Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài:"A stochastic height-diameter model for maritime pine ecoregions in Galicia (northwestern Spain)" | Ann. For. Sci. 62 2005 455-465 INRA EDP Sciences 2005 DOI forest 2005042 455 Original article A stochastic height-diameter model for maritime pine ecoregions in Galicia northwestern Spain Fernando Castedo DoRADOa Marcos Barrio ANTAb Bernard R. PARRESOLc Juan Gabriel Álvarez GoNZÁLEZb a Departamento de Ingeniería Agraria Universidad de León Escuela Superior y Técnica de Ingeniería Agraria Campus de Ponferrada 24400 Ponferrada León Spain b Departamento de Ingeniería Agroforestal Universidad de Santiago de Compostela Escuela Politécnica Superior Campus universitario 27002 Lugo Spain c USDA Forest Service Southern Research Station PO Box 2680 Asheville North Carolina 28802 USA Received 15 November 2004 accepted 25 March 2005 Abstract - A stochastic height-diameter model was developed for maritime pine Pinus pinaster Ait. in Galicia northwestern Spain . Four well-known growth functions were initially considered in this work however only Schnute s function performed adequately. A set of 20 695 pairs of height-diameter measures collected in thinned and unthinned pure and even-aged stands were used to fit the model. These stands were located throughout Galicia Autonomous Region covering a wide range of forest stands and site conditions. Since unequal error variance occurs the generalized non-linear least squares method was used to take into account the error structure. Different weighting factors were employed to remove the heterogeneous variance of the errors. Because the local model including only tree dimensions as explanatory variables did not provide adequate results stand variables were tested and incorporated into the height-diameter model. Ecoregion differences in the heightdiameter relationship were analysed using the non-linear extra sum of squares method and the Lakkis-Jones test. Both tests showed that model parameters were significantly different between the two ecoregions normally defined for this species coast and interior. The effect of thinning was
