Thinning Northern Hardwoods in New England by Dominant-Tree Removal—Early Results

Abstract

Abstract 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 last 60+ years.