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Invasive species detected in southern Maine

On Oct. 18, a rare and invasive beetle known as the Emerald Ash Borer, scientifically known as Agrilus planipennis, was found in Portland, Maine. The beetle is called the Emerald Ash Borer due to its iridescent green carapace and was found in a trap designed to catch these invasive insects that help with early detection.

Gary Fish, Maine’s state horticulturist, reported that this threatening beetle likely came into Portland from a firewood transfer from Lebanon, a city approximately 50 miles south of Portland that recently faced an infestation.

The Emerald Ash Borer poses a great threat to Portland’s ecology. The beetle is known for its ability to swiftly destroy ash trees as they burrow into the trees and cut off the supply of nutrients. Ash trees make up a plentiful amount of Portland’s ecosystem and forests and are an important ecological and community asset.

Ash is only about 2% of the Maine forest and about 4% of the hardwoods in Maine,” Fish noted. “That in itself is an impact, when you lose that much of our forest.”

According to the USDA, there are nearly 24 billion trees in the state of Maine’s forests. This means there are 1 to 3 million ash trees in the state of Maine. According to Fish, the entire ash tree population could be destroyed by Emerald Ash Borers within 10 to 15 years. 

Emerald Ash Borers’, while they threaten the health of individual trees, pose a large risk to the ecological integrity of a community. Buffalo Olmsted Parks Conservancy of Buffalo, New York, reported that ash trees can catch excess stormwater, increase the quality of air and absorb carbon. These factors have been scientifically proven to prevent natural disasters and aid in the management of dangerous carbon emissions.

The state of Maine simply cannot have a healthy environment without ash trees. If the Emerald Ash Borers continues to threaten the forests of Maine, the state may face the risk of increased flooding, increased air pollution and other serious issues that will impact the communities of Maine. 

Some of Maine’s bureaucracies recognized and recently responded to this serious and threatening Emerald Ash Borer infestation.

The Maine Department of Agriculture responded to the infestation with a “stop movement order.” This order forbids the movement of ash trees and firewood into Portland and neighboring areas, such as Windham, Scarborough, North Yarmouth, Gorham and Chebaque Island. The order encompasses more than 10 square miles of southern Maine’s communities.

In addition, the Maine Forest Service has released a species of non-stinging wasps in an attempt to control the Emerald Ash Borer population.

This is the third Emerald Ash Borer infestation Maine has seen since April of 2019, when York and Aroostook counties found ash trees with evidence of the beetle.

While it is difficult for people to mitigate the spread of this insect, there is one important step individuals can take to prevent the transfer and infestation of this invasive species. Since Emerald Ash Borers are usually spread through firewood transfers, it is important not to bring your own firewood into the state.

For students that like to go camping, but live outside of the state of Maine, they should know that bringing firewood into the state is at best not legal and at worst a huge threat to our forest resources,” Fish said. “[The threat] is not only from the Emerald Ash Borer, but many other tree-killing organisms can be spread in firewood. That is also true now for firewood that may have been cut in York County and far northern Aroostook County.”

For more information about emerald ash borers, go to For a map of the stop movement order, go to

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