A new study led by the European Commission’s Joint Research Centre (JRC) has found that the resilience of tropical, arid, and temperate forests has declined over a two-decade period.
The authors of the report authors estimate that, overall, around 23% of intact, undisturbed forests may have reached a critical threshold, with resilience continuing to decline.
This decline could have critical consequences for the key ecosystem services that forests offer, such as carbon storage.
The authors recommend that these observed trends in forest resilience should be taken into consideration in the design of land-based mitigation and adaptation plans as well as conservation and restoration activities.
Forests and their role
Forests cover nearly one third of the Earth’s land surface and play a fundamental role in the global carbon cycle, absorbing a third of anthropogenic carbon emissions and mitigating climate change.
But they also provide a series of ecosystem services that contribute to societal well-being, such as regulation of water flows, protection of soils, and conservation of biodiversity.
Anthropogenic
This refers to the influence of human beings on nature – mainly relates to the environment and in the context of pollution.
“The persistence and functionality of forest ecosystems are highly dependent on their capacity to withstand and recover from natural and anthropogenic perturbations,” according to a JRC spokesperson.
“This capacity is defined as their resilience. Experimental evidence of sudden increases in tree mortality across different biomes throughout much of the Americas and in Europe is raising concerns about variation in forest resilience, yet not enough is known about how it is evolving in response to climate change.”
Resilience of forests
In a new study led by the JRC and published in Nature, researchers have integrated satellite-based vegetation indices with machine-learning techniques to show how forest resilience has changed within the timeframe from 2000 to 2020.
Results show that the resilience of tropical, arid, and temperate forests has declined over this period, according to the JRC.
These changes are associated with:
- Reduced water availability;
- Increasing climate variability.
By contrast, boreal forests show “divergent local patterns with an average increasing trend in resilience, probably benefitting from warming and CO2 fertilisation, which may, at present, still override the adverse effects of climate change”.
What is a boreal forest?
According to the International Boreal Forest Research Association (IBFRA), the boreal forest is the world’s largest land biome, spanning eight countries: Canada, China, Finland, Japan, Norway, Russia, Sweden and the United States. It is typically comprised of coniferous tree species such as pine, spruce and fir with some broadleaf species such as poplar and birch.
These patterns emerge consistently in both managed and intact forests, corroborating the existence of common large-scale climate drivers.