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Oliver L. Phillips - One of the best experts on this subject based on the ideXlab platform.
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estimating aboveground net biomass change for tropical and subtropical Forests refinement of ipcc default rates using Forest Plot data
Global Change Biology, 2019Co-Authors: Daniela Requena Suarez, Oliver L. Phillips, Danae M A Rozendaal, Esteban Alvarezdavila, Kristina J Andersonteixeira, Alejandro Araujomurakami, Luzmila Arroyo, Timothy R Baker, Frans BongersAbstract:As countries advance in greenhouse gas (GHG) accounting for climate change mitigation, consistent estimates of aboveground net biomass change (∆AGB) are needed. Countries with limited Forest monitoring capabilities in the tropics and subtropics rely on IPCC 2006 default ∆AGB rates, which are values per ecological zone, per continent. Similarly, research on Forest biomass change at large scale also make use of these rates. IPCC 2006 default rates come from a handful of studies, provide no uncertainty indications, and do not distinguish between older secondary Forests and old‐growth Forests. As part of the 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, we incorporate ∆AGB data available from 2006 onwards, comprising 176 chronosequences in secondary Forests and 536 permanent Plots in old‐growth and managed/logged Forests located in 42 countries in Africa, North and South America, and Asia. We generated ∆AGB rate estimates for younger secondary Forests (≤20 years), older secondary Forests (>20 years and up to 100 years) and old‐growth Forests, and accounted for uncertainties in our estimates. In tropical rainForests, for which data availability was the highest, our ∆AGB rate estimates ranged from 3.4 (Asia) to 7.6 (Africa) Mg ha‐1 yr‐1 in younger secondary Forests, from 2.3 (North and South Ameri09ca) to 3.5 (Africa) Mg ha‐1 yr‐1 in older secondary Forests, and 0.7 (Asia) to 1.3 (Africa) Mg ha‐1 yr‐1 in old‐growth Forests. We provide a rigorous and traceable refinement of the IPCC 2006 default rates in tropical and subtropical ecological zones, and identify which areas require more research on ∆AGB. In this respect, this study should be considered as an important step towards quantifying the role of tropical and subtropical Forests as carbon sinks with higher accuracy; our new rates can be used for large‐scale GHG accounting by governmental bodies, non‐governmental organisations and in scientific research.
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ForestPlots.net: a web application and research tool to manage and analyse tropical Forest Plot data
Journal of Vegetation Science, 2011Co-Authors: Gabriela Lopez-gonzalez, Simon L. Lewis, Mark Burkitt, Oliver L. PhillipsAbstract:Tropical Forests are biologically diverse ecosystems that play important roles in the carbon cycle and maintenance of global biodiversity. Understanding how tropical Forests respond to environmental changes is important, as changes in carbon storage can modulate the rate and magnitude of climate change. Applying an ecoinformatics approach for managing long-term Forest inventory Plot data, where individual trees are tracked over time, facilitates regional and cross-continental Forest research to evaluate changes in taxonomic composition, growth, recruitment and mortality rates, and carbon and biomass stocks. We developed ForestPlots.net as a secure, online inventory data repository and to facilitate data management of long-term tropical Forest Plots to promote scientific collaborations among independent researchers. The key novel features of the database are: (a) a design that efficiently deals with time-series data; (b) data management tools to assess potential errors; and (c) a query library to generate outputs (e.g. biomass and carbon stock changes over time).
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ECOINFORMATICS: REPORT ForestPlots.net: a web application and research tool to manage and analyse tropical Forest Plot data
2011Co-Authors: Gabriela Lopez-gonzalez, Simon L. Lewis, Mark Burkitt, Oliver L. PhillipsAbstract:Tropical Forests are biologically diverse ecosystems that play important roles in the carbon cycle and maintenance of global biodiversity. Understanding how tropical Forests respond to environmental changes is important, as changes in carbon storage can modulate the rate and magnitude of climate change. Applying an ecoinformatics approach for managing long-term Forest inventory Plot data, where individual trees are tracked over time, facilitates regional and cross-continental Forest research to evaluate changes in taxonomic composition, growth, recruitment and mortality rates, and carbon and biomass stocks. We developed ForestPlots.net as a secure, online inventory data repository and to facilitate data management of long-term tropical Forest Plots to promote scientific collaborations among independent researchers. The key novel features of the database are: (a) a design that efficiently deals with time-series data; (b) data management tools to assess potential errors; and (c) a query library to generate outputs (e.g. biomass and carbon stock changes over time).
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Species loss and aboveground carbon storage in a tropical Forest.
Science, 2005Co-Authors: Daniel E. Bunker, Oliver L. Phillips, Fabrice Declerck, Jason C. Bradford, Robert K. Colwell, Ivette Perfecto, Mahesh Sankaran, Shahid NaeemAbstract:Tropical Forest biodiversity is declining, but the resulting effects on key ecosystem services, such as carbon storage and sequestration, remain unknown. We assessed the influence of the loss of tropical tree species on carbon storage by simulating 18 possible extinction scenarios within a well-studied 50-hectare tropical Forest Plot in Panama, which contains 227 tree species. Among extinction scenarios, aboveground carbon stocks varied by more than 600%, and biological insurance varied by more than 400%. These results indicate that future carbon storage in tropical Forests will be influenced strongly by future species composition.
Stephen P. Hubbell - One of the best experts on this subject based on the ideXlab platform.
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The variation of tree beta diversity across a global network of Forest Plots
Global Ecology and Biogeography, 2012Co-Authors: Miquel De Cáceres, Richard Condit, Renato Valencia, Zhanqing Hao, Pierre Legendre, Min Cao, Li-wan Chang, George B. Chuyong, Chang-fu Hsieh, Stephen P. HubbellAbstract:Aims With the aim of understanding why some of the world's Forests exhibit higher tree beta diversity values than others, we asked: (1) what is the contribution of environmentally related variation versus pure spatial and local stochastic variation to tree beta diversity assessed at the Forest Plot scale; (2) at what resolution are these beta-diversity components more apparent; and (3) what determines the variation in tree beta diversity observed across regions/continents? Location World-wide. Methods We compiled an unprecedented data set of 10 large-scale stem-mapping Forest Plots differing in latitude, tree species richness and topographic variability. We assessed the tree beta diversity found within each Forest Plot separately. The non-directional variation in tree species composition among cells of the Plot was our measure of beta diversity. We compared the beta diversity of each Plot with the value expected under a null model. We also apportioned the beta diversity into four components: pure topographic, spatially structured topographic, pure spatial and unexplained. We used linear mixed models to interpret the variation of beta diversity values across the Plots. Results Total tree beta diversity within a Forest Plot decreased with increasing cell size, and increased with tree species richness and the amount of topographic variability of the Plot. The topography-related component of beta diversity was correlated with the amount of topographic variability but was unrelated to its species richness. The unexplained variation was correlated with the beta diversity expected under the null model and with species richness. Main conclusions Because different components of beta diversity have different determinants, comparisons of tree beta diversity across regions should quantify not only overall variation in species composition but also its components. Global-scale patterns in tree beta diversity are largely coupled with changes in gamma richness due to the relationship between the latter and the variation generated by local stochastic assembly processes.
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long term research impacts on seedling community structure and composition in a permanent Forest Plot
Forest Ecology and Management, 2006Co-Authors: Gregory R Goldsmith, Richard Condit, Stephen P. Hubbell, Liza S Comita, Leslie L MorefieldAbstract:Long-term ecological research projects have become cornerstones for the study ofForest dynamics worldwide. The intense, large-scale research efforts necessary to monitor ecological processes may alter natural processes and be a source of error in analyses. This study evaluated whether trampling due to concentrated researcher presence has altered the structure and composition of the seedling layer in the 50 ha permanent sample Plot on Barro Colorado Island (BCI), Panama. Since 1980, major research projects in the Plot have included complete tree censuses every 5 years, weekly seed trap collection, and the more recent annual censuses of 20,000 1 m 2 seedling quadrats. We compared data from these pre-existing seedling quadrats with data from 600 newly established seedling quadrats in an area of much lower research intensity adjacent to the 50 ha Plot and tested for differences in seedling density, height-class distributions, species richness and composition. Although we expected to find evidence of researcher impacts on the seedling layer, we found no significant differences in seedling community structure or composition inside and outside of the BCI50 ha Plot.Weconclude that there isnoevidence that researchefforts withinthe BCIPlothavethus farresultedin significantchanges inthe seedling layer. The extent of research impacts is likely to differ under varying environmental conditions and research protocols. Continued efforts should be made to quantify the impacts of research methodology at long-term research sites in order to detect site-specific or long-term changes. # 2006 Elsevier B.V. All rights reserved.
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habitat associations of trees and shrubs in a 50 ha neotropical Forest Plot
Journal of Ecology, 2001Co-Authors: Kyle E Harms, Stephen P. Hubbell, Richard Condit, Robin B. FosterAbstract:Summary 1 Tests of habitat association among species of tropical trees and shrubs often assume that individual stems can be treated as independent sample units, even though limited dispersal conflicts with this assumption by causing new recruits to occur near maternal parents and siblings. 2 We developed methods for assessing patterns of association between mapped plants and mapped habitat types that explicitly incorporate spatial structure, thereby eliminating the need to assume independence among stems. 3 We used these methods to determine habitat-association patterns for 171 species of trees and shrubs within the permanent 50-ha Forest Dynamics Project Plot on Barro Colorado Island, Panama. 4 Many fewer significant habitat associations result from the new methods than from traditional, but inappropriate, chi-square tests. The low-lying plateau, the most extensive habitat on the 50-ha Plot, had nine species positively associated with it and 19 species negatively associated, leaving 143 species whose distributions were not biased with respect to this habitat. A small swamp in the Plot was the most distinct habitat, with 32 species positively and 20 species negatively associated, leaving more than two-thirds of the species neither positively nor negatively associated. 5 To the extent that habitat association reflects habitat specialization, our results suggest that local habitat specialization plays a limited role in the maintenance of species diversity in this Forest.
Richard Condit - One of the best experts on this subject based on the ideXlab platform.
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The variation of tree beta diversity across a global network of Forest Plots
Global Ecology and Biogeography, 2012Co-Authors: Miquel De Cáceres, Richard Condit, Renato Valencia, Zhanqing Hao, Pierre Legendre, Min Cao, Li-wan Chang, George B. Chuyong, Chang-fu Hsieh, Stephen P. HubbellAbstract:Aims With the aim of understanding why some of the world's Forests exhibit higher tree beta diversity values than others, we asked: (1) what is the contribution of environmentally related variation versus pure spatial and local stochastic variation to tree beta diversity assessed at the Forest Plot scale; (2) at what resolution are these beta-diversity components more apparent; and (3) what determines the variation in tree beta diversity observed across regions/continents? Location World-wide. Methods We compiled an unprecedented data set of 10 large-scale stem-mapping Forest Plots differing in latitude, tree species richness and topographic variability. We assessed the tree beta diversity found within each Forest Plot separately. The non-directional variation in tree species composition among cells of the Plot was our measure of beta diversity. We compared the beta diversity of each Plot with the value expected under a null model. We also apportioned the beta diversity into four components: pure topographic, spatially structured topographic, pure spatial and unexplained. We used linear mixed models to interpret the variation of beta diversity values across the Plots. Results Total tree beta diversity within a Forest Plot decreased with increasing cell size, and increased with tree species richness and the amount of topographic variability of the Plot. The topography-related component of beta diversity was correlated with the amount of topographic variability but was unrelated to its species richness. The unexplained variation was correlated with the beta diversity expected under the null model and with species richness. Main conclusions Because different components of beta diversity have different determinants, comparisons of tree beta diversity across regions should quantify not only overall variation in species composition but also its components. Global-scale patterns in tree beta diversity are largely coupled with changes in gamma richness due to the relationship between the latter and the variation generated by local stochastic assembly processes.
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Dissecting biomass dynamics in a large Amazonian Forest Plot
Journal of Tropical Ecology, 2009Co-Authors: Renato Valencia, Richard Condit, Helene C. Muller-landau, Consuelo Hernandez, Hugo NavarreteAbstract:Above-ground biomass (AGE)is increasing in most of the AmazonForests. One hypothesis is that Forests are responding to widespread and intense human intervention prior to the European conquest (>500 y ago). In this study we confront this hypothesis with changes in AGE over 6.3 y in a large western Amazonian Forest Plot (>150 000 shrubs and trees and 1100 species wtthdbh > 10rnmin25 ha). We examined AGBflux in dilTerenthabitats and across diameter classes. The Forest lost small stems (4.6%), gainedlarge trees (2.6%), and gained biomass (0. 7t){)) . The change in AGE stock was due entirely to this upward shift in size leading to more canopy trees and fewer saplings after just 6 y. Across habitats, the biggest increment in biomass was in the secondary-Forest patch (3.4% y-l) which we know was cleared about 27 y ago, whereas mature Forest on ridges and valleys had small increases (0.10% and 0.09% y-l, respectively), In both censuses, AGE stocks were >50% higher on the ridge than in the valley while relative growth and mortality were higher in the valley. Mean wood specific gravity (WSG)decreased with increasing diameter class; WSG did not change much between censuses in mature Forests and did not contribute to the change in AGE stocks. Our Forest increased its standing biomass, but far less than the average reported for other Amazonian Forests (l.c. 0.30 vs. 0.98 Mg ha"! y-l). We find no evidence to support the notion that this Forest is recovering from long-past human intervention. Instead of a long-term recovery, we believe the Forest changed in response to natural fluctuations of the environment (e.g. changes in precipitation, higher CO2 ) , windstorms or other more recent events, The significant differences in AGE stocks between valley and ridge suggest that the terra flrmc Forests are a mosaic of natural habitats, and that this mosaic is in part responsible for the variation in biomass stocks detected in Amazonianterra flrme Forests. Resumen: La blomasa aerea de la mayorfa de los bosques amaz6nicos esta incrementando. Una hip6tesis es que los bosques estan respondiendo a un disturbio humano intenso y arnpliamente dlstrfbutdo, anterior a Ia llegada de los conquistadores europeos (>500 afios atras). En este estudio se confronta esta hipotesis con los cambios en btomusa encontrados en 6.3 enos en una parcela de gran escala de la Amazonia occidental (c- 150.000 arbustos y arboles con dtametro a la altura del pecho 2:10 mm y 1100 especies en 25 ha). Los resultados se examinan por categorias de dtametro y habitat. En este perfodo el bosque perdi6 tallos pequefios (4.6%), gano arboles grandes (2,6%) y gano biomasa (0.7%). La ganancia en biomasa fue dehida enteramente al incremento de arboles de gran tamafio que signlflco mas arboles de dosel y menos juveniles en apenas 6 afios. Entre los habitats, el mayor incremento en biomasa se oncontrc en un parche de bosque secundarto de colina (3.4%/afio), cuya edad es de 27 afios, mientras el bosque maduro de las colinas y los valles incremento escasamente (O.lUX} y 0.09%/afio, respectivamente). Tanto al inicio como al final del estudio, el stock de biomasa fue > SOtYr) mas grande en Ia colina que en el valle mlcntras que cl crecimiento y Ia mortalidad relative fueron mayores en cl valle. La media de la gravedad especffica de la madera (GEM) fue menor a mayor clase dlametrica: en el bosque maduro, el cambio en la GEMfue lnslgniflcante y no contribuy6 al aumento en stocks de biomasa. El bosque Incremento la bfomasu aerea pero mucho menos que el promedio reportado para otros bosques amazontcos (i.e. 0.30 vs. 0.98 Mg ha-1/ailo). No se encontro evidencia que apoyela noci6nde que el bosque se esta recuperando de un disturbio de gran escala ocurrido en el pasado. En su lugar, se cree que cl bosque camblo en respuesta a fluctuaciones naturales del ambiente (e.g. cambios en precipltacion, mayor concentraci6n de CO2 ) , vendavales u otro tipo de eventos mas recientes. La diferencia significativa en los stocks de biomasa encontrada entre el valle y la colina sugiere que la tierra firme es un mosaico de habitats naturales y que cste mosaico podria explicar en parte la varlaoion encontrada en los stocks de biomasa de bosques umazonlcos de tierra flrmc.
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long term research impacts on seedling community structure and composition in a permanent Forest Plot
Forest Ecology and Management, 2006Co-Authors: Gregory R Goldsmith, Richard Condit, Stephen P. Hubbell, Liza S Comita, Leslie L MorefieldAbstract:Long-term ecological research projects have become cornerstones for the study ofForest dynamics worldwide. The intense, large-scale research efforts necessary to monitor ecological processes may alter natural processes and be a source of error in analyses. This study evaluated whether trampling due to concentrated researcher presence has altered the structure and composition of the seedling layer in the 50 ha permanent sample Plot on Barro Colorado Island (BCI), Panama. Since 1980, major research projects in the Plot have included complete tree censuses every 5 years, weekly seed trap collection, and the more recent annual censuses of 20,000 1 m 2 seedling quadrats. We compared data from these pre-existing seedling quadrats with data from 600 newly established seedling quadrats in an area of much lower research intensity adjacent to the 50 ha Plot and tested for differences in seedling density, height-class distributions, species richness and composition. Although we expected to find evidence of researcher impacts on the seedling layer, we found no significant differences in seedling community structure or composition inside and outside of the BCI50 ha Plot.Weconclude that there isnoevidence that researchefforts withinthe BCIPlothavethus farresultedin significantchanges inthe seedling layer. The extent of research impacts is likely to differ under varying environmental conditions and research protocols. Continued efforts should be made to quantify the impacts of research methodology at long-term research sites in order to detect site-specific or long-term changes. # 2006 Elsevier B.V. All rights reserved.
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tree species distributions and local habitat variation in the amazon large Forest Plot in eastern ecuador
Journal of Ecology, 2004Co-Authors: Renato Valencia, Robin B. Foster, Richard Condit, Consuelo Hernandez, Gorky Villa, Jenschristian Svenning, Katya Romoleroux, Elizabeth LososAbstract:Summary 1 We mapped and identified all trees ≥ 10 mm in diameter in 25 ha of lowland wet Forest in Amazonian Ecuador, and found 1104 morphospecies among 152 353 individuals. The largest number of species was mid-sized canopy trees with maximum height 10‐20 m and understorey treelets with maximum height of 5‐10 m. 2 Several species of understorey treelets in the genera Matisia and Rinorea dominated the Forest numerically, while important canopy species were Iriartea deltoidea and Eschweilera coriacea . 3 We examined how species partition local topographic variation into niches, and how much this partitioning contributes to Forest diversity. Evidence in favour of topographic niche-partitioning was found: similarity in species composition between ridge and valley quadrats was lower than similarity between two valley (or two ridge) quadrats, and 25% of the species had large abundance differences between valley and ridge-top. On the other hand, 25% of the species were generalists, with similar abundance on both valley and ridges, and half the species had only moderate abundance differences between valley and ridge. 4 Topographic niche-partitioning was not finely grained. There were no more than three distinct vegetation zones: valley, mid-slope, and upper-ridge, and the latter two differed only slightly in species composition. 5 Similarity in species composition declined with distance even within a topographic habitat, to about the same degree as it declined between habitats. This suggests patchiness not related to topographic variation, and possibly due to dispersal limitation. 6 We conclude that partitioning of topographic niches does make a contribution to the α -diversity of Amazonian trees, but only a minor one. It provides no explanation for the co-occurrence of hundreds of topographic generalists, nor for the hundreds of species with similar life-form appearing on a single ridge-top.
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habitat associations of trees and shrubs in a 50 ha neotropical Forest Plot
Journal of Ecology, 2001Co-Authors: Kyle E Harms, Stephen P. Hubbell, Richard Condit, Robin B. FosterAbstract:Summary 1 Tests of habitat association among species of tropical trees and shrubs often assume that individual stems can be treated as independent sample units, even though limited dispersal conflicts with this assumption by causing new recruits to occur near maternal parents and siblings. 2 We developed methods for assessing patterns of association between mapped plants and mapped habitat types that explicitly incorporate spatial structure, thereby eliminating the need to assume independence among stems. 3 We used these methods to determine habitat-association patterns for 171 species of trees and shrubs within the permanent 50-ha Forest Dynamics Project Plot on Barro Colorado Island, Panama. 4 Many fewer significant habitat associations result from the new methods than from traditional, but inappropriate, chi-square tests. The low-lying plateau, the most extensive habitat on the 50-ha Plot, had nine species positively associated with it and 19 species negatively associated, leaving 143 species whose distributions were not biased with respect to this habitat. A small swamp in the Plot was the most distinct habitat, with 32 species positively and 20 species negatively associated, leaving more than two-thirds of the species neither positively nor negatively associated. 5 To the extent that habitat association reflects habitat specialization, our results suggest that local habitat specialization plays a limited role in the maintenance of species diversity in this Forest.
Margarita Arianoutsou - One of the best experts on this subject based on the ideXlab platform.
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tree growth climate relationships in a Forest Plot network on mediterranean mountains
Science of The Total Environment, 2017Co-Authors: Nikolaos M Fyllas, Anastasia Christopoulou, Alexandros Galanidis, Chrysanthi Michelaki, Panayiotis G Dimitrakopoulos, Peter Z Fule, Margarita ArianoutsouAbstract:In this study we analysed a novel tree-growth dataset, inferred from annual ring-width measurements, of 7 Forest tree species from 12 mountain regions in Greece, in order to identify tree growth - climate relationships. The tree species of interest were: Abies cephalonica, Abies borisii-regis, Picea abies, Pinus nigra, Pinus sylvestris, Fagus sylvatica and Quercus frainetto growing across a gradient of climate conditions with mean annual temperature ranging from 5.7 to 12.6°C and total annual precipitation from 500 to 950mm. In total, 344 tree cores (one per tree) were analysed across a network of 20 study sites. We found that water availability during the summer period (May-August) was a strong predictor of interannual variation in tree growth for all study species. Across species and sites, annual tree growth was positively related to summer season precipitation (PSP). The responsiveness of annual growth to PSP was tightly related to species and site specific measurements of instantaneous photosynthetic water use efficiency (WUE), suggesting that the growth of species with efficient water use is more responsive to variations in precipitation during the dry months of the year. Our findings support the importance of water availability for the growth of mountainous Mediterranean tree species and highlight that future reductions in precipitation are likely to lead to reduced tree-growth under climate change conditions.
Mark A. Finney - One of the best experts on this subject based on the ideXlab platform.
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Mapping Forest vegetation for the western United States using modified random Forests imputation of FIA Forest Plots
Ecosphere, 2016Co-Authors: Karin L. Riley, Isaac C. Grenfell, Mark A. FinneyAbstract:Maps of the number, size, and species of trees in Forests across the western United States are desirable for many applications such as estimating terrestrial carbon resources, predicting tree mortality following wildfires, and for Forest inventory. However, detailed mapping of trees for large areas is not feasible with current technologies, but statistical methods for matching the Forest Plot data with biophysical characteristics of the landscape offer a practical means to populate landscapes with a limited set of Forest Plot inventory data. We used a modified random Forests approach with Landscape Fire and Resource Management Planning Tools (LANDFIRE) vegetation and biophysical predictors to impute Plot data collected by the US Forest Service's Forest Inventory Analysis (FIA) to the landscape at 30-m grid resolution. This method imputes the Plot with the best statistical match, according to a “Forest” of decision trees, to each pixel of gridded landscape data. In this work, we used the LANDFIRE data set for gridded input because it is publicly available, offers seamless coverage of variables needed for fire models, and is consistent with other data sets, including burn probabilities and flame length probabilities generated for the continental United States. The main output of this project is a map of imputed Plot identifiers at 30 × 30 m spatial resolution for the western United States that can be linked to the FIA databases to produce tree-level maps or to map other Plot attributes. In addition, we used the imputed inventory data to generate maps of Forest cover, Forest height, and vegetation group at 30 × 30 m resolution for all Forested pixels in the western United States, as a means of assessing the accuracy of our methodology. The results showed good correspondence between the target LANDFIRE data and the imputed Plot data, with an overall within-class agreement of 79% for Forest cover, 96% for Forest height, and 92% for vegetation group.
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Seeing the Forest for the trees: utilizing modified random Forests imputation of Forest Plot data for landscape-level analyses
2015Co-Authors: Karin L. Riley, Isaac C. Grenfell, Mark A. FinneyAbstract:Mapping the number, size, and species of trees in Forests across the western United States has utility for a number of research endeavors, ranging from estimation of terrestrial carbon resources to tree mortality following wildfires. For landscape fire and Forest simulations that use the Forest Vegetation Simulator (FVS), a tree-level dataset, or “tree list”, is a necessity. FVS is widely used at the stand level for simulating fire effects on tree mortality, carbon, and biomass, but uses at the landscape level are limited by availability of Forest inventory data for large contiguous areas. Detailed mapping of trees for large areas is not feasible with current technologies, but statistical methods for matching Forest Plot data with biophysical characteristics of the landscape offers a practical means to populate landscapes with a limited set of Forest Plot inventory data. We used a modified Random Forests approach with Landfire vegetation and biophysical predictors to impute Plot data from the U.S. Forest Service’s Forest Inventory Analysis (FIA). This method imputes the Plot with the best statistical match, according to a “Forest” of decision trees, to each pixel of gridded landscape data. Landfire data was used in this project because it is publicly available, offers seamless coverage of variables needed for fire models, and is consistent with other datasets, including burn probabilities and flame length probabilities generated for the continental U.S. by Fire Program Analysis (FPA). We used the imputed inventory data to generate maps of Forest cover, Forest height, and existing vegetation group at 30-meter resolution for the entire western U.S. The results showed good correspondence between the target Landfire data and the imputed Plot data. In future work, we plan to use the imputed grid of inventory data for landscape simulation studies to analyze a wide range of fuel management problems.
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Utilizing random Forests imputation of Forest Plot data for landscape-level wildfire analyses
Advances in forest fire research, 2014Co-Authors: Karin L. Riley, Isaac C. Grenfell, Nicholas L. Crookston, Mark A. FinneyAbstract:Maps of the number, size, and species of trees in Forests across the United States are desirable for a number of applications. For landscape-level fire and Forest simulations that use the Forest Vegetation Simulator (FVS), a spatial tree-level dataset, or “tree list”, is a necessity. FVS is widely used at the stand level for simulating fire effects on tree mortality, carbon, and biomass, but uses at the landscape level are limited by lack of availability of Forest inventory data for large contiguous areas. Detailed mapping of trees across large areas is not feasible with current technologies, but statistical methods for matching Forest Plot data with biophysical characteristics of the landscape offer a practical means to populate landscapes with a limited set of Forest Plot inventory data. We used a modified random Forests approach, with Landfire vegetation and biophysical predictors at 30m grid resolution. In essence, the random Forests method creates a “Forest” of decision trees in order to choose the Forest Plot with the best statistical match for each grid cell in the landscape. Landfire data was used in this project because is publicly available, offers seamless coverage of variables needed for fire models, and is consistent with other datasets, including burn probabilities and flame length probabilities generated for the continental US by Fire Program Analysis (FPA). We used the imputed Forest Plot data to generate a map of Forest cover and height as well as existing vegetation group for a study area in eastern Oregon, and examined correlations with Landfire data. The results showed good correspondence between the two data sets (84-97% within-class agreement, depending on the variable). In future research, the new imputed grid of inventory data will be used for landscape simulation studies to determine risk to terrestrial carbon resources from wildfire as well as to investigate the effect of fuel treatments on burn probability and fire sizes.