Mapping the Risk of Conversion in the Cumberland Plateau Ecosystem Part 1: Documenting Change in the

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Mapping the Risk of Conversion in the Cumberland
Plateau EcosystemPart 1 Documenting Change in
the Deciduous Forest Using Historical Landsat
Imagery

• David J. CampagnaJohn F. Amos
• SkyTruth
• Shepherdstown, West Virginia
• 14 April 2006

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The Cumberland Plateau

• The deciduous forest of the Cumberland Plateau is
  a hotspot of biodiversity in the greater
  Southern Appalachian Mountains (Evans and others,
  2002)
• One of the most diverse communities of woody
  plants
• Important neotropical migratory songbird habitat
• Headwaters to some of the most biologically
  diverse freshwater stream systems

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Cumberland Plateau Ecoregion

• Cumberland Plateau spans Tennessee midway between
  Knoxville and Nashville
• The southern part is divided by the Sequatchie
  Valley
• Plateau 1000 feet higher than Eastern Highland
  Rim to the west
• Receives slightly more precipitation, has cooler
  annual temperatures than surrounding
  lower-elevation ecoregions
• 70 is forests of mostly mixed hardwoods

EPA Ecoregions, Griffith et al. (1994 1995)
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Southern Appalachian Forests At Risk

• Like most southern forests, the Cumberland
  Plateau forest is claimed to be threatened by
  increasing pace of urban development and by
  forestry practices
• Forest Service landmark study, Southern Forest
  Resource Assessment (2001), predicts the South
  will lose more than 30 million acres of
  forestland to development over the next four
  decades
• Cumberland Plateau hosts one of the largest
  privately-owned tracts of contiguous deciduous
  forest
• Forestry practices include conversion of
  deciduous forest to pine plantations

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Where and How Much to Conserve?

• Conservation efforts complex for such a large
  ecosystem with private ownership
• A major challenge is identifying forest tracts
  having high conservation value
• High biodiversity
• High potential for protection / rehabilitation
• Greatest risk of conversion if no action taken

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Risk of Conversion

• Our project will develop the methodology and
  tools that will map the risk of conversion within
  an ecosystem
• Determine drivers that, when present, increase a
  tracts vulnerability to conversion
• Funded in part by a grant from WestWind Foundation

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Risk of Conversion

• Risk-based assessment of the Cumberland forest
  will be accomplished in three phases
• Determine actual change over a 25-year period in
  5-year intervals
• Correlate change with natural and social
  variables to determine drivers of change
• Create risk model to map out areas of high
  probability of converting from natural forest to
  pine plantation

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Phase 1 Change Analysis

• Change analysis, a common use of remote sensing
  for environmental analysis, identifies regions
  that have transformed from one category of land
  use, or type of land cover, to another
• Change in the Cumberland forest is documented
  through the use of historical Landsat satellite
  imagery

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Phase 1 Change Analysis

• Change Analysis is accomplished in three stages
• Supervised Classification of individual images
• Combine Leaf-On and Leaf-Off classification
  results to best delineate Evergreen, Deciduous
  and Mixed Forest classes
• Map change in 5-year periods
• Information concerning rate of change and
  multiple changes within 25-year period for an
  area
• Map Change over 25-year period
• Document the change of the Cumberland forest
  with focus on the conversion to pine plantations

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Landsat Data Suite

• Landsat data covering most of the ecoregion was
  acquired in 5-year periods from 1975 to 2001
• Total of 12 images georectified to UTM zone 16
• Subset images to cover only Cumberland Plateau,
  Escarpments and Sequatchie Valley
• Leaf-on and leaf-off conditions
• Single Landsat scene simplifies analysis

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Leaf-Off Leaf-On Images
18 June 2001
26 February 2001
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Land Cover Classification

• Based on a modified Anderson Level II land cover
  classification system that uses six classes
• Evergreen
• Deciduous
• Mixed Forest
• Agriculture / New Growth
• Barren / Urban
• Water
• Classification performed using training data and
  Maximum Likelihood algorithm
• Hierarchical decision model combines leaf-on and
  leaf-off classification results

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Accuracy Results

• Accuracy of classified image results was assessed
  using color-infrared aerial photographs from the
  USGS covering parts of Van Buren, Grundy, and
  Sequatchie counties
• Available dates
• 1973/05/04 8 0 CIR 120000 229 x 229 Vert Recon
• 1980/04/05 8 1 CIR 124105 229 x 229 Vert Recon
• 1988/07/09 8 0 CIR 64000 229 x 229 Vert Recon
• 256 random points were generated and used to
  compare classification results with aerial
  photographs

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1975 MSS Accuracy Results
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1990 TM Accuracy Results
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Accuracy Results

• Sufficient accuracy demonstrated to allow
  confident change analysis
• Approximately 90 accuracy rates for
  distinguishing Deciduous and Pine forests
• Greatest error between Cleared and
  Agriculture classes
• Not a meaningful error as changes in agricultural
  fields vary significantly with respect to season
  and farming practices

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1975 Land Cover

• The earliest image date is used as the baseline
  from which change is measured
• In 1975, Cumberland Deciduous and Mixed Forest
  covered 1,949,585 acres

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Change Analysis in 5-Year Intervals

• Change analysis of the Cumberland Forest in
  5-year intervals shows changes typically occur as
  transition from forest class, to cleared, to new
  vegetation, and in some cases back to cleared
• Captures changes in land cover state
• Some areas mapped as cleared in 2001 were
  converted to pine plantations previously
• Such use would have been missed if using only
  paired (1975-2001) change analysis

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Change in a Portion of Van Buren County

• To illustrate changes captured over 5-year
  intervals, we will examine a portion of Van Buren
  County