Forest vulnerability and tree mortality in the Mediterranean: Impacts and Opportunities

The Mediterranean basin is a mosaic of human and natural landscapes, many of which are important forests and woodlands. Among global biomes, it has been under the longest anthropogenic stress, and today, in addition to the ongoing warming, it experiences drying. In my talk I will give examples from new research on the impacts of these processes on Mediterranean forests, as well as opportunities for increasing their sustainability under intensifying change.

Aleppo pine is perhaps the single most important forest tree species for the region, and has been grown for decades in common garden plots of provenances from around the region. Forest scientists from Spain, Italy, Greece and Israel, teamed up to synthesize the results of these provenance trials. Together, we produced the temperature and precipitation growth sensitivity profiles for Aleppo pine. Next, these profiles were applied on future climate maps, to show the potential expansion of this key species northward, as well as its extinction in many southern locations. In a seven decades-long tree mortality study across Israel, this mortality pattern is already occurring, driven by hotter and longer drought periods.

My current research is focused on finding new avenues to ensure the long-term existence of forests and trees in the Mediterranean. Examples include: (1) Mixed forests, with native broadleaf and conifer species coexisting, have high resilience, thanks to interspecific niche partitioning; (2) Native fruit trees have higher drought resistance than their cultivated relatives, and should be protected and integrated into local agriculture; (3) Native savannah trees from the southern fringes of the region are becoming more important, and offer new resilience strategies; and (4) Variations among Aleppo pine ecotypes give hope for the future suitability of this species across the Mediterranean.