An emerald ash borer. Credit: Courtesy of the University of Maine

Maine forestry officials are broadening restrictions about the movement of some wood and forest products to try to stop the spread of a pair of invasive pests.

The new rules are designed to halt the spread of the emerald ash borer and hemlock woolly adelgid. The pests can cause damage to the state’s forests.

The Maine Department of Agriculture, Conservation and Forestry said it’s expanding quarantine rules about the emerald ash borer to include northern Cumberland County and southern Oxford County. The rules regulate the movement of items such as hardwood firewood and ash products with bark.

The quarantine area to prevent the hemlock woolly adelgid also has expanded. The area now includes all of Knox, Lincoln, Sagadahoc and York counties and parts of five others. The quarantine regulates hemlock seedlings and branches and other items.

The state said it’s important to implement the measures now because flight season for the borer begins in a little more than a month.