Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Growth, allocation and leaf gas exchanges of hybrid poplar plants in their establishment phase on previously forested sites: effect of different vegetation . | Ann. For. Sci. 64 2007 275-285 INRA EDP Sciences 2007 DOI forest 2007005 275 Original article Growth allocation and leaf gas exchanges of hybrid poplar plants in their establishment phase on previously forested sites effect of different vegetation management techniques Lluis COLLa b Christian MESSIERa Sylvain DELAGRANGEa c Frank BERNINGERa a Centre d Étude de la Forêt CEF Université du Québec à Montréal . 8888 Montréal Qc H3C 3P8 Canada b Present address Centre Tecnològic Forestal de Catalunya CTFC Pujada del seminari s n 25280 Solsona Spain c Present address Institut Québécois d Aménagement de la Forêt Feuillue IQAFF 58 rue Principale Ripon Qc J0V 1V0 Canada Received 3 July 2006 accepted 13 October 2006 Abstract - The effect of different vegetation control methods mowing and cultivation between plantation rows herbicide application and cover plant sowing on hybrid poplar P. maximowiczii X balsamifera growth biomass allocation and leaf carbon assimilation was investigated in two plantations 1- and 2-year-old established in previously forested sites of south-eastern Québec. Any vegetation control treatment applied the same year in which the plantation was established did not have an effect on hybrid poplar aboveground growth. However significant differences among treatments were observed belowground where the removal of the competing vegetation at the tree base increased the fine root leaf biomass ratio of plants thus probably facilitating their establishment. In contrast 2-year-old plants grew better when treated with herbicides but no positive effect of the mechanical treatments was detected. In both sites trees growing on herbicide-treated plots showed considerably higher leaf carbon assimilation and leaf N concentration which were both strongly correlated. We conclude that a strong vegetation competition for nutrients takes effect on hybrid poplar plantations on previously forested sites since there was no water shortage for any treatment during the .
