Effect of Deer Browsing on Reproduction in the Northern Hardwood-Hemlock Type in Northeastern Wisconsin

Abstract

foresters and biologists in the Lake States for many years. Preferred and second-choice species are sugar maple (Acer saccharum), red maple (Acer rubrum), yellow birch (Betula lutea), basswood (Tilia americana), white ash (Fraxinus americana), and hemlock (Tsuga canadensis). The browse furnished by both natural reproduction and slash left after logging is eagerly sought after by deer. Observations show that hardwood reproduction, particularly sugar maple, can withstand heavy browsing for many years without mortality. It does, however, become stunted and malformed as a result of browsing (Fig. 1). The rather slow growth of the reproduction in selectively cut stands of northern hardwoods, accentuated by the effect of deer browsing which prevents the reproduction from getting out of reach, represents a serious problem in hardwood management. The result is usually a stand where there is little or no gradation in height between small reproduction and trees of sapling size. As the stand becomes older, a serious gap in diameter-class distribution is also produced. To assess the seriousness of the problem, four exclosures were established on the Nicolet National Forest in northeastern Wisconsin. The main objectives were to determine the effect of deer browsing on (1) height growth, (2) form of the trees, and (3) mortality.