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The Forest Changescape: a view from above Daniel J. Hayes ORNL Environmental Science Division SAMSI - Program on Mathematical and Statistical Ecology (ECOL) Workshop Wednesday, 20 August 2014 Research Triangle Park, NC What is a “changescape”? Credit: Joe Hughes (image) and Doug Kaylor (term coinage) A Spatiotemporal Perspective on 30 Years of Forest Change as Viewed from Space Dan Hayes, Joe Hughes, Doug Kaylor, and Virginia Dale – Oak Ridge National Laboratory and the University of Tennessee Jeff Masek – NASA Goddard Space Flight Center Robert Kennedy and Warren Cohen – US Forest Service and Oregon State University A Spatiotemporal Perspective on 30 Years of Forest Change as Viewed from Space Outline • Forest disturbance ecology – Ecosystem services – Characteristics of disturbance – Vulnerability / Resilience • Remote Sensing & Change Detection – Discrete date comparison – Trend analysis • New Methods • The Eastern U.S. Forest Changescape • Challenges and Opportunities – Methods – Applications Forest Ecosystem Services All over the world, society depends on critical ecosystem services provided by forests. Source: The Millennium Ecosystem Assessment (2005) Forest Dynamics Change is ubiquitous and unceasing in forest ecosystems and landscapes Source: USDA Forest Service, Southern Research Station Landscape Region Continent “Pulse” Disturbances Local Spatial Scale of Impact Adapted from Bender et al. (1984), Peterson et al. (1998) and Dale et al. (1998) Characteristics of Disturbance CLIMATE CHANGE PERMAFROST THAW DROUGHT HURRICANES INVASIVES INSECT OUTBREAKS FIRE DISEASE DEFORESTATION LOGGING WINDTHROW Abrupt Gradual Temporal Scale of Impact “Press” Disturbances Continent Region Landscape Local PERMAFROST THAW DROUGHT HURRICANES INVASIVES INSECT OUTBREAKS FIRE Anthropogenic Spatial Scale of Impact CLIMATE CHANGE Natural Adapted from Bender et al. (1984), Peterson et al. (1998) and Dale et al. (1998) Characteristics of Disturbance DISEASE DEFORESTATION LOGGING WINDTHROW Abrupt Gradual Temporal Scale of Impact Continent Region Landscape Local PERMAFROST THAW DROUGHT HURRICANES INVASIVES INSECT OUTBREAKS FIRE Anthropogenic Spatial Scale of Impact CLIMATE CHANGE Natural Adapted from Bender et al. (1984), Peterson et al. (1998) and Dale et al. (1998) Disturbance Interactions DISEASE DEFORESTATION LOGGING WINDTHROW Abrupt Gradual Temporal Scale of Impact Vulnerability / Resiliency of Forests Dale et al. (2001) BioScience Shifts in disturbance regime outside the normal range of variability? Dale, Hughes and Hayes (in review) nps.gov Bill de Groot, NR-Can A continental tour of “natural” (or indirectly anthropogenic) disturbances… for.gov.bc.ca maineforestry.net ucanr.edu NASA / J. Chambers D. Kaylor, UTK Alberta Geological Survey A continental tour of anthropogenic disturbances… Bangor Daily News Google Earth NASA / Tom Sever Vivian Stockman, OVEC • 2003 Remote Sensing of Forest Disturbances Change Detection Techniques • Up to 2009: – Discrete comparison (differencing, thresholding, classification, etc.) between each specific image (airphoto or satellite) acquisition date (two or more years) • Since 2009: – Trend analysis over a more full and continuous archive of satellite imagery Remote Sensing of Forest Disturbances Large and severe “pulse” disturbance (deforestation) on Landsat imagery Hayes and Sader (2001) PERS Remote Sensing of Forest Disturbances Large and severe “pulse” disturbance (clear-cutting) on Landsat imagery Cohen et al. (2002) Ecosystems Remote Sensing of Forest Disturbances Trends in disturbance and recovery: exploiting the full historical Landsat archive Kennedy et al. (2010) RSE Methods: Image acquisition • Trends in disturbance and recovery: exploiting the full historical Landsat archive What do you do with this stuff?? Landsat Thematic Mapper • 30m spatial resolution (per pixel) • 6 spectral bands (wavelength ranges) • Repeat observations every 16 days • Coverage since 1972 (moreor-less) • Full archive freely available (since 2009) Methods: Pre-processing Summer clear-sky composite (aka cloud removal) Hughes and Hayes (2014) Remote Sensing Methods: Vegetation Indices Landsat spectral bands Hughes and Hayes (2014) Remote Sensing Methods: Vegetation Indices Normalized Difference Vegetation Index (NDVI) (NIR – Red)/(NIR + Red) (Band4 – Band3)/(Band4 + Band3) Methods: Trend Analysis Vegetation Index (Single Pixel Through Time) Hughes and Hayes (2014) Remote Sensing Results: Spatial patterns of severity Methods: Validation Cohen et al. (2010) RSE Vegetation Index Hughes and Hayes (2014) Remote Sensing Results: Broad-scale patterns Monitoring rates of disturbance: the North American Forest Dynamics project Goward et al.; Masek et al. Can we detect more subtle trends? • Stress-related decline? Source: Warren Cohen Results: Beyond the single pixel Disturbance Increases Patch Variance in Vegetation Index Hughes et al. in prep Methods: Patch Identification Vegetation Index – “Patch-ified”: TVR Hughes et al. in prep Hughes and Hayes (2014) Remote Sensing Remote Sensing of Forest Disturbances Can we distinguish between different disturbance agents? USFS Areal Insect and Disease Survey (IDS) Remote Sensing of Forest Disturbances Can we distinguish between different disturbance agents? USFS Areal Insect and Disease Survey (IDS) Results: Patch Variance Agents Distinguished by Patch Variance Hughes et al. in prep Methods: Scales of Disturbance Vegetation Index – “Patch-ified” α = 0.20 α = 0.05 Hughes et al. in prep Hughes and Hayes (2014) Remote Sensing α = 0.02 Methods: Automated Classification Training a neural network Hughes et al. in prep Results: Spatial Patterns Results: Validation Evaluation and Analysis Hughes et al. in prep Results: Temporal Patterns % of area affected Southern Pine Beetle Results: Regional Patterns Southern Pine Beetle Gypsy Moth Beech Bark Disease Hemlock Wooly Adelgid Fire TOTAL Future Directions • The method – More “truth”: testing / validation – Model parameter sensitivity (e.g. α in TVR) – Train for anthropogenic agents (land use change) • The analysis – First comprehensive reports, statistics and maps of disturbance (by time, space, severity & agent) for eastern U.S. – Conservation (protected areas) and management Future Directions • The applications – Impacts of climate change, pollution, etc. on vegetation productivity (both increases and declines) – Impacts of disturbance on the forest carbon sink – Detection of thaw-driven landscape change in permafrost ecosystems (Arctic Tundra and Boreal Forest) Thank You! Dan Hayes [email protected] Oak Ridge National Laboratory: Meeting the challenges of the 21st century www.ornl.gov