Early seedling response to group selection harvesting in a northern hardwood forest

We evaluated the immediate effects of group selection harvesting on the establishment of yellow birch (Betula alleghaniensis Britt.) and black cherry (Prunus serotina Ehrh.) seedlings in maple-dominated hardwood stands of Algonquin Provincial Park, Ontario. Group selection gaps were compared to single-tree selection cutting and uncut reference stands pre-harvest and one growing season post-harvest using a before-after-control-impact (BACI) design. The percent cover of yellow birch seedlings increased significantly more in gaps than in single-tree selection and reference plots. Black cherry seedling cover increased significantly more in gaps than in reference plots, but increased at a similar rate in gaps and single-tree selection plots. Increased soil exposure and closer seed trees resulted in increased yellow birch recruitment when harvesting occurred in the late-summer-fall. These factors had little influence on yellow birch recruitment when harvesting occurred in the winter. The proportion of black cherry in the stand overstory had the greatest influence on black cherry recruitment; however, the uneven distribution of black cherry between stands may have precluded our ability to reliably test the influence of other factors. Concomitant increases in potential competitors such as wild red raspberry (Rubus strigosus Michx.) and sedges (Carex spp.) and the continued dominance of sugar maple (Acer saccharum Marsh) in gap openings may limit yellow birch and black cherry regeneration in successive growing seasons. While continued monitoring is required, our short-term results demonstrate that fall harvesting with group selection is effective at stimulating natural regeneration of yellow birch and black cherry.