Improving forest drought resilience through tree xylem eco-physiological mechanisms

Descripción del proyecto

Aumentar la resiliencia de los bosques a la sequía

El cambio climático amenaza cada vez más a los árboles, que son fundamentales para regular los ciclos del agua y el carbono de la Tierra. A medida que los veranos son cada vez más calurosos y secos, la mortalidad inducida por la sequía se convierte en una preocupación creciente en los bosques europeos y otros biomas mundiales. Debido a su tamaño y longevidad, los árboles padecen dificultades para adaptarse con suficiente rapidez al rápido ritmo del cambio climático mundial. Sin embargo, los bosques siguen siendo ecosistemas fundamentales que no podemos permitirnos perder. El proyecto RESILFOREST, financiado por el Consejo Europeo de Investigación, pretende colmar las lagunas de conocimiento sobre las respuestas de los árboles a la sequía, concretamente en lo que respecta al embolismo del xilema, la falta de carbono y los procesos de recuperación. Mediante mediciones de campo, experimentos controlados y modelización avanzada, el equipo del proyecto descubrirá los mecanismos ecofisiológicos que subyacen a la resiliencia a la sequía. La investigación ayudará a desarrollar estrategias para mejorar la gestión forestal.

Objetivo

Trees play a major role in Earths water and carbon cycles. Climate change puts trees under a growing threat of drought-induced mortality. This already happens in Europe, where summers are becoming hotter and drier, and across global forest biomes. Due to their large size and long lifespan, trees need time to adapt and migrate, time they lack under the fast rate of global change. On the other hand, foersts are amog the most important ecosystems we simply cannot afford to lose.
Loss of xylem hydraulic conductivity due to eruption of air bubbles is termed xylem embolism. Despite many years of studying tree responses to drought, it is still debated whether xylem embolism actually kills trees. Simultaneous processes like carbon starvation, leaf desiccation and heat damage make it harder to pinpoint the direct effects of drought on xylem enbolism. Further, while the extent of embolism avoidance has been characterized in many tree species, embolism tolerance has been rarely studied, and recovery processes are mostly unknown. Finally, a wide research gap exists between eco-physiological mechanisms at the tree scale and implications at the forest scale. This research proposal portrays a clear roadmap to resolving the open questions in tree hydraulic mechanisms under drought, and to integrating them at the forest scale.
Increasing drought resilience in forests through eco-physiological mechanisms requires (1) in-situ field measurements, (2) controlled experiments to decipher tree mechanisms, and (3) advanced modeling to upscale tree-level measurements into the forest scale and support future forest management.
We will combine novel techniques (custom-made micro-CT, field detection of xylem embolism and water potential, spatial mass spectrometry imaging, and more); field measurements and manipulations on mature trees; greenhouse experiments on diverse tree species; and computational modeling, to test new hypotheses aimed at increasing drought resilience of forests.