The Effects of Alternative Diameter-Limit Cutting Treatments: Some Findings from a Long-Term Northern Conifer Experiment

Partial harvests in which only large and valuable trees are removed have long been common in the United States and Canada. These types of cuttings often have degrading effects on residual stand condition, though there is little data on the topic. Fortunately, modified and fixed diameter-limit and commercial clearcutting, as well as the uneven-aged silvicultural system of selection, have been applied by the USDA Forest Service on the Penobscot Experimental Forest in Maine for over 50 years. Results suggest that the degree of degradation, and thus potential for future management, are affected by both the removal criteria and the number of previous harvests. Treatment differences were not great following a single harvest. However, repeated applications of fixed diameter-limit and commercial clearcutting resulted in residual stands that were similar to one another in some aspects of structure and composition, and distinct from selection and modified diameter-limit cut stands.