COMPATIBLE STEM VOLUME AND TAPER EQUATIONS FOR FIVE MAJOR TREE SPECIES IN NORTHEAST CHINA

Compatible segmented taper and volume equations were developed for Dahurian larch, Korean spruce, Manchurian fir, planted Dahurian larch and Mongolian pine in northeast China The model form developed by Max and Burkhart (1976) was fitted to the data of 720 sample trees. The data was randomly split into two sets for each species: 80% of total data was used for model fitting, and 20% of total data was reserved for model validation. The proposed equation provided good results for the whole tree and different stem sections. Mean prediction errors for diameter and volume were less than 1.9 cm and 0.005 m(3), respectively. The recommended model provided adequate diameter and merchantable volume estimates against ten relative height classes, examined for each species. Additionally, the model's estimates were superior to the existing volume tables for these commercial species, particularly for Korean spruce, Manchurian fir, and planted Dahurian larch.