Comparison of three stem profile equations for Quercus robur L.

SYNOPSIS Stem profile equations were developed for Quercus robur using height up to the crown base in lieu of total height. Diameter at the crown base was subtracted from each measured stem diameter so that the transformed diameter at crown base is zero which provides compatibility with stem profile equations while maintaining tree stem profile. Three different taper functions were fitted to the transformed data and compared in respect of their ability to predict upper stem diameters, volumes and heights at different points along the stem. Equations, derived from the taper functions modified for the height up to the crown base, are also given in the appendix to predict height at a specific diameter and volume between two specified heights.