciais geométricas ou lineares simples, permitiram boas estimativas da área foliar. Do ponto de vista prático, sugere-se optar pela equação linear simples envolvendo o produto C x L, considerando-se o coeficiente linear igual a zero. Desse modo, a estimativa da área foliar de Momordica charantia pode ser feita pela fórmula Sf = 0,4963 x (C x L, e a de Pyrostegia venusta, por Sf = 0,6649 x (C x L.The aim of this study was to obtain a mathematical equation to estimate the leaf area of Momordica charantia and Pyrostegia venusta using linear leaf blade measurements. Correlation studies were conducted involving real leaf area (Sf and leaf length (C, maximum leaf width (L and C x L. The linear and geometric equations involving parameter C provided good leaf area estimates. From a practical viewpoint, the simple linear equation of the regression model is suggested using the C x L parameter, i.e., considering the linear coefficient equal to zero. Thus, leaf area estimate of Momordica charantia can be obtained by using the equation Sf = 0.4963 x (C x L, and that of Pyrostegia venusta by using equation Sf = 0.6649 x (C x L.

  13. Variability of leaf characteristics in different pedunculate oak genotypes (Ouercus robur L

    Directory of Open Access Journals (Sweden)

    Nikolić Nataša P.

    2006-01-01

    Full Text Available The objective of this study was to determine genotype influences on pedunculate oak's leaf traits: leaf area, specific leaf area (leaf area per unit of leaf mass, concentration of photosynthetic pigments, rates of photosynthesis and respiration, and nutrient concentrations (nitrogen phosphorus, potassium, calcium, and sodium. Leaf samples were taken from seventeen Q. robur genotypes originating from clonal seed orchard Banov Brod (Srem, Vojvodina, Serbia. Leaf area of the studied genotypes ranged from 248.4 to 628.8 cm2, SLA from 109.4 to 160.7 cm2 dry matter-1, rates of photosynthesis and respiration from 6.98 to 20.32 and from 6.73 to 14.65 µmol O2 m-2 s-1, respectively. The leaves of genotype 35 contained the highest concentration of photosynthetic pigments, while the lowest were recorded in genotype 29. The following pattern of nutrient concentrations was obtained for the studied genotypes: N>Ca>K>P>Na. Genotype variability of P K, Ca, and Na concentrations was more pronounced when compared with nitrogen. Estimated quantitative differences are the consequence of interaction of certain genotype and common environmental conditions for all trees. These results will provide information on intraspecific variation of the studied leaf characteristics.

  14. A data fusion Kalman filter algorithm to estimate leaf area index evolution by using Modis LAI and PROBA-V top of canopy synthesis data

    Science.gov (United States)

    Novelli, Antonio

    2016-08-01

    Leaf Area Index (LAI) is essential in ecosystem and agronomic studies, since it measures energy and gas exchanges between vegetation and atmosphere. In the last decades, LAI values have widely been estimated from passive remotely sensed data. Common approaches are based on semi-empirical/statistic techniques or on radiative transfer model inversion. Although the scientific community has been providing several LAI retrieval methods, the estimated results are often affected by noise and measurement uncertainties. The sequential data assimilation theory provides a theoretical framework to combine an imperfect model with incomplete observation data. In this document a data fusion Kalman filter algorithm is proposed in order to estimate the time evolution of LAI by combining MODIS LAI data and PROBA-V surface reflectance data. The reflectance data were linked to LAI by using the Reduced Simple Ratio index. The main working hypotheses were lacking input data necessary for climatic models and canopy reflectance models.

  15. A model of canopy irradiance in relation to changing leaf area in a phytotron-grown snap bean ( Phaseolus vulgaris L.) Crop

    Science.gov (United States)

    Lieth, J. H.; Reynolds, J. F.

    1984-03-01

    Simple exponential decay models were used to describe the variation in irradiance profiles within a snap bean ( Phaseolus vulgaris L.) canopy over a 33-day period of canopy development. The extinction coefficients of these models were varied over time as a function of changing canopy leaf area; nonlinear least-squares procedures were used to estimate parameter values. The resultant model response surfaces depict the changes in canopy irradiance that accompany canopy maturation and illustrate the dynamic nature of canopy closure. A criterion index is defined to aid in assessing the applicability of these models for use in whole-plant simulation models, and an evaluation of these models is given based on this index, their predictive accuracy, and the utility for use within varying modeling frameworks.

  16. Baseline groundwater model update for p-area groundwater operable unit, NBN

    Energy Technology Data Exchange (ETDEWEB)

    Ross, J. [Savannah River Site (SRS), Aiken, SC (United States); Amidon, M. [Savannah River Site (SRS), Aiken, SC (United States)

    2015-09-01

    This report documents the development of a numerical groundwater flow and transport model of the hydrogeologic system of the P-Area Reactor Groundwater Operable Unit at the Savannah River Site (SRS) (Figure 1-1). The P-Area model provides a tool to aid in understanding the hydrologic and geochemical processes that control the development and migration of the current tritium, tetrachloroethene (PCE), and trichloroethene (TCE) plumes in this region.

  17. Assimilation of Soil Wetness Index and Leaf Area Index into the ISBA-A-gs land surface model: grassland case study

    Directory of Open Access Journals (Sweden)

    A. L. Barbu

    2011-02-01

    Full Text Available The performance of the joint assimilation in a land surface model of a Soil Wetness Index (SWI product provided by an exponential filter together with Leaf Area Index (LAI is investigated. The data assimilation is evaluated with different setups using the SURFEX modeling platform, for a period of seven years (2001–2007, at the SMOSREX grassland site in southwestern France. The results obtained with a Simplified Extended Kalman Filter demonstrate the effectiveness of a joint data assimilation scheme when both SWI and Leaf Area Index are merged into the ISBA-A-gs land surface model. The assimilation of a retrieved Soil Wetness Index product presents several challenges that are investigated in this study. A significant improvement of around 13% of the root-zone soil water content is obtained by assimilating dimensionless root-zone SWI data. For comparison, the assimilation of in situ surface soil moisture is considered as well. A lower impact on the root zone is noticed. Under specific conditions, the transfer of the information from the surface to the root zone was found not accurate. Also, our results indicate that the assimilation of in situ LAI data may correct a number of deficiencies in the model, such as low LAI values in the senescence phase by using a seasonal-dependent error definition for background and observations. In order to verify the specification of the errors for SWI and LAI products, a posteriori diagnostics are employed. This approach highlights the importance of the assimilation design on the quality of the analysis. The impact of data assimilation scheme on CO2 fluxes is also quantified by using measurements of net CO2 fluxes gathered at the SMOSREX site from 2005 to 2007. An improvement of about 5% in terms of rms error is obtained.

  18. Baseline risk assessment for groundwater operable units at the Chemical Plant Area and the Ordnance Works Area, Weldon Spring, Missouri

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-07-14

    The U.S. Department of Energy (DOE) and the U.S. Department of the Army (DA) are evaluating conditions in groundwater and springs at the DOE chemical plant area and the DA ordnance works area near Weldon Spring, Missouri. The two areas are located in St. Charles County, about 48 km (30 mi) west of St. Louis. The 88-ha (217-acre) chemical plant area is chemically and radioactively contaminated as a result of uranium-processing activities conducted by the U.S. Atomic Energy Commission in the 1950s and 1960s and explosives-production activities conducted by the U.S. Army (Army) in the 1940s. The 6,974-ha (17,232-acre) ordnance works area is primarily chemically contaminated as a result of trinitrotoluene (TNT) and dinitrotoluene (DNT) manufacturing activities during World War II. This baseline risk assessment (BRA) is being conducted as part of the remedial investigation/feasibility study (RUFS) required under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980, as amended. The purpose of the BRA is to evaluate potential human health and ecological impacts from contamination associated with the groundwater operable units (GWOUs) of the chemical plant area and ordnance works area. An RI/FS work plan issued jointly in 1995 by the DOE and DA (DOE 1995) analyzed existing conditions at the GWOUs. The work plan included a conceptual hydrogeological model based on data available when the report was prepared; this model indicated that the aquifer of concern is common to both areas. Hence, to optimize further data collection and interpretation efforts, the DOE and DA have decided to conduct a joint RI/BRA. Characterization data obtained from the chemical plant area wells indicate that uranium is present at levels slightly higher than background, with a few concentrations exceeding the proposed U.S. Environmental Protection Agency (EPA) maximum contaminant level (MCL) of 20 {micro}g/L (EPA 1996c). Concentrations of other radionuclides (e

  19. Closure Report for Corrective Action Unit 230: Area 22 Sewage Lagoons and Corrective Action Unit 320: Area 22 Desert Rock Airport Strainer Box Nevada Test Site, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    D. S. Tobiason

    2001-07-01

    This Closure Report (CR) describes the remediation activities performed and the results of verification sampling conducted at Corrective Action Unit (CAU) 230, Area 22 Sewage Lagoons and CAU 320, Area 22 Desert Rock Airport Strainer Box. The CAU is currently listed in Appendix III of the Federal Facility Agreement and Consent Order (FFACO, 1996). The CAU is located in Area 22 of the Nevada Test Site (NTS) (Figure 1) and consists of the following Corrective Action Sites (CASs): 22-03-01- Sewage Lagoon (CAU 230); and 22-99-01- Strainer Box (CAU 320). Included with CAS 22-99-01 is a buried Imhoff tank and a sludge bed. These CAUs will be collectively referred to in this plan as the Area 22 Sewage Lagoons site. Site characterization activities were done during September 1999. Characterization of the manholes associated with the septic system leading to the Imhoff tank was done during March 2000. The results of the characterization presented in the Corrective Action Decision Document (CADD) indicated that only the sludge bed (CAS 22-99-01) contained constituents of concern (COC) above action levels and required remediation (U.S. Department of Energy, Nevada Operations Office [DOE/NV], 2000a).

  20. EP BASED PSO METHOD FOR SOLVING PROFIT BASED MULTI AREA UNIT COMMITMENT PROBLEM

    Directory of Open Access Journals (Sweden)

    K. VENKATESAN

    2015-04-01

    Full Text Available This paper presents a new approach to solve the profit based multi area unit commitment problem (PBMAUCP using an evolutionary programming based particle swarm optimization (EPPSO method. The objective of this paper is to maximize the profit of generation companies (GENCOs with considering system social benefit. The proposed method helps GENCOs to make a decision, how much power and reserve should be sold in markets, and how to schedule generators in order to receive the maximum profit. Joint operation of generation resources can result in significant operational cost savings. Power transfer between the areas through the tie lines depends upon the operating cost of generation at each hour and tie line transfer limits. The tie line transfer limits were considered as a set of constraints during optimization process to ensure the system security and reliability. The overall algorithm can be implemented on an IBM PC, which can process a fairly large system in a reasonable period of time. Case study of four areas with different load pattern each containing 7 units (NTPS and 26 units connected via tie lines have been taken for analysis. Numerical results showed comparing the profit of evolutionary programming-based particle swarm optimization method (EPPSO with conventional dynamic programming (DP, evolutionary programming (EP, and particle swarm optimization (PSO method. Experimental results shows that the application of this evolutionary programming based particle swarm optimization method have the potential to solve profit based multi area unit commitment problem with lesser computation time.

  1. Climate change impacts on extreme temperature mortality in select metropolitan areas of the United States

    Science.gov (United States)

    Projected mortality from climate change-driven impacts on extremely hot and cold days increases significantly over the 21st century in a large group of United States Metropolitan Statistical Areas. Increases in projected mortality from more hot days are greater than decreases in ...

  2. Hydrologic resources management program and underground test area operable unit fy 1997

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D. F., LLNL

    1998-05-01

    This report present the results of FY 1997 technical studies conducted by the Lawrence Livermore National Laboratory (LLNL) as part of the Hydrology and Radionuclide Migration Program (HRMP) and Underground Test Area Operable Unit (UGTA). The HRMP is sponsored by the US Department of Energy to assess the environmental (radiochemical and hydrologic) consequences of underground nuclear weapons testing at the Nevada Test Site.

  3. Natural Environments, Obesity, and Physical Activity in Nonmetropolitan Areas of the United States

    Science.gov (United States)

    Michimi, Akihiko; Wimberly, Michael C.

    2012-01-01

    Purpose: To assess the associations of the natural environment with obesity and physical activity in nonmetropolitan areas of the United States among representative samples by using 2 indices of outdoor activity potential (OAP) at the county level. Methods: We used the data from 457,820 and 473,296 noninstitutionalized adults aged over 18 years…

  4. A diagram for defined solar radiation absorbed per unit area of flat plate solar collectors

    Energy Technology Data Exchange (ETDEWEB)

    Tekin, Y.; Altuntop, N. [Erciyes University, Dept. of Mechanical Engineering (Turkey); Cengel, Y.A. [Nevada Reno University, Dept. of Mechanical Engineering, NV (United States); Cengel, Y.A. [Nevada University, Dept. Mechanical Engineering, Reno, NV (United States)

    2000-07-01

    In Erciyes University, the Solar House (28.75 m{sup 2}) is heated from the floor by using flat plate liquid solar collectors. Required solar radiation for heating and heat losses are calculated. In this work, the required calculations for Erciyes Solar House were generalized and required calculation were done to evaluate absorbed solar radiation per unit surface of the flat plate liquid collector. At the end, three generalized diagrams for nine different months are obtained using obtained numerical values. The goal of preparing diagrams is to determine absorbed solar radiation per unit surface area of flat plate liquid collector at any instant at any latitude, In this work, the diagram is explained by means of sample calculations for November. This diagram was prepared to find out absorbed solar radiation per unit area of black surface collector by means obtained equations. With this diagram, all instant solar radiation can be evaluated in 19 steps. (authors)

  5. Interim Status Closure Plan Open Burning Treatment Unit Technical Area 16-399 Burn Tray

    Energy Technology Data Exchange (ETDEWEB)

    Vigil-Holterman, Luciana R. [Los Alamos National Laboratory

    2012-05-07

    This closure plan describes the activities necessary to close one of the interim status hazardous waste open burning treatment units at Technical Area (TA) 16 at the Los Alamos National Laboratory (LANL or the Facility), hereinafter referred to as the 'TA-16-399 Burn Tray' or 'the unit'. The information provided in this closure plan addresses the closure requirements specified in the Code of Federal Regulations (CFR), Title 40, Part 265, Subparts G and P for the thermal treatment units operated at the Facility under the Resource Conservation and Recovery Act (RCRA) and the New Mexico Hazardous Waste Act. Closure of the open burning treatment unit will be completed in accordance with Section 4.1 of this closure plan.

  6. Corrective Action Investigation Plan for Corrective Action Unit 374: Area 20 Schooner Unit Crater Nevada Test Site, Nevada, Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    Patrick Matthews

    2010-02-01

    Corrective Action Unit 374 is located in Areas 18 and 20 of the Nevada Test Site, which is approximately 65 miles northwest of Las Vegas, Nevada. Corrective Action Unit 374 comprises the five corrective action sites (CASs) listed below: • 18-22-05, Drum • 18-22-06, Drums (20) • 18-22-08, Drum • 18-23-01, Danny Boy Contamination Area • 20-45-03, U-20u Crater (Schooner) These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives (CAAs). Additional information will be obtained by conducting a corrective action investigation before evaluating CAAs and selecting the appropriate corrective action for each CAS. The results of the field investigation will support a defensible evaluation of viable CAAs that will be presented in the Corrective Action Decision Document. The sites will be investigated based on the data quality objectives (DQOs) developed on October 20, 2009, by representatives of the Nevada Division of Environmental Protection and the U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office. The DQO process was used to identify and define the type, amount, and quality of data needed to develop and evaluate appropriate corrective actions for CAU 374.

  7. Disentangling leaf area and environmental effects on the response of the net ecosystem CO2 exchange to diffuse radiation.

    Science.gov (United States)

    Wohlfahrt, Georg; Hammerle, Albin; Haslwanter, Alois; Bahn, Michael; Tappeiner, Ulrike; Cernusca, Alexander

    2008-08-01

    There is an ongoing discussion about why the net ecosystem CO2 exchange (NEE) of some ecosystems is less sensitive to diffuse radiation than others and about the role other environmental factors play in determining the response of NEE to diffuse radiation. Using a six-year data set from a temperate mountain grassland in Austria we show that differences between ecosystems may be reconciled based on their green area index (GAI; square meter green plant area per square meter ground area) - the sensitivity to diffuse radiation increasing with GAI. Our data suggest diffuse radiation to have a negligible influence on NEE below a GAI of 2 m(2) m(-2). Changes in air/soil temperature and air humidity concurrent with the fraction of diffuse radiation were found to amplify the sensitivity of the investigated temperate mountain grassland ecosystem to diffuse radiation.

  8. [C and N allocation patterns in planted forests and their release patterns during leaf litter decomposition in subalpine area of west Sichuan].

    Science.gov (United States)

    Liu, Zeng-wen; Duan, Er-jun; Pan, Kai-wen; Zhang, Li-ping; Du, Hong-xia

    2009-01-01

    With the planted forest ecosystems of Cercidiphyllum japonicum, Betula utilis, Pinus yunnansinsis, and Picea asperata in subalpine area of west Sichuan as test objects, their total biomass and the C and N contents in soils and tree organs were determined. The results showed that the allocation of C in tree organs had less correlation with the age of the organs, while that of N and C/N ratio had closer relationship with the age. The N content in young organs was higher than that in aged ones, whereas the C/N ratio was higher in aged organs than in young organs, and higher in the leaf litters of needle-leaved forests than in those of broad-leaved forests. There was an obvious enrichment of C and N in the topsoil of test forests. The accumulated amounts of C and N in the whole planted forest ecosystem, including tree, litter, and 0-40 cm soil layer, were 176.75-228.05 t x hm(-2) and 11.06-16.54 t x hm(-2), respectively, and the nutrients allocation ratio between soil-litter and tree was (1.9-3.3):1 for C and (15.6-41.5):1 for N. Needle-leaved forests functioned as a stronger "C-sink" than broad-leaved forests. The decomposition rate of the leaf litters in needle-leaved forests was larger than that in broad-leaved forests, with the turnover rate being 2.2-3.7 years and 3.9-4.2 years, respectively. During the decomposition of leaf litter, the C in all of the four forests released at super-speed, with the turnover rate being 1.9-3.4 years. As for N, it also released at super-speed in C. japonicum and B. utilis forests, with the turnover rate being 1.9-3.2 years, but released at low speed in P. yunnansinsis and P. asperata forests, with the turnover rate being 6.7-8.5 years.

  9. Soil Moisture Mapping in an Arid Area Using a Land Unit Area (LUA Sampling Approach and Geostatistical Interpolation Techniques

    Directory of Open Access Journals (Sweden)

    Saeid Gharechelou

    2016-03-01

    Full Text Available Soil moisture (SM plays a key role in many environmental processes and has a high spatial and temporal variability. Collecting sample SM data through field surveys (e.g., for validation of remote sensing-derived products can be very expensive and time consuming if a study area is large, and producing accurate SM maps from the sample point data is a difficult task as well. In this study, geospatial processing techniques are used to combine several geo-environmental layers relevant to SM (soil, geology, rainfall, land cover, etc. into a land unit area (LUA map, which delineates regions with relatively homogeneous geological/geomorphological, land use/land cover, and climate characteristics. This LUA map is used to guide the collection of sample SM data in the field, and the field data is finally spatially interpolated to create a wall-to-wall map of SM in the study area (Garmsar, Iran. The main goal of this research is to create a SM map in an arid area, using a land unit area (LUA approach to obtain the most appropriate sample locations for collecting SM field data. Several environmental GIS layers, which have an impact on SM, were combined to generate a LUA map, and then field surveying was done in each class of the LUA map. A SM map was produced based on LUA, remote sensing data indexes, and spatial interpolation of the field survey sample data. The several interpolation methods (inverse distance weighting, kriging, and co-kriging were evaluated for generating SM maps from the sample data. The produced maps were compared to each other and validated using ground truth data. The results show that the LUA approach is a reasonable method to create the homogenous field to introduce a representative sample for field soil surveying. The geostatistical SM map achieved adequate accuracy; however, trend analysis and distribution of the soil sample point locations within the LUA types should be further investigated to achieve even better results. Co

  10. Coordination of Leaf Photosynthesis, Transpiration, and Structural Traits in Rice and Wild Relatives (Genus Oryza).

    Science.gov (United States)

    Giuliani, Rita; Koteyeva, Nuria; Voznesenskaya, Elena; Evans, Marc A; Cousins, Asaph B; Edwards, Gerald E

    2013-07-01

    The genus Oryza, which includes rice (Oryza sativa and Oryza glaberrima) and wild relatives, is a useful genus to study leaf properties in order to identify structural features that control CO(2) access to chloroplasts, photosynthesis, water use efficiency, and drought tolerance. Traits, 26 structural and 17 functional, associated with photosynthesis and transpiration were quantified on 24 accessions (representatives of 17 species and eight genomes). Hypotheses of associations within, and between, structure, photosynthesis, and transpiration were tested. Two main clusters of positively interrelated leaf traits were identified: in the first cluster were structural features, leaf thickness (Thick(leaf)), mesophyll (M) cell surface area exposed to intercellular air space per unit of leaf surface area (S(mes)), and M cell size; a second group included functional traits, net photosynthetic rate, transpiration rate, M conductance to CO(2) diffusion (g(m)), stomatal conductance to gas diffusion (g(s)), and the g(m)/g(s) ratio.While net photosynthetic rate was positively correlated with gm, neither was significantly linked with any individual structural traits. The results suggest that changes in gm depend on covariations of multiple leaf (S(mes)) and M cell (including cell wall thickness) structural traits. There was an inverse relationship between Thick(leaf) and transpiration rate and a significant positive association between Thick(leaf) and leaf transpiration efficiency. Interestingly, high g(m) together with high g(m)/g(s) and a low S(mes)/g(m) ratio (M resistance to CO(2) diffusion per unit of cell surface area exposed to intercellular air space) appear to be ideal for supporting leaf photosynthesis while preserving water; in addition, thick M cell walls may be beneficial for plant drought tolerance.

  11. Distribution of leaf characteristics in relation to orientation within the canopy of woody species

    Science.gov (United States)

    Escudero, Alfonso; Fernández, José; Cordero, Angel; Mediavilla, Sonia

    2013-04-01

    Over the last few decades considerable effort has been devoted to research of leaf adaptations to environmental conditions. Many studies have reported strong differences in leaf mass per unit area (LMA) within a single tree depending on the photosynthetic photon flux density (PPFD) incident on different locations in the crown. There are fewer studies, however, of the effects of differences in the timing of light incidence during the day on different crown orientations. Leaves from isolated trees of Quercus suber and Quercus ilex in a cold Mediterranean climate were sampled to analyze differences in LMA and other leaf traits among different crown orientations. Gas-exchange rates, leaf water potentials, leaf temperatures and PPFD incident on leaf surfaces in different crown orientations were also measured throughout one entire summer day for each species. Mean daily PPFD values were similar for the leaves from the eastern and western sides of the canopy. On the western side, PPFD reached maximum values during the afternoon. Maximum leaf temperatures were approximately 10-20% higher on the west side, whereas minimum leaf water potentials were between 10 and 24% higher on the east side. Maximum transpiration rates were approximately 22% greater on the west, because of the greater leaf-to-air vapor pressure deficits (LAVPD). Mean individual leaf area was around 10% larger on the east than on the west side of the trees. In contrast, there were no significant differences in LMA between east and west sides of the crown. Contrary to our expectations, more severe water stress on the west side did not result in increases in LMA, although it was associated with lower individual leaf area. We conclude that increases in LMA measured by other authors along gradients of water stress would be due to differences in light intensity between dry and humid sites.

  12. Evaluating the condition of a mangrove forest of the Mexican Pacific based on an estimated leaf area index mapping approach.

    Science.gov (United States)

    Kovacs, J M; King, J M L; Flores de Santiago, F; Flores-Verdugo, F

    2009-10-01

    Given the alarming global rates of mangrove forest loss it is important that resource managers have access to updated information regarding both the extent and condition of their mangrove forests. Mexican mangroves in particular have been identified as experiencing an exceptional high annual rate of loss. However, conflicting studies, using remote sensing techniques, of the current state of many of these forests may be hindering all efforts to conserve and manage what remains. Focusing on one such system, the Teacapán-Agua Brava-Las Haciendas estuarine-mangrove complex of the Mexican Pacific, an attempt was made to develop a rapid method of mapping the current condition of the mangroves based on estimated LAI. Specifically, using an AccuPAR LP-80 Ceptometer, 300 indirect in situ LAI measurements were taken at various sites within the black mangrove (Avicennia germinans) dominated forests of the northern section of this system. From this sample, 225 measurements were then used to develop linear regression models based on their relationship with corresponding values derived from QuickBird very high resolution optical satellite data. Specifically, regression analyses of the in situ LAI with both the normalized difference vegetation index (NDVI) and the simple ration (SR) vegetation index revealed significant positive relationships [LAI versus NDVI (R (2) = 0.63); LAI versus SR (R (2) = 0.68)]. Moreover, using the remaining sample, further examination of standard errors and of an F test of the residual variances indicated little difference between the two models. Based on the NDVI model, a map of estimated mangrove LAI was then created. Excluding the dead mangrove areas (i.e. LAI = 0), which represented 40% of the total 30.4 km(2) of mangrove area identified in the scene, a mean estimated LAI value of 2.71 was recorded. By grouping the healthy fringe mangrove with the healthy riverine mangrove and by grouping the dwarf mangrove together with the poor condition

  13. Modelo matemático para estimativa da área foliar total de bananeira 'Prata-anã' Esteem method of total leaf area of 'Prata anã' banana tree

    Directory of Open Access Journals (Sweden)

    Moises Zucoloto

    2008-12-01

    Full Text Available O objetivo deste trabalho foi desenvolver um modelo para estimar a área foliar total de bananeira, cultivar Prata-Anã, utilizando dimensões lineares da terceira folha, como o comprimento, a largura e o número total de folhas na emissão da inflorescência. As regressões lineares foram determinadas considerando-se a área foliar total de cada planta (AFT como variável dependente e o comprimento (C e a largura (L da terceira folha, o produto de CxL, o número total de folhas por planta (N e o produto de CxLxN como variáveis independentes. O modelo linear que melhor estimou a área foliar total (AFTe da bananeira 'Prata-Anã', ao nível de 5% de significância com R² de 0,89, foi a equação AFTe = 0,5187(CxLxN + 9603,5.The objective of this work was to estimate the total leaf area of banana, cultivar Prata Anã, according to the linear dimensions of the third leaf, such as the length and the width and the total number of leves in the inflorescence emission. The linear regressions were determined considering total leaf area of each plant (AFT such as dependent variable and the length (C and the width (L of the third leaf, the product of CxL, the total number of leaf per plant (N and the product of CxLxN as independent variables. The best linear model that estimated the total leaf area (AFTe of banana 'Prata Anã' at the level of 5% of significance with R² of 0,89 was the equation AFTe = 0.5187 (CxLxN + 9603.5.

  14. Transuranic Storage Area (TSA)-2 container storage unit RCRA closure plan

    Energy Technology Data Exchange (ETDEWEB)

    Lodman, D.W.; Spry, M.J.; Nolte, E.P.; Barry, G.A.

    1992-11-01

    This document describes the proposed plans for closure of the Transuranic Storage Area (TSA)-2 container storage unit at the Idaho National Engineering Laboratory in accordance with the Resource Conservation and Recovery Act closure requirements. The location, size, capacity, history, and current status of the unit are described. Future plans for the unit include incorporating the earthen-covered portion of the TSA-2 pad into a TSA retrieval enclosure along with the TSA-1 and TSAR pads, and closure of the portion of the TSA-2 pad under the Air Support Weather Shield (ASWS-2). This plan addresses closure of the ASWS-2 by decontaminating structures and equipment that may have contacted the waste. Sufficient sampling and documentation of all closure activities will be performed to demonstrate clean closure. A tentative schedule is provided in the form of a milestone chart.

  15. CORRELATIONS OF THERMAL CONDUCTIVITY BETWEEN STRATIGRAPHIC UNITS IN THE BROADER AREA OF ZAGREB

    Directory of Open Access Journals (Sweden)

    Miron Kovačić

    2007-12-01

    Full Text Available Thermal conductivity (KTV of geological formations is one of the parameters responsible for the propagation of the heat under the earth surface. During geothermal investigations in the broader area of the Croatian capital of Zagreb the thermal conductivity was measured on the rock samples from the surface and the boreholes. The results of the measurements are presented in this work and used as a basis for calculations of the thermal conductivity of distinct geological formations within the investigated area. It was found out that the values of the thermal conductivity of the rocks in the investigated area vary greatly. The measurements are within the well known scope for certain rock types. The thermal conductivity of the rocks from the Tertiary units corresponds with the average values being typical for such kind of rocks, while the basement carbonate rocks are characterized by the values being by 1 W/K-1m-1 higher than the average. After comparing the thermal conductivity of the stratigraphic units in the broader area of Zagreb it has been established that the values of the thermal conductivity of geological formations in the investigated area are also very different, and that they generally rise with their age. The relative relationships show that the Quaternary, Pliocene and Tertiary sedimentary rocks act as thermal insulators, while Triassic rocks behave as the heat conductor (the paper is published in Croatian.

  16. Closure Report for Corrective Action Unit 143: Area 25 Contaminated Waste Dumps, Nevada Test Site, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    D. S. Tobiason

    2002-03-01

    This Closure Report (CR) has been prepared for the Area 25 Contaminated Waste Dumps (CWD), Corrective Action Unit (CAU) 143 in accordance with the Federal Facility Agreement and Consent Order [FFACO] (FFACO, 1996) and the Nevada Division of Environmental Protection (NDEP)-approved Corrective Action Plan (CAP) for CAU 143: Area 25, Contaminated Waste Dumps, Nevada Test Site, Nevada. CAU 143 consists of two Corrective Action Sites (CASs): 25-23-09 CWD No.1, and 25-23-03 CWD No.2. The Area 25 CWDs are historic disposal units within the Area 25 Reactor Maintenance, Assembly, and Disassembly (R-MAD), and Engine Maintenance, Assembly, and Disassembly (E-MAD) compounds located on the Nevada Test Site (NTS). The R-MAD and E-MAD facilities originally supported a portion of the Nuclear Rocket Development Station in Area 25 of the NTS. CWD No.1 CAS 25-23-09 received solid radioactive waste from the R-MAD Compound (East Trestle and West Trench Berms) and 25-23-03 CWD No.2 received solid radioactive waste from the E-MAD Compound (E-MAD Trench).

  17. 7 CFR 28.517 - Leaf Grade No. 7.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade No. 7. 28.517 Section 28.517 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.517 Leaf Grade No. 7. American Pima cotton which in leaf is inferior to...

  18. 7 CFR 28.514 - Leaf Grade No. 4.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade No. 4. 28.514 Section 28.514 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.514 Leaf Grade No. 4. Leaf grade No. 4 shall be American Pima cotton which...

  19. 7 CFR 28.516 - Leaf Grade No. 6.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade No. 6. 28.516 Section 28.516 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.516 Leaf Grade No. 6. Leaf grade No. 6 shall be American Pima cotton which...

  20. 7 CFR 28.513 - Leaf Grade No. 3.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade No. 3. 28.513 Section 28.513 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.513 Leaf Grade No. 3. Leaf grade No. 3 shall be American Pima cotton which...

  1. 7 CFR 28.515 - Leaf Grade No. 5.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade No. 5. 28.515 Section 28.515 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.515 Leaf Grade No. 5. Leaf grade No. 5 shall be American Pima cotton which...

  2. 7 CFR 28.511 - Leaf Grade No. 1.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade No. 1. 28.511 Section 28.511 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.511 Leaf Grade No. 1. Leaf grade No. 1 shall be American Pima cotton which...

  3. 7 CFR 28.512 - Leaf Grade No. 2.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf Grade No. 2. 28.512 Section 28.512 Agriculture..., TESTING, AND STANDARDS Standards Official Cotton Standards of the United States for the Leaf Grade of American Pima Cotton § 28.512 Leaf Grade No. 2. Leaf grade No. 2 shall be American Pima cotton which...

  4. What Is a Leaf? An Online Tutorial and Tests

    Science.gov (United States)

    Burrows, Geoffrey

    2008-01-01

    A leaf is a fundamental unit in botany and understanding what constitutes a leaf is fundamental to many plant science activities. My observations and subsequent testing indicated that many students could not confidently and consistently recognise a leaf from a leaflet, or recognise basic leaf arrangements and the various types of compound or…

  5. Corrective Action Investigation Plan for Corrective Action Unit 375: Area 30 Buggy Unit Craters, Nevada Test Site, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Patrick Matthews

    2010-03-01

    Corrective Action Unit (CAU) 375 is located in Areas 25 and 30 of the Nevada Test Site, which is approximately 65 miles northwest of Las Vegas, Nevada. Corrective Action Unit 375 comprises the two corrective action sites (CASs) listed below: • 25-23-22, Contaminated Soils Site • 30-45-01, U-30a, b, c, d, e Craters Existing information on the nature and extent of potential contamination present at the CAU 375 CASs is insufficient to evaluate and recommend corrective action alternatives (CAAs). This document details an investigation plan that will provide for the gathering of sufficient information to evaluate and recommend CAAs. Corrective Action Site 25-23-22 is composed of the releases associated with nuclear rocket testing at Test Cell A (TCA). Test Cell A was used to test and develop nuclear rocket motors as part of the Nuclear Rocket Development Station from its construction in 1958 until 1966, when rocket testing began being conducted at Test Cell C. The rocket motors were built with an unshielded nuclear reactor that produced as much as 1,100 kilowatts (at full power) to heat liquid hydrogen to 4,000 degrees Fahrenheit, at which time the expanded gases were focused out a nozzle to produce thrust. The fuel rods in the reactor were not clad and were designed to release fission fragments to the atmosphere, but due to vibrations and loss of cooling during some operational tests, fuel fragments in excess of planned releases became entrained in the exhaust and spread in the immediate surrounding area. Cleanup efforts have been undertaken at times to collect the fuel rod fragments and other contamination. Previous environmental investigations in the TCA area have resulted in the creation of a number of use restrictions. The industrial area of TCA is encompassed by a fence and is currently posted as a radioactive material area. Corrective Action Site 30-45-01 (releases associated with the Buggy Plowshare test) is located in Area 30 on Chukar Mesa. It was a

  6. Combined Genetic and Modeling Approaches Reveal That Epidermal Cell Area and Number in Leaves Are Controlled by Leaf and Plant Developmental Processes in Arabidopsis

    NARCIS (Netherlands)

    Tisne, S.; Reymond, M.; Vile, D.; Fabre, J.; Dauzat, M.; Koornneef, M.; Granier, C.

    2008-01-01

    Both leaf production and leaf expansion are tightly linked to cell expansion and cell division, but the functional relationships between all these variables are not clearly established. To get insight into these relationships, a quantitative genetic analysis was performed in 118 recombinant inbred l

  7. Current status of chrono stratigraphic units named from Belgium and adjacent areas

    Institute of Scientific and Technical Information of China (English)

    Léon Dejonghe

    2007-01-01

    @@ The recommendations of the InternationalCommission on Stratigraphy edited in 1976by Hedberg and in 1994 by Salvador havegenerally been well accepted by the Belgiancommunity of geologists as represented bynational stratigraphic subcommissions set upunder the Belgian National Committee ofGeological Sciences. However, the applica-tion of these recommendations has takensome time and the need has been felt for doc-uments to synthesise the current situationregarding stratigraphic units named fromBelgium and adjacent areas.

  8. RISK FOR MALARIA IN UNITED STATES DONORS DEFERRED FOR TRAVEL TO MALARIA-ENDEMIC AREAS

    Science.gov (United States)

    Spencer, Bryan; Steele, Whitney; Custer, Brian; Kleinman, Steven; Cable, Ritchard; Wilkinson, Susan; Wright, David

    2009-01-01

    BACKGROUND Deferral for travel to malaria-endemic areas excludes many blood donors in the United States. Most transfusion-transmitted malaria is associated with lengthy residence in malaria-endemic areas rather than routine travel. This study compares the impact of existing deferral requirements to the risk that a presenting donor with malaria travel history harbors malaria parasites under current and hypothetical alternate regulations. STUDY DESIGN AND METHODS Deferred donors from six blood centers were sampled to estimate a national cohort of donors deferred annually for malaria travel to different geographic regions. Risk for malaria infection following travel to each region, and distribution of incubation periods for each malaria species were estimated for U.S. travelers. Region-specific travel risks were used to estimate the risk that a presenting blood donor with malaria travel might asymptomatically harbor malaria parasites at different intervals following return to the United States. RESULTS Travel to Africa presents risk for malaria infection >1000 times that of travel to malaria-endemic parts of Mexico, yet Mexico accounts for >10 times as many deferred donors. Shortening the deferral period from 12 to 3 months for travelers to Mexico increases the risk of collecting a contaminated unit by only 1 unit per 57 years (sensitivity analysis, 1 every 29 - 114 years), at annual gain of >56,000 donations. CONCLUSION This study provides the first systematic appraisal of the U.S. requirements for donor qualification regarding travel to malarial areas. Consideration should be given to relaxing the guidelines for travel to very low-risk areas such as Mexico. PMID:19903290

  9. IMPACT OF SALINITY AND SODICITY ON BIOMASS, TOTAL NITROGEN, NITRATE REDUCTASE ACTIVITY, LEAF AREA, AND CHLOROPHYLL CONTENTS IN MAIZE (ZEA MAYS L.

    Directory of Open Access Journals (Sweden)

    M. GUFRAN KHAN*, SHIMELIS*, G., ALEMU, H.* AND KEBENU, F**

    2014-11-01

    Full Text Available ABSTRACT: Salinity and sodicity are major constraint in increasing crop production at global level. Millions of the hectares of the land are too saline to produce economic yield.  In Ethiopia, 11 million ha of land is salt affected, about half of these soils are saline and remaining half are saline - sodic and sodic soil. As most of the arable land and quality water resources have already been exploited, the use of saline or urban/industrial waste water may be a viable alternative for further agro production. In view of such perspectives, an investigation was conducted to examine the effect of salinity (NaCl and sodicity (Na2CO3 on  biomass, total nitrogen, nitrate reductase activity, leaf area, and chlorophyll contents in Maize (Zea mays L. plants. The appropriate amount of NaCl and Na2CO3  was  dissolved in distilled water for appraisal of artificial  salinity and sodicity levels ( 0 , 4, 8,  and 12  and  mScm-1 in soil medium. Plants were also supplied with potassium (0 and 5mM KNO3 as remedial treatment. Maize plants were analyzed for germination, early growth, biomass, total nitrogen, Nitrate reductase activity, Leaf area, and chlorophyll contents as grown under different ECe levels of salinity and sodicity. The extent of salinity and sodicity effects was compared on the basis of different parameters. It was observed that plants showed substantial reduction in all parameters due to imposition of salinity and sodicity in root medium and it was more so due to sodicity. However, the use of additional potassium brought about an enhancement in these parameters.  It is suggested that plants may be raised in saline soil and saline water however; the extent of success depends upon salinity and sodicity levels, remedial treatments and plant species. The outcome of the present work may contribute towards viable utilization of saline soil and water for enhancing agro production of suitable crops, a desired goal to achieve food security.

  10. Anatomical basis of the change in leaf mass per area and nitrogen investment with relative irradiance within the canopy of eight temperate tree species

    Science.gov (United States)

    Aranda, I.; Pardo, F.; Gil, L.; Pardos, J. A.

    2004-05-01

    Changes in leaf mass per area (LMA), nitrogen content on a mass-basis (N m) and on an area basis (N a) with relative irradiance were assessed in leaves of eight temperate species harvested at different depths in a canopy. Relative irradiance (GSF) at the points of leaf sampling was estimated by hemispheric photographs. There was a strong species-dependent positive relationship between LMA and GSF for all species. Shade-tolerant species such as Fagus sylvatica showed lower LMA for the same GSF than less tolerant species as Quercus pyrenaica or Quercus petraea. The only evergreen species in the study, Ilex aquifollium, had the highest LMA, independent of light environment, with minimum values much higher than the rest of the broad-leaved species studied. There was no relation between N m and GSF for most species studied and only a very weak relation for the relative shade-intolerant species Q. pyrenaica. Within each species, the pattern of N a investment with regard to GSF was linked mainly to LMA. At the same relative irradiance, differences in N a among species were conditioned both by the LMA-GSF relationship and by the species N m value. The lowest N m value was measured in I. aquifollium (14.3 ± 0.6 mg g -1); intermediate values in Crataegus monogyna (16.9 ± 0.6 mg g -1) and Prunus avium (19.1 ± 0.6 mg g -1) and higher values, all in a narrow range (21.3 ± 0.6 to 23 ± 0.6 mg g -1), were measured for the other five species. Changes in LMA with the relative irradiance were linked both to lamina thickness (LT) and to palisade/spongy parenchyma ratio (PP/SP). In the second case, the LMA changes may be related to an increase in lamina density as palisade parenchyma involves higher cell packing than spongy parenchyma. However, since PP/SP ratio showed a weak species-specific relationship with LMA, the increase in LT should be the main cause of LMA variation.

  11. Intraspecific relationships among wood density, leaf structural traits and environment in four co-occurring species of Nothofagus in New Zealand.

    Directory of Open Access Journals (Sweden)

    Sarah J Richardson

    Full Text Available Plant functional traits capture important variation in plant strategy and function. Recent literature has revealed that within-species variation in traits is greater than previously supposed. However, we still have a poor understanding of how intraspecific variation is coordinated among different traits, and how it is driven by environment. We quantified intraspecific variation in wood density and five leaf traits underpinning the leaf economics spectrum (leaf dry matter content, leaf mass per unit area, size, thickness and density within and among four widespread Nothofagus tree species in southern New Zealand. We tested whether intraspecific relationships between wood density and leaf traits followed widely reported interspecific relationships, and whether variation in these traits was coordinated through shared responses to environmental factors. Sample sites varied widely in environmental variables, including soil fertility (25-900 mg kg(-1 total P, precipitation (668-4875 mm yr(-1, temperature (5.2-12.4 °C mean annual temperature and latitude (41-46 °S. Leaf traits were strongly correlated with one another within species, but not with wood density. There was some evidence for a positive relationship between wood density and leaf tissue density and dry matter content, but no evidence that leaf mass or leaf size were correlated with wood density; this highlights that leaf mass per unit area cannot be used as a surrogate for component leaf traits such as tissue density. Trait variation was predicted by environmental factors, but not consistently among different traits; e.g., only leaf thickness and leaf density responded to the same environmental cues as wood density. We conclude that although intraspecific variation in wood density and leaf traits is strongly driven by environmental factors, these responses are not strongly coordinated among functional traits even across co-occurring, closely-related plant species.

  12. Impact of different leaf velocities and dose rates on the number of monitor units and the dose-volume-histograms using intensity modulated radiotherapy with sliding-window technique

    Directory of Open Access Journals (Sweden)

    Hess Clemens F

    2008-09-01

    Full Text Available Abstract Background Intensity modulated radiotherapy (IMRT using sliding window technique utilises a leaf sequencing algorithm, which takes some control system limitations like dose rates (DR and velocity of the leafs (LV into account. The effect of altering these limitations on the number of monitor units and radiation dose to the organs at risk (OAR were analysed. Methods IMRT plans for different LVs from 1.0 cm/sec to 10.0 cm/sec and different DRs from 100 MU/min to 600 MU/min for two patients with prostate cancer and two patients with squamous cell cancer of the scalp (SCCscalp were calculated using the same "optimal fluence map". For each field the number of monitor units, the dose volume histograms and the differences in the "actual fluence maps" of the fields were analysed. Results With increase of the DR and decrease of the LV the number of monitor units increased and consequentially the radiation dose given to the OAR. In particular the serial OARs of patients with SCCscalp, which are located outside the end position of the leafs and inside the open field, received an additional dose of a higher DR and lower LV is used. Conclusion For best protection of organs at risk, a low DR and high LV should be applied. But the consequence of a low DR is both a long treatment time and also that a LV of higher than 3.0 cm/sec is mechanically not applicable. Our recommendation for an optimisation of the discussed parameters is a leaf velocity of 2.5 cm/sec and a dose rate of 300–400 MU/min (prostate cancer and 100–200 MU/min (SCCscalp for best protection of organs at risk, short treatment time and number of monitor units.

  13. Modeling Coniferous Canopy Structure over Extensive Areas for Ray Tracing Simulations: Scaling from the Leaf to the Stand Level

    Science.gov (United States)

    van Aardt, J. A.; van Leeuwen, M.; Kelbe, D.; Kampe, T.; Krause, K.

    2015-12-01

    Remote sensing is widely accepted as a useful technology for characterizing the Earth surface in an objective, reproducible, and economically feasible manner. To date, the calibration and validation of remote sensing data sets and biophysical parameter estimates remain challenging due to the requirements to sample large areas for ground-truth data collection, and restrictions to sample these data within narrow temporal windows centered around flight campaigns or satellite overpasses. The computer graphics community have taken significant steps to ameliorate some of these challenges by providing an ability to generate synthetic images based on geometrically and optically realistic representations of complex targets and imaging instruments. These synthetic data can be used for conceptual and diagnostic tests of instrumentation prior to sensor deployment or to examine linkages between biophysical characteristics of the Earth surface and at-sensor radiance. In the last two decades, the use of image generation techniques for remote sensing of the vegetated environment has evolved from the simulation of simple homogeneous, hypothetical vegetation canopies, to advanced scenes and renderings with a high degree of photo-realism. Reported virtual scenes comprise up to 100M surface facets; however, due to the tighter coupling between hardware and software development, the full potential of image generation techniques for forestry applications yet remains to be fully explored. In this presentation, we examine the potential computer graphics techniques have for the analysis of forest structure-function relationships and demonstrate techniques that provide for the modeling of extremely high-faceted virtual forest canopies, comprising billions of scene elements. We demonstrate the use of ray tracing simulations for the analysis of gap size distributions and characterization of foliage clumping within spatial footprints that allow for a tight matching between characteristics

  14. Geothermal resource areas database for monitoring the progress of development in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, J.D.; Lepman, S.R.; Leung, K.; Phillips, S.L.

    1981-01-01

    The Geothermal Resource Areas Database (GRAD) and associated data system provide broad coverage of information on the development of geothermal resources in the United States. The system is designed to serve the information requirements of the National Progress Monitoring System. GRAD covers development from the initial exploratory phase through plant construction and operation. Emphasis is on actual facts or events rather than projections and scenarios. The selection and organization of data are based on a model of geothermal development. Subjects in GRAD include: names and addresses, leases, area descriptions, geothermal wells, power plants, direct use facilities, and environmental and regulatory aspects of development. Data collected in the various subject areas are critically evaluated, and then entered into an on-line interactive computer system. The system is publically available for retrieval and use. The background of the project, conceptual development, software development, and data collection are described here. Appendices describe the structure of the database in detail.

  15. Spatial Enhancement of MODIS-based Images of Leaf Area Index: Application to the Boreal Forest Region of Northern Alberta, Canada

    Directory of Open Access Journals (Sweden)

    Charles P.-A. Bourque

    2010-01-01

    Full Text Available Leaf area index (LAI is one of the most commonly used ecological variables in describing forests. Since 2000, 1-km resolution Moderate Resolution Imaging Spectroradiometer (MODIS-based 8-day composites of LAI have been operationally available from the National Aeronautics and Space Administration (NASA, USA, at no cost to the user. In this paper, we present a simple protocol to enhance the spatial resolution of NASA-produced LAI composites to 250-m resolution. This is done by fusing MODIS-based estimates of enhanced vegetation index (EVI, consisting of 16-day 250-m resolution composites (also from NASA, with estimates of LAI. We apply the protocol to derive 250-m resolution maps of LAI for the boreal forest region of northern Alberta, Canada. Data fusion was possible in this study because of the inherent linear correlation that exists between EVI and LAI for the April to October growing period of 2005–2008, producing r2-values of 0.85–0.95 and p-values < 0.0001. Comparison of MODIS-based LAI with field-based measurements using the Tracing Radiation and Architecture of Canopies (TRAC sensor and LAI-2000 Plant Canopy Analyzer showed reasonable agreement across values; statistical comparison of LAI data points produced an r2-value of 0.71 and a p-value < 0.0001. Seventy one percent of MODIS-based LAI were within ±20% of field estimates.

  16. Retrieving the gap fraction, element clumping index, and leaf area index of individual trees using single-scan data from a terrestrial laser scanner

    Science.gov (United States)

    Li, Yumei; Guo, Qinghua; Su, Yanjun; Tao, Shengli; Zhao, Kaiguang; Xu, Guangcai

    2017-08-01

    Terrestrial laser scanning (TLS) is a promising tool for estimating leaf area index (LAI). However, very few studies have considered the effect of clumping index Ω in the calculation of ;true; LAI. In this study, we developed a new point cloud slicing method based on different incident zenith angles θ and retrieved the gap fraction using multiple-return information to obtain more accurate ;true; LAI estimations. In addition, we described a new Ω retrieval method based on the gap size analysis theory to correct the effect of foliage occlusion. Ground validation data were collected by destructively sampling 35 trees and measuring all their leaves. Results show that the TLS-based ;true; LAI estimations based on a single TLS scan are strongly correlated with the destructively sampled LAI measurements (R2 = 0.76, RMSE = 0.47). Moreover, our Ω retrieval method can effectively correct the effect of foliage occlusion. Other factors, such as the slicing resolution, percentage of laser beams with multiple returns, and scanning distance, have little effect on the final LAI estimation.

  17. Retrieval of Seasonal Leaf Area Index from Simulated EnMAP Data through Optimized LUT-Based Inversion of the PROSAIL Model

    Directory of Open Access Journals (Sweden)

    Matthias Locherer

    2015-08-01

    Full Text Available The upcoming satellite mission EnMAP offers the opportunity to retrieve information on the seasonal development of vegetation parameters on a regional scale based on hyperspectral data. This study aims to investigate whether an analysis method for the retrieval of leaf area index (LAI, developed and validated on the 4 m resolution scale of six airborne datasets covering the 2012 growing period, is transferable to the spaceborne 30 m resolution scale of the future EnMAP mission. The widely used PROSAIL model is applied to generate look-up-table (LUT libraries, by which the model is inverted to derive LAI information. With the goal of defining the impact of different selection criteria in the inversion process, different techniques for the LUT based inversion are tested, such as several cost functions, type and amount of artificial noise, number of considered solutions and type of averaging method. The optimal inversion procedure (Laplace, median, 4% inverse multiplicative noise, 350 out of 100,000 averages is identified by validating the results against corresponding in-situ measurements (n = 330 of LAI. Finally, the best performing LUT inversion (R2 = 0.65, RMSE = 0.64 is adapted to simulated EnMAP data, generated from the airborne acquisitions. The comparison of the retrieval results to upscaled maps of LAI, previously validated on the 4 m scale, shows that the optimized retrieval method can successfully be transferred to spaceborne EnMAP data.

  18. Image based remote sensing method for modeling black-eyed beans (Vigna unguiculata) Leaf Area Index (LAI) and Crop Height (CH) over Cyprus

    Science.gov (United States)

    Papadavid, Giorgos; Fasoula, Dionysia; Hadjimitsis, Michael; Skevi Perdikou, P.; Hadjimitsis, Diofantos

    2013-03-01

    In this paper, Leaf Area Index (LAI) and Crop Height (CH) are modeled to the most known spectral vegetation index — NDVI — using remotely sensed data. This approach has advantages compared to the classic approaches based on a theoretical background. A GER-1500 field spectro-radiometer was used in this study in order to retrieve the necessary spectrum data for estimating a spectral vegetation index (NDVI), for establishing a semiempirical relationship between black-eyed beans' canopy factors and remotely sensed data. Such semi-empirical models can be used then for agricultural and environmental studies. A field campaign was undertaken with measurements of LAI and CH using the Sun-Scan canopy analyzer, acquired simultaneously with the spectroradiometric (GER1500) measurements between May and June of 2010. Field spectroscopy and remotely sensed imagery have been combined and used in order to retrieve and validate the results of this study. The results showed that there are strong statistical relationships between LAI or CH and NDVI which can be used for modeling crop canopy factors (LAI, CH) to remotely sensed data. The model for each case was verified by the factor of determination. Specifically, these models assist to avoid direct measurements of the LAI and CH for all the dates for which satellite images are available and support future users or future studies regarding crop canopy parameters.

  19. Effects of grazing on leaf area index, fractional cover and evapotranspiration by a desert phreatophyte community at a former uranium mill site on the Colorado Plateau

    Science.gov (United States)

    Bresloff, Cynthia J.; Nguyen, Uyen; Glenn, Edward P.; Waugh, Jody; Nagler, Pamela L.

    2013-01-01

    This study employed ground and remote sensing methods to monitor the effects of grazing on leaf area index (LAI), fractional cover (fc) and evapotranspiration (ET) of a desert phreatophyte community over an 11 year period at a former uranium mill site on the Colorado Plateau, U.S. Nitrate, ammonium and sulfate are migrating away from the mill site in a shallow alluvial aquifer. The phreatophyte community, consisting of Atriplex canescens (ATCA) and Sarcobatus vermiculatus (SAVE) shrubs, intercepts groundwater and could potentially slow the movement of the contaminant plume through evapotranspiration (ET). However, the site has been heavily grazed by livestock, reducing plant cover and LAI. We used livestock exclosures and revegetation plots to determine the effects of grazing on LAI, fc and ET, then projected the findings over the whole site using multi-platform remote sensing methods. We show that ET is approximately equal to annual precipitation at the site, but when ATCA and SAVE are protected from grazing they can develop high fc and LAI values, and ET can exceed annual precipitation, with the excess coming from groundwater discharge. Therefore, control of grazing could be an effective method to slow migration of contaminants at this and similar sites in the western U.S.

  20. Gravimetric Vegetation Water Content Estimation for Corn Using L-Band Bi-Angular, Dual-Polarized Brightness Temperatures and Leaf Area Index

    Directory of Open Access Journals (Sweden)

    Qi Wang

    2015-08-01

    Full Text Available In this study, an algorithm to retrieve the gravimetric vegetation water content (GVWC, % of corn was developed. First, the method for obtaining the optical depth from L-band (1.4 GHz bi-angular, dual-polarized brightness temperatures (TB for short vegetation was investigated. Then, the quantitative relationship between the corn optical depth, corn GVWC and corn leaf area index (LAI was constructed. Finally, using the Polarimetric L-band Microwave Radiometer (PLMR airborne data in the 2012 Heihe Watershed Allied Telemetry Experimental Research (HiWATER project, the Global Land Surface Satellite (GLASS LAI product, the height and areal density of the corn stalks, the corn GVWC was estimated (corn GLASS-GVWC. Both the in situ measured corn GVWC and the corn GVWC retrieved based on the in situ measured corn LAI (corn LAINET-GVWC were used to validate the accuracy of the corn GLASS-GVWC. The results show that the GVWC retrieval method proposed in this study is feasible for monitoring the corn GVWC. However, the accuracy of the retrieval results is highly sensitive to the accuracy of the LAI input parameters.

  1. Ground and remote sensing-based measurements of leaf area index in a transitional forest and seasonal flooded forest in Brazil

    Science.gov (United States)

    Biudes, Marcelo Sacardi; Machado, Nadja Gomes; Danelichen, Victor Hugo de Morais; Souza, Maísa Caldas; Vourlitis, George Louis; Nogueira, José de Souza

    2014-08-01

    Leaf area index (LAI) is a key driver of forest productivity and evapotranspiration; however, it is a difficult and labor-intensive variable to measure, making its measurement impractical for large-scale and long-term studies of tropical forest structure and function. In contrast, satellite estimates of LAI have shown promise for large-scale and long-term studies, but their performance has been equivocal and the biases are not well known. We measured total, overstory, and understory LAI of an Amazon-savanna transitional forest (ASTF) over 3 years and a seasonal flooded forest (SFF) during 4 years using a light extinction method and two remote sensing methods (LAI MODIS product and the Landsat-METRIC method), with the objectives of (1) evaluating the performance of the remote sensing methods, and (2) understanding how total, overstory and understory LAI interact with micrometeorological variables. Total, overstory and understory LAI differed between both sites, with ASTF having higher LAI values than SFF, but neither site exhibited year-to-year variation in LAI despite large differences in meteorological variables. LAI values at the two sites have different patterns of correlation with micrometeorological variables. ASTF exhibited smaller seasonal variations in LAI than SFF. In contrast, SFF exhibited small changes in total LAI; however, dry season declines in overstory LAI were counteracted by understory increases in LAI. MODIS LAI correlated weakly to total LAI for SFF but not for ASTF, while METRIC LAI had no correlation to total LAI. However, MODIS LAI correlated strongly with overstory LAI for both sites, but had no correlation with understory LAI. Furthermore, LAI estimates based on canopy light extinction were correlated positively with seasonal variations in rainfall and soil water content and negatively with vapor pressure deficit and solar radiation; however, in some cases satellite-derived estimates of LAI exhibited no correlation with climate variables

  2. Ethnomathematics study: uncovering units of length, area, and volume in Kampung Naga Society

    Science.gov (United States)

    Septianawati, T.; Turmudi; Puspita, E.

    2017-02-01

    During this time, mathematics is considered as something neutral and not associated with culture. It can be seen from mathematics learning in the school which adopt many of foreign mathematics learning are considered more advanced (western). In fact, Indonesia is a rich country in cultural diversity. In the cultural activities, there are mathematical ideas that were considered a important thing in the mathematics learning. A study that examines the idea or mathematical practices in a variety of cultural activities are known as ethnomathematics. In Indonesia, there are some ethnic maintain their ancestral traditions, one of them is Kampung Naga. Therefore, this study was conducted in Kampung Naga. This study aims to uncover units of length, area, and volume used by Kampung Naga society. This study used a qualitative approach and ethnography methods. In this research, data collection is done through the principles of ethnography such as observation, interviews, documentation, and field notes. The results of this study are units of length, area, and volume used by Kampung Naga society and its conversion into standard units. This research is expected to give information to the public that mathematics has a relationship with culture and become recommendation to mathematics curriculum in Indonesia.

  3. Agriculture, Crops - CULTIVATED_AREAS_USDA_IN: Cultivated Areas in Indiana in 2004 (United States Department of Agriculture, 1:100,000, Polygon Shapefile)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — The United States Department of Agriculture (USDA), National Agricultural Statistics Service (NASS) area sampling frame is a delineation of all parcels of land for...

  4. Photosynthetic efficiency of healthy leaf area influenced by angular leaf spot severity in bean field/ Influência da severidade de mancha angular na eficiência fotossintética da área foliar sadia de feijoeiro, sob condições de campo

    Directory of Open Access Journals (Sweden)

    Cláudia Vieira Godoy

    2005-06-01

    Full Text Available This paper aimed to show the relationship among healthy leaf area, angular leaf spot severity and bean yield, under field conditions, indicating the influence of this relationship on photosynthetic efficiency of leaf tissue remaining on plants. Leaf area and severity of angular leaf spot [Phaeoisariopsis griseola (Sacc. Ferraris] of bean were weekly assessed, beginning at 30 days after emergence (DAE. Different levels of severity were reached varying the timing of fungicide spraying (fentin hydroxide 0.10% + tebuconazole 0.04%. Variations on total leaf area were consequence of natural variation on plants and also due to different physic and chemical soil conditions among plots. The relation between healthy leaf area duration (HAD and area under disease progress curve (AUDPC and yield (g m-2 presented R2=74.8% and healthy area absorption (HAA, AUDPC and yield (g m-2 presented R2=74.7%. Results indicated reduction of yield when severity (AUDPC was high, even in plots with same level of healthy leaf area. So, the disease influenced the photosynthetic efficiency of healthy leaf area, besides avoiding the production of the necrotic tissue.O objetivo do trabalho foi demonstrar, em parcelas experimentais sob condições de campo, a relação entre área foliar sadia, severidade de mancha angular e produção em feijoeiro indicando a influência desta relação na eficiência fotossintética do tecido foliar remanescentes nas plantas. Área foliar e severidade de mancha angular [Phaeoisariopsis griseola (Sacc. Ferraris] de feijoeiro foram avaliadas semanalmente, iniciando-se aos 30 dias após a emergência (DAE. Obtiveram-se diferentes níveis de severidade variando-se a data de início de aplicação da mistura fungicida (fentin hydroxide 0,10% + tebuconazole 0,04%. Variações na quantidade de área foliar foram obtidas em função da variação inerente entre plantas e das diferenças de condições físicoquímicas encontradas no solo das parcelas

  5. The times they are a-changin': seasonal variations of leaf spectra in relation with leaf biochemical and biophysical properties

    Science.gov (United States)

    Yang, X.; Tang, J.; Mustard, J. F.

    2013-12-01

    Leaf traits such as chlorophyll concentration, leaf mass per area (LMA), and mesophyll cell area exposed to the internal area space per leaf area (Ames/A) are key biochemical or biophysical properties to understand the vegetation functioning. Measurements of leaf spectra provided a non-destructive way to estimate those parameters. Many studies have linked leaf spectra with some of leaf traits successfully, but the understanding of spectra-traits relationship is still limited in the following aspects: (1) how does the ability of spectra to estimate leaf traits change (or not) throughout the growing season? (2) How to quantify leaf internal structure with leaf spectra? (3) What are the leaf traits that contribute to the structure parameter in leaf reflectance model such as PROSPECT? To answer the questions above, we conducted weekly measurements of leaf spectra, leaf biochemical properties (chlorophyll, carotenoids, water, and total carbon and nitrogen) and biophysical properties (LMA and internal structures) during the growing seasons of year 2011 and 2012. We found that leaf traits express themselves in the leaf spectra at different wavelengths; the relationships between spectra and leaf traits vary throughout the season. Leaf internal structure parameters are mostly related to the near-infrared reflectance. The structure parameter (N) in PROSPECT is related to the Ames/A, LMA, and water content. Our results have broad implications for using hyperspectral imagers/sensors to monitor vegetations that have clear seasonal patterns.

  6. Full-Waveform, Wide-Swath Lidar Imaging of Forested and Urban Areas in Leaf-On Conditions: Development, Results and Future Direction

    Science.gov (United States)

    Blair, James B.; Hofton, M.; Rabine, David; Welch, Wayne; Ramos, Luis; Padden, Phillip

    2003-01-01

    Full-Waveform lidar measurements provide unprecedented views of the vertical and horizontal structure of vegetation and the topography of the Earth s surface. Utilizing a high signal-to-noise ratio lidar system, larger than typical laser footprints (10-20 m), and the recorded time history of interaction between a short-duration (approx. 10 ns) pulse of laser light and the surface of the Earth, full-waveform lidar is able to simultaneously image sub-canopy topography as well as the vertical structure of any overlying vegetation. These data reveal the true 3-D vegetation structure in leaf-on conditions enabling important biophysical parameters such as above-ground biomass to be estimated with unprecedented accuracy. An airborne lidar mission was conducted July-August 2003 in support of the North America Carbon Program. NASA s Laser Vegetation Imaging Sensor (LVIS) was used to image approximately 2,000 km$^2$ in Maine, New Hampshire, Massachusetts and Maryland. Areas with available ground and other data were included (e.g., experimental forests, FLUXNET sites) in order to facilitate as many bio- and geophysical investigations as possible. Data collected included ground elevation and canopy height measurements for each laser footprint, as well as the vertical distribution of intercepted surfaces. Data will be publicly distributed within 6- 12 months of collection. Further details of the mission, including the lidar system technology, the locations of the mapped areas, and examples of the numerous data products that can be derived from the return waveform data products will be presented. Future applications including detection of ground and vegetation canopy changes and a spaceborne implementation of wide-swath, full-waveform imaging lidar will also be discussed.

  7. Comparing the Dry Season In-Situ Leaf Area Index (LAI Derived from High-Resolution RapidEye Imagery with MODIS LAI in a Namibian Savanna

    Directory of Open Access Journals (Sweden)

    Manuel J. Mayr

    2015-04-01

    Full Text Available The Leaf Area Index (LAI is one of the most frequently applied measures to characterize vegetation and its dynamics and functions with remote sensing. Satellite missions, such as NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS operationally produce global datasets of LAI. Due to their role as an input to large-scale modeling activities, evaluation and verification of such datasets are of high importance. In this context, savannas appear to be underrepresented with regards to their heterogeneous appearance (e.g., tree/grass-ratio, seasonality. Here, we aim to examine the LAI in a heterogeneous savanna ecosystem located in Namibia’s Owamboland during the dry season. Ground measurements of LAI are used to derive a high-resolution LAI model with RapidEye satellite data. This model is related to the corresponding MODIS LAI/FPAR (Fraction of Absorbed Photosynthetically Active Radiation scene (MOD15A2 in order to evaluate its performance at the intended annual minimum during the dry season. Based on a field survey we first assessed vegetation patterns from species composition and elevation for 109 sites. Secondly, we measured in situ LAI to quantitatively estimate the available vegetation (mean = 0.28. Green LAI samples were then empirically modeled (LAImodel with high resolution RapidEye imagery derived Difference Vegetation Index (DVI using a linear regression (R2 = 0.71. As indicated by several measures of model performance, the comparison with MOD15A2 revealed moderate consistency mostly due to overestimation by the aggregated LAImodel. Model constraints aside, this study may point to important issues for MOD15A2 in savannas concerning the underlying MODIS Land Cover product (MCD12Q1 and a potential adjustment by means of the MODIS Burned Area product (MCD45A1.

  8. Estimativa da área foliar de plantas daninhas: Brachiaria decumbens Stapf. e Brachiaria brizantha (Hochst. Stapf Leaf area estimative in weeds Brachiaria decumbens Stapf and Brachiaria brizantha (Hochst. Stapf

    Directory of Open Access Journals (Sweden)

    Silvano Bianco

    2000-01-01

    Full Text Available Com o objetivo de obter uma equação que, através de parâmetros lineares dimensionais das folhas, permita a estimativa da área foliar de Brachiaria decumbens Stapf. e Brachiaria brizantha (Hochst. Stapf., estudaram-se correlações entre a área foliar real (Sf e parâmetros dimensionais do limbo foliar, como o comprimento ao longo da nervura principal (C e a largura máxima (L, perpendicular à nervura principal. Todas as equações, exponenciais, geométricas ou lineares simples, permitiram boas estimativas da área foliar. Do ponto de vista prático, sugere-se optar pela equação linear simples envolvendo o produto C x L, considerando o coeficiente linear igual a zero. Desse modo, a estimativa da área foliar de B. decumbens pode ser feita pela fórmula Sf = 0,9810 x (C x L, ou seja, 98,10% do produto entre o comprimento ao longo da nervura principal e a largura máxima, enquanto que, para a B. brizantha a estimativa da área foliar pode ser feita pela fórmula SF = 0,7468 x (C x L, ou seja 74,68% do produto entre o comprimento ao longo da nervura principal e a largura máxima da folha.In order to obtain equations which make feasible the leaf area estiomate from linear measures of the leaf blade, correlation studies were done involving the real leaf blade area and main vein leaf lenght (C, maximum leaf width (L and C*L. All the equations, linear, geometric and exponential, provide good leaf area estimate for both species. In the practical sense, it is suggested the use of the simple linear equation of the regression model using the C*L parameter and taking the linear coefficient equal zero. Then, the Brachiaria decumbens leaf area can be estimate using the equation Sf = 0,9810 (C*L and the Brachiaria brizantha by using the equation Sf = 0,7468*(C*L.

  9. Use of Physio-Hydrological Units for SMOS Validation at the Valencia Anchor Station Study Area

    Science.gov (United States)

    Millán-Scheiding, C.; Antolín, C.; Marco, J.; Soriano, M. P.; Torre, E.; Requena, F.; Carbó, E.; Cano, A.; Lopez-Baeza, E.

    2009-04-01

    The SMOS space mission will soil moisture over the continents and ocean surface salinity with the sufficient resolution to be used in global climate change studies. With the aim of validating SMOS land data and products at the Valencia Anchor Station site (VAS) in a Mediterranean Ecosystem area of Spain, we have designed a sample methodology using a subdivision of the landscape in environmental units related to the spatial variability of soil moisture (Millán-Scheiding, 2006; Lopez-Baeza, et al. 2008). These physio-hydrological units are heterogeneously structured entities which present a certain degree of internal uniformity of hydrological parameters. The units are delimited by integrating areas with the same physio-morphology, soil type, vegetation, geology and topography (Flugel, et al 2003; Millán-Scheiding et al, 2007). Each of these units presented over the same pedological characteristics, vegetation cover, and landscape position should have a certain degree of internal uniformity in its hydrological parameters and therefore similar soil moisture (SM). The main assumption for each unit is that the dynamical variation of the hydrological parameters within one unit should be minimum compared to the dynamics of another unit. This methodology will hopefully provide an effective sampling design consisting of a reduced number of measuring points, sparsely distributed over the area, or alternatively, using SM validation networks where each sampling point is located where it is representative of the mean soil moisture of a complete unit area. The Experimental Plan for the SMOS Validation Rehearsal Campaign at the VAS area of April-May 2008 used this environmental subdivision in the selection and sampling of over 21.000 soil moisture points in a control area of 10 x 10 km2. The ground measurements were carried out during 4 nights corresponding to a drying out period of the soil. The sampling consisted of 700 plots with 4 volumetric SM cylinders and 7 Delta-T Theta

  10. Leafing patterns and leaf traits of four evergreen shrubs in the Patagonian Monte, Argentina

    Science.gov (United States)

    Campanella, María Victoria; Bertiller, Mónica B.

    2009-11-01

    We assessed leafing patterns (rate, timing, and duration of leafing) and leaf traits (leaf longevity, leaf mass per area and leaf-chemistry) in four co-occurring evergreen shrubs of the genus Larrea and Chuquiraga (each having two species) in the arid Patagonian Monte of Argentina. We asked whether species with leaves well-defended against water shortage (high LMA, leaf longevity, and lignin concentration, and low N concentration) have lower leaf production, duration of the leafing period, and inter-annual variation of leafing than species with the opposite traits. We observed two distinctive leafing patterns each related to one genus. Chuquiraga species produced new leaves concentrated in a massive short leafing event (5-48 days) while new leaves of Larrea species emerged gradually (128-258 days). Observed leafing patterns were consistent with simultaneous and successive leafing types previously described for woody plants. The peak of leaf production occurred earlier in Chuquiraga species (mid September) than in Larrea species (mid October-late November). Moreover, Chuquiraga species displayed leaves with the longest leaf lifespan, while leaves of Larrea species had the lowest LMA and the highest N and soluble phenolics concentrations. We also observed that only the leaf production of Larrea species increased in humid years. We concluded that co-occurring evergreen species in the Patagonian Monte displayed different leafing patterns, which were associated with some relevant leaf traits acting as plant defenses against water stress and herbivores. Differences in leafing patterns could provide evidence of ecological differentiation among coexisting species of the same life form.

  11. Effects of branch height on leaf gas exchange, branch hydraulic conductance and branch sap flux in open-grown ponderosa pine.

    Science.gov (United States)

    Hubbard, Robert M; Bond, Barbara J; Senock, Randy S; Ryan, Michael G

    2002-06-01

    Recent studies have shown that stomata respond to changes in hydraulic conductance of the flow path from soil to leaf. In open-grown tall trees, branches of different heights may have different hydraulic conductances because of differences in path length and growth. We determined if leaf gas exchange, branch sap flux, leaf specific hydraulic conductance, foliar carbon isotope composition (delta13C) and ratios of leaf area to sapwood area within branches were dependent on branch height (10 and 25 m) within the crowns of four open-grown ponderosa pine (Pinus ponderosa Laws.) trees. We found no difference in leaf gas exchange or leaf specific hydraulic conductance from soil to leaf between the upper and lower canopy of our study trees. Branch sap flux per unit leaf area and per unit sapwood area did not differ between the 10- and 25-m canopy positions; however, branch sap flux per unit sapwood area at the 25-m position had consistently lower values. Branches at the 25-m canopy position had lower leaf to sapwood area ratios (0.17 m2 cm-2) compared with branches at the 10-m position (0.27 m2 cm-2) (P = 0.03). Leaf specific conductance of branches in the upper crown did not differ from that in the lower crown. Other studies at our site indicate lower hydraulic conductance, sap flux, whole-tree canopy conductance and photosynthesis in old trees compared with young trees. This study suggests that height alone may not explain these differences.

  12. Airborne Gravimetry Survey for the Marine Area of the United Arab Emirates

    DEFF Research Database (Denmark)

    Forsberg, René; Olesen, Arne Vestergaard; Alshamsi, Adel

    2012-01-01

    The Military Survey Department (MSD) of the United Arab Emirates (UAE) undertook an airborne gravity survey project for the marine area of the country in 2009, especially to strengthen the marine and coastal geoid in the near-shore regions. For the airborne gravity survey, 5 km spacing coast-para...... for the airborne gravity data is better than 2.0 mGal r.m.s., as judged from the airborne track crossovers. The new airborne gravimetry data changed the UAE coastal geoid by up to 30 cm in some regions, highlighting the importance of airborne gravity coastal surveys....

  13. Paleoseismic targets, seismic hazard, and urban areas in the Central and Eastern United States

    Science.gov (United States)

    Wheeler, R.L.

    2008-01-01

    Published geologic information from the central and eastern United States identifies 83 faults, groups of sand blows, named seismic zones, and other geological features as known or suspected products of Quaternary tectonic faulting. About one fifth of the features are known to contain faulted Quaternary materials or seismically induced liquefaction phenomena, but the origin and associated seismic hazard of most of the other features remain uncertain. Most of the features are in or near large urban areas. The largest cluster of features is in the Boston-Washington urban corridor (2005 estimated population: 50 million). The proximity of most features to populous areas identifies paleoseismic targets with potential to impact urban-hazard estimates.

  14. USGS mineral-resource assessment of Sagebrush Focal Areas in the western United States

    Science.gov (United States)

    Frank, David G.; Frost, Thomas P.; Day, Warren C.; ,

    2016-10-04

    U.S. Geological Survey (USGS) scientists have completed an assessment of the mineral-resource potential of nearly 10 million acres of Federal and adjacent lands in Idaho, Montana, Nevada, Oregon, Utah, and Wyoming. The assessment of these lands, identified as Sagebrush Focal Areas, was done at the request of the Bureau of Land Management. The assessment results will be used in the decision-making process that the Department of the Interior is pursuing toward the protection of large areas of contiguous sagebrush habitat for the greater sage-grouse (Centrocercus urophasianus) in the Western United States. The detailed results of this ambitious study are published in the five volumes of USGS Scientific Investigations Report 2016–5089 and seven accompanying data releases.

  15. Corrective Action Plan for Corrective Action Unit 407: Roller Coaster RADSAFE Area, Tonopah Test Range, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    T. M. Fitzmaurice

    2000-05-01

    This Corrective Action Plan (CAP) has been prepared for the Roller Coaster RADSAFE Area Corrective Action Unit 407 in accordance with the Federal Facility and Consent Order (Nevada Division of Environmental Protection [NDEP] et al., 1996). This CAP provides the methodology for implementing the approved Corrective Action Alternative as listed in the Corrective Action Decision Document (U.S. Department of Energy, Nevada Operations Office, 1999). The RCRSA was used during May and June of 1963 to decontaminate vehicles, equipment, and personnel from the Clean Slate tests. The Constituents of Concern (COCs) identified during the site characterization include plutonium, uranium, and americium. No other COCS were identified. The following closure actions will be implemented under this plan: (1) Remove and dispose of surface soils which are over three times background for the area. Soils identified for removal will be disposed of at an approved disposal facility. Excavated areas will be backfilled with clean borrow soil fi-om a nearby location. (2) An engineered cover will be constructed over the waste disposal pit area where subsurface COCS will remain. (3) Upon completion of the closure and approval of the Closure Report by NDEP, administrative controls, use restrictions, and site postings will be used to prevent intrusive activities at the site. Barbed wire fencing will be installed along the perimeter of this unit. Post closure monitoring will consist of site inspections to determine the condition of the engineered cover. Any identified maintenance and repair requirements will be remedied within 90 working days of discovery and documented in writing at the time of repair. Results of all inspections/repairs for a given year will be addressed in a single report submitted annually to the NDEP.

  16. Leaf morphology correlates with water and light availability:What consequences for simple and compound leaves?

    Institute of Scientific and Technical Information of China (English)

    Fei Xu; Weihua Guo; Weihong Xu; Yinghua Wei; Renqing Wang

    2009-01-01

    Leaves are organs sensitive to environmental changes in the process of evolution and may exhibit phenotypic plasticity as a response to abiotic stress.However,affirmation of leaf morphological plasticity and its regulations in different environments are still unclear.We performed a simulated experiment to study the variations of leaf morphology in different gradients of water and light availability.Considering different types of leaves and venation,we chose pinnate-veined simple leaves of Quercus acutissima and compound leaves of Robinia pseudoacacia as the study objects.The morphological parameters we investigated include leaf size,shape and venation pattern which can be easily measured in the field.Significant variations occurred in many parameters due to the effects of the environment and/or allometry.There were broadly consistent trends for leaf morphological variations along the gradients.The leaf size became smaller with a short supply of resources.Leaf elongation and fractions of the lamina area altered to enhance resources acquisition and conservation.Trade-offs between investments in support and functional structures optimized the venation pattern of major and minor veins.Leaflets partially played a role such as leaf teeth,for they are not only individual units,but also a part of the compound leaf.We suggest that more or less the same trends in morphological variations may be an important explanation for coexisting species to adapt to similar habitats and form the niche differentiation.

  17. Measuring Plant Leaf Area by Scanner and ImageJ Software%平台扫描仪结合ImageJ软件测定番茄叶面积

    Institute of Scientific and Technical Information of China (English)

    高建昌; 郭广君; 国艳梅; 王孝宣; 杜永臣

    2011-01-01

    The accuracy of measuring tomato ( Lycopersicon esculentum Mill. ) leaf area by ImageJ software was confirmed through measuring scanned standard shape. There was no significant difference for area with 100, 200 and 300 DPI. And 200 DPI was better. Two methods of paper-cutting and image processing for measuring tomato leaf area were compared and there was no significant difference. Based on the result, the method of measuring tomato leaf area with scanner and ImageJ software was established.%利用扫描仪获取标准图形,对ImageJ软件测定番茄叶面积的准确性进行了验证.发现不同的扫描分辨率(100、200和300DPI)对图形面积没有显著影响,200DPI的分辨率为较好的扫描参数.以番茄叶片为试材,对剪纸法与图像处理法进行比较,发现二者差异不显著.在此基础上,建立了一种扫描仪结合ImageJ软件测定番茄叶面积的方法.

  18. Area racism and birth outcomes among Blacks in the United States.

    Science.gov (United States)

    Chae, David H; Clouston, Sean; Martz, Connor D; Hatzenbuehler, Mark L; Cooper, Hannah L F; Turpin, Rodman; Stephens-Davidowitz, Seth; Kramer, Michael R

    2017-04-13

    There is increasing evidence that racism is a cause of poor health outcomes in the United States, including adverse birth outcomes among Blacks. However, research on the health consequences of racism has faced measurement challenges due to the more subtle nature of contemporary racism, which is not necessarily amenable to assessment through traditionally used survey methods. In this study, we circumvent some of these limitations by examining a previously developed Internet query-based proxy of area racism (Stephens-Davidowitz, 2014) in relation to preterm birth and low birthweight among Blacks. Area racism was measured in 196 designated market areas as the proportion of total Google searches conducted between 2004 and 2007 containing the "n-word." This measure was linked to county-level birth data among Blacks between 2005 and 2008, which were compiled by the National Center for Health Statistics; preterm birth and low birthweight were defined as racism was associated with relative increases of 5% in the prevalence of preterm birth and 5% in the prevalence of low birthweight among Blacks. Our study provides evidence for the utility of an Internet query-based measure as a proxy for racism at the area-level in epidemiologic studies, and is also suggestive of the role of racism in contributing to poor birth outcomes among Blacks. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Relationship of Terminal Duct Lobular Unit Involution of the Breast with Area and Volume Mammographic Densities

    Science.gov (United States)

    Gierach, Gretchen L.; Patel, Deesha A.; Pfeiffer, Ruth M.; Figueroa, Jonine D.; Linville, Laura; Papathomas, Daphne; Johnson, Jason M.; Chicoine, Rachael E.; Herschorn, Sally D.; Shepherd, John A.; Wang, Jeff; Malkov, Serghei; Vacek, Pamela M.; Weaver, Donald L.; Fan, Bo; Mahmoudzadeh, Amir Pasha; Palakal, Maya; Xiang, Jackie; Oh, Hannah; Horne, Hisani N.; Sprague, Brian L.; Hewitt, Stephen M.; Brinton, Louise A.; Sherman, Mark E.

    2016-01-01

    Elevated mammographic density (MD) is an established breast cancer risk factor. Reduced involution of terminal duct lobular units (TDLUs), the histologic source of most breast cancers, has been associated with higher MD and breast cancer risk. We investigated relationships of TDLU involution with area and volumetric MD, measured throughout the breast and surrounding biopsy targets (peri-lesional). Three measures inversely related to TDLU involution (TDLU count/mm2, median TDLU span, median acini count/TDLU) assessed in benign diagnostic biopsies from 348 women, ages 40–65, were related to MD area (quantified with thresholding software) and volume (assessed with a density phantom) by analysis of covariance, stratified by menopausal status and adjusted for confounders. Among premenopausal women, TDLU count was directly associated with percent peri-lesional MD (P-trend=0.03), but not with absolute dense area/volume. Greater TDLU span was associated with elevated percent dense area/volume (P-trendbreast cancer risk suggest that associations of MD with breast cancer may partly reflect amounts of at-risk epithelium. If confirmed, these results could suggest a prevention paradigm based on enhancing TDLU involution and monitoring efficacy by assessing MD reduction. PMID:26645278

  20. 中梁山石灰岩山地30种主要植物叶片性状研究%Leaf Traits of Main Plants on Limestone Area in Zhongliang Mountain

    Institute of Scientific and Technical Information of China (English)

    刘宏伟; 王微; 左娟; 陶建平

    2014-01-01

    为探讨生长在喀斯特石灰岩山地植物叶片性状适应特征,在重庆中梁山海石公园选取乔、灌、草三种生活型植物共30种,分别测定其叶干质量(mLDMC )、比叶面积(SLA)、叶pH、叶碳质量(mLCC )、叶氮质量(mLNC )和叶碳氮比等六个叶片性状因子.结果表明:不同叶片性状因子变异系数不同,其中,植物 mLDMC 、SLA和mLNC变异较大,分别为28.7%,50.8%和21.4%;mLDMC和 SLA在不同生活型植物中存在显著差异,与乔木和灌木相比,草本具有较低的mLDMC和较大的 SLA ,而乔木和灌木在两者之间差异不显著;所有叶片性状因子中,植物mLDMC和 SLA呈显著负相关,其他因子间没有显著相关性.可见,mLDMC和 SLA是植物资源利用分类轴上划分植物类群的最佳指标,石灰岩地区不同生活型植物叶片性状不同,这是植物和环境相互选择综合作用的结果.%To explore the adaptive feature of plant leaf traits in Karst limestone area ,30 species of three life forms ,namely ,trees ,shrubs and herbs from Zhongling mountain in Chongqing city of Southwest China have been selected and their leaf dry matter content (mLDMC ) ,specific leaf area(SLA) ,leaf pH ,leaf carbon concentration(mLCC ) ,leaf nitrogen concentration (mLNC ) and leaf carbon nitrogen ratio (C/N) measured . The results show that the coefficient of variation differed between different leaf traits and a large variation has been observed in mLDMC and SLA being 28 .7% ,0 .8% ,1 .4% ,respectively .mLDMC and SLA differed significantly among three life forms .Compared with trees and shrubs ,herbs have lower mLDMC and higher SLA ,but no significant difference is observed between trees and shrubs .mLDMC and SLA are significantly negatively correlated of all leaf traits .However ,there is no significant correlation among other leaf traits . It is concluded that mLDMC and SL A could be used to predict the plant

  1. Vertical farming increases lettuce yield per unit area compared to conventional horizontal hydroponics.

    Science.gov (United States)

    Touliatos, Dionysios; Dodd, Ian C; McAinsh, Martin

    2016-08-01

    Vertical farming systems (VFS) have been proposed as an engineering solution to increase productivity per unit area of cultivated land by extending crop production into the vertical dimension. To test whether this approach presents a viable alternative to horizontal crop production systems, a VFS (where plants were grown in upright cylindrical columns) was compared against a conventional horizontal hydroponic system (HHS) using lettuce (Lactuca sativa L. cv. "Little Gem") as a model crop. Both systems had similar root zone volume and planting density. Half-strength Hoagland's solution was applied to plants grown in perlite in an indoor controlled environment room, with metal halide lamps providing artificial lighting. Light distribution (photosynthetic photon flux density, PPFD) and yield (shoot fresh weight) within each system were assessed. Although PPFD and shoot fresh weight decreased significantly in the VFS from top to base, the VFS produced more crop per unit of growing floor area when compared with the HHS. Our results clearly demonstrate that VFS presents an attractive alternative to horizontal hydroponic growth systems and suggest that further increases in yield could be achieved by incorporating artificial lighting in the VFS.

  2. Leaf Area Index (LAI Estimation in Boreal Mixedwood Forest of Ontario, Canada Using Light Detection and Ranging (LiDAR and WorldView-2 Imagery

    Directory of Open Access Journals (Sweden)

    Paul Treitz

    2013-10-01

    Full Text Available Leaf Area Index (LAI is an important input variable for forest ecosystem modeling as it is a factor in predicting productivity and biomass, two key aspects of forest health. Current in situ methods of determining LAI are sometimes destructive and generally very time consuming. Other LAI derivation methods, mainly satellite-based in nature, do not provide sufficient spatial resolution or the precision required by forest managers for tactical planning. This paper focuses on estimating LAI from: (i height and density metrics derived from Light Detection and Ranging (LiDAR; (ii spectral vegetation indices (SVIs, in particular the Normalized Difference Vegetation Index (NDVI; and (iii a combination of these methods. For the Hearst Forest of Northern Ontario, in situ measurements of LAI were derived from digital hemispherical photographs (DHPs while remote sensing variables were derived from low density LiDAR (i.e., 1 m−2 and high spatial resolution WorldView-2 data (2 m. Multiple Linear Regression (MLR models were generated using these variables. Results from these analyses demonstrate: (i moderate explanatory power (i.e., R2 = 0.53 for LiDAR height and density metrics that have proven to be related to canopy structure; (ii no relationship when using SVIs; and (iii no significant improvement of LiDAR models when combining them with SVI variables. The results suggest that LiDAR models in boreal forest environments provide satisfactory estimations of LAI, even with narrow ranges of LAI for model calibration. Models derived from low point density LiDAR in a mixedwood boreal environment seem to offer a reliable method of estimating LAI at high spatial resolution for decision makers in the forestry community. This method can be easily incorporated into simultaneous modeling efforts for forest inventory variables using LiDAR.

  3. The relationship of hyper-spectral vegetation indices with leaf area index (LAI) over the growth cycle of wheat and chickpea at 3 nm spectral resolution

    Science.gov (United States)

    Gupta, R. K.; Vijayan, D.; Prasad, T. S.

    2006-01-01

    Hyperspectral ratio and normalized difference vegetation indices were computed from the 3 nm bandwidth ground-based spectral data taken in 400-950 nm wave length region over the crop growth cycle (CGC) of wheat and chickpea. Synthesized broad band Landsat TM-RVI, TM-NDVI and TM-SAVI were also computed using this narrow bandwidth spectral observations. Regression analysis was carried out for these indices with leaf area index (LAI) for wheat and chickpea over CGC and the r2 values were found poor in 0.2-0.53 range for wheat and in 0.41-0.82 range for chickpea. Significant relationship with LAI were found for wheat ( r2 in 0.86-0.97 range) when growth and decline phases were analyzed independently. Here, r2 values for chickpea were less than that for wheat. The high difference in rate of change of slope for hRVI is a good discriminator for high ET (wheat) and low ET (chickpea) crops. To find out the potential hyperspectral ratios and normalized difference indices that could provide strong relationship with LAI, a correlation-based analysis was carried out for LAI with all the possible combinations of ratios and normalized difference indices in 400-950 nm region (at 3 nm spectral interval) independently for growth and decline phases of LAI and found that in addition to traditional near-IR and red pairs, the pairs within near-IR, near-IR and visible extending to near-IR were also significantly related to LAI.

  4. Comparative Analysis of EO-1 ALI and Hyperion, and Landsat ETM+ Data for Mapping Forest Crown Closure and Leaf Area Index.

    Science.gov (United States)

    Pu, Ruiliang; Gong, Peng; Yu, Qian

    2008-06-06

    In this study, a comparative analysis of capabilities of three sensors for mapping forest crown closure (CC) and leaf area index (LAI) was conducted. The three sensors are Hyperspectral Imager (Hyperion) and Advanced Land Imager (ALI) onboard EO-1 satellite and Landsat-7 Enhanced Thematic Mapper Plus (ETM+). A total of 38 mixed coniferous forest CC and 38 LAI measurements were collected at Blodgett Forest Research Station, University of California at Berkeley, USA. The analysis method consists of (1) extracting spectral vegetation indices (VIs), spectral texture information and maximum noise fractions (MNFs), (2) establishing multivariate prediction models, (3) predicting and mapping pixel-based CC and LAI values, and (4) validating the mapped CC and LAI results with field validated photo-interpreted CC and LAI values. The experimental results indicate that the Hyperion data are the most effective for mapping forest CC and LAI (CC mapped accuracy (MA) = 76.0%, LAI MA = 74.7%), followed by ALI data (CC MA = 74.5%, LAI MA = 70.7%), with ETM+ data results being least effective (CC MA = 71.1%, LAI MA = 63.4%). This analysis demonstrates that the Hyperion sensor outperforms the other two sensors: ALI and ETM+. This is because of its high spectral resolution with rich subtle spectral information, of its short-wave infrared data for constructing optimal VIs that are slightly affected by the atmosphere, and of its more available MNFs than the other two sensors to be selected for establishing prediction models. Compared to ETM+ data, ALI data are better for mapping forest CC and LAI due to ALI data with more bands and higher signal-to-noise ratios than those of ETM+ data.

  5. Closure Report for Corrective Action Unit 240: Area 25 Vehicle Washdown Nevada Test Site, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    D. L. Gustafason

    2001-03-01

    The Area 25 Vehicle Washdown, Corrective Action Unit (CAU) 240, was clean-closed following the approved Corrective Action Decision Document closure alternative and in accordance with the Federal Facility Agreement and Consent Order (FFACO, 1996). The CAU consists of thee Corrective Action Sites (CASs): 25-07-01 - Vehicle Washdown Area (Propellant Pad); 25-07-02 - Vehicle Washdown Area (F and J Roads Pad); and 25-07-03 - Vehicle Washdown Station (RADSAFE Pad). Characterization activities indicated that only CAS 25-07-02 (F and J Roads Pad) contained constituents of concern (COCs) above action levels and required remediation. The COCs detected were Total Petroleum Hydrocarbons (TPH) as diesel, cesium-137, and strontium-90. The F and J Roads Pad may have been used for the decontamination of vehicles and possibly disassembled engine and reactor parts from Test Cell C. Activities occurred there during the 1960s through early 1970s. The F and J Roads Pad consisted of a 9- by 5-meter (m) (30- by 15-foot [ft]) concrete pad and a 14- by 13-m (46-by 43-ft) gravel sump. The clean-closure corrective action consisted of excavation, disposal, verification sampling, backfilling, and regrading. Closure activities began on August 21, 2000, and ended on September 19, 2000. Waste disposal activities were completed on December 12, 2000. A total of 172 cubic meters (223 cubic yards) of impacted soil was excavated and disposed. The concrete pad was also removed and disposed. Verification samples were collected from the bottom and sidewalls of the excavation and analyzed for TPH diesel and 20-minute gamma spectroscopy. The sample results indicated that all impacted soil above remediation standards was removed. The closure was completed following the approved Corrective Action Plan. All impacted waste was disposed in the Area 6 Hydrocarbon Landfill. All non-impacted debris was disposed in the Area 9 Construction Landfill and the Area 23 Sanitary Landfill.

  6. LeafJ: an ImageJ plugin for semi-automated leaf shape measurement.

    Science.gov (United States)

    Maloof, Julin N; Nozue, Kazunari; Mumbach, Maxwell R; Palmer, Christine M

    2013-01-21

    High throughput phenotyping (phenomics) is a powerful tool for linking genes to their functions (see review and recent examples). Leaves are the primary photosynthetic organ, and their size and shape vary developmentally and environmentally within a plant. For these reasons studies on leaf morphology require measurement of multiple parameters from numerous leaves, which is best done by semi-automated phenomics tools. Canopy shade is an important environmental cue that affects plant architecture and life history; the suite of responses is collectively called the shade avoidance syndrome (SAS). Among SAS responses, shade induced leaf petiole elongation and changes in blade area are particularly useful as indices. To date, leaf shape programs (e.g. SHAPE, LAMINA, LeafAnalyzer, LEAFPROCESSOR) can measure leaf outlines and categorize leaf shapes, but can not output petiole length. Lack of large-scale measurement systems of leaf petioles has inhibited phenomics approaches to SAS research. In this paper, we describe a newly developed ImageJ plugin, called LeafJ, which can rapidly measure petiole length and leaf blade parameters of the model plant Arabidopsis thaliana. For the occasional leaf that required manual correction of the petiole/leaf blade boundary we used a touch-screen tablet. Further, leaf cell shape and leaf cell numbers are important determinants of leaf size. Separate from LeafJ we also present a protocol for using a touch-screen tablet for measuring cell shape, area, and size. Our leaf trait measurement system is not limited to shade-avoidance research and will accelerate leaf phenotyping of many mutants and screening plants by leaf phenotyping.

  7. Soybean Area and Yield Estimation Using MODIS and Landsat Data in the Conterminous United States

    Science.gov (United States)

    Song, X. P.; Hansen, M.; Potapov, P.; Stehman, S. V.; Krylov, A.; King, L.; Adusei, B.

    2015-12-01

    The world's population is projected to grow to 9 billion by 2050. The increasing population, amplified by people's increasing consumption of animal products will create a massive demand for food and feed from grain production. As such, global food security will remain a worldwide concern for the next half century. Addressing the food security issue requires data and information support, including research and operational programs for crop monitoring, modeling and yield forecasting. Satellite observations, owing to their synoptic and repetitive nature, have the unique advantage of providing timely information on crop growth at regional to global scales. However, it remains a challenge to accurately identify crop type, estimate areal extent and forecast crop yield with satellite data. Here we employ a stratified random sampling framework for estimating soybean area and yield in the conterminous United States using satellite data collected by the MODIS and Landsat sensors. Complementing each other, the temporally-rich MODIS data are used to capture rapid phenological transitions of soybean crops, whereas the moderate-resolution Landsat data are used to delineate more spatial details for accurate area estimation. For every sample, we derive generic phenological metrics from MODIS and Landsat data and employ machine learning algorithms to identify soybean pixels with reference data generated from RapidEye images and verified by extensive field visits. We also characterize empirical relationships between satellite metrics and soybean yield compiled by the USDA National Agricultural Statistics Service (NASS). Preliminary results suggest that MODIS data alone underestimate soybean area considerably, whereas Landsat data can provide accurate estimate on soybean area. However, soybean yield can be predicted using MODIS-based reflectance metrics. Our sample depict well the spatial variation of soybean yield over the conterminous United States. In addition, the area

  8. Leaf thermal and hydraulic capacitances - structural safeguards for rapid ambient fluctuations

    Science.gov (United States)

    Schymanski, S. J.; Or, D.; Zwieniecki, M.

    2011-12-01

    Leaves may be subjected to rapidly fluctuating irradiation or thermal conditions due to motion of sun flecks and clouds or passage of warm and dry wind gusts. Given a stomatal characteristic time scale (~5 min) for adjusting transpiration flux, fluctuations of environmental conditions at shorter time scales (~1 min) could push leaf hydraulic and thermal status beyond its operational limits resulting in xylem cavitation or overheating. As active stomatal protection may not be adequate, we propose that leaf thermal and hydraulic capacitances and hence leaf specific mass (hydrated thickness) provide passive protection and play a critical role for autonomous and intrinsic capacitive-based responses to rapid fluctuations. For example, a simple variable leaf mass per unit area can affect both thermal and hydraulic capacitances. Thus a thin leaf (0.2 mm) exposed to a sunfleck can experience an increase in leaf temperature by 20K in the order of 3 minutes, i.e. before stomata can activate evaporative cooling. Increasing leaf thickness can be an effective measure to increase the buffer for such environmental fluctuations, so that slower regulatory measures such as stomatal adjustments can take over before detrimental effects take place. Systematic measurements of thermal changes in response to step changes in radiation conditions were obtained using laser illumination and infra-red thermal imaging of leaf laser-illuminated area across a wide range of leaf morphologies from major plant divisions (ferns, gymnosperms and angiosperms). Results confirm inverse relationships between leaf thickness and temperature rise (measured as steady state temperature increase). Hydraulic impacts of such structural capacitance on xylem function will be discussed.

  9. Variation in light absorption properties of mentha aquatica L. as a function of leaf form: Implications for plant growth

    DEFF Research Database (Denmark)

    Enriquez, Susana; Jensen, Kaj Sand

    2008-01-01

    area increased. This relationship indicates that dispersive samples, such as leaves, although efficient light traps, can also be affected by the "package effect." Mentha aquatica leaves, by expanding their biomass (increased specific leaf area [SLA]), improve their light absorption efficiency per unit...

  10. Spatio-temporal prediction of leaf area index of rubber plantation using HJ-1A/1B CCD images and recurrent neural network

    Science.gov (United States)

    Chen, Bangqian; Wu, Zhixiang; Wang, Jikun; Dong, Jinwei; Guan, Liming; Chen, Junming; Yang, Kai; Xie, Guishui

    2015-04-01

    Rubber (Hevea brasiliensis) plantations are one of the most important economic forest in tropical area. Retrieving leaf area index (LAI) and its dynamics by remote sensing is of great significance in ecological study and production management, such as yield prediction and post-hurricane damage evaluation. Thirteen HJ-1A/1B CCD images, which possess the spatial advantage of Landsat TM/ETM+ and 2-days temporal resolution of MODIS, were introduced to predict the spatial-temporal LAI of rubber plantation on Hainan Island by Nonlinear AutoRegressive networks with eXogenous inputs (NARX) model. Monthly measured LAIs at 30 stands by LAI-2000 between 2012 and 2013 were used to explore the LAI dynamics and their relationship with spectral bands and seven vegetation indices, and to develop and validate model. The NARX model, which was built base on input variables of day of year (DOY), four spectral bands and weight difference vegetation index (WDVI), possessed good accuracies during the model building for the data set of training (N = 202, R2 = 0.98, RMSE = 0.13), validation (N = 43, R2 = 0.93, RMSE = 0.24) and testing (N = 43, R2 = 0.87, RMSE = 0.31), respectively. The model performed well during field validation (N = 24, R2 = 0.88, RMSE = 0.24) and most of its mapping results showed better agreement (R2 = 0.54-0.58, RMSE = 0.47-0.71) with the field data than the results of corresponding stepwise regression models (R2 = 0.43-0.51, RMSE = 0.52-0.82). Besides, the LAI statistical values from the spatio-temporal LAI maps and their dynamics, which increased dramatically from late March (2.36 ± 0.59) to early May (3.22 ± 0.64) and then gradually slow down until reached the maximum value in early October (4.21 ± 0.87), were quite consistent with the statistical results of the field data. The study demonstrates the feasibility and reliability of retrieving spatio-temporal LAI of rubber plantations by an artificial neural network (ANN) approach, and provides some insight on the

  11. Closure Report for Corrective Action Unit 135: Areas 25 Underground Storage Tanks, Nevada Test Site, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    D. H. Cox

    2001-06-01

    Corrective Action Unit (CAU) 135, Area 25 Underground Storage Tanks, was closed in accordance with the approved Corrective Action Plan (DOE/NV, 2000). CAU 135 consists of three Corrective Action Sites (CAS). Two of these CAS's were identified in the Corrective Action Investigation Data Quality Objective meeting as being improperly identified as underground storage tanks. CAS 25-02-03 identified as the Deluge Valve Pit was actually an underground electrical vault and CAS 25-02-10 identified as an Underground Storage Tank was actually a former above ground storage tank filled with demineralized water. Both of these CAS's are recommended for a no further action closure. CAS 25-02-01 the Underground Storage Tanks commonly referred to as the Engine Maintenance Assembly and Disassembly Waste Holdup Tanks and Vault was closed by decontaminating the vault structure and conducting a radiological verification survey to document compliance with the Nevada Test Site unrestricted use release criteria. The Area 25 Underground Storage Tanks, (CAS 25-02-01), referred to as the Engine Maintenance, Assembly, and Disassembly (E-MAD) Waste Holdup Tanks and Vault, were used to receive liquid waste from all of the radioactive and cell service area drains at the E-MAD Facility. Based on the results of the Corrective Action Investigation conducted in June 1999, discussed in ''The Corrective Action Investigation Plan for Corrective Action Unit 135: Area 25 Underground Storage Tanks, Nevada Test Site, Nevada'' (DOE/NV, 199a), one sample from the radiological survey of the concrete vault interior exceeded radionuclide preliminary action levels. The analytes from the sediment samples exceeded the preliminary action levels for polychlorinated biphenyls, Resource Conservation and Recovery Act metals, total petroleum hydrocarbons as diesel-range organics, and radionuclides. The CAU 135 closure activities consisted of scabbling radiological ''hot spots

  12. Closure Report for Corrective Action Unit 398: Area 25 Spill Sites, Nevada Test Site, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    K. B. Campbell

    2003-04-01

    This Closure Report (CR) documents the activities performed to close Corrective Action Unit (CAU) 398: Area 25 Spill Sites, in accordance with the Federal Facility Agreement and Consent Order (FFACO) of 1996, and the Nevada Division of Environmental Protection (NDEP)-approved Streamlined Approach for Environmental Restoration (SA4FER) Plan for CAU 398: Area 25 Spill Sites, Nevada Test Site, Nevada (U.S. Department of Energy, Nevada Operations Office [DOEN], 2001). CAU 398 consists of the following thirteen Corrective Action Sites (CASs) all located in Area 25 of the Nevada Test Site (NTS) (Figure 1): CAS 25-25-02, Oil Spills, CAS 25-25-03, Oil Spills, CAS 25-25-04, Oil Spills, CAS 25-25-05, Oil Spills, CAS 25-25-06, Oil Spills, CAS 25-25-07, Hydraulic Oil Spill(s), CAS 25-25-08, Hydraulic Oil Spill(s), CAS 25-25-16, Diesel Spill (from CAS 25-01-02), CAS 25-25-17, Subsurface Hydraulic Oil Spill, CAS 25-44-0 1, Fuel Spill, CAS 25-44-04, Acid Spill (from CAS 25-01-01), CAS 25-44-02, Spill, and CAS 25-44-03, Spill. Copies of the analytical results for the site verification samples are included in Appendix B. Copies of the CAU Use Restriction Information forms are included in Appendix C.

  13. Overview of electromagnetic methods applied in active volcanic areas of western United States

    Science.gov (United States)

    Skokan, Catherine K.

    1993-06-01

    A better understanding of active volcanic areas in the United States through electromagnetic geophysical studies received foundation from the many surveys done for geothermal exploration in the 1970's. Investigations by governmental, industrial, and academic agencies include (but are not limited to) mapping of the Cascades. Long Valley/Mono area, the Jemez volcanic field, Yellowstone Park, and an area in Colorado. For one example — Mt. Konocti in the Mayacamas Mountains, California — gravity, magnetic, and seismic, as well as electromagnetic methods have all been used in an attempt to gain a better understanding of the subsurface structure. In each of these volcanic regions, anomalous zones were mapped. When conductive, these anomalies were interpreted to be correlated with hydrothermal activity and not to represent a magma chamber. Electrical and electromagnetic geophysical methods can offer valuable information in the understanding of volcanoes by being the method which is most sensitive to change in temperature and, therefore, can best map heat budget and hydrological character to aid in prediction of eruptions.

  14. Leaf Physiological and Morphological Responses to Shade in Grass-Stage Seedlings and Young Trees of Longleaf Pine

    Directory of Open Access Journals (Sweden)

    Lisa J. Samuelson

    2012-08-01

    Full Text Available Longleaf pine has been classified as very shade intolerant but leaf physiological plasticity to light is not well understood, especially given longleaf pine’s persistent seedling grass stage. We examined leaf morphological and physiological responses to light in one-year-old grass-stage seedlings and young trees ranging in height from 4.6 m to 6.3 m to test the hypothesis that young longleaf pine would demonstrate leaf phenotypic plasticity to light environment. Seedlings were grown in a greenhouse under ambient levels of photosynthetically active radiation (PAR or a 50% reduction in ambient PAR and whole branches of trees were shaded to provide a 50% reduction in ambient PAR. In seedlings, shading reduced leaf mass per unit area (LMA, the light compensation point, and leaf dark respiration (RD, and increased the ratio of light-saturated photosynthesis to RD and chlorophyll b and total chlorophyll expressed per unit leaf dry weight. In trees, shading reduced LMA, increased chlorophyll a, chlorophyll b and total chlorophyll on a leaf dry weight basis, and increased allocation of total foliar nitrogen to chlorophyll nitrogen. Changes in leaf morphological and physiological traits indicate a degree of shade tolerance that may have implications for even and uneven-aged management of longleaf pine.

  15. Design and implementation of interface units for high speed fiber optics local area networks and broadband integrated services digital networks

    Science.gov (United States)

    Tobagi, Fouad A.; Dalgic, Ismail; Pang, Joseph

    1990-01-01

    The design and implementation of interface units for high speed Fiber Optic Local Area Networks and Broadband Integrated Services Digital Networks are discussed. During the last years, a number of network adapters that are designed to support high speed communications have emerged. This approach to the design of a high speed network interface unit was to implement package processing functions in hardware, using VLSI technology. The VLSI hardware implementation of a buffer management unit, which is required in such architectures, is described.

  16. Closure Report for Corrective Action Unit 358: Areas 18, 19, 20 Cellars/Mud Pits, Nevada Test Site, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office; Bechtel Nevada

    2004-01-01

    This closure report documents that the closure activities performed at Corrective Action Unit 358: Areas 18, 19, 20 Cellars/Mud Pits, were in accordance with the Nevada Division of Environmental Protection approved Streamlined Approach for Environmental Restoration Plan for Corrective Action Unit 358.

  17. Eielson Air Force Base operable unit 2 and other areas record of decision

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, R.E.; Smith, R.M.

    1994-10-01

    This decision document presents the selected remedial actions and no action decisions for Operable Unit 2 (OU2) at Eielson Air Force Base (AFB), Alaska, chosen in accordance with state and federal regulations. This document also presents the decision that no further action is required for 21 other source areas at Eielson AFB. This decision is based on the administrative record file for this site. OU2 addresses sites contaminated by leaks and spills of fuels. Soils contaminated with petroleum products occur at or near the source of contamination. Contaminated subsurface soil and groundwater occur in plumes on the top of a shallow groundwater table that fluctuates seasonally. These sites pose a risk to human health and the environment because of ingestion, inhalation, and dermal contact with contaminated groundwater. The purpose of this response is to prevent current or future exposure to the contaminated groundwater, to reduce further contaminant migration into the groundwater, and to remediate groundwater.

  18. 2008 Groundwater Monitoring Report Project Shoal Area, Corrective Action Unit 447

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-03-01

    This report presents the 2008 groundwater monitoring results collected by the U.S. Department of Energy (DOE) Office of Legacy Management (LM) at the Project Shoal Area (PSA) Subsurface Corrective Action Unit (CAU) 447 located in Churchill County, Nevada. Responsibility for the environmental site restoration of the PSA was transferred from the DOE Office of Environmental Management to LM on October 1, 2006. The environmental restoration process and corrective action strategy for CAU 447 are conducted in accordance with the Federal Facility Agreement and Consent Order (FFACO 1996, as amended February 2008) entered into by DOE, the U.S. Department of Defense, and the State of Nevada. The corrective action strategy for the site includes proof of concept monitoring in support of site closure. This report summarizes investigation activities associated with CAU 447 that were conducted at the site during 2008. This is the second groundwater monitoring report prepared by LM for the PSA

  19. United States Pharmacopeia activities in the area of vaccines, virology and immunology.

    Science.gov (United States)

    Morris, Tina S

    2005-03-18

    The United States Pharmacopeia (USP) develops public standards for medical products that are enforceable by FDA. USP general information chapters have been providing industrial and academic researchers alike with crucial guidance especially in areas where there is absence of regulatory guidance. In an effort to meet the challenge of rapid advances in vaccine research and manufacturing, the Council of Experts Committee for Vaccines, Virology, and Immunology of the US Pharmacopeia has recently initiated two new general chapters to provide advice for researchers and manufacturers in the vaccine and virology fields and beyond. Chapter 1235 Vaccines and Vaccine Test Methods will focus on manufacturing and analytical requirements for the different types of vaccines currently in manufacture and development. Chapter 1237 Virology Test Methods will discuss modern diagnostic virology techniques and a variety of tests as applicable to vaccine and biologics manufacturing.

  20. 2010 Groundwater Monitoring Report Project Shoal Area, Corrective Action Unit 447

    Energy Technology Data Exchange (ETDEWEB)

    None

    2011-02-01

    This report presents the 2010 groundwater monitoring results collected by the U.S. Department of Energy (DOE) Office of Legacy Management (LM) at the Project Shoal Area (PSA) Subsurface Corrective Action Unit (CAU) 447 in Churchill County, Nevada. Responsibility for the environmental site restoration of the PSA was transferred from the DOE Office of Environmental Management to LM on October 1, 2006. The environmental restoration process and corrective action strategy for CAU 447 are conducted in accordance with the Federal Facility Agreement and Consent Order (FFACO 1996, as amended March 2010) entered into by DOE, the U.S. Department of Defense, and the State of Nevada. The corrective action strategy for the site includes monitoring in support of site closure. This report summarizes the results from the groundwater monitoring program during fiscal year 2010.

  1. 2009 Groundwater Monitoring Report Project Shoal Area, Corrective Action Unit 447

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-03-01

    This report presents the 2009 groundwater monitoring results collected by the U.S. Department of Energy (DOE) Office of Legacy Management (LM) at the Project Shoal Area (PSA) Subsurface Corrective Action Unit (CAU) 447 in Churchill County, Nevada. Responsibility for the environmental site restoration of the PSA was transferred from the DOE Office of Environmental Management to LM on October 1, 2006. The environmental restoration process and corrective action strategy for CAU 447 are conducted in accordance with the Federal Facility Agreement and Consent Order (FFACO 1996, as amended February 2008) entered into by DOE, the U.S. Department of Defense, and the State of Nevada. The corrective action strategy for the site includes monitoring in support of site closure. This report summarizes investigation activities associated with CAU 447 that were conducted at the PSA during fiscal year 2009.

  2. Effects of urban development on stream ecosystems in nine metropolitan study areas across the United States

    Science.gov (United States)

    Coles, James F.; McMahon, Gerard; Bell, Amanda H.; Brown, Larry R.; Fitzpatrick, Faith A.; Scudder Eikenberry, Barbara C.; Woodside, Michael D.; Cuffney, Thomas F.; Bryant, Wade L.; Cappiella, Karen; Fraley-McNeal, Lisa; Stack, William P.

    2012-01-01

    Urban development is an important agent of environmental change in the United States. The urban footprint on the American landscape has expanded during a century and a half of almost continuous development. Eighty percent of Americans now live in metropolitan areas, and the advantages and challenges of living in these developed areas—convenience, congestion, employment, pollution—are part of the day-to-day realities of most Americans. Nowhere are the environmental changes associated with urban development more evident than in urban streams. Contaminants, habitat destruction, and increasing streamflow flashiness resulting from urban development have been associated with the disruption of biological communities, particularly the loss of sensitive aquatic species. Every stream is connected downstream to larger water bodies, including rivers, reservoirs, and ultimately coastal waters. Inputs of chemical contaminants or sediments at any point along the stream can cause degradation downstream with adverse effects on biological communities and on economically valuable resources, such as fisheries and tourism.

  3. 2008 Groundwater Monitoring Report Central Nevada Test Area, Corrective Action Unit 443

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-03-01

    This report presents the 2008 groundwater monitoring results collected by the U.S. Department of Energy (DOE) Office of Legacy Management (LM) for the Central Nevada Test Area (CNTA) Subsurface Corrective Action Unit (CAU) 443. Responsibility for the environmental site restoration of the CNTA was transferred from the DOE Office of Environmental Management (DOE-EM) to DOE-LM on October 1, 2006. The environmental restoration process and corrective action strategy for CAU 443 are conducted in accordance with the Federal Facility Agreement and Consent Order (FFACO 2005) entered into by DOE, the U.S. Department of Defense, and the State of Nevada. The corrective action strategy for the site includes proof-of-concept monitoring in support of site closure. This report summarizes investigation activities associated with CAU 443 that were conducted at the site during fiscal year 2008. This is the second groundwater monitoring report prepared by DOE-LM for the CNTA.

  4. National Assessment of Oil and Gas Project - Yukon Flats Assessment Area (002) Assessment Units

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The Assessment Unit is the fundamental unit used in the National Assessment Project for the assessment of undiscovered oil and gas resources. The Assessment Unit is...

  5. Carbon storage and sequestration by trees in urban and community areas of the United States.

    Science.gov (United States)

    Nowak, David J; Greenfield, Eric J; Hoehn, Robert E; Lapoint, Elizabeth

    2013-07-01

    Carbon storage and sequestration by urban trees in the United States was quantified to assess the magnitude and role of urban forests in relation to climate change. Urban tree field data from 28 cities and 6 states were used to determine the average carbon density per unit of tree cover. These data were applied to statewide urban tree cover measurements to determine total urban forest carbon storage and annual sequestration by state and nationally. Urban whole tree carbon storage densities average 7.69 kg C m(-2) of tree cover and sequestration densities average 0.28 kg C m(-2) of tree cover per year. Total tree carbon storage in U.S. urban areas (c. 2005) is estimated at 643 million tonnes ($50.5 billion value; 95% CI = 597 million and 690 million tonnes) and annual sequestration is estimated at 25.6 million tonnes ($2.0 billion value; 95% CI = 23.7 million to 27.4 million tonnes).

  6. Corrective Action Decision Document for Corrective Action Unit 417: Central Nevada Test Area Surface, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    U.S. Department of Energy Nevada Operations Office

    1999-04-02

    This Corrective Action Decision Document (CADD) identifies and rationalizes the U.S. Department of Energy, Nevada Operations Office's selection of a recommended corrective action alternative (CAA) appropriate to facilitate the closure of Corrective Action Unit (CAU) 417: Central Nevada Test Area Surface, Nevada, under the Federal Facility Agreement and Consent Order. Located in Hot Creek Valley in Nye County, Nevada, and consisting of three separate land withdrawal areas (UC-1, UC-3, and UC-4), CAU 417 is comprised of 34 corrective action sites (CASs) including 2 underground storage tanks, 5 septic systems, 8 shaker pad/cuttings disposal areas, 1 decontamination facility pit, 1 burn area, 1 scrap/trash dump, 1 outlier area, 8 housekeeping sites, and 16 mud pits. Four field events were conducted between September 1996 and June 1998 to complete a corrective action investigation indicating that the only contaminant of concern was total petroleum hydrocarbon (TPH) which was found in 18 of the CASs. A total of 1,028 samples were analyzed. During this investigation, a statistical approach was used to determine which depth intervals or layers inside individual mud pits and shaker pad areas were above the State action levels for the TPH. Other related field sampling activities (i.e., expedited site characterization methods, surface geophysical surveys, direct-push geophysical surveys, direct-push soil sampling, and rotosonic drilling located septic leachfields) were conducted in this four-phase investigation; however, no further contaminants of concern (COCs) were identified. During and after the investigation activities, several of the sites which had surface debris but no COCs were cleaned up as housekeeping sites, two septic tanks were closed in place, and two underground storage tanks were removed. The focus of this CADD was to identify CAAs which would promote the prevention or mitigation of human exposure to surface and subsurface soils with contaminant

  7. Experimental Investigation on Laminated Composite Leaf springs Subjected to Cyclic Loading

    OpenAIRE

    Rajesh, S.; G.B.Bhaskar

    2014-01-01

    An automobile industry have an interest in replacement of conventional leaf spring with composite leaf spring to get better performance with less weight. This paper deals with by replacing the conventional leaf spring with composite leaf spring. The dimensions of an existing conventional steel leaf spring of a light commercial vehicle were taken to fabricate the special die which is further used to manufacture the composite leaf spring. A single leaf with constant cross sectional area similar...

  8. Separating overstory and understory leaf area indices for global needleleaf and deciduous broadleaf forests by fusion of MODIS and MISR data

    Science.gov (United States)

    Liu, Yang; Liu, Ronggao; Pisek, Jan; Chen, Jing M.

    2017-03-01

    Forest overstory and understory layers differ in carbon and water cycle regimes and phenology, as well as ecosystem functions. Separate retrievals of leaf area index (LAI) for these two layers would help to improve modeling forest biogeochemical cycles, evaluating forest ecosystem functions and also remote sensing of forest canopies by inversion of canopy reflectance models. In this paper, overstory and understory LAI values were estimated separately for global needleleaf and deciduous broadleaf forests by fusing MISR and MODIS observations. Monthly forest understory LAI was retrieved from the forest understory reflectivity estimated using MISR data. After correcting for the background contribution using monthly mean forest understory reflectivities, the forest overstory LAI was estimated from MODIS observations. The results demonstrate that the largest extent of forest understory vegetation is present in the boreal forest zones at northern latitudes. Significant seasonal variations occur for understory vegetation in these zones with LAI values up to 2-3 from June to August. The mean proportion of understory LAI to total LAI is greater than 30 %. Higher understory LAI values are found in needleleaf forests (with a mean value of 1.06 for evergreen needleleaf forests and 1.04 for deciduous needleleaf forests) than in deciduous broadleaf forests (0.96) due to the more clumped foliage and easier penetration of light to the forest floor in needleleaf forests. Spatially and seasonally variable forest understory reflectivity helps to account for the effects of the forest background on LAI retrieval while compared with constant forest background. The retrieved forest overstory and understory LAI values were compared with an existing dataset for larch forests in eastern Siberia (40-75° N, 45-180° E). The retrieved overstory and understory LAI is close to that of the existing dataset, with an absolute error of 0.02 (0.06), relative error of 1.3 % (14.3 %) and RMSE of 0

  9. Integrating ASCAT surface soil moisture and GEOV1 leaf area index into the SURFEX modelling platform: a land data assimilation application over France

    Directory of Open Access Journals (Sweden)

    A. L. Barbu

    2014-01-01

    Full Text Available The land monitoring service of the European Copernicus programme has developed a set of satellite-based biogeophysical products, including surface soil moisture (SSM and leaf area index (LAI. This study investigates the impact of joint assimilation of remotely sensed SSM derived from Advanced Scatterometer (ASCAT backscatter data and the Copernicus Global Land GEOV1 satellite-based LAI product into the the vegetation growth version of the Interactions between Soil Biosphere Atmosphere (ISBA-A-gs land surface model within the the externalised surface model (SURFEX modelling platform of Météo-France. The ASCAT data were bias corrected with respect to the model climatology by using a seasonal-based CDF (Cumulative Distribution Function matching technique. A multivariate multi-scale land data assimilation system (LDAS based on the extended Kalman Filter (EKF is used for monitoring the soil moisture, terrestrial vegetation, surface carbon and energy fluxes across the domain of France at a spatial resolution of 8 km. Each model grid box is divided into a number of land covers, each having its own set of prognostic variables. The filter algorithm is designed to provide a distinct analysis for each land cover while using one observation per grid box. The updated values are aggregated by computing a weighted average. In this study, it is demonstrated that the assimilation scheme works effectively within the ISBA-A-gs model over a four-year period (2008–2011. The EKF is able to extract useful information from the data signal at the grid scale and distribute the root-zone soil moisture and LAI increments throughout the mosaic structure of the model. The impact of the assimilation on the vegetation phenology and on the water and carbon fluxes varies from one season to another. The spring drought of 2011 is an interesting case study of the potential of the assimilation to improve drought monitoring. A comparison between simulated and in situ soil

  10. Corrective Action Plan for Corrective Action Unit 214: Bunkers and Storage Areas, Nevada Test Site, Nevada - Revision 0 - March 2005

    Energy Technology Data Exchange (ETDEWEB)

    U.S. Department of Energy, National Nuclear Security Administration, Nevada Site Office; Bechtel Nevada

    2005-03-01

    Corrective Action Unit 214, Bunkers and Storage Areas, is identified in the Federal Facility Agreement and Consent Order of 1996. Corrective Action Unit 214 consists of nine Corrective Action Sites located in Areas 5, 11, and 25 of the Nevada Test Site. The Nevada Test Site is located approximately 105 kilometers (65 miles) northwest of Las Vegas, Nevada, in Nye County. Corrective Action Unit 214 was previously characterized in 2004, and results were presented in the Corrective Action Decision Document for 214. Site characterization indicated that soil and/or debris exceeded clean-up criteria for Total Petroleum Hydrocarbons, pesticides, metals, and radiological contamination.

  11. Determination of the relationship among capillary pressure, saturation and interfacial area: a pore unit assembly approach

    Directory of Open Access Journals (Sweden)

    Nikooee E.

    2016-01-01

    Full Text Available Three state variables namely, degree of saturation (Sw, capillary pressure (Pc and specific air-water interfacial area (aaw are indispensable for modelling coupled processes relevant to unsaturated soils mechanics, agriculture, and contaminant hydrology. They play a key role in simulating various phenomena and the determination of various parameters and physical characteristics such as the unsaturated soil shear strength, field capacity, wilting point, air and water diffusivity and the rate of dissolution of contaminants. The determination of soil water retention curve (Sw-Pc as well as the specific interfacial area (aaw using available experimental techniques is a challenging and time consuming task. Therefore, a numerical technique that employs basic soil properties to obtain these variables is of much value and high practical and theoretical importance. In the current study, the porous network extracted from a discrete element model (the so-called pore unit-assembly has been used to directly model the drying and wetting processes inside a granular soil packing and to obtain the values of Pc, Sw and aaw. The results of the simulations are in good agreement with the experimental data, which points to the efficacy and adequacy of the introduced algorithms and involved assumptions for this purpose.

  12. Closure Report for Corrective Action Unit 346: Areas 8, 10 Housekeeping Sites, Nevada Test Site, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    K. B. Campbell

    2003-08-01

    This Closure Report documents the closure activities conducted for Corrective Action Unit (CAU) 346: Areas 8, 10 Housekeeping Sites. CAU 346 is listed in Appendix III of the Federal Facility Agreement and Consent Order (FFACO, 1996) and consists of the following 14 Corrective Action Sites (CASs) located in Areas 8 and 10 of the Nevada Test Site (NTS): (1) CAS 08-22-04: Drums (2); (2) CAS 08-22-11: Drums; Bucket; (3) CAS 08-24-02: Battery; (4) CAS 10-14-01: Transformer; (5) CAS 10-22-06: Drum (Gas Block); (6) CAS 10-22-10: Drum (Gas Block); (7) CAS 10-22-12: Drum (Gas Block); (8) CAS 10-22-13: Drum (Gas Block); (9) CAS 10-22-16: Drum (Gas Block); (10) CAS 10-22-22: Drum; (11) CAS 10-22-25: Drum; (12) CAS 10-22-36: Paint Can; (13) CAS 10-22-37: Gas Block; and (14) CAS 10-24-11: Battery. Closure activities consisted of closing each CAS by removing debris and/or material, disposing of the generated waste, and verifying that each site was clean-closed by visual inspection and/or laboratory analysis of soil verification samples.

  13. Selection of organic Rankine cycle working fluid based on unit-heat-exchange-area net power

    Institute of Scientific and Technical Information of China (English)

    郭美茹; 朱启的; 孙志强; 周天; 周孑民

    2015-01-01

    To improve energy conversion efficiency, optimization of the working fluids in organic Rankine cycles (ORCs) was explored in the range of low-temperature heat sources. The concept of unit-heat-exchange-area (UHEA) net power, embodying the cost/performance ratio of an ORC system, was proposed as a new indicator to judge the suitability of ORC working fluids on a given condition. The heat exchange area was computed by an improved evaporator model without fixing the minimum temperature difference between working fluid and hot fluid, and the flow pattern transition during heat exchange was also taken into account. The maximum UHEA net powers obtained show that dry organic fluids are more suitable for ORCs than wet organic fluids to recover low-temperature heat. The organic fluid 1-butene is recommended if the inlet temperature of hot fluid is 353.15−363.15 K or 443.15−453.15 K, heptane is more suitable at 373.15−423.15 K, and R245ca is a good option at 483.15−503.15 K.

  14. SU-E-T-306: Dosimetric Comparison of Leaf with Or Without Interdigitation in Multiple Brain Metastasis VMAT Treatment Planning

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-06-15

    Purpose: To evaluate the effects of leaf with or without interdigitation in multiple brain metastasis volumetric modulated arc therapy (VMAT) plans. Methods: Twenty patients with 2 to 6 brain metastases of our hospital were retrospectively studied to be planned with dual arc VMAT using Monaco 3.3 TPS on the Elekta Synergy linear accelerator. The prescription dose of PTV was 60Gy/30 fractions. Two plans with or without leaf interdigitation were designed. The homogeneity index (HI), conformity index (CI), dose volume histograms (DVHs), monitor unit (MU), treatment time (T), the segments, the dose coverage of the target, were all evaluated. Results: The plans with leaf interdigitation could achieve better CI (p<0.05) than without leaf interdigitation, while no significant difference were found in HI (p> 0.05) and the dose coverage of the target (p> 0.05).The MU,T, and the segments of the plan with leaf interdigitation were more than the plan without leaf interdigitation (p<0.05). There was no significant difference found in radiation dose of spinal cord, lenses and parotids, while the maximum dose of brain stem of leaf without interdigitation was higher than leaf with interdigitation (p< 0.05). It was worth noting that the areas of low dose regions with leaf interdigitation plan were much less than the without leaf interdigitation plan in the doublication planes (p< 0.05). Conclusion: This study shows that leaf with interdigitation has some advantages than leaf without interdigitation in multiple brain metastasis VMAT plans although the clinical relevance remains to be proven.

  15. USGS 1:1,000,000-Scale Urban Areas of the United States 201504 FileGDB

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set includes urban areas in the United States, Puerto Rico, and the U.S. Virgin Islands. The data were derived from the 2010 TIGER/Line Urban Areas data...

  16. STREAMLINED APPROACH FOR ENVIRONMENTAL RESTORATION PLAN FOR CORRECTIVE ACTION UNIT 116: AREA 25 TEST CELL C FACILITYNEVADA TEST SITE, NEVADA

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    This Streamlined Approach for Environmental Restoration Plan identifies the activities required for the closure of Corrective Action Unit 116, Area 25 Test Cell C Facility. The Test Cell C Facility is located in Area 25 of the Nevada Test Site approximately 25 miles northwest of Mercury, Nevada.

  17. Mesophyll conductance and leaf carbon isotope composition of two high elevation conifers along an altitudinal gradient

    Science.gov (United States)

    Guo, J.; Beverly, D.; Cook, C.; Ewers, B.; Williams, D. G.

    2016-12-01

    Carbon isotope ratio values (δ13C) of conifer leaf material generally increases with elevation, potentially reflecting decreases in the leaf internal to ambient CO2 concentration ratio (Ci/Ca) during photosynthesis. Reduced stomatal conductance or increased carboxylation capacity with increasing elevation could account for these patterns. But some studies reported conifers δ13C increased with altitude consistently, but Ci/Ca did not significantly decrease and leaf nitrogen content remained constant with increasing of altitude in Central Rockies. Variation in leaf mesophyll conductance to CO2 diffusion, which influences leaf δ13C independently of effects related to stomatal conductance and carboxylation demand, might reconcile these conflicting observations. Leaf mass per unit area (LMA) increases with altitude and often correlates with δ13C and mesophyll conductance. Therefore, we hypothesized that increases in δ13C of conifers with altitude are controlled mainly by changes in mesophyll conductance. To test this hypothesis, leaf δ13C, photosynthetic capacity, leaf nitrogen content, LMA, and mesophyll conductance were determined on leaves of two dominant conifers (Pinus contorta and Picea engelmannii) along a 90-km transect in SE Wyoming at altitudes ranging from 2400 to 3200 m above sea level. Mesophyll conductance was determined by on-line 13C discrimination using isotope laser spectroscopy. We expected to observe relatively small differences in stomatal conductance and decreases in mesophyll conductance from lower and higher altitude sites. Such a pattern would have important implications for how differences in leaf δ13C values across altitude are interpreted in relation to forest water use and productivity from scaling of leaf-level water-use efficiency.

  18. Predicting tree water use and drought tolerance from leaf traits in the Los Angeles urban ecosystem

    Science.gov (United States)

    John, G. P.; Scoffoni, C.; Sack, L.

    2013-12-01

    Urban green space provides a suite of valuable ecosystem services. In semiarid systems, like Los Angeles, trees rely primarily on irrigation water for transpiration. Managers may need to reduce irrigation associated with urban trees given climate change, urban expansion, and the steady decrease in available freshwater. While leaf and whole plant water relations have been extensively studied, we are only now gaining a detailed understanding of diverse leaf anatomical designs, and their use for predicting physiology and water use at landscape scale. For 50 diverse urban species, we quantified leaf anatomical and physiological traits important to tree drought tolerance and water use efficiency including turgor loss point, vein architecture, cellular anatomy, leaf mass per unit area, and petiole and leaf dimensions. We hypothesized detailed relationships to develop models relating leaf functional traits to tree water relations. These models provide key insights regarding the role of anatomical designs in leaf stress tolerance and water use efficiency. Additionally we predicted how traits measured at the leaf level would scale with existing data for individuals at the whole plant level. We tested our predictions by determining correlations between leaf level anatomical traits and drought tolerance. Additionally, we determined correlations between functional traits, physiology and water use, and the climate of origin for the urban species. Leaf level measurements will be valuable for rapid estimation of more difficult to measure whole plant water relations traits important at the landscape scale. The Los Angeles urban ecosystem can serve as a model for other semiarid system and provide more informed system wide water conservation strategies.

  19. Cedar leaf oil poisoning

    Science.gov (United States)

    Cedar leaf oil is made from some types of cedar trees. Cedar leaf oil poisoning occurs when someone swallows this substance. ... The substance in cedar leaf oil that can be harmful is thujone (a hydrocarbon).

  20. Closure Report for Corrective Action Unit 110: Areas 3 RWMS U-3ax/bl Disposal Unit, Nevada Test Site, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    J. L. Smith

    2001-08-01

    This Closure Report (CR) has been prepared for the Area 3 Radioactive Waste Management Site (RWMS) U-3ax/bl Disposal Unit Corrective Action Unit (CAU) 110 in accordance with the reissued (November 2000) Resource Conservation and Recovery Act (RCRA) Part B operational permit NEV HW009 (Nevada Division of Environmental Protection [NDEP], 2000) and the Federal Facility and Consent Order (FFACO) (NDEP et al., 1996). CAU 110 consists of one Corrective Action Site 03-23-04, described as the U-3ax/bl Subsidence Crater. Certifications of closure are located in Appendix A. The U-3ax/bl is a historic disposal unit within the Area 3 RWMS located on the Nevada Test Site (NTS). The unit, which was formed by excavating the area between two subsidence craters (U-3ax and U-3bl), was operationally closed in 1987. The U-3ax/bl disposal unit was closed under the RCRA, as a hazardous waste landfill. Existing records indicate that, from July 1968 to December 1987, U-3ax/bl received 2.3 x 10{sup 5} cubic meters (m{sup 3}) (8.12 x 10{sup 6} cubic feet [ft{sup 3}]) of waste. NTS atmospheric nuclear device testing generated approximately 95% of the total waste volume disposed of in U-3ax/bl; 80% of the total volume was generated from the Waste Consolidation Project. Area 3 is located in Yucca Flat, within the northeast quadrant of the NTS. The Yucca Flat watershed is a structurally closed basin encompassing an area of approximately 780 square kilometers (300 square miles). The structural geomorphology of Yucca Flat is typical of the Basin and Range Physiographic Province. Yucca Flat lies in one of the most arid regions of the country. Water balance calculations for Area 3 indicate that it is normally in a state of moisture deficit.

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

    Science.gov (United States)

    Köhler, P.; Huth, A.

    2010-08-01

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

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

    Directory of Open Access Journals (Sweden)

    P. Köhler

    2010-08-01

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

  3. Reduced uncertainty of regional scale CLM predictions of net carbon fluxes and leaf area indices with estimated plant-specific parameters

    Science.gov (United States)

    Post, Hanna; Hendricks Franssen, Harrie-Jan; Han, Xujun; Baatz, Roland; Montzka, Carsten; Schmidt, Marius; Vereecken, Harry

    2016-04-01

    Reliable estimates of carbon fluxes and states at regional scales are required to reduce uncertainties in regional carbon balance estimates and to support decision making in environmental politics. In this work the Community Land Model version 4.5 (CLM4.5-BGC) was applied at a high spatial resolution (1 km2) for the Rur catchment in western Germany. In order to improve the model-data consistency of net ecosystem exchange (NEE) and leaf area index (LAI) for this study area, five plant functional type (PFT)-specific CLM4.5-BGC parameters were estimated with time series of half-hourly NEE data for one year in 2011/2012, using the DiffeRential Evolution Adaptive Metropolis (DREAM) algorithm, a Markov Chain Monte Carlo (MCMC) approach. The parameters were estimated separately for four different plant functional types (needleleaf evergreen temperate tree, broadleaf deciduous temperate tree, C3-grass and C3-crop) at four different sites. The four sites are located inside or close to the Rur catchment. We evaluated modeled NEE for one year in 2012/2013 with NEE measured at seven eddy covariance sites in the catchment, including the four parameter estimation sites. Modeled LAI was evaluated by means of LAI derived from remotely sensed RapidEye images of about 18 days in 2011/2012. Performance indices were based on a comparison between measurements and (i) a reference run with CLM default parameters, and (ii) a 60 instance CLM ensemble with parameters sampled from the DREAM posterior probability density functions (pdfs). The difference between the observed and simulated NEE sum reduced 23% if estimated parameters instead of default parameters were used as input. The mean absolute difference between modeled and measured LAI was reduced by 59% on average. Simulated LAI was not only improved in terms of the absolute value but in some cases also in terms of the timing (beginning of vegetation onset), which was directly related to a substantial improvement of the NEE estimates in

  4. Teen Birth Rates for Urban and Rural Areas in the United States, 2007-2015.

    Science.gov (United States)

    Hamilton, Brady E; Rossen, Lauren M; Branum, Amy M

    2016-11-01

    Data from the National Vital Statistics System •Birth rates for teenagers aged 15-19 declined in urban and rural counties from 2007 through 2015, with the largest declines in large urban counties and the smallest declines in rural counties. •From 2007 through 2015, the teen birth rate was lowest in large urban counties and highest in rural counties. •Declines in teen birth rates in all urban counties between 2007 and 2015 were largest in Arizona, Massachusetts, Connecticut, Minnesota, and Colorado, with 17 states experiencing a decline of 50% or more. •Declines in teen birth rates in all rural counties between 2007 and 2015 were largest (50% or more) in Colorado and Connecticut. •In 2015, teen birth rates were highest in rural counties and lowest in large urban counties for non-Hispanic white, non-Hispanic black, and Hispanic females. Teen birth rates have demonstrated an unprecedented decline in the United States since 2007 (1). Declines occurred in all states and among all major racial and Hispanic-origin groups, yet disparities by both geography and demographic characteristics persist (2,3). Although teen birth rates and related declines have been described by state, patterns by urban-rural location have not yet been examined. This report describes trends in teen birth rates in urban (metropolitan) and rural (nonmetropolitan) areas in the United States overall and by state from 2007 through 2015 and by race and Hispanic origin for 2015. All material appearing in this report is in the public domain and may be reproduced or copied without permission; citation as to source, however, is appreciated.

  5. The Instrumental Music Program Unit in the South-West Queensland Priority Country Area. Priority Country Area Program Evaluation Series: Report No. 8.

    Science.gov (United States)

    Briody, P.

    The Instrumental Music Program Unit in the South-West Priority Country Area (a vast, generally arid hot region some 800 km by 450 km) is a unique, dynamic, and successful program, enjoying an extremely high degree of enthusiastic support from all involved--administrators, instructors, students, schools, and communities. Begun in 1977, there are…

  6. 2015 Cartographic Boundary File, Metropolitan Statistical Area/Micropolitan Statistical Area for United States, 1:500,000

    Data.gov (United States)

    US Census Bureau, Department of Commerce — The 2015 cartographic boundary shapefiles are simplified representations of selected geographic areas from the U.S. Census Bureau's Master Address File /...

  7. 2014 Cartographic Boundary File, Metropolitan Statistical Area/Micropolitan Statistical Area for United States, 1:5,000,000

    Data.gov (United States)

    US Census Bureau, Department of Commerce — The 2014 cartographic boundary shapefiles are simplified representations of selected geographic areas from the U.S. Census Bureau's Master Address File /...

  8. 2014 Cartographic Boundary File, Metropolitan Statistical Area/Micropolitan Statistical Area for United States, 1:20,000,000

    Data.gov (United States)

    US Census Bureau, Department of Commerce — The 2014 cartographic boundary shapefiles are simplified representations of selected geographic areas from the U.S. Census Bureau's Master Address File /...

  9. 2014 Cartographic Boundary File, Metropolitan Statistical Area/Micropolitan Statistical Area for United States, 1:500,000

    Data.gov (United States)

    US Census Bureau, Department of Commerce — The 2014 cartographic boundary shapefiles are simplified representations of selected geographic areas from the U.S. Census Bureau's Master Address File /...

  10. 2015 Cartographic Boundary File, Metropolitan Statistical Area/Micropolitan Statistical Area for United States, 1:20,000,000

    Data.gov (United States)

    US Census Bureau, Department of Commerce — The 2015 cartographic boundary KMLs are simplified representations of selected geographic areas from the U.S. Census Bureau's Master Address File / Topologically...

  11. 2015 Cartographic Boundary File, Metropolitan Statistical Area/Micropolitan Statistical Area for United States, 1:5,000,000

    Data.gov (United States)

    US Census Bureau, Department of Commerce — The 2015 cartographic boundary KMLs are simplified representations of selected geographic areas from the U.S. Census Bureau's Master Address File / Topologically...

  12. 2015 Cartographic Boundary File, Metropolitan Statistical Area/Micropolitan Statistical Area for United States, 1:20,000,000

    Data.gov (United States)

    US Census Bureau, Department of Commerce — The 2015 cartographic boundary shapefiles are simplified representations of selected geographic areas from the U.S. Census Bureau's Master Address File /...

  13. 2014 Cartographic Boundary File, Metropolitan Statistical Area/Micropolitan Statistical Area for United States, 1:20,000,000

    Data.gov (United States)

    US Census Bureau, Department of Commerce — The 2014 cartographic boundary KMLs are simplified representations of selected geographic areas from the U.S. Census Bureau's Master Address File / Topologically...

  14. 2015 Cartographic Boundary File, Metropolitan Statistical Area/Micropolitan Statistical Area for United States, 1:500,000

    Data.gov (United States)

    US Census Bureau, Department of Commerce — The 2015 cartographic boundary KMLs are simplified representations of selected geographic areas from the U.S. Census Bureau's Master Address File / Topologically...

  15. 2014 Cartographic Boundary File, Metropolitan Statistical Area/Micropolitan Statistical Area for United States, 1:500,000

    Data.gov (United States)

    US Census Bureau, Department of Commerce — The 2014 cartographic boundary KMLs are simplified representations of selected geographic areas from the U.S. Census Bureau's Master Address File / Topologically...

  16. 2015 Cartographic Boundary File, Metropolitan Statistical Area/Micropolitan Statistical Area for United States, 1:5,000,000

    Data.gov (United States)

    US Census Bureau, Department of Commerce — The 2015 cartographic boundary shapefiles are simplified representations of selected geographic areas from the U.S. Census Bureau's Master Address File /...

  17. 2014 Cartographic Boundary File, Metropolitan Statistical Area/Micropolitan Statistical Area for United States, 1:5,000,000

    Data.gov (United States)

    US Census Bureau, Department of Commerce — The 2014 cartographic boundary KMLs are simplified representations of selected geographic areas from the U.S. Census Bureau's Master Address File / Topologically...

  18. Closure Report for Corrective Action Unit 151: Septic Systems and Discharge Area, Nevada Test Site, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    NSTec Environmental Restoration

    2008-04-01

    Corrective Action Unit (CAU) 151 is identified in the Federal Facility Agreement and Consent Order (FFACO) as Septic Systems and Discharge Area. CAU 151 consists of the following eight Corrective Action Sites (CASs), located in Areas 2, 12, and 18 of the Nevada Test Site, approximately 65 miles northwest of Las Vegas, Nevada: (1) CAS 02-05-01, UE-2ce Pond; (2) CAS 12-03-01, Sewage Lagoons (6); (3) CAS 12-04-01, Septic Tanks; (4) CAS 12-04-02, Septic Tanks; (5) CAS 12-04-03, Septic Tank; (6) CAS 12-47-01, Wastewater Pond; (7) CAS 18-03-01, Sewage Lagoon; and (8) CAS 18-99-09, Sewer Line (Exposed). CAU 151 closure activities were conducted according to the FFACO (FFACO, 1996; as amended February 2008) and the Corrective Action Plan for CAU 151 (U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office, 2007) from October 2007 to January 2008. The corrective action alternatives included no further action, clean closure, and closure in place with administrative controls. CAU 151 closure activities are summarized in Table 1. Closure activities generated liquid remediation waste, sanitary waste, hydrocarbon waste, and mixed waste. Waste generated was appropriately managed and disposed. Waste that is currently staged onsite is being appropriately managed and will be disposed under approved waste profiles in permitted landfills. Waste minimization activities included waste characterization sampling and segregation of waste streams. Some waste exceeded land disposal restriction limits and required offsite treatment prior to disposal. Other waste meeting land disposal restrictions was disposed of in appropriate onsite or offsite landfills. Waste disposition documentation is included as Appendix C.

  19. Closure Report for Corrective Action Unit 536: Area 3 Release Site, Nevada Test Site, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    NSTec Environmental Restoration

    2007-06-01

    Corrective Action Unit (CAU) 536 is located in Area 3 of the Nevada Test Site. CAU 536 is listed in the Federal Facility Agreement and Consent Order of 1996 as Area 3 Release Site, and comprises a single Corrective Action Site (CAS): {sm_bullet} CAS 03-44-02, Steam Jenny Discharge The Nevada Division of Environmental Protection (NDEP)-approved corrective action alternative for CAS 03-44-02 is clean closure. Closure activities included removing and disposing of total petroleum hydrocarbon (TPH)- and polyaromatic hydrocarbon (PAH)-impacted soil, soil impacted with plutonium (Pu)-239, and concrete pad debris. CAU 536 was closed in accordance with the NDEP-approved CAU 536 Corrective Action Plan (CAP), with minor deviations as approved by NDEP. The closure activities specified in the CAP were based on the recommendations presented in the CAU 536 Corrective Action Decision Document (U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office, 2004). This Closure Report documents CAU 536 closure activities. During closure activities, approximately 1,000 cubic yards (yd3) of hydrocarbon waste in the form of TPH- and PAH-impacted soil and debris, approximately 8 yd3 of Pu-239-impacted soil, and approximately 100 yd3 of concrete debris were generated, managed, and disposed of appropriately. Additionally, a previously uncharacterized, buried drum was excavated, removed, and disposed of as hydrocarbon waste as a best management practice. Waste minimization techniques, such as the utilization of laboratory analysis to characterize and classify waste streams, were employed during the performance of closure

  20. Closure Report for Corrective Action Unit 151: Septic Systems and Discharge Area, Nevada Test Site, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    NSTec Environmental Restoration

    2008-04-01

    Corrective Action Unit (CAU) 151 is identified in the Federal Facility Agreement and Consent Order (FFACO) as Septic Systems and Discharge Area. CAU 151 consists of the following eight Corrective Action Sites (CASs), located in Areas 2, 12, and 18 of the Nevada Test Site, approximately 65 miles northwest of Las Vegas, Nevada: (1) CAS 02-05-01, UE-2ce Pond; (2) CAS 12-03-01, Sewage Lagoons (6); (3) CAS 12-04-01, Septic Tanks; (4) CAS 12-04-02, Septic Tanks; (5) CAS 12-04-03, Septic Tank; (6) CAS 12-47-01, Wastewater Pond; (7) CAS 18-03-01, Sewage Lagoon; and (8) CAS 18-99-09, Sewer Line (Exposed). CAU 151 closure activities were conducted according to the FFACO (FFACO, 1996; as amended February 2008) and the Corrective Action Plan for CAU 151 (U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office, 2007) from October 2007 to January 2008. The corrective action alternatives included no further action, clean closure, and closure in place with administrative controls. CAU 151 closure activities are summarized in Table 1. Closure activities generated liquid remediation waste, sanitary waste, hydrocarbon waste, and mixed waste. Waste generated was appropriately managed and disposed. Waste that is currently staged onsite is being appropriately managed and will be disposed under approved waste profiles in permitted landfills. Waste minimization activities included waste characterization sampling and segregation of waste streams. Some waste exceeded land disposal restriction limits and required offsite treatment prior to disposal. Other waste meeting land disposal restrictions was disposed of in appropriate onsite or offsite landfills. Waste disposition documentation is included as Appendix C.

  1. Corrective Action Plan for Corrective Action Unit 417: Central Nevada Test Area Surface, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    K. Campbell

    2000-04-01

    This Corrective Action Plan provides methods for implementing the approved corrective action alternative as provided in the Corrective Action Decision Document for the Central Nevada Test Area (CNTA), Corrective Action Unit (CAU) 417 (DOE/NV, 1999). The CNTA is located in the Hot Creek Valley in Nye County, Nevada, approximately 137 kilometers (85 miles) northeast of Tonopah, Nevada. The CNTA consists of three separate land withdrawal areas commonly referred to as UC-1, UC-3, and UC-4, all of which are accessible to the public. CAU 417 consists of 34 Corrective Action Sites (CASs). Results of the investigation activities completed in 1998 are presented in Appendix D of the Corrective Action Decision Document (DOE/NV, 1999). According to the results, the only Constituent of Concern at the CNTA is total petroleum hydrocarbons (TPH). Of the 34 CASs, corrective action was proposed for 16 sites in 13 CASs. In fiscal year 1999, a Phase I Work Plan was prepared for the construction of a cover on the UC-4 Mud Pit C to gather information on cover constructibility and to perform site management activities. With Nevada Division of Environmental Protection concurrence, the Phase I field activities began in August 1999. A multi-layered cover using a Geosynthetic Clay Liner as an infiltration barrier was constructed over the UC-4 Mud Pit. Some TPH impacted material was relocated, concrete monuments were installed at nine sites, signs warning of site conditions were posted at seven sites, and subsidence markers were installed on the UC-4 Mud Pit C cover. Results from the field activities indicated that the UC-4 Mud Pit C cover design was constructable and could be used at the UC-1 Central Mud Pit (CMP). However, because of the size of the UC-1 CMP this design would be extremely costly. An alternative cover design, a vegetated cover, is proposed for the UC-1 CMP.

  2. Estimation of leaf area for greenhouse cucumber by linear measurements under salinity and grafting Estimativa da área foliar do pepino em ambiente protegido por medidas lineares sob salinidade e enxertia

    Directory of Open Access Journals (Sweden)

    Flávio Favaro Blanco

    2005-08-01

    Full Text Available The measurement of leaf area by linear parameters is a useful tool when plants cannot be destroyed for direct measurement. The objectives of this study were to establish equations to estimate the leaf area of greenhouse-cucumber and to evaluate the effects of salinity and grafting on this estimative. Non-grafted cucumber seedlings, cv. 'Hokushin', were transplanted in a greenhouse and were irrigated with water of different salinities (1.0, 3.2 and 5.0 dS m-1. In the second growing period, the same cultivar was grafted on Cucurbita spp. and the plants were irrigated with water of 1.4, 3.0 and 5.3 dS m-1. Leaves of different sizes were collected from both experiments and leaf area was determined by an integrating area meter. Leaf length (L and width (W were also recorded. An equation for estimating the leaf area from L and W was developed for a given salinity level or grafting condition and estimated well the area of leaves collected in the other treatments. The leaf area (LA of cucumber 'Hokushin' could be estimated using the equation LA = 0.88LW - 4.27, for any grafting and salinity conditions.A determinação da área foliar por medidas lineares é uma ferramenta útil quando as plantas não podem ser destruídas para que a medição direta seja realizada. Os objetivos desse trabalho foram definir equações para a estimativa da área foliar do pepino em ambiente protegido e avaliar os efeitos da salinidade e da a enxertia nessa estimativa. Mudas de pepino, cv. 'Hokushin', não enxertadas, foram transplantadas em um ambiente protegido e irrigadas com água de diferentes salinidades (1,0, 3,2 e 5,0 dS m-1. No segundo período de cultivo, a mesma cultivar foi enxertada sobre Cucurbita spp., sendo as plantas irrigadas com água de 1,4, 3,0 e 5,3 dS m-1. Foram coletadas folhas de diferentes tamanhos dos dois cultivos e dos três tratamentos e a área foliar foi determinada por um medidor de área foliar. O comprimento (C e a largura (L da folha

  3. Post-Closure Inspection Report for Corrective Action Unit 90: Area 2 Bitcutter Containment

    Energy Technology Data Exchange (ETDEWEB)

    NSTec Environmental Restoration

    2007-08-01

    Corrective Action Unit (CAU) 90, Area 2 Bitcutter Containment, is identified in the ''Federal Facility Agreement and Consent Order'' of 1996. The post-closure requirements for CAU 90 are described in Section VII.B.8.b of the Nevada Test Site ''Resource Conservation and Recovery Act'' Permit for a Hazardous Waste Management Facility Number NEV HW0021, dated November 2005. Post-closure activities consist of the following: Semiannual inspections of the site using inspection checklists; Photographic documentation; Field note documentation; and Preparation and submittal of an annual Post-Closure Inspection Report. This annual report covers the period of July 2006 to June 2007 and consists of a summary of the results of the inspections, copies of the inspection checklists and field notes, maintenance and repair records (if any), photographs, and conclusions and recommendations. The inspection checklists are provided in Appendix A, a copy of the field notes is provided in Appendix B, and copies of photographs taken during the inspections are provided in Appendix C.

  4. Well Completion Report for Corrective Action Unit 443 Central Nevada Test Area Nye County, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-12-01

    The drilling program described in this report is part of a new corrective action strategy for Corrective Action Unit (CAU) 443 at the Central Nevada Test Area (CNTA). The drilling program included drilling two boreholes, geophysical well logging, construction of two monitoring/validation (MV) wells with piezometers (MV-4 and MV-5), development of monitor wells and piezometers, recompletion of two existing wells (HTH-1 and UC-1-P-1S), removal of pumps from existing wells (MV-1, MV-2, and MV-3), redevelopment of piezometers associated with existing wells (MV-1, MV-2, and MV-3), and installation of submersible pumps. The new corrective action strategy includes initiating a new 5-year proof-of-concept monitoring period to validate the compliance boundary at CNTA (DOE 2007). The new 5-year proof-of-concept monitoring period begins upon completion of the new monitor wells and collection of samples for laboratory analysis. The new strategy is described in the Corrective Action Decision Document/Corrective Action Plan addendum (DOE 2008a) that the Nevada Division of Environmental Protection approved (NDEP 2008).

  5. 2009 Groundwater Monitoring Report Central Nevada Test Area, Corrective Action Unit 443

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-09-01

    This report presents the 2009 groundwater monitoring results collected by the U.S. Department of Energy (DOE) Office of Legacy Management (LM) for the Central Nevada Test Area (CNTA) Subsurface Corrective Action Unit (CAU) 443. Responsibility for the environmental site restoration of CNTA was transferred from the DOE Office of Environmental Management to LM on October 1, 2006. The environmental restoration process and corrective action strategy for CAU 443 are conducted in accordance with the Federal Facility Agreement and Consent Order entered into by DOE, the U.S. Department of Defense, and the State of Nevada. The corrective action strategy for the site includes proof-of-concept monitoring in support of site closure. This report summarizes investigation activities associated with CAU 443 that were conducted at the site from October 2008 through December 2009. It also represents the first year of the enhanced monitoring network and begins the new 5-year proof-of-concept monitoring period that is intended to validate the compliance boundary

  6. Groundwater Monitoring Report Central Nevada Test Area, Corrective Action Unit 443

    Energy Technology Data Exchange (ETDEWEB)

    None

    2008-04-01

    This report presents the 2007 groundwater monitoring results collected by the U.S. Department of Energy (DOE) Office of Legacy Management (LM) for the Central Nevada Test Area (CNTA) Corrective Action Unit (CAU) 443. Responsibility for the environmental site restoration of the CNTA was transferred from the DOE Office of Environmental Management (DOE-EM) to DOE-LM on October 1, 2006. Requirements for CAU 443 are specified in the Federal Facility Agreement and Consent Order (FFACO 2005) entered into by DOE, the U.S. Department of Defense, and the State of Nevada and includes groundwater monitoring in support of site closure. This is the first groundwater monitoring report prepared by DOE-LM for the CNTA The CNTA is located north of U.S. Highway 6, approximately 30