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.

This study investigates the larvicidal activities of plant extracts and tannins against wood-damaging insects. Scots pine (Pinus sylvestris), beech (Fagus orientalis), and poplar wood (Populus tremula) were subjected to larvae of Spondylis buprestoides (Coleoptera: Cerambycidae) by impregnating them with mimosa (Acacia mollissima), quebracho (Schinopsis lorentzii) and redpine bark (Pinus brutia) extracts. At the end of the 6-month experiment, the numbers of dead and live larvae as well as the mean mass losses of woods were determined. In terms of wood species, the lowest larva resistance was observed in Scots pine wood, while the highest larva resistance was achieved by beech wood. The lowest mass losses and the highest dead termite rates in all tree species were observed when the concentration of mimosa and quebracho extracts was 12%. On the other hand, the pine bark extract showed a lower larvicide effect than the other two extracts.