Thinning northern hardwoods in new do minant-tree removal - Early results

摘要

Commercial thinning is a widely accepted practice in northern hardwood stands of New England. Commercial thinning guidelines for eastern hardwoods generally recommend releasing selected crop trees or the removal of trees in less-than-dominant crown classes unless they are of poor health or quality. However, many northern hardwood stands in New England have a dominant crown class with a high proportion of paper birch and aspen. These species mature at an early age (50-70 years) and usually are marketable in stands of that age. In this study, most of the paper birch and aspen (the largest trees) in a 69-year-old northern hardwood stand were removed in a thinning operation, leaving a medium- to well-stocked stand of longer-lived species. Analysis of 4 years of subsequent diameter growth showed that the thinned residual trees (1) grew faster than the unthinned ones, (2) generally responded as well as trees after a range of earlier precommercial treatments, and (3) generally responded as well as residual trees after a more conventional thinning conducted in 1936, indicating that potential growth after thinning has not changed materially over the lost 60+ years.