Exploring the effect of seedling’s drought vulnerability on treeline dynamics under climatic change using quantitative wood anatomy

Global warming has modified the distribution of some forests growing at their altitudinal limit (treelines): some have been advancing (leading to loss of alpine biodiversity and changes in surface reflectance of mountain and polar areas), others remained stable leaving a lag between the position of uppermost tree stands and the treeline isotherm (TI, common seasonal mean temperature indicative for potential treeline position).

Despite these striking worldwide patterns, there is a lack of systematic observation to understand the drivers of differential treeline response to global warming. The extent of the treeline lag behind warming may be associated with seedlings survival.

However, as temperature is considered the main factor responsible for treeline, the role of seedling drought sensitivity as driver of differential treeline response to global warming is poorly understood.

Certain xylem anatomical traits (XA) such as conduits wall thickness-area ratio, conduits area and layers, pits, and parenchyma area may confer drought adaptations, ultimately affecting survival and growth under increasing warming conditions. The proposed research will help understand the drivers of differential treeline response to global warming.

I will analyse the effect of XA on the distance of the uppermost tree stands to TI in representative European treeline tree species. We will determine the treelines lag across several regions. I will quantify XA and their plasticity, and correlate them with treeline position.

My contribution to achieve the project objectives relies on quantitative wood anatomy experience for studying drought adaptations in tree species, and examining patterns between drought resistance and anatomical variation.

This project brings me experience abroad to get a permanent position at a high-quality research institution, with a high-life quality, focusing on independent research on wood anatomical influence on plant function under stressful environments.