Stem Taper Equations for Six Major Tree Species in Korea 

Yeong Mo Son, Kyeong Hak Lee, Woo Kyun Lee and Soon Duk Kwon

 

ABSTRACT : Data were collected to develop equations for predicting stem taper for six major species in Korea.
These species are Pinus densijlora, Pinus koraiensis, Pinus rigida, Larix kaempferi, Quercus acutissima, and Quercus mongolica. The models tested for choosing the best-fit equations were Max & Burkhart's model, Kozak's model, and Lee's model. Performance of the equations in predicting stem diameter at a specific point along a stem was evaluated with fit and validation statistics and distribution of residuals on predicted values. In result, all three models behaved similarly and estimated diameter well at all points along the stem, although Kozak's model gave slightly better values of fit statistics. In plotting residuals against predicted diameter, Max & Burkhart's model showed underestimation in predicting small diameter and Lee's model did the same in predicting large diameter. On the other hand, Kozak's model was quite evenly distributed over the whole range of diameter. Based on the above analysis of three models in predicting stem taper, Kozak's model was chosen for the best-fit stem taper equations, and its parameter estimates were given for six species.

 

Key words : Stem, Taper equation, Kozak model, Pinus densiflora, Pinus koraiensis, Pinus rigida, Larix kaempferi, Quercus acutissima, Quercus mogolica.