It S Getting Harder For Forests To Recover From Disasters

When a forest loses resilience, it means it’s gradually losing its ability to bounce back after fires, droughts, logging and other disruptive events, said the study, published on July 13 in Nature. Past a certain point, some forests may approach a kind of tipping point — a threshold that launches them into a rapid decline.

And beyond that, some studies suggest, a forest may not be able to fully recover at all. It may instead transform into some other ecosystem entirely, like a grassland or savanna.

Now, scientists are turning their gaze to the rest of the world. This week’s study looks at forests all over the globe, from the warm tropics to the boreal forests of northern Canada and Russia.

Led by Giovanni Forzieri of the University of Florence in Italy, the research team utilized machine learning techniques to analyze 20 years of data on global vegetation, from 2000 to 2020. They used satellite data on ecosystem productivity — an indicator of the health of the trees — to evaluate the speed and ease with which forests are able to recover from disturbances.

Many northern boreal forests, they found, actually are growing in resilience. Warming and increasing carbon dioxide rates may be offsetting other negative effects of climate change in these regions, the researchers suggest — at least for now.

Still, even some boreal forests are experiencing localized resilience losses, including parts of central Russia and western Canada.

Elsewhere the picture is bleak. Forests in the tropical, temperate and arid regions of the world are experiencing significant declines in resilience.

Intact forests — forests that aren’t managed or harvested by humans — tend to have higher baseline levels of resilience to start. Still, both intact forests and managed forests are losing their resilience over time at similar rates.

That suggests to scientists that the declines aren’t related to human management techniques. They’re probably driven by climate change.