The Forest Changescape: a view from above

Transcription

1 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

2 What is a changescape? Credit: Joe Hughes (image) and Doug Kaylor (term coinage)

3 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

4 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

5 Forest Ecosystem Services All over the world, society depends on critical ecosystem services provided by forests. Source: The Millennium Ecosystem Assessment (2005)

6 Forest Dynamics Change is ubiquitous and unceasing in forest ecosystems and landscapes Source: USDA Forest Service, Southern Research Station

7 Characteristics of Disturbance Adapted from Bender et al. (1984), Peterson et al. (1998) and Dale et al. (1998) Pulse Disturbances Spatial Scale of Impact Local Landscape Region Continent HURRICANES FIRE DEFORESTATION WINDTHROW Abrupt CLIMATE CHANGE INSECT OUTBREAKS PERMAFROST THAW LOGGING DROUGHT DISEASE Temporal Scale of Impact INVASIVES Gradual Press Disturbances

8 Characteristics of Disturbance Adapted from Bender et al. (1984), Peterson et al. (1998) and Dale et al. (1998) Spatial Scale of Impact Local Landscape Region Continent HURRICANES FIRE DEFORESTATION WINDTHROW CLIMATE CHANGE INSECT OUTBREAKS PERMAFROST THAW LOGGING DROUGHT DISEASE INVASIVES Natural Anthropogenic Abrupt Temporal Scale of Impact Gradual

9 Disturbance Interactions Adapted from Bender et al. (1984), Peterson et al. (1998) and Dale et al. (1998) Spatial Scale of Impact Local Landscape Region Continent HURRICANES FIRE DEFORESTATION WINDTHROW CLIMATE CHANGE INSECT OUTBREAKS PERMAFROST THAW LOGGING DROUGHT DISEASE INVASIVES Natural Anthropogenic Abrupt Temporal Scale of Impact Gradual

10 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)

11 nps.gov Bill de Groot, NR-Can A continental tour of natural (or indirectly anthropogenic) for.gov.bc.ca disturbances maineforestry.net ucanr.edu NASA / J. Chambers D. Kaylor, UTK

12 Alberta Geological Survey A continental tour of anthropogenic disturbances Bangor Daily News Google Earth NASA / Tom Sever Vivian Stockman, OVEC 2003

13 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

14 Remote Sensing of Forest Disturbances Large and severe pulse disturbance (deforestation) on Landsat imagery Hayes and Sader (2001) PERS

15 Remote Sensing of Forest Disturbances Large and severe pulse disturbance (clear-cutting) on Landsat imagery Cohen et al. (2002) Ecosystems

16 Remote Sensing of Forest Disturbances Trends in disturbance and recovery: exploiting the full historical Landsat archive Kennedy et al. (2010) RSE

17 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)

18 Methods: Pre-processing Summer clear-sky composite (aka cloud removal) Hughes and Hayes (2014) Remote Sensing

19 Methods: Vegetation Indices Landsat spectral bands Hughes and Hayes (2014) Remote Sensing

20 Methods: Vegetation Indices Normalized Difference Vegetation Index (NDVI) (NIR Red)/(NIR + Red) (Band4 Band3)/(Band4 + Band3)

21 Methods: Trend Analysis Vegetation Index (Single Pixel Through Time) Hughes and Hayes (2014) Remote Sensing

22 Results: Spatial patterns of severity

23 Methods: Validation Vegetation Index Cohen et al. (2010) RSE Hughes and Hayes (2014) Remote Sensing

24 Results: Broad-scale patterns Monitoring rates of disturbance: the North American Forest Dynamics project Goward et al.; Masek et al.

25 Can we detect more subtle trends? Stress-related decline? Source: Warren Cohen

26 Results: Beyond the single pixel Disturbance Increases Patch Variance in Vegetation Index Hughes et al. in prep

27 Methods: Patch Identification Vegetation Index Patch-ified : TVR Hughes et al. in prep Hughes and Hayes (2014) Remote Sensing

28 Remote Sensing of Forest Disturbances Can we distinguish between different disturbance agents? USFS Areal Insect and Disease Survey (IDS)

29 Remote Sensing of Forest Disturbances Can we distinguish between different disturbance agents? USFS Areal Insect and Disease Survey (IDS)

30 Results: Patch Variance Agents Distinguished by Patch Variance Hughes et al. in prep

31 Methods: Scales of Disturbance Vegetation Index Patch-ified α = 0.20 α = 0.05 α = 0.02 Hughes et al. in prep Hughes and Hayes (2014) Remote Sensing

32 Methods: Automated Classification Training a neural network Hughes et al. in prep

33 Results: Spatial Patterns

34 Results: Validation Evaluation and Analysis Hughes et al. in prep

35 Results: Temporal Patterns % of area affected Southern Pine Beetle

36 Results: Regional Patterns Southern Pine Beetle Gypsy Moth Beech Bark Disease Hemlock Wooly Adelgid Fire TOTAL

37 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

38 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)

39 Thank You! Dan Hayes Oak Ridge National Laboratory: Meeting the challenges of the 21st century