Individual-tree growth and mortality models for Scots pine (Pinus sylvestris L.) in north-east Spain

A distance-independent diameter growth model, a static height model and mortality models for Pinus sylvestris L. in north-east Spain were developed based on 24 permanent sample plots established in 1964 by the Instituto Nacional de Investigaciones Agrarias (INIA). The model set enables the simulation of stand development on an individual tree basis. To predict mortality, two types of models were prepared - a model of the self-thinning limit and two logistic models for the probability of a tree to survive the coming 5-year-period. The plots ranged in site index from 13 to 26 m (dominant height at 100 years), and were measured an average of 5 times. The data for the diameter growth model consisted of 10 843 observations and ranged in age from 33 to 132 years. The relative bias for the diameter growth model was 1.2%. The relative biases for the height and self-thinning models were 0.10 and 0.23%, respectively. The relative RMSE values were 64.1, 8.29 and 17%, respectively, for the diameter growth, height and self-thinning models. The two tree-level survival functions used the past average growth, basal area of trees larger than the subject tree and the past 5-year growth as predictors.