Some physiological and biochemical changes In oak trees after fire

ABSTRACT Background: Forest fires are considered integral parts of many forest ecosystems despite being a disaster influencing the forest ecosystem dynamics significantly. A fire that occurred within the borders of Düzce-Konuralp State Forest Enterprise affected 16 ha of oak forest. The present study aimed to investigate the physiological and biochemical changes in two oak species (Quercus pubescens and Q. cerris) at post-fire period. For this purpose, seasonal shoot and leaf samples were collected from 15 trees (5 trees from high and low fire intensity and control groups) for each oak species. The samples were subjected to xylem, water potential, and stomatal conductivity analysis in the field and carbohydrate concentration and proline analyses in the laboratory. Results: It was found that leaf surface area decreased, and the root-leaf water connection was broken depending on the intensity of the fire. As the fire severity increased, water potential and stomatal conductivity of trees increased; proline and carbohydrate concentration amounts decreased. Q. pubescens had lower water potential and stomatal conductivity than Q. cerris but higher proline and carbohydrate concentration amounts. Conclusion: Q. pubescens was more resistant to drought stress during the post-fire season than Q. cerris from the aspect of physiological and biochemical characteristics.