2010 年 15 巻 2 号 p. 81-98
Clearcut size limitations established both for private land and public land may affect and compound the fragmentation of forested landscapes. To better understand how these restrictions influence forest fragmentation, we designed an experiment to test and assess the effects caused by different maximum clearcut size restrictions on landscapes with different spatial patterns of land ownership. First, we developed forest plans with wood-flow and clearcut size constraints, using datasets composed of different land sizes (small, medium, and large) and spatial patterns (clumped, dispersed, and random). Six reasonable maximum clearcut sizes were assumed for industrial landowners of the southern U.S. Landscape metrics were selected as indicators of forest fragmentation; these included number of patches, patch density, total edge, edge density, perimeter-area fractal dimension, mean proximity, contagion. Results show that regardless of forest size and spatial pattern of land ownership, as the maximum clearcut size increased the number of patches, patch density, total edge and edge density decreased, while mean proximity increased. Results also suggest that wood-flow constraints have an effect on measures of fragmentation, and by adding this type of constraint to a forest planning problem, the effects attributable to different clearcut size restrictions may be mitigated.