An Improved Method for Classifying Forest Fragmentation

1. Center for Land use Education and Research An Improved Method for Classifying Forest Fragmentation Jason Parent and James Hurd jason.parent@uconn.edu

2. “Forest fragmentation is the process of dividing large tracts of forest into smaller isolated tracts surrounded by human-modified environments.” Society of American Foresters (1998)

3. “ …continued declines and fragmentation of the forestland base may lead to the impairment of our forest ecosystems’ ability to protect water flow and quality, to provide healthy and diverse forest habitat, and to remain a viable economic resource that provides recreation, timber, and other forest products.” Society of American Foresters (1998)

4. Why map forest fragmentation? • Identify areas in which to focus management efforts aimed at minimizing forest fragmentation. • Allow better land use planning to minimize forest fragmentation in the future

5. An improved method to map forest fragmentation • Vogt et al. (2007) propose a method that classifies forest based on pixel-level patterns. • The authors found this method to yield more accurate results than the method proposed by Riitters et al. (2002).

6. Forest classes • Four classes of forest are identified – in terms of the type of fragmentation present: • Core – interior forest pixels that are not degraded from “edge effects”. • Perforated – forest along the inside edge of an small forest perforation. • Edge – forest along the outside edge of a forest patch. • Patch – small fragments of forest that are entirely degraded by “edge effects”.

7. Forest classes

8. A tool for mapping fragmentation in the landscape • We present the Landscape Fragmentation Analysis tool (LFA) for mapping fragmentation in the landscape. • Based on the method developed by Vogt et al. (2007). • LFA procedures are functionally equivalent and yield identical results but are more efficient. • LFA procedures are more intuitive. • Can analyze fragmentation for any land cover type: • Forest land, shrub land, urban land, etc. • The LFA tool is a python script that runs in ArcToolbox. • Requires ArcView 9.2 with Spatial Analyst

9. Input land cover map • The LFA tool requires a 3 class land cover map as input: …assuming forest is the land cover type of interest… • 1 = non-forest • 2 = water • 3 = forest • Water is not considered to be a fragmenting feature and does not affect the analysis. • To include water as a fragmenting feature, include water in the non-forest class (value = 1).

10. Forest Non-forest Water Extracting land covers of interest

11. Edge width • Edge-width is the distance over which non-forest land covers can degrade forest land covers. • Core, perforated, edge, and patch forest are defined in terms of the “edge width”. • Numerous studies have documented “edge effects” on wildlife habitat: • Edge-width varies by species and can range from 50 meters to several hundred meters. • 100 meters is often used as a general edge-width.

12. Defining core, peripheral, and patch forest Assuming an edge-width of 100 meters… • Core forests consist of any forest pixels that are more than 100 meters from non-forest. • Peripheral forest consists of forest pixels that are within 100 meters of non-forest and the tract contains core forest. • Further classified into edge and perforated forest • Patch forests do not contain any forest pixels that are more than 100 meters from non-forest – they are entirely encompassed by the edge-effect.

13. <= 100 m from non-forest > 100 m from non-forest no core pixels in tract core pixels in tract Forest core forest peripheral forest patch forest Classifying core, peripheral, and patch forest Note: assuming edge-width is 100 meters

14. core 0 m 100 300 200 Core, patch, and peripheral forest

15. all pixels less than 100 m of forest <= 100 m from forest non-forest patch Non-forest Classifying non-forest patches Note: assuming edge-width is 100 meters

16. 0 m 100 300 200 Non-forest patches

17. not adjacent to non-forest patch adjacent to non-forest patch edge forest perforated forest Classifying perforated and edge forest peripheral forest

18. core 0 m 100 300 200 Core, patch, edge and perforated forest

19. Input land cover Input edge width Output map Specifying parameters for LFA

20. Downloading the LFA tool • The Landscape Fragmentation Analysis tool is available through the Center for Land use Education and Research (CLEAR) at: • http://www.clear.uconn.edu/tools/geospatial/Landscape_Fragmentation.zip • Forest fragmentation analysis results for Connecticut Changing Landscape land cover data will also be available through CLEAR’s website: • www.clear.uconn.edu

21. References • Vogt, P., K. Riitters, C. Estreguil, J. Kozak, T. Wade, J. Wickham. 2007. Mapping spatial patterns with morphological image processing. Landscape Ecology 22: 171-177. • Riitters, K., J. Wickham, R. O’Neill, K. Jones, E. Smith, J. Coulston, T. Wade, J. Smith. 2002. Fragmentation of continental United States forests. Ecosystems 5 : 815-822.

22. Center for Land use Education and Research Questions? An Improved Method for Classifying Forest Fragmentation Jason Parent and James Hurd jason.parent@uconn.edu