Distinctive aspects of carbon, water and energy partitioning in a semi-arid forest

Arid and semi-arid regions belong to the most vulnerable climate change “hot spots” while also contributing to global scale variations in the carbon and water cycles. In particular, this is because of their high sensitivity to changes in precipitation and surface energy budgets and to the large changes in land-use taking place in these regions. This requires improving the representation of these ecosystems in land surface and ecosystem models. Improving observational approaches is also required to assess variations in their water carbon and energy exchange and to identify underlying processes. The more exotic observational sites, such as those at the semi-arid ‘timber-line’, do not always fit the large-scale patterns, but provide important test beds for predicted changes in ecosystem functioning. I will review a few of examples from the Yatir site operating at the edge of the Negev desert in Israel for past 19 years, to demonstrate distinctive ecosystem response to environmental conditions, such as response to extreme events, changes in phenology, energy flux partitioning, carbon sequestration, and remote sensing signals.