The land biosphere influences the Earth climate through complex interactions and ultimately through its effect on atmospheric CO2 concentrations and on the surface energy balance. In this context, little information is available on forests in dry environments and our extensive study in semi-arid forests in Israel is therefore unique; its significance goes beyond the local scale owing to the persistent predictions of warming and drying for large proportions of the global land area. Recently, it was demonstrated that the survival and high productivity of forests under dry conditions is associated with the development of a distinctive ‘convector effect’ that results in massive fluxes of sensible heat from the surface to the atmosphere, significantly affecting both the forest microclimate, and the local environment and atmospheric dynamics. Combined with other ecophysiological adjustments, the semi-arid forest ecosystem has the potential not only to survive under predicted climate change, but also to alter local and, potentially, regional climates. The objective of this project is to quantify both the processes underlying the distinctive forest functioning in the dry environment, and the impact it has on the local environment and climate. This will be achieved by transforming previous results from the canopy scale to a range of scales starting at the leaf and reaching up to the entire planetary boundary layer scale (from the bottom 20 m up to 10 km of the surface-atmosphere interface). This will be based on the integration of unique platforms and locations of the Weizmann team in Israel, with the expertise and technological capabilities of the KIT team for atmospheric boundary layer dynamics, controlled environmental research facility, and modeling. The significance of this project is to provide quantitative information on the potential of afforestation in currently little explored but vast semi-arid regions (~18% of the land surface), on forest functioning and carbon sequestration if warming and drying trends continue, and on the effects of changes in local circulation, moisture, and surface temperatures on the regional climate. This will provide new means for management and policy development associated with adaptation and mitigation in dry environments under present-day and future conditions.
Rotenberg, E. and Yakir, D. Contribution of semi-arid forests to the climate system. Science 327(5964), 451-454. 2010.
Rotenberg, E. and Yakir, D. Distinct patterns of changes in surface energy budget associated with forestation in the semiarid region. Global Change Biology 17(4), 1536-1548. 1-4-2011.
Eder, F., De Roo, F., Rotenberg, E., Yakir, D., Schmid, H. P., and Mauder, M. Secondary circulations at a solitary forest surrounded by semi-arid shrubland and its impact on eddy-covariance measurements. Agricultural and Forest Meteorology 211-212, 115-127. 2015.