Abstract

New models for tree height stem volume and taper (stem profile) were developed using a q-exponential function in the symbolic computational language MAPLE. Three previously constructed models and a new q-exponential model for height stem volume and taper wereemployed to compare predicted values with empirical values of height, stem volume and diameter outside bark. Performance statistics for the height stem volume and taper equations included four statistical indices: mean bias, mean absolute bias, mean percentage of absolute bias, and a coefficient of determination. A stem analysis of 1925 Scots pine (Pinus sylvestris) trees provided the data for this study. The new q-exponential models were superior to the previously constructed models in predicting height, stem volume and taper.

Key words: Stem taper model, q-exponential function, tree allometry, Scots pine.