Natural Regeneration Patterns in Even-Aged Mixed Stands in Southern New England

A regeneration survey in southern New England in three different cover types indicated that most of the seedhngs present were less than 19.7 in. in height. Although red oak was a principal component of he overstory, it represented a small proportion of regeneration. Black b•rch and red maple were common regeneration components. There was a general relationship between overstory density and the amount of regeneration. Toobtain atural regeneration, a general broad optimum range of overstory densities between 20-80 ft2/ac of basal area is suggested. Successful red oak and sugar maple regeneration was obtained with overstory densities of these species between 20-40 ft2/ac. A higher proportion f these species d•d not result in more regeneration. White p•ne regeneration was closely related to the amount of white pine in the overstory, however. The density of mountain laurel seemed tohave little effect on the establishment of regeneration. The greater the length of time since last harvest, he more oak seedlings would be present in hardwood stands. The opposite was true for red maple, black birch, and hemlock. North. J. AppL For. 7:163-168, December 1990. Natural stands in southern New England are commonly comprised of diverse mixtures of as many as 12-15 commercial tree species. Information on the management of these stands is sparse. Some studies have been pubhshed that characterize natural succession patterns in this region (Good and Good 1972), but they do not address management practices or implications. Foresters commonly use silvicultural guides for northern hardwoods (Leak et al. 1987), and a similar guide developed for oak stands in the central states (Gingrich 1967). These guides prescribe intermediate thinnings for the goal of timber production based on optimal stocking but do not address methods of stand regeneration. Other management guides suggest methods, but again these are designed for either oaks in the central states (Sander 1977) or northern hardwoods in northern central states (Tubbs 1977). Currently there is a paucity of applied management information for the mixed stands that are commonly found in southern New England. Many stands in southern New England are even-aged, and a large proportion are in mature age classes. For example, 56% of Massachusetts' commercial timberland is in the sawtimber size class (Dickson and McAfee 1988). In fact, the area in sawtimber stands has increased by 72% since 1972 (Dickson and McAfee 1988). It is not too early to begin considering the natural regeneration of these stands, but no guidelines exist. It is likely that the regeneration ecology of species in these mixed stands in southern New England may be different from what is observed in other parts of their natural ranges. The possible interactions between these species may represent additional influences that are not otherwise important elsewhere in the natural range.