Variation of some nutritional elements content in beech-chestnut mixed forests' trees according to diameter at breast height in western Black Sea Region of Turkey

The aim of this study is to represent the climatic conditions of the Western Black Sea coastal region of Düzce-Akçakoca beech (Fagus orientalis Lipsky) and chestnut (Casta-nea sativa Mill.) Mixed trees in different diameters and heights of subsoil (root) and above ground (trunk, branch, bark) Determination of nitrogen (N), phosphorus (P), po-tassium (K) and sulfur (S) contents of the leaf parts. The research sites are located in the Öksin (Euxin) part of the Euro-Siberian (Euro-Siberian) flora region and as representing the coastal part of the Western Black Sea climatic type with the distribution of eastern beech and Anatolian chestnut it was selected from the Kaplandede mountain section of Deredibi Chiefship of Akçakoca Forestry Management Directorate of Bolu Regional Forestry Directorate. N, P, K and S contents of 24 beech trees and 24 chestnut trees were calculated. The highest ratios of N, P, K and S were found in leaves of beech and were estimated 2.18%, 0.14%, 0.68% and 0.003%, respectively. The highest ratios were also found in leaves of chestnut and estimated 2,09%, 0,14%, 0,07% and 0,003%, re-spectively. The lowest ratios in beech tree were estimated 0.09% in stem wood for N and P, 0.10% in branch wood for K ve and 0.002% in root-stem-branch-bark for S. The lowest estimated ratios were similar in chestnut tree and were 0.08% in stem wood for N and P, 0.001% in branch wood for K and 0.002% in root-stem-branch-bark for S. The amount of measured elements were estimated by multiplying percentage ratio of them with biomass amounts. According to this the highest amounts of N, P and S were found in root and while they were estimated 1.7kg, 1.1kg and 21.5g for beech, 1.2kg, 0.8kg and 13.3g were estimated for chestnut, respectively. While the estimated highest amount of K for beech was 2.3kg in stem wood, it was 507g in root for chestnut. The lowest amounts estimated for beech were 0.01kg N in bark, 0.9kg P in leaves, 6.5g K in branch and 0.08g S in bark. It was estimated 0.03kg N in bark, 2.7g, 0.3g and 2.7g P, K and S in leaves, respectively. After all these estimations for being able to estimate total and all tree components amounts of N, P, K and S (branch, leaves, stem and root) re-gression equations were created. These values can be used in field efficiency related to sustainable climate management nutrient calculations. Practitioners and researchers who know only the diameter of the tree will be able to easily calculate N, P, K, S and Na values over a wide area. In addition, this data can be stored as long-term information for the region.