Old-growth forests may act as a buffer against rising temperatures, as scientists have found that old forests are better at keeping plants cool in a warming world.
In this latest study, the researchers collected temperature data in 2012 and 2013 at 183 locations. About a third of the locations were plantations. The scientists also analyzed data on forest structure collected through LiDAR, an aerial mapping technique that uses lasers to detect very small-scale structural differences in forests.
"Though it is well-known that closed-canopy forests tend to be cooler than open areas, little is known about more subtle temperature differences between mature forest types," said Sarah Frey of the OSU College of Forestry and lead author of the study. "We found that the subtle but important gradient in structure from forest plantations to old growth can have a marked effect on temperatures in these forests."
Temperature isn't just impacted by forests. It's also affected by elevation and even small changes in topography. However, the researchers found that the way forests are managed is a critical factor in explaining major temperature differences.
"To the untrained eye, plantations might look similar to old-growth forest in terms of the aspects that are well known to influence temperature, particularly canopy cover," said Matt Betts of Oregon State Universe and co-author of the study. "So the magnitude of the cooling effect of old-growth structure is somewhat surprising."
In fact, the researchers found that the type of forest determined the cooling effect. More specifically, old-growth forests had more of a cooling effect than plantation forests.
With that said, the researchers did find that variations in the landscape, such as elevation and slope, helped explain temperature differences over short distances of 100 feet or less. With that said, on broader scales the forest made more of an impact.
The results are important when it comes to conservation efforts. More specifically, it shows that old growth forests are important for helping keep temperatures cool. As temperatures rise with climate change, it's more important than ever to take steps to help mitigate the impacts of a changing world.
The findings were published in the April 22 issue of the journal Science Advances.
