Development of height-diameter models for oak species in Bilecik region

In this study, height-diameter models were developed for the natural and mixed oak stands of the Bilecik Region. For this purpose, diameter and height measurements were made on 2339 trees in 70 sample areas. The data were divided randomly into two groups. One of the groups was used to develop a model and the other group was used to test the models developed. For the natural mixed oak stands, firstly, some well-known and commonly used diameter-height models were tested to determine the most suitable base diameter-height model and the Gompertz model was found as the most suitable diameter-height model. In the second stage, some generalized diameter-length models were tested for same dataset. In the third stage, a generalized diameter-height model for the region was developed by testing the most successful simple height-diameter model and some stand parameters (number of trees per hectare, stand mean diameter, dominant diameter, and dominant height). In the last stage, the height-diameter model was developed using the mixed effect modeling approach. The developed model was calibrated using a different number of sample trees in each sample plot. As a result of the study, it was concluded that the developed model can be used for reliable height estimations in natural and mixed oak stands in the Bilecik region.