Forest Health and Monitoring

forest tent caterpillar on leaf
Forest tent caterpillar on leaf. (Maine Forest Service)

The Division of Forest Health & Monitoring was established in 1921 to protect the forest, shade and ornamental tree resources of the state from significant insect and disease damage and to provide pest management and damage prevention for homeowners, municipalities, and forest land owners and managers, thereby preserving the overall health of Maine's forest resources (video).

Here are our most frequently asked about tree pests and diseases for the fall 2022:

  • Beech Leaf Disease Beech leaf disease is an emerging disease.
    (Target: Beech)
  • Hemlock Woolly Adelgid Hemlock woolly adelgid populations are extreme and are causing tree decline and mortality in portions of coastal Maine.
    (Target: Hemlocks)
  • Emerald Ash Borer Emerald ash borer has recently been found in two new counties (Kennebec and Androscoggin. Let us know if you think you have seen damage from emerald ash borer.
    (Target: Ash)
  • Spongy Moth (PDF | 304 KB)  Western Maine and several other scattered locations are currently experiencing a spongy moth (formerly Gypsy Moth) outbreak.
    (Target: Hardwoods)
  • Browntail Moth Maine is currently experiencing a browntail moth outbreak.
    (Target: Hardwoods)



Want to know more about where pest activity has been observed and quarantines exist? We are working on a consolidated map, but in the meantime, please find these resources for specific observations:


Learn more about what quarantines might affect your forest and tree products at the links below.


Here is a sampling of recent webinars from our staff. You can view other Forest Health Recordings on our YouTube playlist.

Municipal Emerald Ash Borer Update December 5, 2022

The Maine Department of Agriculture, Conservation and Forestry provided an update for city and town tree and forest managers and public works staff on the known status of emerald ash borer in Maine, current state efforts, municipal opportunities as well as updates on other insects and diseases affecting forests and trees.

Overview of Beech Leaf Disease June 17, 2022

Presenters: Cameron McIntire, Plant Pathologist with the USDA Forest Service in Durham, NH and Aaron Berghdal, Plant Pathologist with the Maine Forest Service, Forest Health and Monitoring Division.

Mr. McIntire and Mr. Berghdal provide updates on the current situation of Beech Leaf Disease in Maine.

Landowner Class 101: The Basics of Diagnosing Tree Disorders in Maine June 21, 2021

This presentation in the June 2021 Landowner 101 class covers diagnosing tree disorders in Maine, as well as the latest on the recent discovery of beech leaf disease in Maine.

Towards Early Detection of Oak Wilt in Maine July 8, 2020

Forest Pathologist Aaron Bergdahl presented information about recognition of oak wilt disease.

Contact Us:

Didn’t find what you were looking for? Don’t forget to check out the Hot Topics, and feel free to contact us for more information.

Postal address:

168 State House Station
Augusta, Maine 04333-0168
Phone: (207) 287-2431

Physical location:

90 Blossom Lane
Augusta, Maine 04333

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Several Maine Forest Service programs are wholly or partially funded by the USDA Forest Service under various authorities.

In accordance with Federal law and U.S. Department of Agriculture policy, this institution is prohibited from discriminating on the basis of race, color, national origin, sex, age or disability. (Not all prohibited bases apply to all programs.)

To file a complaint of discrimination: write
USDA, Director, Office of Civil Rights
Room 326-W, Whitten Building
14th and Independence Avenue, SW
Washington, DC 20250-9410
or call (202)720-5964 (voice or TDD).

USDA is an equal opportunity provider and employer.