RESPONSE OF 7 HARDWOOD TREE SPECIES TO HERBICIDE, ROTOTILLING, AND LEGUME COVER AT 2 SOUTHERN QUEBEC PLANTATION SITES

Treatments of herbicide, rototilling, and sowing of a legume cover (Lotus corniculatus and Trifolium repens) were applied to Fraxinus americana, Juglans nigra, Prunus serotina, Quercus alba, Q. macrocarpa, Q. rubra and Tilia americana. A control treatment, retaining existing herbaceous vegetation, was also included. After 3 growing seasons tree growth was highest in the herbicide and rototilling treatments. Improved growth was associated with high foliar N, and sometimes P content. The growth gains provided by weed control were reduced on the site with the poorest soil drainage. Despite the introduction of herbaceous legumes, the weed biomass increased during the first 2 yr, and tree growth in this treatment was rarely superior to the control. -from Authors