Illinois Study Finds Tree Hollows Shield Wildlife From Extreme Heat

Champaign, IL – Old trees may offer wildlife more than food and shelter, with new University of Illinois research finding that cavities inside trees can provide significant protection from extreme heat and cold.

According to the University of Illinois Urbana-Champaign, researchers conducted what they described as the first global literature review and analysis examining how effectively tree cavities buffer animals from outside temperature extremes.

The study found that tree cavities can remain about 3 to 4 degrees Celsius cooler than the surrounding air during hot conditions. That equals roughly 5 to 7 degrees Fahrenheit of cooling.

Some larger or deeper cavities provided even greater relief, remaining as much as 15 degrees Celsius — or about 27 degrees Fahrenheit — cooler than outside temperatures, according to the university.

Researchers also found the natural shelters can work in the opposite direction during cold weather, providing animals with a warmer refuge when temperatures fall.

“Everywhere we looked, trees were great for buffering outside air temperature extremes,” senior study author Joy O’Keefe, a Natural Resources and Environmental Sciences associate professor and Illinois Extension wildlife specialist, said in the university’s announcement.

Conservation scientist and NRES graduate Katrina Cotton worked with O’Keefe on the global review.

The findings could have implications for wildlife ranging from small mammals to other animals that depend on tree hollows for shelter. Researchers said understanding the temperature benefits of cavities could also help inform forest-management decisions as periods of extreme heat and cold affect ecosystems.

The research further highlights the ecological importance of older trees, which are more likely to contain the hollows and cavities used by wildlife.

University researchers said the work could help land managers better understand how preserving suitable trees may provide animals with important natural protection during temperature extremes.