Tree water transport dynamics in a changing climate

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. 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. Development of such novel technology shows great potential for irrigation scheduling in horticulture. Thresholds that define the transition from a healthy to an unhealthy tree status might be affected by CO₂. Not only the potential of elevated atmospheric CO₂ concentration in mitigating adverse effects of drought on leaf and whole-tree functioning is important to consider. Also tree internal, locally respired CO₂ might play a crucial role in tree survival under climate-change-driven drought, especially when it is refixed by woody tissue photosynthesis. Such studies help us to revisit predictions of tree water transport dynamics and tree water management under climate change scenarios.