Resumen de Stand-level yield model for Scots pine (Pinus sylvestris L.) in north-east Spain
J. Miina, Gregorio Montero González, Mario Tomé, Marc Palahí Lozano
Simultaneus stand-level growth and yield models for Pinus sylvestris in north-east Spain were developed based os 21 permanent sample plots established in 1964 by the Instituto Nacional de Investigaciones Agrarios (INIA). The plats ranged in site index from 13 to 26 m (dominant height at 100 years), and were measured as average of 5 times. The estimation date consisted of 79 growth periods of stands ranging in age from 36 lo 132 years. Non-linear three-stage teast squares method was used to simultaneously fit prediction and projection equations for stand basal area, volume and stand density. An existing model for dominant height growth fitted with the same estimation dote was used to project dominant height. The models were evaluated both quantitatively and qualitatively. Correlation among error components of the prediction equations for basal area and volume as well as the projection equations for number of trees per hectare and volume were strong and significant. The mean biases for basal area, volume and number of trees per hectare predictions were positive. The presented system of models can serve for forest-level management planning as a simple yield prediction system that requires only stand level input data
