While it’s common knowledge that mountain peaks are colder than the valleys below, new research from the University of Vermont (UVM) turns what we know about forests and climate on its head. A published study Ecology and Evolution, examines forests that experience “cold air accumulation,” a phenomenon in which cold air from higher elevations flows into lower valleys, changing expected temperatures (warm at the bottom, cold at the top). — this often happens in mountainous regions. In other words, as you descend from the mountain to the valley, the air temperature decreases.

“We see that as the temperature reverses, the vegetation also reverses,” says Melissa Pastore, lead author of the study and former UVM doctoral student. “Instead of finding cooler species such as spruce and fir at higher elevations, we found them at lower elevations—the exact opposite of what we expected.”

And the impact on these ecosystems is significant: “The accumulation of cold air basically structures the forest,” says study co-author and UVM professor Carol Ader.

This understanding “can help forest managers prioritize and protect areas with frequent and severe accumulation of cold weather to protect cold-loving species as the climate warms,” says Ader.

Researchers spent two years studying three forest areas in New England, ranging from the shallow, crater-like Nulhegan Basin in Vermont’s Northeast Kingdom to the higher peaks and deeper valleys of the Green Mountains. They collected data on the tree species found in elevation transects and monitored the temperature on an hourly basis.

Ader says researchers have discovered that this is not a random nighttime seasonal event as historically believed, but that the accumulation of cold air occurs frequently into the daylight hours throughout the year. This phenomenon occurred everywhere they examined, but was strongest where there was the least elevation change.

Housing in a changing climate

Pastore said places where this phenomenon has been observed could be important for conservation efforts aimed at preserving cold-adapted species even as the climate warms on a larger scale. “These cold air accumulation zones can be valuable targets for small areas protected from climate change; These are areas that can be protected from, or even isolated from, climate change and are home to species that can adapt to cold. We know he’s vulnerable.”

He adds that protecting such places could give species enough time to adapt to climate change by migrating or mixing genes with neighbors to acquire the traits needed to survive in a warmer world.

“These cold habitats can become springboards for some species; you can buy them time,” Pastore says.

Preserving such areas could have practical applications “including carbon storage and small recreation opportunities,” says Adair, adding that cool-loving conifer communities tend to store more carbon than hardwoods and forest soils can stay moist longer. heavy rains.

Ader says cold air accumulation has been observed elsewhere historically, but this study is the first to measure this extent across multiple areas under the forest canopy, and further research is planned to examine its temporal and geographic scales.

Pastore warns that incorporating cold weather is not a panacea. These forests are still warming—I don’t want to say it’s a completely safe haven, because climate change will happen there, too—but it may be slower, and perhaps species that would go extinct in warmer climates may remain in the forest longer. these places”.

The research is highly relevant to a changing climate, as ecologists try to model what might happen to species that require cold conditions. “If you don’t have this process in your model,” Adair says, “you miss that there are areas where cold-loving species can survive and persist.”

Ader says the study is a promising change of pace. “I’m excited about the fact that this is good news in a way. These areas could help cold-adapted species survive.” He adds: “A lot of my research is about telling people why bad things happen, so that’s nice. This is not all good news, but it is good news. These places exist. We can use these. They are important. explicitly structure forests”.