Minnesota Profile: Quaking Aspen (Populus tremuloides)
Also called trembling aspen, poplar, and popple, it can grow 75 feet high with a trunk diameter of up to 20 inches. Its life expectancy is about 70 years, though Minnesota has aspen that exceed 100 years.
Aspen is native and hardy statewide except in the west where forest land turns into prairie. It is the most widely distributed tree species in North America.
This pioneer -- one of the first trees to pop up after a timber harvest or fire -- grows well on sandy, gravelly soils but thrives best on clay loam in full sunlight.
Its thin bark is white to gray-green and almost smooth with black marks around the base of the limbs. With age it becomes warty. Leaves are up to 4 inches long, broadly oval, pointed, finely toothed, green and shiny above, dull green below, and brilliant yellow in the fall. Leafstalks are flattened at right angles to the leaves, causing the leaves to quake or tremble in a breeze. In the spring, seeds appear in cottony masses called catkins. Aspen also spreads by suckering, sprouting from the roots.
Aspen and other quick-growing species replaced logged pine forests. During and after the Depression, aspen overtook thousands of acres of abandoned farms and forest land. Beginning in the 1930s, fire management gave aspen an edge over competing species. Today, aspen dominates more than a third of Minnesota forests.
Considered a weed tree not long ago, it is now the major species used in Minnesota's forest products industry, supplying pulp for papermaking, logs for lumber, and fiber for oriented strand board.
Much of the state's aspen is old. Although there are many acres of young aspen, there are very few acres of middle-aged trees, 20 to 40 years old, which means that for a span of 10 to 20 years there will be a significant decrease in the amount of harvestable timber. Much of the old aspen being harvested is being used to produce oriented strand board and paper before it is lost to decay.
--Meg Hanisch, DNR Forestry Public Affairs Specialist