Group and single-tree selection cutting in mixed tolerant hardwood-white pine stands: Early establishment dynamics of white pine and associated species

Abstract

In mixed tolerant hardwood - white pine stands of Southwestern Quebec, the effects of group selection cutting on eastern white pine (Pinus strobus L.), red oak (Quercus rubra L.), yellow birch (Betula alleghaniensis Britton) and paper birch (Betula papyrifera Marsh.) regeneration are compared to the currently used single-tree selection cutting. The experimental design, initiated in 1998, comprised three cover reduction treatments (circular gap (45 m, 1590 m2)), 25% and 35% single-tree selection cutting), two scarification treatments (scarified and non-scarified) and two seeding treatments for white pine (seeded and non-seeded). The effect of white pine seed predation was studied in the gaps and the adjacent understory, with exclosures for small mammals. After three years, scarification had a positive effect on white pine, yellow birch and paper birch regeneration but also on aspen (Populus spp.) and pin cherry (Prunus pensylvanica L.f.) in the three cover reduction treatments. Red oak regeneration was negatively affected by scarification. Shade-tolerant species (sugar maple (Acer saccharum Marsh.) and American beech (Fagus grandifolia Ehrh.)) tended to be less present in the regeneration gaps than in the single-tree selection cutting. Considering that white pine seed predation can be critical in mixed tolerant hardwood - white pine stands, a greater rate of seeding is recommended for direct seeding.