Identifying ash
In order to prepare for the onset of EAB in our forests, it is important to know how to distinguish between ash species and keep records of where ash is located to be able to monitor for EAB, collect seed, and implement management plans.
Brown, green, and white ash grow on a gradient of soil moisture from high to medium. Brown ash is most competitive in areas where it “keeps its feet wet” in wetlands or along streams, while green ash grows in similarly moist soils and also in more upland areas, and white ash in upland sites with mesic (moist) soils. You can use aerial imagery to identify potential ash tree stands within forests: Check out this video made by Colleen Teerling for instruction on how to use Google Earth to find stands.
One can identify different types of ash by their distinctive bark, leaves, fruit, twigs, and wood. For a detailed look at the distinctions between white, green, and brown ash, check out this graphic of their distinguishing characteristics, or refer to this excerpt from the Forest Trees of Maine guide. We also recommend checking out the State of Maine’s webpage, Is it an Ash Tree? Please note that Wabanaki knowledge holders only harvest brown ash trees with certain characteristics, so even if you find a brown ash tree on your property, it may not be basket quality.
Community Science Ash Inventory: Collect & submit ash data!
As the dual threats of EAB and climate change are impacting Maine’s forests, it is more urgent than ever before to obtain geographic and characteristic data about ash trees in private and conserved lands. You can help our efforts to monitor, collect seed, and manage ash by submitting your ash inventory data to the Ecosystem Investigative Network. Data you collect will help the Maine Forest Service monitor emerald ash borer outbreaks, support APCAW in finding potential seed-bearing trees for research, and Wabanaki ash harvesters find potential basket quality ash trees. Instructions and data sheets detailing how to collect data and inventory ash forests can be found on the Ecosystem Investigative Network’s Protecting Ash for the Future page. (Disclaimer: Location data you collect about brown ash will not be shared publicly).
If you are a forester or land steward with time and resources to support your work, consider doing a more thorough inventory of ash on the land you care for by following the instructions in Tyler Everett’s Ash Inventory Field Manual.
Contribute to EAB monitoring efforts in Maine
Although as of 2025, EAB has been detected in nearly every county in Maine, it is still important to monitor the spread of EAB to keep the county-level hardwood movement quarantine updated and for timely management planning. Current detections in Maine are regularly updated and posted on this page of the Maine Forest Service’s Website along with current regulations.
You can help the Maine Forest Service’s monitoring efforts out by scouting for signs of EAB in forests near you. Report a suspect to the State here and your observations will help inform wood quarantine boundaries and other regulations regarding ash.
It is somewhat rare to see the beetle itself on an ash tree, but the potential presence of EAB can be indicated by woodpecker activity, crown dieback, epicormic shoots, d-shaped exit holes and s-shaped feeding galleries underneath their bark. Check out this infographic made by the State, What are the signs and symptoms of an EAB infestation? for more information and pictures.
If you have an ash tree on your land, you can help out State monitoring efforts by participating in the Maine Trap Tree Network (view the link for detailed instructions). Through this program you will be asked to girdle an ash tree in May or June, which causes the tree to release stress hormones that attract any EAB in the area. If you choose to participate, please use this on-line form to report it to the Maine Forest Service. You can also reach out at foresthealth@maine.gov or (207) 287-2431 if you have trouble with the form. The Maine Forest Service will follow up with instructions in the fall for processing the tree.
Other statewide monitoring efforts include:
- Purple Trap Survey USDA’s detection trap
- Biosurveillance Monitoring for EAB with the Cerceris wasp
Long-term ash management strategies
As EAB spreads, the widespread death of ash trees will be costly and result in dysfunctional ecosystems. Researchers have developed numerous findings about strategies to manage ash, inlcuding biological controls, insecticides, protection of mother trees for seed collection, regenerating alternative species, and monitoring for lingering ash. There is no one size fits all solution, and engaging in multiple types of management will be necessary. Each person who cares for forests will have to decide which strategies work for them in considering the amount of ash on their land, economic feasibility, and support.
As a starting point, you can review these Ten Recommendations for Managing Ash by the Forest Stewards Guild and the Managing Northeastern Forests Threatened by EAB guide. Or, explore three recommended management strategies on the featured tabs below.
Regardless of whether EAB has reached your area, it is recommended that municipalities, conservation organizations, and private landowners develop ash management plans. Many municipalities in Maine already have EAB response plans so we recommend that you get in contact with your local regulators for advice and additional resources. Here is an example of a Municipal EAB Management plan in Maine.
As another model, check out the St. Regis Mohawk Tribe’s Community Response Plan to EAB to understand the complexity and possibilities of ash management from the perspective of one Indigenous community.
Although some landowners may choose to cut all their ash in advance of emerald ash borer, this strategy is not recommended. While some ash trees may survive EAB infestation, there is no chance they will survive a chainsaw. Cutting ash rules out the possibility of identifying lingering ash.
Also, retaining a diversity of ages and male and female trees could support regeneration of ash ecosystems even amidst EAB infestations. Maintaining a living seed bank of ash trees will guarantee that ash can be reforested after initial EAB infestations. For example the EAB guide for Maine Forest Managers recommends maintaining overstory ash trees in order to promote regeneration and monitor for lingering ash. Regeneration is a crucial part of ensuring that sustainable sources of brown ash exist on the landscape for Wabanaki use and ecosystem health.
Insecticide treatments can save in the long term on removal costs and preserve seed-bearing trees. Check out these resources for more information:
- Insecticide Options for Protecting Ash Trees from Emerald Ash Borer by the North Central IPM center
- For Homeowners: Ash Treatment Guide (PDF) by the State of Maine
- Organic options are available, though they are less effective and more expensive.
Please note that it is not known whether trees that have been treated with insecticides can be safely used by basketmakers.
The Maine Forest Service (MFS) cooperates with USDA Animal and Plant Health Inspection Service (APHIS) in a biological control effort to manage emerald ash borer (EAB). USDA labs provide three types of stingless wasps, or parasitoids, that will attack either EAB larvae or eggs. Like EAB, these insects are native to Asia. They specialize in attacking EAB and help reduce its numbers. MFS is looking for more sites to release these biological controls agents. Read more about this effort here, or USDA’s Q&A about these biocontrols here.
Monitoring for Lingering Ash
Potential lingering ash identified through mortality monitoring in Annandale-on-Hudson, New York, in June 2025 approximately 13 years after initial detection of EAB in the area.
The Monitoring and Managing Ash (MaMA) program, within the Ecological Research Institute, defines lingering ash as “chemically untreated trees that were mature (≥ 4” DBH) during peak EAB invasion and stayed healthy ≥ 2 yrs. after EAB killed≥ 95% of nearby ash” (Rosenthal & Wildova, 2025). MaMA organizes a series of community science projects that can assist in revealing lingering ash at different phases of invasion. Once potential lingering ash trees have been identified, their scion and seed can be collected for resistance breeding research. This research, led by the US Forest Service, crosses trees with lingering traits and studies EAB resistance in their progeny. You can listen to one of the leaders of this research, Dr. Jennifer Koch, describe this research design beginning at minute 40 of this webinar. Results are already showing that selective breeding can produce ash trees that kill EAB at a higher rate than non-bred trees.
If you plan to leave a section of ash on land you manage untreated and uncut, this area may be well suited for long-term monitoring plot research which can discern lingering ash trees. To learn more about participating in community science projects of this nature, check out MaMA’s website.
To see which community science trip is appropriate for the level of EAB infestation in your area, check out the MaMA Action Maps.