Landscape impacts from valuing core area in national forest planning

Forest core area was valued in a mathematical programming model to support decision-making for the most recent USDA Forest Service plans for national forests in Minnesota. A comparison of management schedules developed by the model to a strategy of simply designating pre-allocated areas for large patch production shows that valuing core area substantially increases the average patch size of mature forest. Analyses of maps of management schedules over the 100-year planning horizon using Fragstats, a computer program for spatial analysis, show substantial differences in spatial measures such as the overall distribution of patch sizes and edge-to-patch-area ratios. Model results reflect the fact that increasing patch sizes improves the efficiency of producing core area because less area of mature forest is then needed for buffer area to protect core area. Although the model cannot address patch size directly, results point to locations where large patches can likely be produced without large sacrifices in other objectives. Compared to other spatial modeling approaches, the approach is appealing because emphasis is on forest conditions rather than the size of harvested areas. Results demonstrate that multiple model runs can give forest planners insight regarding tradeoffs between spatial management objectives and other management objectives for areas as large as a national forest.