YELLOWSTONE NATIONAL PARK — According to Yellowstone National Park (YNP), local wildlife aren’t the only species to adapt to surviving the cold. In a Facebook post this week, YNP highlights how trees evolved to have a variety of winter strategies.
“Unlike animals, trees can’t migrate in search of food and warmth,” YNP writes.
YNP Public Affairs Office tells Buckrail that for the Rocky Mountain conifers and trees that dominate the Greater Yellowstone Ecosystem, low temperatures are rarely an issue. This is because these trees have evolved in cold-weather climates and have characteristics that allow them to mitigate the challenges.
This could look like conifers retaining their needles through the winter to extend their ability to photosynthesize or aspens and cottonwoods dropping their leaves to reduce water loss and conserve nutrients, according to the Facebook post.
The National Forest Foundation (NFF) also notes that bark helps insulate trees against below freezing temperatures. However, it is possible that trees can get so cold that they explode, due to the sap freezing and expanding inside the tree and putting pressure on the bark until it breaks.
According to the YNP Public Affairs Office, tree limbs cracking and breaking throughout the Park most often occurs during periods of rapid changes in temperatures and intense cold. Sap is not composed of pure water and has antifreeze properties in the form of sugars and other dissolved minerals, YNP Public Affairs Office explains, which lowers their freezing points.
Bark is also an incredibly efficient insulator against cold temperatures.
“Most often, trees don’t explode; rather bark can become ruptured or cracked with an audible sound,” YNP Public Affairs Office says. “In many cases, these cracks close with no long-term ill effects to the trees.”
While there is not an elevated risk to visitors as a result of these processes, YNP Public Affairs Office notes that people should always be aware of their surroundings in winter and summer.
Learn about how certain plants have learned to survive when frost crystals form here.
