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

Project Information

treelineQWA

Grant agreement ID: 101130817

DOI

10.3030/101130817

Project closed

EC signature date 2 May 2023

Start date 1 June 2023

End date 31 December 2025

Funded under

• Widening participation and spreading excellence

Total cost

No data

EU contribution

€ 150 438,72

Coordinated by

UNIVERZITA KARLOVA
Czechia

Periodic Reporting for period 1 - treelineQWA (Exploring the effect of seedling’s drought vulnerability on treeline dynamics under climatic change using quantitative wood anatomy)

Reporting period: 2023-06-01 to 2025-12-31

Summary of the context and overall objectives of the project

This project focused on independent research on wood anatomical influence on plant function under stressful environments. 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 wood traits may affect survival and growth under increasing warming conditions. The project provided insights to understand the drivers of differential treeline response to global warming. We systematically screened European treeline regions, identified uppermost tree positions and calculated treeline bioclimatic metrics. Wood properties were described, compared between climatically diverse treelines, and their plasticity was analyzed.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

To advance in the understanding of the role of seedling drought sensitivity as driver of differential treeline response to global warming the following main activities were performed:

WP1. The upper tree limit (UTL), the cold-limited upper boundary of the realized tree niche, was analyzed across Europe to assess the predictability of its elevation using latitude, topographic factors, and bioclimatic variables. High-resolution imagery was used to identify current UTLs and derive bioclimatic metrics. UTL elevation was modelled with latitude, diurnal temperature range, climatic water balance, and distance to summit. Latitudinal trends and breakpoints in bioclimatic variables were analyzed, leading to a bioclimatic classification of the European UTL.
Main achievement. Scientific paper submitted by the supervisor to a high impact journal, current status: major changes needed.

WP2 and WP3. Blue Intensity (BI) was applied to quantify high wood density, including latewood and reaction wood, in Picea abies treeline seedlings.
The main achievement of this work was the timely publication of an open access research article, with the principal investigator as first author, in a high-impact journal, providing the basis to advance in understanding the effect of xylem traits on growth, plasticity was considered as planned.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The research provided valuable insights to understand the drivers of differential treeline response to global warming. Main results revealed that high-density wood represents ~40% of stem cross-sections in Picea abies treeline seedlings of 7 climatically diverse European treelines, and that compression wood may strongly influence growth and survival.
The research also will bring a climatic context of European treelines. Main results revealed that there is a complex gradient of meteorologic conditions that influence occurrence and intensity of tree growth allowing woody plants to achieve tree stature.

Graphical abstract of published scientific research paper (output) derived from the project