Tham khảo luận văn - đề án 'báo cáo lâm nghiệp: " stand growth model using volume increment/basal area ratios"', luận văn - báo cáo phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | JOURNAL OF FOREST SCIENCE 54 2008 3 102-108 Stand growth model using volume increment basal area ratios G. J. Martinez Pastur1 J. M. Cellini2 M. V. Lencinas1 p. L. Peri3 1Centro Austral de Investigaciones Cientificas - Consejo Nacional de Investigaciones Cientificas y Técnicas Tierra del Fuego Argentina Facultad de Cs. Agrs. y Ftales. Universidad Nacional de La Plata Buenos Aires Argentina 3Instituto Nacional de Tecnología Agropecuaria Universidad Nacional de la Patagonia Austral - Consejo Nacional de Investigaciones Cientificas y Técnicas Santa Cruz Argentina ABSTRACT Estimation of stand growth is crucial for forest planning. Estimations were usually done using fixed values and recently growth equations have been used. An alternative is through stand growth models. The objective was to develop a simple model for Nothofaguspumilio stands with full density along site quality and age gradients. The sample was obtained from 125 stands. Data on forest structure and samples for tree-ring measurement were taken in all trees to estimate growths using biometric models previously developed. The growth values of each plot during the last twenty years were calculated to fit the model using the ratio of total volume increment basal area as an independent variable. The developed model gives a ratio between stand volume increment and basal area m year in relation to the site quality and stand age. The statistics r2 mean error absolute mean error residual analysis and biological performance were satisfactory. The obtained stand growths varied between 1 and 20 m3 ha year. This simple model allowed to estimate growth values at a stand level from easy field measurements from forest inventories. Keywords biometrics forest planning forest growth stand models Nothofagus pumilio Tree growth volume is one of the main variables within the forest landscape planning Vanclay 1994 . In the past estimations were done using fixed values Piterbarg 1965 and recently individual .
