Oak Decline and Mortality in the Golan Heights

Idan Kopler and Oded Bar-Shalom

Published May 2019 in International Oaks No. 30: 161–168

Abstract

Forest tree decline has been reported worldwide and in Israel, and is related to regional and global climate change. In Israel, oak (Quercus spp.) decline has been documented in the Jerusalem Mts. in Galilee and in the Carmel.
Our research goal is to characterize the health status of oak populations in the Golan Heights under regional stress factors. This was achieved using three plots through stand structure survey and monitoring the water regime of oaks in various stages of decline. In total, 962 oaks were sampled to examine rates of decline during 2016-2017. Negligible measures of decline and a lack of tree mortality were observed in the northern Golan. Total canopy loss of almost 20% and high measures of Quercus ithaburensis (Tabor oak) mortality were recorded in the central and southern Golan populations. Midday stem water potential values were significantly lower in symptomatic trees, though only in the Q. ithaburensis woodlands. At the plot scale, the lack of a significant difference in the mean stem water potential between healthy and symptomatic trees indicates a large hydraulic plasticity.

Keywords

stem water potential, Quercus calliprinos, Quercus coccifera subsp. calliprinos, Quercus ithaburensis, Quercus boissieri, Quercus infectoria subsp. veneris

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