Investigation of physiological changes in the affected Quercus brantii stand by oak charcoal disease

Abstract

The purpose of this work was to monitor the effects of the environmental factors include temperature, precipitation and sun radiation on some physiological aspects of Q. brantii trees in the forest stand involved with the oak charcoal disease during a growing season. We designed a systematic random sampling and all trees were examined for disease status. Our result showed that 70.96% of the trees with different intensities are affected by the charcoal disease. Accordingly, values of predawn leaf water potential (PWP), midday leaf water potential (MWP) and chlorophyll variables showed significant difference in classes of oak charcoal disease. Linear regression analysis showed that the values of PWP, MWP and chlorophyll are changing at the high temperature. Mean of canker length are 20.5 cm and 51.7 cm in class 2 and 3 respectively and there is a great relation between PWP value and canker length (r<sup>2</sup> = 0.914). Canker length also has a linear relation with MWP values (r<sup>2</sup> = 0.627). Drought stress affected the physiological functions of oak trees and considerably reduced their defense potential against pathogen agents.