Tree of Heaven Control Project

In the summer and fall of 2022 and 2023 with grant funds, UCD and partners provided assistance for community members in White Salmon and Bingen with Tree of Heaven on their property.  As of October 2023 we have completed our Tree of Heaven herbicide treatments for this season. Please stay tuned for more information about what the next steps are for our program. Please read on for more information below our video.

Contact us! Email: TOH@ucdwa.org or call 509-493-1936 ext. 6.

Watch the video below to learn more about Tree of Heaven (Ailanthus altissima) and Spotted Lanternfly (Lycorma delicatula). Learn to identify Tree of Heaven and why it's important to control its spread! This video was created by Will Lyons, starring Corrie Podolak, Jeanette Burkhardt and Marty Hudson.

 
 

BACKGROUND

Tree of Heaven (Ailanthus altissima) - you’ve seen it, whether you know it or not, because Tree of Heaven is found throughout the Columbia River Gorge – along road edges, backyards, alleys, edges of parking lots, empty lots, cracks in sidewalks. Ailanthus has been around a long time, brought from China and introduced by travelers and officials seeking hardy street trees, and planted (along with locust and Russian olive) by the hundreds or thousands from The Dalles eastward by Sam Boardman, Oregon’s enterprising and energetic Superintendent of State Parks in the 1930s and ‘40s.  Ailanthus was favored for its toughness. It can seemingly grow anywhere, and quickly! Dense or sandy soil? Fine. Full sun or part shade? Yes. Drought conditions, deserts with low rainfall? No problem.

Although this might seem like the perfect tree, Tree of Heaven also has many undesirable qualities.  It’s an aggressive grower, spreading vegetatively by sending out sprouts, often damaging paved areas, home foundations or underground utilities.  While growing quickly, its wood has very little value, not as firewood or long-lasting shade; it is considered a tree-fall hazard.  It often forms thickets, displacing native trees, and providing little or no habitat for birds, butterflies, or beneficial bugs.  The tree can also be toxic and leaches allelopathic chemicals that may inhibit the growth of or kill neighboring plants.  Tree of Heaven can cause skin irritations or allergies in some people. Wear gloves when pulling or handling and avoid skin contact with the sap.

AGRICULTURAL PEST – SPOTTED LANTERNFLY

A primary reason for controlling Tree of Heaven is that it is the preferred host for the Spotted Lanternfly (Lycorma delicatula).  This piercing, sucking insect, which like Tree of Heaven is native to Asia, is a new and emerging pest in the U.S. for a wide variety of important agricultural crops, including grapes, apples, cherries, hops and many more that are also important to the regional economy.  If established here, the Spotted Lanternfly could cost the state’s agricultural industry $3 billion annually.  The WA State Dept. of Agriculture and the WA State Invasive Species Council are working to develop a statewide Spotted Lanternfly Action Plan and Early Detection/ Rapid Response Strategy.    

Another outcome of large populations of the Spotted Lanternfly is its habit of coating cars, decks, pets, and plants with excessive quantities of a sticky excretion called honeydew. The honeydew is excreted sap from the trees the Spotted Lanternfly feeds on, having pierced them with its sucking mouthparts, which also attracts other insects and produces a sooty mold.  If introduced, the Spotted Lanternfly will feed on dozens of tree species, including maples, willows, and fruit trees.  The bottom line is, we don’t want the Spotted Lanternfly making its home here. 

IDENTIFICATION

The first step to reducing the preferred habitat for Spotted Lanternfly and controlling Tree of Heaven is to properly identify it.  The tree has compound leaflets on each branching leaf like a walnut, ash or sumac, but one key difference is that the Tree of Heaven leaf has a smooth edge, while the others have serrated, or toothed edges.  Snapped twigs and crushed, fresh leaves smell like rotten peanut butter. Tree of Heaven readily sends out many underground suckers and often grows in dense clumps. It has smooth bark, even fuzzy when young, that turns gray and develops shallow, diamond-shaped fissures when mature.  Tree of Heaven seeds are in clustered, papery wings, dispersed by wind and birds, while walnut trees have walnuts and sumacs are distinctive by their red fuzzy spikes.  One mature female Tree of Heaven can produce about 325,000 seeds annually!  This map shows some known locations of the tree in our area.

TREATMENT

Getting rid of Tree of Heaven isn’t always easy. Young seedlings can be pulled out before they’ve developed a long, strong taproot. Dispose in the landfill or by burning, but not composting at home.  Cut stems can grow roots if left on moist ground.  Larger infestations will take persistence and/or herbicides to remove. Do not just cut or mow Tree of Heaven: it will prolifically sucker, and you’ll end up with a hydra-headed nuisance.  Some roots can extend as far as 50 feet underground before sprouting upwards again.  Since cutting the tree and then treating the cut stump with herbicide can simply encourage more root suckering, specific herbicides and application methods should be carefully observed in mid-late summer.  Always follow pesticide labels and read specific guidance; for more detailed treatment methods consult this link: https://columbiagorgecwma.org/weed-listing/best-management-practices/tree-of-heaven/ and see these valuable videos below from Penn State University and Jeff Kessenich, a certified herbicide applicator from the City of Vancouver. These videos below highlight Tree of Heaven control methods:

Additional References and Resources: 

Funding to support this project was provided by the State of Washington Department of Natural Resources Urban and Community Forestry Program and the Columbia Gorge Cooperative Weed Management Area.