Development of stem taper equations for Pinus kesiya in Benguet province, Philippines

Abstract

This study was conducted to develop stem taper models for Pinus kesiya in Benguet Philippines, using four stem taper equations. Fit index (FI), root mean square error (RMSE), bias () and absolute mean difference (AMD) were used as statistical criteria to evaluate the performance of these four models. Results showed that the Kozak88 taper equation provided the best FI and RMSE with 0.98911 and 2.6391, respectively. The Kozak01 model had the best mean bias with an over prediction of 0.0050 cm while MB76 had the highest mean bias of 0.2100 cm. Kozak88 also provided the best AMD with 1.9140 cm. The overall ranking analysis showed that the Kozak88 model had the best performance and the Kozak02 model was considered as the second best model. These stem taper equations can help forest managers in predicting the diameter outside bark (DOB) and merchantable stem volumes of the standing trees of Pinus kesiya in Benguet, Philippines, which is important in growth and yield estimation.