Evaluating the efficacy of high-stumping as a mechanical treatment to control ironwood (Ostrya virginiana)

Abstract

Ironwood (Ostrya virginiana) is becoming increasingly common in the midstory and understory of northern hardwood forests in Wisconsin, particularly in degraded stands and areas subject to significant deer browse. The shade and competition caused by dense layers of ironwood saplings interfere with regeneration of other valuable northern hardwood species. Wisconsin Department of Natural Resources is testing a non-chemical method of ironwood control in northern and southern Wisconsin. High-stumping is a non-chemical control method for ironwood where stems are cut above a standard stump height to increase stress on the plant and reduce vigorous stump resprouting. This study cut  ironwood during the growing season at several stump heights (30cm, 60cm and 91cm) and varied diameters to monitor sprouting and longevity of treated trees. Ironwood stumps have so far been monitored for three years after treatment. Preliminary results indicate that overall mortality was low (Median = 15.5%; Range = 1% - 36%) in the first year after treatment. However, overall mortality increased significantly in the second year post-treatment (Median = 23.5%, Range = 3% - 40%) and again in the third year of post-treatment monitoring (Median = 78.5%; Range = 22% - 95%). High-stumping may be a promising, viable non-chemical means of ironwood control in the understory of northern hardwood stands; offering an option on lands where chemical control methods are not preferred or allowed.