The Tree Board
Dan Bullock, Chair
Frosty Merriot, Board of Trustee Liaison
History: Siberian Elm, Ulmus pumila aka: Chinese elm, dwarf elm, Asiatic elm, was introduced to North America by Frank Meyer who, whilst in the employ of the USDA, made several collecting expeditions to the Far East. The tree was initially cultivated at the USDA Experimental Station at Mandan, North Dakota, where it flourished. It was consequently selected by the USDA for planting in shelter belts across the prairies in the aftermath of the Dustbowl disasters, where its rapid growth and tolerance for drought and cold initially made it a great success. ( Credit Wikipedia ) Over the years, Siberian Elm has proven to be more of a nuisance tree than a valuable urban tree.
Carbondale’s Problem: Siberian Elm trees are ubiquitous in the historic part of Carbondale, and if you have lived here for any significant period, you’ve probably heard someone complain about them. They were originally chosen most likely for some of their tempting characteristics such as rapid growth, ease of care, and extreme hardiness. While indeed they do provide us with shade and a green canopy, they also provide us with many burdens and problems that must be addressed. Siberian Elm Ulmus pumila is widley considered to be an invasive species because of its fast growth, adaptability, and ability to grow in poor soils. Posing as a threat to out-competing native species, it is actually listed as a noxious weed in the neighboring state of New Mexico.
Why Get Rid of them in the City?: Beyond Siberian Elm’s negative ecological impacts, it makes for a poor street tree because it creates heavy woody litter, and its smaller branches are prone to breaking potentially causing damage. The major solvable problem we face with our Siberian Elm Street trees is their seedlings, or as I like to call them “weedlings”, dispersed by their profuse seed production. They cause damage to foundations, driveways, roads, sidewalks, fences and other structures as they grow against and around these structures. Siberian Elms thrive where other plants fail ( ie: in poor, dry hot soils ) and grow rapidly, expanding rapidly against anything it touches. The real challenge in preventing damage from the Elm seedlings and saplings is that they tolerate being cut back. Even the smallest Elm can withstand being cut completely to the ground only to grow back on a thicker stalk. This means that weed eaters and lawn mowers are almost entirely ineffective at controlling Siberian Elm unless they are used regularly.
What is the Town of Carbondale doing to address the problem?: The Mature Siberian Elms that line the streets of much of old town Carbondale were planted during a different part of the town’s history before there was the knowledge about the drawbacks of planting Siberian Elm as a street tree. The town’s approach to managing the 300 or so mature Siberian Elms on town property is to gradually phase them out. This allows us to continue to enjoy a large street tree canopy while we continually manage the trees removing the worst trees first. With new funding for replacing street trees as they are removed, the goal is to plant a variety of species which will eventually make up a more diverse and beneficial urban forest.
What can I do?: It’s important and wise to remove Elm seedlings before they cause damage to your foundation, paved surfaces, or fences. The best way to control Siberian Elm is to “ get them while they’re young.” The root system MUST be removed or killed otherwise it will grow back. This is true for small seedlings all the way up to mature trees. The BEST way to control this tree is to uproot seedlings with a diameter of ¼ inch or less. Pulling them by hand or using some sort of weed prying device works best. Unfortunately, once the seedling grows to about 3/8 to ½ inch in diameter the root system becomes too well-anchored to be removed mechanically. Check out the link below for different control options: