Predicting the effects of woodcutting and moose browsing on forest development in Gros Morne National Park, Newfoundland, Canada

Long-term scenario analysis was used to predict the effects of domestic harvesting and moose (Alces alces) browsing on forest growing stock, species composition, and age-class distribution for two groups of managed forest blocks dominated by balsam fir (Abies balsamea [L.] Mill.) in Gros Morne National Park (GMNP), western Newfoundland. Four scenarios were examined. The first scenario assumed no timber harvesting and light moose browsing. Transition rules applied to this scenario came from neighbouring industrial forests, where moose populations are regulated by hunting. The other test scenarios use GMNP-specific transition rules to address increased moose browsing in the park, where hunting has been prohibitedsince the park’s inception in 1973. One of the three tested scenarios was also given a “no timber harvest treatment” so that the effects of moose browsing on park forests may be quantified by comparison with the first scenario. The two remaining test scenarios were designed to address compound effects of timber harvesting and moose browsing within the park, each representingan alternative management sce- nario currently being implemented in GMNP. For both harvest scenarios, the overall achievable wood volume was found to be at least five orders of magnitude lower than growing stock, thus providing sufficient volume for the ongoing domestic wood- cutting program (1973-2060) in the park. The proposed levels of woodcutting were predicted to have little impact on forest growing stock and old-growth forest after 160 years of management, but not on maintaining white birch (Betula papyrifera Marsh.), which is already in low numbers. In contrast, moose browsing, although it was predicted to have little effect on age-class distribution, was estimated to cause a 12% to 32% reduction in growing stock over a 160-year planning horizon, depending on the scenario. This was characterized by a 47% to 50% reduction in growing stock of balsam fir and a 50% to 87% reduction in white birch, and a commensurate expansion in low-density black spruce (Picea mariana [Mill.] BSP) and grassland cover.