TAILIEUCHUNG - Báo cáo lâm nghiệp: "Using past growth to improve individual-tree diameter growth models for uneven-aged mixtures of Pinus sylvestris L. and Pinus nigra Arn. in Catalonia, north-east Spain"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí lâm nghiệp đề tài: Using past growth to improve individual-tree diameter growth models for uneven-aged mixtures of Pinus sylvestris L. and Pinus nigra Arn. in Catalonia, north-east Spain. | Ann. For. Sci. 61 2004 409-417 INRA EDP Sciences 2004 DOI forest 2004034 409 Original article Using past growth to improve individual-tree diameter growth models for uneven-aged mixtures of Pinus sylvestris L. and Pinus nigra Arn. in Catalonia north-east Spain Antoni TRASOBARESa Timo PUKKALAb a Centre Tecnològic Forestal de Catalunya Pujada del seminari s n 25280 Solsona Spain b Faculty of Forestry University of Joensuu PO Box 111 80101 Joensuu Finland Received 18 February 2003 accepted 20 August 2003 Abstract - In this study growth models of individual tree diameter for uneven-aged mixtures of P. sylvestris and P. nigra in Catalonia were developed using a past growth index as site descriptor. These models were compared to an earlier model based on the same data that did not use past growth as a predictor. The growth index was calculated as a ratio of the measured and predicted past growth of sample trees within a given stand the predictors pertaining to an average site. The models for future growth were based on 7 982 and 5 673 observations and the models for past growth on 1 997 and 1 686 observations for P. sylvestris and P. nigra respectively. Due to the applied Snowdon correction the biases for the diameter growth models were zero. The relative RMSE values were for the earlier P. sylvestris model and for the new model and for the earlier P. nigra model and for the new model. The accuracy of stand-level predictions 10-year change in basal area of living pines in the inventory plots was better for the new models Bias and RMSE than for the earlier ones Bias and RMSE . The results indicate that the new models adapt to specific stand conditions better than models that omit past growth measurements. growth index mixed models mixed stand Scots pine black pine Résumé - Utilisation de la croissance passée pour revaluation du site dans des modèles non spatialisés de croissance en diamètre pour des peuplements irréguliers

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