Relationships between site index modeling of crimean juniper and habitat factors

The aim of this study is to examine the relationships between height growth and some site factors of Crimean juniper in southwestern Anatolia. The data was collected from 130 sample plots selected from 10 districts in western Anatolia. The age and height of the Crimean juniper were measured in each sample plot. Surface soil samples collected from each sample plot were analyzed for pH, organic matter, carbonate content, texture, stoniness, available water capacity, wilting point, and field capacity. All site index values were calculated at a standard age of 100 years old. Spearman and Pearson correlation analyses were used to determine the relationships between plus tree and site factors. According to Spearman's correlation analysis, the site index showed a negative relationship with limestone. According to the results of the Pearson correlation analysis, the numerical variables LATTUD, SLOPE, SURSTON, and HINDEX had a 1% relationship with the site index, and RINDEX had a 5% relationship. Once the binary relationships had been determined, the multivariate relationships were modelled using generalized additive models. The best site index model was obtained using a generalized additive model 1 (R = 0.63), including latitude, longitude, altitude, slope, and stoniness.