Differences in stem taper of black alder (Alnus glutinosa subsp. barbata) by origin

Abstract

Black alder (Alnus glutinosa subsp. barbata (C.A. Mey.) Yalt.) is an important tree species in Turkey both economically and ecologically. Accurate taper and volume equations are required by most inventory systems to estimate upper stem diameter, form, and tree volume. Stem analysis data were used to examine the differences in taper and volume of black alder trees grown in naturally regenerated, plantation, and coppice stands. Statistically significant differences were observed in taper and volume of black alder trees grown in stands from these three origins. Error in total stem volume inside bark was the greatest when the taper model was fitted to plantation data and applied to seed data compared with the model fitted to coppice data and applied to seed data. Therefore, to accurately predict upper stem diameter and total or merchantable stem volume, in addition to selecting species-specific taper models, forest managers should consider the origin of the model-fitting data when choosing an appropriate taper model for their stands.