Linking Land-Use Projections and Forest Fragmentation Analysis

Plantinga, Andrew J.; Alig, Ralph J.; Eichman, Henry; Lewis, David J. 2007. Linking land-use projections and forest fragmentation analysis. Res. Pap. PNWRP-570. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Station. 41 p. An econometric model of private land-use decisions is used to project land use to 2030 for each county in the continental United States. On a national scale, forest area is projected to increase overall between 0.1 and 0.2 percent per year between now and 2030. However, forest area is projected to decrease in a majority of regions, including the key forestry regions of the South and the Pacific Northwest Westside. Urban area is projected to increase by 68 million acres, and cropland, pasture, rangeland, and Conservation Reserve Program land is projected to decline in area. Regional econometric models are needed to better represent region-specific economic relationships. County-level models of forest fragmentation indices are estimated for the Western United States. The core forest model is found to perform better than the model of like adjacencies for forest land. A spatially detailed analysis of forest fragmentation in Polk County, Oregon, reveals that forests become more fragmented even though forest area increases. By linking the land-use projection and forest fragmentation models, we project increases in the average county shares of core forest in 8 of the 11 Western States. The average like adjacency measure increases in six of the states. The aggregate and spatially detailed fragmentation methods are compared by projecting the fragmentation indices to 2022 for Polk County, Oregon. Considerable differences in the results were produced with the two methods, especially in the case of the like adjacency metric.