CT Forest Fragmentation

The map below shows just the forest fragmentation layers. To see them in context with other land cover layers, visit the Connecticut Land Cover Viewer.


For each date, the 12 category input land cover was reclassified into three categories:

  • fragmenting features (developed, turf & grass, other grasses, agricultural fields, barren land, utility corridors),
  • forest features (deciduous forest, coniferous forest, forested wetland),
  • non-fragmenting features (water, non-forested wetland, tidal wetland all of which will not affect the fragmentation analysis).

CLEAR’s Landscape Fragmentation Tool was used to identify four forest fragmentation categories using a 300 foot edge width applied to the reclassified land cover:

The analysis is based on the following research:

  • Vogt, P., K. Riitters, C. Estrenguil, J. Kozak, T. Wade, J. Wickham. 2007. Mapping spatial patterns with morphological image processing. Landscape Ecology 22: 171-177


The forest fragmentation tool classifies forests in four general categories:

Class Class Name Class Description
1 Patch Forest small isolated fragments of forest that are surrounded by non-forest features and completely degraded by "edge effects"
2 Edge Forest forest pixels along the exterior perimeter of a forest that are degraded by "edge effects" (for example the forest immediately along a major highway or large agricultural field)
3 Perforated Forest forest pixels along the edge of an interior gap in a forest that are degraded by "edge effects" (for example the forest immediately surrounding a small house lot in the middle of the forest)
Core Forest forest pixels that are not degraded by "edge effects" and are relatively far from the forest-nonforest boundary. The Landscape Fragmentation Tool further divides these by size.
4      Small core smaller than 250 acres
5      Medium core between 250 and 500 acres
6      Large core larger than 500 acres

Edge effects are abrupt changes in vegetative populations or community structures found at the boundary of two or more different habitats.

NOTE. Core forest sub-categories used in this analysis are based on scientific literature and suggest general thresholds for minimum viable forest patch sizes. The relationship between how viable a forest patch is and patch size is dependent on the species of interest.

Edge Width

The edge width parameter is the distance over which the fragmented land cover type of interest (i.e. forest) can be degraded by the fragmenting land cover types (i.e. development, agricultural fields, etc). The literature indicates that the edge width varies by the species or issue of interest.

  • Edge widths reported in the ecology literature range from 50 meters to several hundred meters depending on the issue of interest.
  • An edge width of 100 meters (330 feet) is often used for general purposes analysis.
  • The edge width parameter determines the width of the edge and perforated forest zones as well as the thickness of patches.