REHABILITATION TRIALS IN A BOG PEATLAND IN QUEBEC

Two rehabilitation experiments were performed following peat extraction on a bog peatland in Saint-Bonaventure, Quebec, Canada. In 2000, first experiment was started in order to determine the optimal rate of fertilization for small fruits and forest trees at planting period. The treatments consisted of a short-rotation intensive culture of willows (Salix vinimalis L.), two cultures of small fruits; black chokeberry (Aronia melanocarpa (Michx.) Ell.) and northern highbush blueberry (Vaccinium corymbosum L.), as well as tree plantations of red maple (Acer rubrum L.), tamarack (Larix laricina (Du Roi) Koch.), black spruce (Picea mariana (Mill.) B.S.P.), jack pine (Pinus banksiana Lamb.) and hybrid poplar (Populus spp.). Plant performance was assessed after 1 year (willows) or 9 years by measuring survival, total height, annual growth, leaf nutrient concentration and when applicable, biomass or fruit yield. In almost all trials, adding nutrients at establishment increased plant survival and growth. Only the blueberry showed better survival without fertilizer whereas the hybrid poplar trial failed completely. After 9 years, tamarack and black chokeberry showed the best plant survival and growth compared to the conventional plantations. Otherwise, fruit yields were very low. In 2009, willows (at 15,000 per hectare) and Switchgrass were planted. The treatments consisted of two residual peat depths (30 and 60 cm) in which two levels of fertilizer were tested (control and 100 kg ha^-1 of N (12.8-2.7-10.2)). The willows establishment was comparable to the other intensive cultures, when the peat depth was over 30 cm and nutrients were added at establishment. Switchgrass did not survive over the winter. Further experiments are planned to assess the success of short-rotation intensive culture of willows on cut-over peatland.