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I R S S. Mapping of stress on native tree species across western U.S.A. & Canada: interpretation of climatically-induced changes using a physiologically-based approach. Richard Waring 1 Thomas Hilker 1 Nicholas Coops 2 Amanda Mathys 2 1 Oregon State University
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I R S S Mapping of stress on native tree species across western U.S.A. & Canada: interpretation of climatically-induced changes using a physiologically-based approach Richard Waring1 Thomas Hilker1 Nicholas Coops2 Amanda Mathys2 1 Oregon State University 2 University of British Columbia
Challenge: can we map where some tree species will die & others migrate in response to a changed climate? • In a previous NASA grant we predicted where a majority of 15 species in the Pacific N.W. might expect to be subject to fire, insect, or disease attack within broadly defined ecoregionswith 70 to 80% accuracy. • In this NASA grant, we seek to expand the areas to the entire West for 25 tree species and to improve spatial accuracy to 1km 2by: a) mapping variation in soil properties b) limiting predictions to areas where a tree species is known to be present on Forest Service survey plots c) field verification (or falsification) of model predictions
Site productivity varies with climate and soil conditions: The maximum greenness (Leaf Area Index) of the vegetation during mid-summer directly mirrors variation in site productivity, even with disturbance 3-PG Modeled LAI MODIS LAI Coops, Waring, Hilker. 2012. Remote Sensing of Env. 126:160-173
Modeling gross photosynthesis (GPP) • Assume Max GPP is the product of light absorbed by LAI each month and the photosynthetic efficiency of leaves, the latter dependent on soil fertility. • Actual GPP = • Max GPP * f(temp)*f(frost)*f(vpd)*f(avail H20) • Each of the functions vary from 0 (shutdown) to 1 (optimum)
Decision tree analysis[Values in reference to optimum for Douglas-fir] (more frost) (cooler temp) (< humid) (soils saturated) (After Coops & Waring. 2011. Climatic Change 105:313-328)
Presence & absence of 25 tree species on >43,400 survey plots predicted with an average accuracy of 80% Unpublished material :NASA Grant NNX11A029G
Process-based decision-tree models predict where climatic conditions since 2000 are more or less favorable than they were previously (1950-75) Douglas-fir Ponderosa pine Unpublished material :NASA Grant NNX11A029G
Modeled change in summer soil water stress since 2000 compared to 1950-75 period Range: --0.5 to +0.5
Modeled change in spring frost since 2000 compared to 1950-75 period No change in 2000 Range:- 0.06 to 0.3
Ponderosa pine: predicted area under stress in N. California,and vulnerable since 2000 compared to 1950-75 climatic conditions CALIFORNIA Unpublished material :NASA Grant NNX11A029G
Whitebark pine: predicted areas under stress since 2000 in the vicinity of Bozeman, MT Unpublished material :NASA Grant NNX11A029G
Summary • Inverting the process-based model to predict soil fertility & soil water holding capacity improves our ability to explain local patterns of tree death (Peterman et al. 2012). • Including soil properties did not improve broad scale accuracy in predicting presence or absence on field survey plots (80%), but we expect improved accuracy at local scales for specific species • We will restrict field inspections to areas where tree species have been recorded and are modeled to be in a changed state
PUBLICATIONS • AUSTRALIA • Smettem, K.R.J., R.H. Waring, N. Callow, M. Wilson & Q. Mu (2013) Satellite-derived estimates of forest leaf area index in south west Western Australia are not tightly coupled to inter-annual variations in rainfall: implications for groundwater decline in a drying climate. Global Change Biology (in press). • SOUTHWEST USA • Peterman, W., R.H. Waring, T. Seager, and W.L. Pollock (2012) Soil properties affect pinyonpine-juniper response to drought.Ecohydrology (on line June 13th, 2012). • BRITISH COLUMBIA & ALBERTA, CANADA • Coops, N.C., M.A. Wulden, and R.H. Waring (2012) Modeling lodgepole and jack pine vulnerability to mountain pine beetle expansion into the Canadian boreal forest. Forest Ecology and Management 274:1601-171. • ALL WESTERN STATES AND CANADIAN PROVINCES • Coops, N.C., R.H. Waring & T. Hilker (2012) Prediction of soil properties using a process-based forest growth model to match satellite-derived estimates of leaf area index. Remote Sensing of Environment 126:160-173.