Development of compatible stem taper and volume equations for brutian pine stands in Antalya-Gebiz region

Brutian pine (Pinus brutia Ten.) is an important forest tree that has a distribution on an area of 5.8 million hectares in our country. Reliable and accurate volume estimates are needed for this species, which has a prominent place in the forest industry, in order to meet the demand in ever-changing market conditions. In our country, volume estimations are still made with single-entry volume tables. However, these local volume tables are insufficient for reliable and accurate volume estimation. It is stated that one of the most correct approaches to meet the deficiency in this subject is the use of compatible stem diameter and stem volume equations. In this study, compatible stem diameter and volume equations were developed for Brutian pine stands in Antalya-Gebiz region. For this purpose, parameter estimates were made for the stem diameter and stem volume equations that have been developed by Kozak et al. (1969), Max and Burkhart (1976), Parresol et al. (1987) and Clark et al. (1991). All developed models yielded successful results in both stem diameter and stem volume estimations. The errors in the diameter and volume estimations were found to be less than 3 cm and less than 0.01 m3, respectively. In addition, diameter and volume estimates were made at 10 distinct parts of the stem to determine the accuracy and reliability of the models developed. Additionally, the stem volume models developed in this study were compared with the volume estimates obtained with the double-entry volume table developed by Alemdağ (1962), and it was seen that all four tested volume equations gave better results than the local volume table. Among the four stem diameter and stem volume models developed, the most successful results were obtained with the model developed by Clark et al. (1991).