tailieunhanh - Báo cáo lâm nghiệp: "Evaluation of competition and light estimation indices for predicting diameter growth in mature boreal mixed forests"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Evaluation of competition and light estimation indices for predicting diameter growth in mature boreal mixed forests. | Ann. For. Sci. 64 2007 477-490 INRA EDP Sciences 2007 DOI forest 2007025 Available online at Original article Evaluation of competition and light estimation indices for predicting diameter growth in mature boreal mixed forests Kenneth J. Stadt Carolyn HUSTON K. David Coates Zhili Feng Mark . Dale Victor J. LlEFFERS Department of Renewable Resources General Services Building 751 University of Alberta Edmonton Alberta T6G 2H1 Canada Received 23 March 2006 accepted 15 February 2007 Abstract - A series of conventional distance-independent and distance-dependent competition indices a highly flexible distance-dependent crowding index and two light resource estimation indices were compared to predict individual tree diameter growth of five species of mature trees from natural-origin boreal mixed forests. The crowding index was the superior index for most species and ecosites. However distance-independent indices such as basal area of competing trees were also effective. Distance-dependent light estimation indices which estimate the fraction of seasonal photosynthetically-active radiation available to each tree ranked intermediate to low. Determining separate competition indices for each competitor species accounted for more variation than ignoring species or classifying by ecological groups. Species competitive ability ranked most competitive to least paper birch a white spruce a trembling aspen lodgepole pine balsam poplar. Stratification by ecosite further improved model performance. However the overall impact of competition on mature trees in these forests appears to be small. competition index photosynthetically active radiation distance dependence growth model boreal mixed forest Résumé - Evaluation de la competition et indices d eclairement pour la prediction de la croissance radiale dans des forêts boréales mixtes adultes. Ce travail a évalué la capacité d indices de compétition à prédire la croissance radiale individuelle d arbres .