PREDICTING TREE CROWN RATIO FOR UNTHINNED AND THINNED SCOTS PINE STANDS

A nonlinear model that yields logical predictions for tree crown ratio is presented. The model is based on data from permanent experimental plots located in even-aged Scots pine (Pinus sylvestris L.) stands in southern and central Finland. Regressor variables in the model are stand dominant height, stand basal area, tree diameter, and tree height. The effect of thinning on tree crown ratio is modelled by incorporating a thinning response variable into the model. Thinning effect is dependent on thinning intensity and time elapsed from thinning, the latter of which is represented by the difference between current stand dominant height and dominant height at the time of thinning.