DECLINE OF FOREST ECOSYSTEM THROUGH CLIMATE CHANGE: DIEBACK IN PERSIAN OAK (QUERCUS BRANTII LINDL.)

Abstract

Climate change could alter forest disturbances, such as insect outbreaks, invasive species, wildfires, storms, and disease. In the present study, the influence of climate change on the structure and decline of Persian oak in the Zagros forest stands is scrutinized. A regular random sampling with fixed sample plots through two sampling periods was applied in 1998 and 2018. Further, the precipitation, temperature, frost, and relative humidity climatic elements pattern was studied from 1988 to 2018. The cross-sectional of standard-form oak was decreased from 19.2, 23.3, and 24 m3.ha in the first sampling stage to 12.3, 16.8, 17.8 m3.ha in the second sampling in Vizhenan, Chelleh, Ghalajeh, respectively. Levene’s test for equality of variances and mean comparison findings via an independent t-test showed a significant difference between the compared groups in 1998 and 2018. The Mann-Kendall analysis results of climatic elements showed that the precipitation, frost, and relative humidity decreased, and the temperature increased during the study period. Noticeable stability was perceived in the studied indices in the first decade and partially in the second decade, but there were many fluctuations in the third decade. According to the findings, it can be assumed that climate change and the occurrence of severe drought stresses cause oak trees to suffer from physiological vulnerability.