Site quality equations for Pinus sylvestris L. plantations in Galicia (northwestern Spain)

摘要

Difference equations deiived on the basis of the Sloboda and McDill-Amateis differential functions, and from the integral form of the Bertalanffy-Richards, Korf and Hossfeld growth functions were used to model the dominant height growth of Scots pine(Pinus sylvestris L.) in Galicia (north-western Spain), Data from stem analysis and permanent sample plots were combined and used for fitting. Both numerical and graphical analyses were used to compare alternative models. The cross-validation approach was used to analyse the predictive ability of the models. The algebraic difference form of the differential function proposed by McDill and Amateis resulted in the best compromise between biological and statistical aspects, producing the most adequate sitecurves. It is therefore recommended for height growth prediction and site classification of Scots pine plantations in Galicia This equation is base-age invariant, so any number of points (A_1, H_1) on a specific site curve can be used to make predictions for a given age A2 and the predicted height H_2 will always be the same.