Residual Tree Damage Along Forwarder Trails from Cut-to-Length Thinning in Maine Spruce Stands

Abstract

Abstract In Maine and adjacent eastern Canadian provinces, cut-to-length harvesting has emerged as an ecologically attractive method of thinning conifer plantations and natural stands. Yet regional information on the extent of residual stand damage associated with this system is lacking. Eight naturally regenerated red spruce (Picea rubens) stands in northern Maine were studied; all stands were thinned in 1997–1998 with a processor and forwarder combination. Field methods consisted of examining individual trees near forwarder trails for bole damage and measuring the size and aboveground height of individual wounds. The frequency of trees damaged in each stand ranged from 25–46%. The four sites with the highest pre- and post-cut tree densities generally had the greatest number of damaged trees. Trees located along forwarder trails were more frequently damaged than nontrailside trees. The average individual wound size ranged from 2.6–8.7 in.2; 82–98% of the wounds in each stand were less than or equal to 10 in.2 in size. Usually, wounds on trailside trees were not significantly larger than wounds on nontrailside trees. Regardless of tree location, most wounds were located 3–6 ft above ground level.