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A Forest Fragmentation Index to Quantify the Rate of Forest Change

A Forest Fragmentation Index to Quantify the Rate of Forest Change. James D. Hurd, Emily H. Wilson, Daniel L. Civco Center for Land Use Education and Research (CLEAR) Department of Natural Resources Management & Engineering The University of Connecticut U-4087, Room 308, 1376 Storrs Road

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A Forest Fragmentation Index to Quantify the Rate of Forest Change

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  1. A Forest Fragmentation Index to Quantify the Rate of Forest Change James D. Hurd, Emily H. Wilson, Daniel L. Civco Center for Land Use Education and Research (CLEAR) Department of Natural Resources Management & Engineering The University of Connecticut U-4087, Room 308, 1376 Storrs Road Storrs, CT 06269-4087

  2. Outline • Background • Objectives • Study Area and Data • Methods • Forest Fragmentation Model • State of Forest Fragmentation • Results • Conclusions • ERDAS Imagine GUI

  3. A NASA Regional Earth Science Applications Center (RESAC) Northeast Applications of Useable Technology In Land planning for Urban Sprawl

  4. To educate the general public on the value and utility of geospatial technologies, particularly RS information. Our RESAC Mission To make the power of remote sensing technology available, accessible and useable to local land use decision makers as they plan their communities.

  5. Better land cover mapping and change detection Urban growth models and metrics Forest fragmentation models and metrics Improved impervious cover estimates NAUTILUS Research

  6. Presumpscot SuAsCo Salmon Stonybrook Research & Education Watersheds A range of land covers and issues

  7. Salmon River Watershed, CT • Focused watershed for NAUTILUS research • CES program and research already • existing in watershed • Rapid Urbanization • State highway connects with major • Hartford market • 5 out of 7 watershed towns are listed as • the fastest growing towns in the State • Key component of the lower Connecticut • River Watershed 140 Sq. Miles

  8. Background • Need for effective methods for deriving information on • Land use change • Forest fragmentation • Urban growth • Loss of agricultural lands • Increase in impervious surface area

  9. Objective To derive a forest fragmentation index that provides a more informational assessment of the state of forest fragmentation within a given area beyond that provided through binary forest/non-forest approaches.

  10. Forest Fragmentation Model • Developed by Riitters et al. (2000) to assess global forest fragmentation from 1 km data. • Adapted for use on TM derived land cover information. • Categorizes forest pixels into 6 types: • Interior forest • Edge forest • Perforated forest • Transition forest • Patch forest • Undetermined forest

  11. Forest pixels Non-forest pixels Forest Fragmentation Model 5 x 5 roving window Adapted from Riitters et al., 2000

  12. Forest pixels Non-forest pixels Forest Fragmentation Model 5 x 5 roving window Considering pairs of pixels in cardinal directions, the total number of adjacent pixel pairs in a 5 x 5 window is 40. In this example, 32 pixel pairs contain at least 1 forest pixel, and of those 23 pairs contain 2 forest pixels. Adapted from Riitters et al., 2000

  13. Forest Fragmentation Model • Interior forest - all of the pixels surrounding the center pixel are forest. Pf = 1.0 Adapted from Riitters et al., 2000

  14. Forest Fragmentation Model • Interior forest - all of the pixels surrounding the center pixel are forest. Pf = 1.0 • Perforated forest - most of the pixels in the surrounding area are forested, but the center pixel appears to be part of the inside edge of a forest patch, such as would occur if a small clearing was made within a patch of forest. Pf > 0.6 and Pf - Pff > 0. Adapted from Riitters et al., 2000

  15. Forest Fragmentation Model • Interior forest - all of the pixels surrounding the center pixel are forest. Pf = 1.0 • Perforated forest - most of the pixels in the surrounding area are forested, but the center pixel appears to be part of the inside edge of a forest patch, such as would occur if a small clearing was made within a patch of forest. Pf > 0.6 and Pf - Pff > 0 • Edge forest - most of the pixels in the surrounding area are forested, but the center pixel appears to be part of the outside edge of forest, such as would occur along the boundary of a large urban area, or agricultural field. Pf > 0.6 and Pf - Pff < 0 Adapted from Riitters et al., 2000

  16. Forest Fragmentation Model • Interior forest - all of the pixels surrounding the center pixel are forest. Pf = 1.0 • Perforated forest - most of the pixels in the surrounding area are forested, but the center pixel appears to be part of the inside edge of a forest patch, such as would occur if a small clearing was made within a patch of forest. Pf > 0.6 and Pf - Pff > 0 • Edge forest - most of the pixels in the surrounding area are forested, but the center pixel appears to be part of the outside edge of forest, such as would occur along the boundary of a large urban area, or agricultural field. Pf > 0.6 and Pf - Pff < 0 • Undetermined forest - most of the pixels in the surrounding area are forested, but this center forest pixel could not be classified as a type of fragmentation in the surrounding area. Pf > 0.6 and Pf = Pff Adapted from Riitters et al., 2000

  17. Forest Fragmentation Model • Interior forest - all of the pixels surrounding the center pixel are forest. Pf = 1.0 • Perforated forest - most of the pixels in the surrounding area are forested, but the center pixel appears to be part of the inside edge of a forest patch, such as would occur if a small clearing was made within a patch of forest. Pf > 0.6 and Pf - Pff > 0 • Edge forest - most of the pixels in the surrounding area are forested, but the center pixel appears to be part of the outside edge of forest, such as would occur along the boundary of a large urban area, or agricultural field. Pf > 0.6 and Pf - Pff < 0 • Undetermined forest - most of the pixels in the surrounding area are forested, but this center forest pixel could not be classified as a type of fragmentation in the surrounding area. Pf > 0.6 and Pf = Pff • Transitional forest - about half of the cells in the surrounding area are forested and the center forest pixel may appear to be part of a patch, edge, or perforation depending on the local forest pattern. 0.4 < Pf < 0.6 Adapted from Riitters et al., 2000

  18. Forest Fragmentation Model • Interior forest - all of the pixels surrounding the center pixel are forest. Pf = 1.0 • Perforated forest - most of the pixels in the surrounding area are forested, but the center pixel appears to be part of the inside edge of a forest patch, such as would occur if a small clearing was made within a patch of forest. Pf > 0.6 and Pf - Pff > 0 • Edge forest - most of the pixels in the surrounding area are forested, but the center pixel appears to be part of the outside edge of forest, such as would occur along the boundary of a large urban area, or agricultural field. Pf > 0.6 and Pf - Pff < 0 • Undetermined forest - most of the pixels in the surrounding area are forested, but this center forest pixel could not be classified as a type of fragmentation in the surrounding area. Pf > 0.6 and Pf = Pff • Transitional forest - about half of the cells in the surrounding area are forested and the center forest pixel may appear to be part of a patch, edge, or perforation depending on the local forest pattern. 0.4 < Pf < 0.6 • Patch forest - pixel is part of a forest patch on a non-forest background, such as a small wooded lot within an urban region. Pf < 0.4 Adapted from Riitters et al., 2000

  19. Forest Fragmentation (center forest pixel identified as perforated) INTERIOR FOR. PERFORATED FOR. EDGE FOREST TRANSITIONAL FOR. PATCH FOREST UNDETERMINED FOREST Forest Fragmentation ModelExample Calculation 1 Landsat Derived Land Cover IKONOS Image of Area White box represents 5X5 pixel area. Identifies center forest pixel.

  20. INTERIOR FOR. PERFORATED FOR. EDGE FOREST TRANSITIONAL FOR. PATCH FOREST UNDETERMINED FOREST Forest Fragmentation ModelExample Calculation 1 Landsat Derived Land Cover Forest Fragmentation Within 5x5 window Non-water pixels = 25 Forest pixels = 24 Pixel pairs, both forest = 36 Pixel pairs, one forest = 4 Perforated forest = Pf > 0.6 and Pf - Pff > 0 Pf is greater than 0.6 and Pf - Pff (0.06) is greater than 0.

  21. Forest Fragmentation (center forest pixel identified as edge) INTERIOR FOR. PERFORATED FOR. EDGE FOREST TRANSITIONAL FOR. PATCH FOREST UNDETERMINED FOREST Forest Fragmentation ModelExample Calculation 2 Landsat Derived Land Cover IKONOS Image of Area White box represents 5X5 pixel area. Identifies center forest pixel.

  22. INTERIOR FOR. PERFORATED FOR. EDGE FOREST TRANSITIONAL FOR. PATCH FOREST UNDETERMINED FOREST Forest Fragmentation ModelExample Calculation 2 Landsat Derived Land Cover Forest Fragmentation Within 5x5 window Non-water pixels = 25 Forest pixels = 18 Pixel pairs, both forest = 26 Pixel pairs, one forest = 6 Edge forest = Pf > 0.6 and Pf - Pff < 0 Pf is greater than 0.6 and Pf - Pff (-0.09) is less than 0.

  23. Forest Fragmentation (center forest pixel identified as patch) INTERIOR FOR. PERFORATED FOR. EDGE FOREST TRANSITIONAL FOR. PATCH FOREST UNDETERMINED FOREST Forest Fragmentation ModelExample Calculation 3 Landsat Derived Land Cover IKONOS Image of Area White box represents 5X5 pixel area. Identifies center forest pixel.

  24. INTERIOR FOR. PERFORATED FOR. EDGE FOREST TRANSITIONAL FOR. PATCH FOREST UNDETERMINED FOREST Forest Fragmentation ModelExample Calculation 3 Landsat Derived Land Cover Forest Fragmentation Within 5x5 window Non-water pixels = 25 Forest pixels = 6 Pixel pairs, both forest = 2 Pixel pairs, one forest = 15 Patch forest = Pf < 0.4 Pf is less than 0.4.

  25. 30 meter interior forest buffer. Forest Frag. post-Buffer Forest Fragmentation Model • Size of window determines width of fragmentation classes (5x5 window = 60 meter width). • User option to buffer interior forest to generate 30 meter wide fragmentation classes. Forest Frag. Before Buffer

  26. 1999 Forest Fragmentation post-Buffer Forest Fragmentation Model Salmon River Watershed 1999 Land Cover 1999 Forest Fragmentation

  27. Forest Fragmentation Model August 9, 1985 August 30, 1990 August 28, 1995 August 31, 1999 Landsat TM RED= Band 4 (NIR) GREEN= Band 5 (MIR) BLUE= Band 6 (red) Land Cover URBAN NON-WOODY VEG DECIDUOUS FOR. CONIFEROUS FOR. WATER WETLAND BARREN Fragmentation INTERIOR FOR. PERFORATED FOR. EDGE FOREST TRANSITIONAL FOR. PATCH FOREST UNDETERMINED FOREST

  28. State of Forest Fragmentation • Input information is the result from the forest fragmentation model. • Two components: • Proportion of forest area to total area (excluding water). (TFP) • Forest continuity (FC) • The product of: • the proportion of weighted area of fragmented forest to total forest area, and… • …the proportion of the largest interior forest patch to total forest area.

  29. Proportion of Forest (non-water) 4,726/5,980 = 0.79 CLASS PIXELS CLASS PIXELS Interior forest 3624 Patch forest 88 Transitional forest 350 Perforated Forest 346 Edge Forest 318 TOTAL FOREST 4,726 Non-water 5,980 Water 94 TOTAL WATERSHED 6,074 State of Forest Fragmentationdetermining TFP

  30. Weighted forest area (4,347.8 / 4726) = 0.92 CLASS PIXELS WEIGHT Interior forest 3,624 X 1.0 3,624.0 Patch forest 88 X 0.2 17.6 Transitional forest 350 X 0.5 175.0 Perforated Forest 346 X 0.8 276.8 Edge Forest 318 X 0.8 254.4 TOTAL FOREST 4,7264,347.8 State of Forest Fragmentationdetermining FC, part 1: weighted forest area The weighting values are based on the Pf values of Riitters model. 1.0 - 0.8 - 0.5 - 0.2 -

  31. CLASS PIXELS Largest interior forest patch proportion Interior forest 3,624 Patch forest 88 Transitional forest 350 Perforated Forest 346 Edge Forest 318 TOTAL FOREST 4,726 2443 / 4726 = 0.52 State of Forest Fragmentationdetermining FC, part 2: largest interior forest Largest Interior Forest Patch 2,443 pixels

  32. State of Forest Fragmentationdetermining FC Proportion of weighted forest x Proportion of largest interior forest patch = Forest Continuity Forest Continuity = 0.92 * 0.52 = 0.48

  33. CLASS PIXELS Urban 307 Forest 2515 Barren 1 1 CLASS PIXELS Interior forest 2483 Patch forest 0 Transitional forest 15 Perforated Forest 4 Edge Forest 13 Forest Continuity 0 1 Proportion of Forest State of Forest FragmentationHypothetical Example 1 Proportion of Forest =0.89 Forest Continuity =0.98

  34. CLASS PIXELS Urban 307 Forest 2515 Barren 1 1 CLASS PIXELS Interior forest 2179 Patch forest 14 Transitional forest 202 Perforated Forest 53 Edge Forest 67 Forest Continuity 0 1 Proportion of Forest State of Forest FragmentationHypothetical Example 2 Proportion of Forest = 0.89 Forest Continuity = 0.37

  35. State of Forest Fragmentation With regards to forest proportion: • Based on current literature, forest fragmentation becomes more severe at about 80% forest cover. • The potential for improving forest connectivity by connecting adjacent forest patches is greatest between 60% and 80% forest cover. • Below 60% forest cover there tends to be more numerous and smaller forest patches.

  36. State of Forest Fragmentation With regards to forest continuity: • Analyzing only the forest area, forestwillrange from fully intact with little or no fragmentation to completely fragmented or non-existent forest.

  37. 1 High amount of forest, High forest continuity High amount of forest, Low forest continuity Moderate amount of forest, High forest continuity Moderate amount of forest, Low forest continuity Low amount of forest, High forest continuity Low amount of forest, Low forest continuity Forest Continuity .5 .6 .8 0 1 Proportion of Forest State of Forest Fragmentation

  38. 1 CLASS PIXELS Interior forest 2981 Patch forest 56 Transitional forest 174 Perforated Forest 408 Edge Forest199 .5 Forest Continuity CLASS PIXELS Urban 307 Non-woody Veg 595 Forest/Wetland 3818 Water 14 Barren 14 .6 .8 0 1 Proportion of Forest State of Forest FragmentationReal World Example 1 Proportion of Forest = 0.76 Forest Continuity = 0.66

  39. 1 CLASS PIXELS Interior forest 3624 Patch forest 88 Transitional forest 350 Perforated Forest 346 Edge Forest 318 .5 Forest Continuity CLASS PIXELS Urban 689 Non-woody Veg 546 Forest/Wetland 4726 Water 94 Barren 19 .6 .8 0 1 Proportion of Forest State of Forest FragmentationReal World Example 2 Proportion of Forest = 0.79 Forest Continuity = 0.46

  40. 1 CLASS PIXELS Interior forest 418 Patch forest 21 Transitional forest 36 Perforated Forest 48 Edge Forest 36 .5 Forest Continuity CLASS PIXELS Urban 77 Non-woody Veg 650 Forest/Wetland 568 Water 32 Barren 6 .6 .8 0 1 Proportion of Forest State of Forest FragmentationReal World Example 3 Proportion of Forest = 0.43 Forest Continuity = 0.66

  41. High amount of forest, High forest continuity High amount of forest, Low forest continuity Moderate amount of forest, High forest continuity Moderate amount of forest, Low forest continuity Low amount of forest, High forest continuity Low amount of forest, Low forest continuity Results 1985 State of Fragmentation Town of Marlborough, CT and intersecting watersheds

  42. High amount of forest, High forest continuity High amount of forest, Low forest continuity Moderate amount of forest, High forest continuity Moderate amount of forest, Low forest continuity Low amount of forest, High forest continuity Low amount of forest, Low forest continuity Results 1990 State of Fragmentation Town of Marlborough, CT and intersecting watersheds

  43. High amount of forest, High forest continuity High amount of forest, Low forest continuity Moderate amount of forest, High forest continuity Moderate amount of forest, Low forest continuity Low amount of forest, High forest continuity Low amount of forest, Low forest continuity Results 1995 State of Fragmentation Town of Marlborough, CT and intersecting watersheds

  44. High amount of forest, High forest continuity High amount of forest, Low forest continuity Moderate amount of forest, High forest continuity Moderate amount of forest, Low forest continuity Low amount of forest, High forest continuity Low amount of forest, Low forest continuity Results 1999 State of Fragmentation Town of Marlborough, CT and intersecting watersheds

  45. High amount of forest, High forest continuity High amount of forest, Low forest continuity Moderate amount of forest, High forest continuity Moderate amount of forest, Low forest continuity Low amount of forest, High forest continuity Low amount of forest, Low forest continuity Results 1985 State of Fragmentation Town of Marlborough, CT and 1 kilometer grid regions

  46. High amount of forest, High forest continuity High amount of forest, Low forest continuity Moderate amount of forest, High forest continuity Moderate amount of forest, Low forest continuity Low amount of forest, High forest continuity Low amount of forest, Low forest continuity Results 1990 State of Fragmentation Town of Marlborough, CT and 1 kilometer grid regions

  47. High amount of forest, High forest continuity High amount of forest, Low forest continuity Moderate amount of forest, High forest continuity Moderate amount of forest, Low forest continuity Low amount of forest, High forest continuity Low amount of forest, Low forest continuity Results 1995 State of Fragmentation Town of Marlborough, CT and 1 kilometer grid regions

  48. High amount of forest, High forest continuity High amount of forest, Low forest continuity Moderate amount of forest, High forest continuity Moderate amount of forest, Low forest continuity Low amount of forest, High forest continuity Low amount of forest, Low forest continuity Results 1999 State of Fragmentation Town of Marlborough, CT and 1 kilometer grid regions

  49. HECTARES CLASS 1985 Water 130 Developed 807 Non-woody Vegetation 930 Interior Forest 6,481 Patch Forest 62 Transitional Forest 373 Perforated Forest 740 Edge Forest 476 Total Forest 8,132 Town Boundary Watershed Boundary Results 1985 Forest Fragmentation Town of Marlborough, CT and intersecting watersheds

  50. HECTARES CLASS 19851990 Water 130 139 Developed 807 997 Non-woody Vegetation 930 979 Interior Forest 6,481 6,027 Patch Forest 62 83 Transitional Forest 373 442 Perforated Forest 740 836 Edge Forest 476 496 Total Forest 8,132 7,884 Town Boundary Watershed Boundary Results 1990 Forest Fragmentation Town of Marlborough, CT and intersecting watersheds

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