Värmetolerans hos tropiska träd och dess implikationer för trädplantering, skogars kollagring och biodiversitet

Tropical forests—adapted to a thermally stable climate—may be particularly vulnerable to global warming but this hypothesis remains poorly evaluated due to data scarcity.

This project uses a unique elevation gradient experiment in Rwanda to explore if projected global warming will lead to exceedance of physiological thermal tolerance limits in tropical trees.

The experiment includes 5400 trees of 20 species with contrasting ecological strategies, grown at three sites with large differences in climate (18-24 °C mean daytime temperature; 1050-2100 mm precipitation) and application of water supply treatments (irrigation and rainfall exclusion). Our ongoing research indicates considerable heat-induced reductions in photosynthesis and survival in some species.

Here we propose new measurements to determine the physiological and biochemical heat sensitivity of a broad range of tree species.

Exceedances of species heat tolerance limits at larger spatial scales will be estimated using both modelling and remote sensing observations (thermal camera and satellite data).

Furthermore, we will explore the link between interspecific variation in heat sensitivity and stand-scale tree community composition and its implications for tree plantation success, forest carbon storage and biodiversity in a warmer world.

The project is a collaboration between partners in Rwanda and Sweden and includes close involvement of key stakeholders in the forest/agroforestry sector in Rwanda.