Mortality versus survival in drought‐affected Aleppo pine forest depends on the extent of rock cover and soil stoniness

Drought-related tree mortality had become a widespread phenomenon in forests around the globe. Recent drought years led to 5-10% mortality in the semi-arid pine forest of Yatir (Israel). The distribution of dead trees was, however, highly heterogeneous with parts of the forest showing >80% dead trees (D plots) and others with mostly live trees (L plots). At the tree level, visible stress was associated with low predawn leaf water potential at the dry season (-2.8 MPa, vs. -2.3 MPa in non-stressed trees), shorter needles (5.5 vs. 7.7 mm) and lower chlorophyll content (0.6 vs. 1 mg g-1 dw). Trends in tree ring widths reflected differences in stress intensity (30% narrower rings in stressed compared with unstressed trees), which could be identified 15-20 years prior to mortality. At the plot scale, no differences in topography, soil type, tree age, or stand density could explain the mortality difference between the D and L plots. It could only be explained by the higher surface rock cov...