Access to Deep soil water - a critical tree trait for Drought stress release?

DeepDrought investigates plants' deep root water uptake in drought mitigation across various species, a critical factor as deep soil drought frequency increases with climate change. The project employs Soil Vegetation Atmosphere Transport (SVAT) models to assess deep soil water availability and forecast climate impacts using three RCPs. It introduces tree water deficit (TWD) and water use efficiency (WUE) as drought stress proxies in the SVAT model. Dendrometers measure TWD to understand short-term transpiration and root water uptake balance, while WUE, derived from stable carbon isotope ratios in leaf and tree-ring material, offers a long-term perspective. The hypothesis is that climate change will lessen winter root zone moistening and increase summer soil drought, possibly clipping off trees' access to vital deep soil water and increasing drought stress.