Artificial Regeneration of Hardwoods in Early Successional Shrub Communities Using Two Clearing Intensities and Herbicide Application

Abstract

Abstract In southern Quebec, returning abandoned farmland to forest production presents a management opportunity. The shrub communities, which naturally colonize abandoned agricultural land, could be enriched by planting hardwood species that occurred in the precolonial forests. This study examines the growth of four hardwood species (Acer saccharum, Fraxinus americana, Prunus serotina, and Juglans nigra) planted on former pastures now covered by shrubby vegetation. Retaining part of this shrubby vegetation may produce improved growth in the planted trees. The experimental plantations were established in 1998 in two sites with different soil conditions and consisted of various treatments to control competition. Analyses seek to determine the effect of these treatments on (i) the light conditions, (ii) the cover of competing vegetation, and (iii) the growth and vigor of planted trees. Results show that increasing shrub clearing intensity has reduced the cover of tall competing vegetation after 5 years. However, light conditions and the cover of low competing vegetation around planted trees no longer vary significantly among treatments after 5 years. Strip clearing (SC) improved the growth of white ash and total clearing improved the growth of black walnut, with respect to site considered. Herbicide use was beneficial for the majority of species. SC presents a useful alternative for hardwood plantations. However, low competing vegetation control remains an important factor for increasing planted tree productivity in these managed shrub communities.