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The following links contain information and data from a number of studies assessing forest fragmentation and urbanization in the Northeast. These studies are ongoing and data are under review. Minor changes and corrections may be made before the final report is published.
Forest Fragmentation
Regional forest fragmentation assessment using satellite data
In this study, data used to calculate forest fragmentation metrics for the Northeast were derived from a modification of the 1992 National Land Cover Data (NLCD). Original, state-level NLCD images were obtained, converted to Arc/INFO grids, and mosaicked to create a single regional image. We reclassified each 30 meter pixel as one of several land uses, including forest, developed, agriculture, natural vegetation, and barren. Land cover classes in this NLCD map were then modified to better align with the FIA definition of forest land. Data on the distribution of roads in the Northeast were used to identify NLCD-designated forest land that might be non-forest by FIA's definition, due to low-density residential development. Forest patches (groups of forested pixels) that didn't meet FIA's minimum size criteria of one acre were also reclassified. Patch- and Landscape- based fragmentation metrics were calculated within county, watershed and ecoregion boundaries.
Brief description of fragmentation metrics (.doc)
Individual State Data for Northeastern States: (.xls)
Forest fragmentation based on photointerpreted data points
The Northeastern FIA unit has collected data on both the extent and location of forest fragmentation and the proximity to human development by using photointerpretation methods. These data include: a) the size of the continuous forested area in which the point falls, b) the distance from that point to the nearest developed land use, and c) the category of the nearest developed land use. This point sample interpretation, from 1:40,00 aerial photography, allows for the identification and "mapping" of some detailed distance and land use variables that are not currently available from other sources. This image is an example of the products available from this kind of mapping (click image to display a larger view).
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Urbanization and Urban Forest Land
The distribution of urban forest land was determined by using a GIS to combine the Bureau of Census urban area data in raster form with a forest/nonforest map produced by modifying the National Land Cover Data (NLCD). Forest land within the urban area boundary was considered urban forest. In an attempt to make the data more flexible for a range of studies on urbanization, this data also contains the area of forest land within different ranges of population density. Depending on the user's perspective on urban pressure and particular information needs, the Bureau of Census threshold for an urban designation may or may not be appropriate. For this reason, forest land area was reported for a range population density classes. Population density was determined using U.S. Census 2000 block-group-level population data and the area of individual block groups
Urbanization of Forest Land in the Northeastern U.S. (.jpg)
Urban/Forest Land by Population Density for Northeastern States:
(.jpg)
For additional information, contact Tonya Lister.
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