Alternative shelterwood approaches for natural regeneration of oak-dominated hardwood stands on mesic sites in southern New England

by

Brent R. Frey, Rajesh Koirala, and Mark S. Ashton

Assistant Professor (BRF), Department of Forestry, 775 Stone Blvd, Mississippi State University, Mississippi State, MS 39762; Forest Policy Analyst (RK), Forest Carbon Partnership Facility, World Bank, 1818 H Street, Washington DC; Professor (MSA), School of Forestry and Environmental Studies, 195 Prospect Street, Yale University, New Haven, CT 06511. BRF is corresponding author. To contact, call 662-325-2775 or email brent.frey@msstate.edu.

Abstract – Few studies have evaluated alternative shelterwood methods for regeneration of oak-hardwood forests in southern New England. Red oaks in second growth stands subjected to selective fellings (high-grading) on mesic sites are reportedly replaced by black birch, red maple and/or sugar maple. Such sites have proven difficult to secure oak regeneration. We studied establishment and growth of regeneration on a mesic-till soil supporting a one-hundred year old, even-aged, oak-hardwood stand. Treatments consisted of different shelterwood establishment cuttings: a uniform shelterwood retaining approximately 50 ft2/acre of regularly spaced canopy dominants (primarily oaks); an irregular treatment retaining a similar basal area and spacing, but with subcanopy reserves of sugar maple; and a group shelterwood which created 100 foot diameter circular openings in which all trees >two inches dbh were removed. We monitored composition, density, and growth of regeneration over an eight-year period. Results showed that the uniform and irregular shelterwood were characterized by vigorous regrowth of oak’s key competitors, black birch and red maple. Results suggest that regeneration cuttings should be more opportunistically timed to oak masting and seedling establishment events, or that follow-up release treatments may be required to reduce competition around individual oaks. Alternatively, the group shelterwood maintained a cohort of red oak seedlings while limiting the growth of key competitors. Group shelterwoods may thus provide an alternative to establish red oak seedlings, which may be more competitive upon later release when openings are expanded. This may be desirable given unpredictable seed production and where intensive cleaning treatments are not feasible.