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US Forest Disturbance Trends observed with Landsat Time Series

US Forest Disturbance Trends observed with Landsat Time Series. Samuel N. Goward 1 (PI), Jeffrey Masek 2 , Warren Cohen 3 , Gretchen Moisen 4 , Chengquan Huang 1 , Robert Kennedy 5 , Karen Schleeweis 1, Rama Nemani 6. 1 Department of Geography, University of Maryland, College Park MD

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US Forest Disturbance Trends observed with Landsat Time Series

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  1. US Forest Disturbance Trends observed with Landsat Time Series

    Samuel N. Goward1 (PI), Jeffrey Masek2, Warren Cohen3, Gretchen Moisen4, Chengquan Huang1, Robert Kennedy5, Karen Schleeweis1, Rama Nemani6 1Department of Geography, University of Maryland, College Park MD 2Biospheric Sciences Lab, NASA Goddard Space Flight Center, Greenbelt, MD 3U.S.D.A. Forest Service, Pacific Northwest Research Station, Corvallis, OR 4U.S.D.A. Forest Service, Rocky Mountain Research Station, Ogden, UT 5Earth and Environment Dept., Boston University, Boston MA 6NASA Ames Research Center, Moffett Field, CA
  2. Disturbance, Age Structure, and Carbon Understanding the history of land use, management, and disturbance is critical because disturbance and recovery are major determinants of the net terrestrial carbon flux.” - 2007 SOCCR (SAP 2.2) Biologic C Flux Biomass time Atmospheric source Old Disturbance Dominated areahistograms Regrowth Dominated Balanced
  3. ForestDisturbanceand NACP 56 NACP project descriptions include “Disturbance” NACP Disturbance Synthesis 2010-2011 (Kasischke) JGR-B Special Section “Impacts of Disturbance on the North American Carbon Cycle” Many new products, analyses
  4. North American Forest Dynamics (NAFD): Landsat-based sample of US forest disturbance 50 sample scenes across US; probability-based sample for area estimates (East, West strata) Annual time series of Landsatdata for each sample (1985-2005) Disturbance events mapped using Vegetation Change Tracker (VCT approach) (Huang et al, 2010)
  5. VegetationChange Tracker (VCT): Huang et al (2010) Example: Fire & Harvest, Sierra Nevada CA
  6. NAFD National Disturbance Rates estimates 1985-2005 average = 2.77 Mha/yr (+/- 0.76) = 1.1% US Forest Land % US Forest Cover Disturbed Masek et al, in review
  7. East versus West East % Forest Cover Disturbed West
  8. US Quadrants Western US Eastern US Central Southeast Coastal Northeast
  9. Estimates of US Disturbance Rates Harvest (Smith et al, 2009) Forest Area Disturbed (Mha/yr) Fire (EPA, 2010) Insects (USFS, 2010) Western Insect Mortality (2005-10)
  10. US ForestCarbonFluxesfromRecentDisturbance (Williams et al., 2012 GBC; in review RSE) CASA calibratedto match FIA biomass-age curves foreachforesttype & region Landscapeagedistributionfrom FIA and NAFD time sincedisturbance Landscape-scaleestimatesof NPP, NEP, biomassbasedonage, type, region
  11. Higher NAFD Disturbance = Lower NEP Estimate Williams et al., in review
  12. 0 %disturbed /yr NAFD Phase III Annual Time Series (1972 -2012) Wall-to-wall (440 * 40+ = > 17,000 annual maps) via NEX computing environment (Nemani – NASA ARC) Systematic Validation (Cohen – USFS PNW) Disturbance Causes (Moisen USFS RMS) Regrowth Dynamics (Masek – NASA GSFC) >2.0 LEDAPS Disturbance Map 1990-2000 (Maseket al., 2008)
  13. Geography of Disturbance Causes(No Insects yet) Schleeweis , 2012
  14. Conclusions US Forest Disturbance Rates estimated at 1.1%/yr from 1985-2005 via NAFD Landsat analysis … but RS methods tend to miss considerable partial disturbance (thinning, insect mortality, storm damage) Overall disturbance rates varied by ~x2 during mapping epoch Western variability driven by fire, insects; Eastern variability driven by management (GDP?)
  15. Forest Carbon Dynamics “The relative importance of these broad factors in accounting for the current [forest carbon] sink is unknown… Understanding the history of land use, management, and disturbance is critical because disturbance and recovery are major determinants of the net terrestrial carbon flux.” - 2007 SOCCR (SAP 2.2)
  16. AttributionofDisturbanceVariability Masek et al, in review
  17. US ForestBiomassand C StoragePotential (PgC) US forestscould~doublecurrent stocks Williams et al., in review
  18. NAFD Staff & Collaborators
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