NEBRASKAland Magazine is dedicated to outstanding photography and informative writing with an engaging mix of articles and photos highlighting Nebraska’s outdoor activities, parklands, wildlife, history and people.
Issue link: http://mag.outdoornebraska.gov/i/725550
24 NEBRASKAland • OCTOBER 2016 I f there were a hall of fame for fall color, aspen trees would have been inducted on the first ballot. The tree's ability to turn entire mountainsides shades of yellow, orange and red draws throngs of people to places where the trees grow, especially in the Mountain West. While not nearly at the same scale, you can see the vivid golden hues of aspens, contrasted against their brilliant white bark, each fall without leaving Nebraska. That fact comes as a surprise to many who assume the patches of yellow leaves they see sparkling in the forest in the fall are simply ash or cottonwoods or other more common trees completing their annual cycle. These small stands are scattered across northern Nebraska, some in seemingly unlikely places. There were once more, many more. Those that remain are relicts that have persisted since the last Ice Age, hanging on as the climate in Nebraska changed. Aspen Biology Two species of aspen trees, members of the deciduous willow or poplar family, are found in North America, growing mostly in dry, colder regions with cool summers. The quaking aspen is the most widely distributed tree on the continent, growing throughout Canada, in the northeastern United States from the Dakotas east as far south as Indiana and Nebraska, in the Mountain West, mostly at higher elevations, and in other places like the Black Hills. The bigtooth aspen is found throughout southeastern Canada and the northeastern U.S. No native stands are known to grow in Nebraska, and the closest populations are in central Iowa. Aspens are fast-growing, with both species typically reaching heights of 60 to 80 feet. Quaking aspens have larger trunks, measuring up to 2½ feet in diameter, compared to 10 inches for bigtooth. The leaves of mature trees are nearly round with toothed edges. Larger teeth on bigtooth leaves give that species its name. The propensity of quaking aspen leaves to flutter and hum in even the slightest breeze are the basis for that species' name. The thin bark of quaking aspen is white or shades of white mixed with gray, green or yellow, with distinctive black knots and horizontal scars. Bigtooth bark is similar except for its olive-green hue. As trees mature, the bark thickens, especially at the base, and turns gray and rough with vertical grooves, often leaving only the upper reaches of the trunk and small branches white and smooth. Aspens are either male or female, and produce seed heads called catkins that are pollinated by the wind. In regions where both species are found, they are known to hybridize. But despite being prolific seed producers, the species rarely grows from them. Aspens are a clonal species, sending up sprouts or suckers from a shallow root system that develop into stems or trees. These stems remain connected by the roots, and entire aspen stands can be made up of a single clone. The largest known clone of quaking aspens is also believed to be the largest organism By Eric Fowler Aspens Ice Age Relicts in Nebraska Dew glistens on aspen leaves at Smith Falls State Park near Valentine. PHOTOS BY ERIC FOWLER