EFFECT OF DEVELOPMENT STAGES ON SOIL CARBON AND NITROGEN STOCKS OF SESSILE OAK (Quercus petrea (Matt.) Liebl): A CASE STUDY OF TAŞKÖPRÜ, KASTAMONU

This study aimed to determine the effects of four different development stages of sessile oak (Quercus petrea (Matt.) Liebl) stands on soil organic carbon (SOC) and total nitrogen (TN) stocks in northwest Turkey. According to the diameter at breast height (dbh), sessile oak stands were classified into four development stages namely: a development stage (<8cm), b development stage (8 to 19.9 cm), c development stage (20 to 35.9 cm) and d development stage (36 to 51.9 cm). Soil samples were taken from three different soil depths (0-10, 10-20, and 20-30 cm). Total 72 soil samples were collected from all development stages. Forest floor litters were also sampled from each development stage. Results showed that soil organic carbon varied significantly between the four development stages (R2=0.714, p=0.000) with the highest stocks under the d development stage (55.0 Mg ha-1) and the lowest under the b development stage (10.6 Mg ha-1). Total N stock was highest under the a development stage (3.39 Mg ha-1), whereas it was lowest under the b development stage (1.18 Mg ha-1). About 71% of SOC was deposited in the upper 30 cm of the soil. The forest floor litter also varied between the four development stages with the highest values under the b development stage and the lowest under the a development stage. As a result, the results of the study indicated that sessile oaks can play a significant role in storing organic carbon and nitrogen in the soil. On the other hand, amounts of SOC and TN stocks can be significantly varied according to stand development stages.