S12 - Session O1 - Keynote: Tree water transport dynamics in a changing climate

Authors: Kathy Steppe *

Worldwide, trees in forests and orchards are threatened by climate change. They must cope with a multitude of stressors, including atmospheric and soil drought. One of the critical global challenges of our current generation is taking action to improve water use in horticulture for which we need an advanced understanding of how trees respond to climate change. In this keynote presentation, we will demonstrate how a combination of plant sensors and mechanistic plant modelling can be used to assess tree water status and automatically distinguish between atmospheric and soil drought stress (Van de Put and Steppe 2022). Development of such novel technology shows great potential for irrigation scheduling in horticulture. Furthermore, we will elaborate on the mitigating effects of CO2. Not only the potential of elevated atmospheric CO2 concentration in mitigating adverse effects of drought on leaf and whole-tree functioning will be discussed (Lauriks et al. 2022a,b). We will also focus on the impact of tree internal, locally respired CO2 concentration, which upon refixation by woody tissue photosynthesis, can be a significant carbon source and might play a crucial role in tree survival under climate-change-driven drought (De Roo et al. 2020). Such studies help us to revisit predictions of tree water transport dynamics and tree water management under climate change scenarios.