Impact of Deer Browsing on Regeneration in Mixed Stands in Southern New England

Browsing preferences by white-tailed deer were evaluated for 6 tree species in northeastern Connecticut. Deer density averaged 23/mile 2.Deer exhibited no species-specific preferences for seedlings reater than 19 in. For seedlings less than 19 in., hemlock and black birch were preferred. Red maple, sugar maple, and white pine seedlings were avoided. Red oak seedlings were neither preferred nor avoided. A much higher proportion of seedlings greater than 19. 7 in. in height was browsed, regardless of species. Browsing preferences for species in the smaller seedling class, combined with a lack of preference for species in the larger class may result in future stands with less diverse tree species composition. Deer densities in excess of23/mile 2 may be incompatible with regeneration of diverse forests in southern New England. North. J. Appl. For. 12(3):115-120. Studies have demonstrated h t d er can egatively affect the establishment of natural regeneration on forested lands in the northeastern United States [Stoeckeler et al. 1957, Tierson et al. 1966, Marquis 1981, Frelich and Lorimer 1985, Tilghman 1989, Metropolitan District Commission (MDC) 1989]. Deer densities of 60-80/ mile 2 on the Quabbin Reservation i central Massachusetts result in virtually no regeneration (MDC 1989). Behrend et al. (1970) and Tilghman (1989) estimated that densities ofapproximately 17-18/mile 2 are compatible with adequate hardwood regeneration in the Adirondack region of northern New York State and the Allegheny region of Pennsylvania. Preferential browsing by deer of some tree species alters the shortand long-term development and future composition of a stand (Marquis 1981, Whitney 1984, Frelich and Lonmer 1985, Tilghman 1989). Furthermore, commercially desirable species, such as red oak and sugar maple, are known to be dependent on an adequate stocking of advanced reproduction in the understory if they are to be successfully regenerated (Marquis et al. 1992, Sander 1977, Hornbeck and Leak 1992, Kelty 1988, Leak et al. 1987). Browsing by deer could therefore significantly impact the establishment of certain species in the understory, and consequent composition and development of future stands. Most northeastern studies have investigated the relationsh•p between deer browsing and regeneration in northern hardwood, hemlock, or Allegheny hardwood (cherry-maple type) stands in New York or Pennsylvania (Stoeckeler et al. 1957, Tierson et al. 1966, Marquis 1981, Frelich and Lorimer 1985, Tilghman 1989). There have been no such investigations published for stands located in the transition hardwood region of southern New England (Connecticut, Massachusetts, and Rhode Island). With a different mixture of species (stands frequently dominated by oak), deer browse preferences and impact on regeneration may be different. In southern New England most forests consist of a mosaic of naturally regenerated even-aged mixed-species stands in the 60-80 yr age class, resulting from a variety of large-scale natural and human-induced isturbances, including agricultural abandonment, clearcutting for fuelwood or pine timber, and the hurricane of 1938. The prevalent species composition of this region is referred to as the "transition hardwoodswhite pine-hemlock forest vegetation zone" by Westveld et al. (1956), and typically includes such species as red oak, black oak, white oak, red maple, sugar maple, black birch, white birch, white ash, several species of hickory, eastern white pine, and eastern hemlock. Braun (1950) referred to the forest composition of southern New England as being in either the hemlock-white pinenorthern hardwoods region or the glaciated section of the oak-chestnut forest region. The boundary between these two regions runs roughly east-west hrough northern Connecti-