Interference to hardwood regeneration in northeastern North America: The effects of raspberries (Rubus spp.) following clear-cutting and shelterwood methods

Abstract

Rubus often becomes the most prominent vegetation within 2-3 years following heavy overstory disturbances at mesic sites within temperate forests of northeastern North America. This review draws together available literature about its dynamics and effects, focusing primarily on raspberry (Rubus idaeus L.) and blackberry (Rubus allegheniensis Porter). It covers some key ecologic functions of raspberries related to nutrient leaching, microclimate near the ground, and organic matter decomposition. It also summarizes published information about the potential interference with desirable tree regeneration at northern hardwood sites within the region. The review concentrates on raspberry (Rubus spp.) dynamics and effects following clearcutting, shelterwood method, and other heavy overstory disturbances. Findings indicate that raspberries commonly develop into a dense cover after cutting and other overstory disturbances reduce the stocking of northern hardwood stands by 40% or more. Ecologically, they shade the ground, intercept and transpire water, and reduce the rate of litter decomposition and nutrient cycling, all of which reduce leaching from a site. On poorly drained, droughty, and shallow soils, raspberries have reportedly delayed the development of hardwood regeneration. However, by 5-7 years, rapidly developing hardwood species have normally grown through the Rubus at most other sites, and the emerging tree community has formed a closed canopy by 10-15 years. The presence of abundant, well-developed, and well-distributed advance tree regeneration ensures prompt restocking of new hardwoods, seems to minimize the potential for interference by raspberries, and precludes any need to release the tree seedlings from a raspberry cover. Copyright © 2006 by the Society of American Foresters.