Productivity modeling of Anatolian black pine forests in Akdağ district (Simav)

This study was carried out to determine the relationships between the site index of Anatolian Black Pine and environmental factors in Akdağ district of Simav, Kütahya. For this purpose, 75 sampling plots were taken by considering the variations of slope, aspect, elevation, slope location and site class above 20 years of age. Soil samples were taken from 0-10, 10-30, 30-60 and 60-100 cm depth levels at each sampling plot. Some physical and chemical properties of soil samples were determined by the laboratories of Research Institute for Forest Soil and Ecology in Eskişehir. Using physiographic factors, climatic characteristics, and soil properties, site index of Anatolian Black Pine were modelled using stepwise regression analysis and regression tree tecnique. Two models were obtained from stepwise regression analysis. The first model included the amount of clay at 10-30 cm depth with an explanation ratio of 13.1% while the second model was built by the amount of clay at 10-30 cm and total lime with an explanation ratio of 21.7%. Using regression tree tecnique, two site index model were also provided. The explained variations of the models were 29.19% and 16.39%, respectively. The first tree model was built by the amount of organic matter in the 0-10 cm depth and the fine soil amount in the 10-30 cm depth. The second model was only built by the amount of clay.