The Siberian elm tree is a beautiful, fast-growing deciduous tree that grows well nearly anywhere. In fact, it grows a little too well. For this reason, it has been labelled an invasive plant, and indeed it has been wreaking havoc on native plants across North America for years. Controlling the Siberian elm is easy enough if you know a few key details about the plant and take the proper steps to eliminate it from your area.
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Know how to identify the Siberian elm. The Siberian elm tree is easily recognizable, according to the National Parks System's Alien Plant Working Group: The leaves are small-toothed, alternate and dark green. They usually range from one- to two-and-a-half inches in length, and the width is usually one-half of the length. Mature trees have furrowed, grayish brown bark, and their height will attain a maximum of roughly 70 feet. Identification is extremely important when considering whether or not to destroy a tree; many trees are excellent habitats for wild animals and have a positive effect on their local ecosystem. An invasive species, though, can destroy valuable plant life and have a devastating impact over large geographic areas if left to themselves. Therefore, if you have a Siberian elm on your property, it is wise to remove it promptly.
Kill it by girdling. According to Jill Kennay and George Fell of the Natural Land Institute, "Girdling trees is the preferred management technique where practical." Girdling is essentially stripping the bark in a band roughly three to four inches wide, all the way around the tree. This process takes longer (one to two years to die completely) than simply cutting down the tree, but it ensures that the tree will never sprout again. Girdling is most effective when done in late spring. Sap is flowing during this time and the bark will peel away more easily. The two shallow, parallel cuts made to form the band that will be peeled away can be done with a hand saw or chainsaw; be very careful not to cut too deep. Only the bark should be peeled away. Otherwise, the tree will behave as though cut down and begin to sprout again the following year.
Cut down the tree and follow up with maintenance. If you don't mind a few routine applications of herbicide, simply cut down the tree and immediately soak the entire trunk in whatever formula you prefer. Reapply two or three additional times during the following year as a precaution. Siberian elms can also propagate by cuttings, so the NPS Alien Plant Working Group recommends gathering all remnants of the cut tree for destruction. Otherwise, be sure to spray any cut branches or twigs left behind as well.
Instigate controlled burning. In large, open fields where a high population of Siberian elms has taken over, seed control will likely be necessary in addition to the individual tree controls mentioned above. Carleton College's Cowling Arboretum recommends a controlled burning of the field after mature trees have been removed. When doing a controlled burn it is highly advised that you contact your local land management office, extension office, and/or fire department for local regulations and ordinances. Due to the invasive nature of this species, one or more of these organizations may be willing to help you perform this part of Siberian elm control safely and effectively.