In winter, the U.S. Fish and Wildlife Service reports, when other trees are dormant, quaking aspen are energy producers. That’s because they “continue to photosynthesize in their greenish-tinged bark, even after their leaves have dropped.”
It is this living bark layer, which contains chlorophyll and can carry out photosynthesis, that makes the aspen so remarkable a winter survivor.
The USFWS continues in its Kenai NWR “Refuge Notebook,” that quaking aspen are well-adapted to the cold. They survive at higher altitudes by staying small. It’s a response to their tolerance for cold and a lack of moisture at higher elevations. Because of this, aspen are often stunted near tree line, but fully grown several hundred feet lower.
Even their root structure is designed for survival, as the aspen’s fibrous sprouts and suckers are “a handy adaptation in marginal climates,” the USFWS explains. The propagation of aspen clones from one massive root network is why aspen tend to all change color at the same time in fall or leaf out together in spring.
Additionally, in summer, it is the shape and thinness of the aspen leaf that allows it to quake (flutter) in the slightest breeze. Its flexible stem prevents wind damage or stripping and may also “improve the photosynthetic rate,” USFWS vegetation ecologist Elizabeth Bella writes.
Who knew that the quaking aspen would be as fascinating when frozen, as it is lovely during autumn?