Compatible Stem Volume and Stem Diameter Equations for Brutian Pine Stands in Antalya-Gebiz Region

Abstract

Brutian pine (Pinus brutia Ten.) is one of the most important tree species ecologically and economically. Reliable and accurate growth and yield models are needed for sustainable forest management and planning of this species. One of the most important components of the growth and yield models is tree stem volume estimates. Usually, tree volume estimations are still made with single-entry volume tables in Turkey. 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 trees in Antalya-Gebiz region. For this purpose, parameter estimates were made for the stem diameter and stem volume equations that have been developed by Max and Burkhart (1976), Parresol et al. (1987), Clark et al. (1991), and Jiang et al. (2005). 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 2.8 cm and less than 0.02 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 predictions obtained from proposed models in this study were compared with the volume estimates obtained with the regional volume table, and it was seen that proposed models 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). In addition, the developed models were also compared with the results of local volume table. Tested models produced better results than the local volume table.