Đang chuẩn bị liên kết để tải về tài liệu:
Báo cáo lâm nghiệp: "A two-step mortality model for even-aged stands of Pinus radiata D. Don in Galicia (Northwestern Spain)"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí lâm nghiệp đề tài: A two-step mortality model for even-aged stands of Pinus radiata D. Don in Galicia (Northwestern Spain). | Ann. For. Sci. 61 2004 439-448 INRA EDP Sciences 2004 DOI 10.1051 forest 2004037 439 Original article A two-step mortality model for even-aged stands of Pinus radiata D. Don in Galicia Northwestern Spain Juan Gabriel Álvarez GoNZÁLEZa Fernando Castedo DoRADOb Ana Daría Ruiz GoNZÁLEZa Carlos Antonio LÓPEZ SÁNCHEZa Klaus VON Gadowc a Departamento de Ingeniería Agroforestal Escuela Politécnica Superior de Lugo Universidad de Santiago de Compostela Campus Universitario s n 27002 Lugo Spain b Departamento de Ingeniería Agraria Escuela Superior y Técnica de Ingeniería Agraria Universidad de León Avda. de Astorga s n 24400 Ponferrrada Spain c Institut fur Waldinventur und Waldwachstum Georg-August-Universitat Gottingen Busgenweg 5 37077 Gottingen Germany Received 7 July 2003 accepted 2 September 2003 Abstract - A two-step mortality model for even-aged Pinus radiata stands in Galicia Northwestern Spain is presented. The model was developed using data from two inventories of a trial network involving l30 permanent plots. The model consists of two complementary equations. The first equation is a logistic function predicting the probability of complete survival depending on stems per hectare age and relative spacing index. The second equation estimates the reduction in the number of stems that is observed in a stand where natural mortality occurs. Fourteen equations were fitted utilising the plots where trees died over the time period analyzed. Estimates from this second model are then reduced using three different stem number projection methods a stochastic approach a deterministic rule-based method and another deterministic approach that compares the probability of mortality using a threshold value. The values and signs of the parameters in both equations are consistent with existing experience about natural mortality of Pinus radiata in the region of Galicia. logistic regression Pinus radiata even-aged forest mortality Résumé - Modèle de mortalité en deux étapes pour des .