Development of tree volume equations for natural brutian pine (pinus brutia ten.) stands in Akhisar region

Tree volume equations are fundamental components of growth and yield models and form the indispensable basis for ecosystem-based management plans. In this study, local outside stem-bark volume equations were developed for natural red pine (Pinus brutia Ten.) stands in the Akhisar region. Measurements were taken on 263 sample trees representing the species, and 16 equations used in the literature were tested. The models were compared using the cross-validation method based on the MAE, RMSE, ME, AIC, and fit index (FI) criteria. Statistical evaluations revealed that the most suitable tree volume equation for natural red pine stands in the region was M4, followed by M13, M5, and M7. The least successful results were obtained from models M9 and M11. Consequently, it was observed that successful outside stem-bark volume estimates could be made in the relevant region using the M4 model with the variables of tree diameter at breast height and total tree height. Again, with the help of this model, it will be possible to provide more reliable tree volume information for forest management plans and carbon stock calculations to be carried out in the region.