I have been doing a fair amount of cross country skiing amongst the Turtle Mountain aspen over the last few weeks. Aspen might not be the Rodney Dangerfield of trees, but it certainly doesn’t get the respect it deserves.
Aspen is really quite an amazing plant. It is the most widely distributed tree species in North America. Its northern border is close to treeline and it is also found in the western mountain ranges from Alaska all the way down to Mexico. It obviously can tolerate a wide range of environmental conditions.
Aspen is an example of what biologists call a keystone species. A keystone species is a species that influences community structure in disproportionally large ways relative to its abundance. In the Turtle Mountains, of course, aspen is the dominant tree. It is also abundant in the Pembina Hills, Killdeer Mountains, and some other locations around the state. But in other areas where it is perhaps less abundant (such as Yellowstone National Park and the northern mixed forests) it has a large influence on other members of the community.
The animal most closely associated with aspen is probably the ruffed grouse. The range of ruffed grouse in North America coincides closely with that of aspen. Good ruffed grouse habitat consists of several age classes of aspen which provide important brood cover, drumming logs, as well as winter cover and food. Extensive areas of old aspen do not provide for all the needs of the grouse.
Aspen is susceptible to fungal infections such as heart rot. As a result, it is an important tree to a variety of insects that invade the damaged tissues. Of course all those insects are important food sources for woodpeckers and other insect eating birds as well as various cavity nesting birds. Aspen is also an important browse species to many big game animals such as moose and deer. Aspen really has a big influence on life in the forest.
Although most people in our region refer to aspen as popple, quaking aspen or trembling aspen are more widespread common names. Unlike most leaf stalks which are round and rather rigid, the leaf stalks of aspen are very flattened in cross section and rather flimsy. As a result, the slightest wind causes the leaves to tremble or quake. As they do so, they bump into each other and produce the “trembling” sound. But of course we don’t hear that sound this time of year. The sound of wind swooshing through the aspen branches will have to do for winter.
Natural North Dakota is supported by NDSU Central Grasslands Research Extension Center and Minot State University-Bottineau, and by the members of Prairie Public. Thanks to Sunny 101.9 in Bottineau for their recording services.