RELATIONSHIPS BETWEEN BARK THICKNESS, TREE AGE AND TREE DIAMETER IN PINUS BRUTIA TEN. PLANTATIONS

The main purpose of the present study is to investigate relationships between bark thickness at breast height (BTbh) and tree age, BTbh and tree diameter, and tree diameter and tree age in Pinus brutia Ten. plantations. Seven Pinus brutia plantation sites at different age groups (ages 10, 15, 18, 20, 25, 30, 35 years) were chosen at Duzlercami Forest District, about 20 km north of Antalya city, Turkey. We sampled 50 trees at each of these even-aged test sites and measured stem diameters at breast height (dbh) (with and without bark) and diameter at ground level (with bark). We used bark thickness (BTbh) on one side of the stem and performed regression and correlation analyses. The results showed that BTbh in P. brutia increased as the tree age increased up to age 30 years, after which it smoothly flattened. The relationships between BTbh (y) and tree age (x) was curvilinear (quadratic) with R-2 > 93%. Tree diameter (at dbh, with bark) as a function of tree age exhibited similar -yet stronger- trends (R-2 > 95%). BTbh and tree diameter also showed a significant linear relationship. Ground level diameter (with bark) and diameter at dbh (with bark) showed very high correlations (R-2 > 99%). Based on data obtained from trees younger than age 36, BTbh in even-aged P. brutia plantations can be predicted with very high confidence by using tree age and/or dbh. Likewise, dbh (with or without bark) can also be estimated by using tree age.