Understanding Cumulative Effects of Aspen Harvest on Wildlife Habitat and Timber Resources in Northern Michigan

To effectively manage wildlife and timber resources, it is essential to understand how different management practices affect forest characteristics and how wildlife respond. Our objective was to model spatial and temporal effects of three aspen (Populus spp.) management scenarios on timber sustainability and wildlife habitat suitability for an 800-km2 area within the western Upper Peninsula of Michigan. We used ruffed grouse (Bonasa umbellus) to demonstrate effects of forest harvest simulations on wildlife. We used goal programming to develop a 10-decade timber harvest schedule to maintain an even representation of aspen age classes in nine habitat types under three management scenarios (i.e., harvest all aspen by 80 years, harvest all aspen >60 years, and intensively harvest aspen by requiring ≥60% to be harvested from the 40-year age class). We then simulated consequences of the harvest schedule using the program HARVEST. Attaining equal age class representation was feasible by decade 8 in the first scenario (i.e., harvest by 80 years), attainable in six habitat types by decade 8 under the second scenario, and not attainable under intensive management. Meeting the goal increased habitat availability for grouse by >1.5% under all scenarios. Volume harvested was sustainable under the first two scenarios at 600,000 m3 per year. Results provide quantitative answers to questions such as how much aspen to cut, where can it be cut, and what the effects are on timber production and grouse habitat availability. As society increases demands on natural resources, answers to such questions are essential to sustain timber and wildlife resources.