TreeStewards.org

Despite its serene name, Ailanthus altissima, more commonly known as Tree of Heaven, is less than a gift from above. A non-native invasive originating in China, Tree of Heaven spreads rapidly, outpacing native plants in its growth and often killing them through chemical secretions in the soil. They also serve as a prime host for another harmful invasive species, the spotted lanternfly. 

Unfortunately, mitigating the spread of this plant is not as simple as just cutting down the trees you see. Learn how you can do your part to slow the spread of this pernicious pest.

1. Identifying Tree of Heaven

Tree of Heaven has several distinctive features. It has bark described as resembling cantaloupe, with long compound leaves that have two distinctive “bumps” or “notches” at the base. The leaves have a distinctive rancid peanut or cat urine-like smell. 

This time of year (late summer to fall) Tree of Heaven is very distinctive, with the female tree sporting peach/salmon/coral colored seeds in clusters.  

If you see any mature female trees on public land, particularly in Arlington and Alexandria, please identify them using the iNaturalist application. This will allow local government officials and researchers to track the spread of these trees. When submitting photos of the trees, please submit photos that show the seed clusters, as well as another photo or two that show the characteristic leaves and bark of the tree to ensure accurate tree ID.

2. Managing Tree of Heaven

As unintuitive as it may seem, cutting down tree of heaven ends up creating a Hydra-like issue: it triggers resprouting from the roots and the stump of the tree, leading to multiple trees taking the place of the original tree.

Only trained staff or contractors should be removing tree of heaven (or any trees!) from public land. For those aiming to mitigate tree of heaven on their private property, you can follow the below steps:

• If the tree is still just a seedling/very small sapling that has NOT produced seeds, you can pull the tree out, ensuring all roots are removed. It’s a bit easier to do this after it has rained when the soil is looser.
• If the tree is producing seeds and/or is relatively well-established, apply a targeted herbicide, being careful to not apply it to surrounding plants. The two recommended options are:
  • Basal bark method: Apply a solution of a 20-25% concentration of oil-soluble triclopyr ester product in an oil-based carrier is highly effective. Using a handheld or backpack sprayer, apply the mixture in a continuous 12-inch wide band around the tree base. The basal bark method requires no cutting and is generally used for trees that are less than six inches in diameter, though larger stems (up to 16 inches) may also be treated effectively
  • Stem injection (hack-and-squirt) method: This technique is very effective when applied during the summer. It requires first making downward-angled cuts into the sapwood around the tree trunk at a comfortable height, using a hand ax. With a spray bottle or wand, squirt the selected product into the cuts within a minute or two, so that the bottom of the cut is covered but the liquid doesn’t run out. This method can be used with trees of any size, though it is most effective with stems over two inches in diameter. A triclopyr product is most often recommended.
• Once the tree has died, then you can safely remove it. 

3. Be on the Lookout for the Spotted Lanternfly

Tree of Heaven is a key host for the spotted lanternfly. Eggs are laid in late fall and can be found on any flat surface such as trailers, logging equipment, and on tree bark. They hatch as “nymphs” in mid-April and become adults in July. 

Clockwise from top left: Adult showing hind wings, adult with folded wings, early black and white nymphs, full-grown nymphs showing red, and egg masses.

If you see any spotted lanternflies, please kill nymphs/adults as able, then report the sighting and location with either a photo of the insect or the sample itself to your local Virginia Cooperative Extensive office.

For more information on Tree of Heaven, consult the Virginia Department of Forestry’s article on Ailanthus Control Methods and their Guide for Virginia Landowners on the Control and Utilization of Tree-of-Heaven. For more information on spotted lanternflies, consult the Virginia Cooperative Extension’s resources on Spotted Lanternfly in Virginia.

Applications for the Fall 2023 Training class are now closed. Thank you so much for your interest! If you are interested in participating in future training classes, please email us at treestewardsarlalexva@gmail.com. We will notify you via email when we plan to host the next class.

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Applications were accepted through July 24th for Fall 2023 Training Class.  Forty spaces were available.

This will be a hybrid training of weekly live Zoom presentations on Tuesday evenings and assigned readings. Additionally, there will be five required in-person weekend sessions with experienced Tree Stewards and tree care professionals. 

The list of topics will include: tree physiology, tree identification, soils, urban tree problems, invasive trees and plants, forest ecology, right tree right place, tree selection and sourcing, tree planting, and tree pruning.

A preliminary schedule of classes will be announced in early August.  Classes will begin with an in-person meeting at Lubber Run Amphitheater on Saturday, September 9.  Classes will finish in early-to-mid November, with an in-person graduation gathering in early December.

Questions? Please feel free to email us.

The Tree Stewards of Arlington and Alexandria were certainly busy in 2022. Our 92 members provided over 4,000 hours of service in the region. In particular, we provided education to around 5,200 people, and provided maintenance to nearly 10,000 trees.

The Tree Stewards participated in a diverse range of activities.

The greatest number of hours volunteered is in our parks, in particular working with our partners in Arlington County and the City of Alexandria to provide hands-on tree care on public property.

Our volunteers also spend a lot of time on public education, in particular ensuring the public understands the importance of our native canopy. We do this through information tables at community events, by hosting tree walks, or hosting virtual presentations.

We also work closely with the Arlington Tree Canopy Fund and consult with homeowners to select the right tree for their yard. This past year we were privileged to work with EcoAction’s Tree Equity Program to successfully reach previously underserved communities.

Tree Stewards of Arlington and Alexandria welcomes all citizens who care about trees to join us. For information on training classes, upcoming activities, requesting a Tree Steward speaker, or to comment on trees in your neighborhood, email: treestewardsarlalexva@gmail.com.

The data in this post comes from TrackItForward, our volunteer hour reporting platform. It consists of self-reported data, submitted by Tree Stewards. It was turned into data visualizations by Tree Steward Emily Potosky.

On April 2, TSAA celebrated the graduation of our 2022 class of Trainees! These new “Interns” have to report 30 volunteer hours in their first year to become full Tree Stewards and earn our signature green polo shirts and nametags.

Over 55 Tree Stewards and Trainees were present at this event in Lacey Woods Park.

On Monday, February 21, 2022, Tree Stewards of Arlington and Alexandria spent time pruning trees in Arlington’s Mosaic Park. By correcting structural defects in young trees, Tree Stewards expect the trees to grow up strong and healthy to shade Mosaic Park in Ballston.

Photos by Tree Steward Jo Allen.