Team : Sureau

PhD student :  ILINCA Elisabeth

Thesis supervisors :  COCHARD Hervé , William M. Hammond, Marylou Mantova

Dates : October 2023 - September 2026

Description

Global climate change is leading to more frequent and intense droughts and heat waves. In France and the United States, these events have caused forest dieback, threatening economically important species. Climate projections indicate future risks to forest growth and survival, requiring the identification of trees capable of withstanding these extreme conditions.

The physiological basis of tree resistance to drought and heat is better understood. Hydraulic failure of the sap transport system plays a crucial role. Cavitation events during droughts lead to vascular embolisms, preventing sap from rising and causing trees to die. Heat waves exacerbate this phenomenon by increasing tree transpiration. A mechanistic model called SurEau has been developed to simulate this mechanism and predict the risk of cavitation.

This thesis aims to explore the variability of key physiological traits among different forest species and provenances. The “interspecific” aspect will be integrated into the ISite Cap2025 project, which aims to characterise the physiological traits of species planted in the Charvols Arboretum and validate the predictions of the SurEau model. The “intraspecific” aspect will be conducted in collaboration with the University of Florida (Fulbright fellowship from October 2024 to June 2025 in William M. Hammond's laboratory: https://www.ecophyslab.com), studying provenances of Loblolly Pine planted in Florida.

This thesis work will provide original data on the drought response of various species. The data on Loblolly Pine will reveal the variability of drought resistance within this species. The knowledge gained could help to better understand the threats of climate change to forests in general and to recommend species or provenances adapted to the future climate.