Modelling dominant height growth and site index curves for rebollo oak (Quercus pyrenaica Willd.)

A dominant height growth model and a site index model were developed for rebollo oak (Quercus pyienaica Willd.) in northwest Spain. Data from 147 stem analysis in 90 permanent plots, where rebollo oak was the main species, were used for modelling. The plots were selected from the National Forest Inventory at random in proportion to four biogeoclimatic stratums. Different traditional and generalized algebraic difference equations were tested. The evaluation criteria included qualitative and quantitative examinations and a testing with independent data from another region. The generalized algebraic difference equation of Cieszewski based on Bailey equation showed the best results for the four stratums. An analysis of the height growth patterns among ecological stratums was made in order to study the necessity of different site index curves. Results indicated the validity Of a common height growth model for the four stratums. In spite of the irregular height growth pattern observed in rebollo oak, probably due to past management, the model obtained allows us to classify and compare correctly rebollo oak stands growing at different sites.