When English settlers first colonized North Haven in about 1762, they found an island largely covered with hardwood forest. Maples, oaks, ash, and other hardwoods were available for building homes and heating them with enough left over to build small boats and schooners. Today, the remnants of that original forest can still be found mixed in with the spruce, balsam, cedar, and fir trees that predominate. Many of the remaining hardwood trees here grow along boundaries of old farms or in hilly, areas too difficult to log. In Mullins Head Park, large oak and ash trees still grow far enough away from the beaches, campgrounds, and walking trails that most visitors don’t notice them.
On a cool morning this fall, Mullins Head Park Commissioner, Chuck Curtis, took me on a trek to a grove of fifty to sixty Ash trees living in a remote, rocky section of the park that had not been logged in nearly a century. I had asked him if there were any ash trees in the park and his response was to show me this large collective of currently leafless trees that were thriving pretty much as they had for decades. Some were quite large, others slender saplings with no more than a five-inch diameter. The ash trees continue to reproduce and grow. They were mixed in together with a number of large oaks that had also escaped logging and disease.
Chuck explained that the grove was large enough that even in the hottest days of summer the air there was cool and fresh. With the oaks and a scattering of Balsam firs, the ash trees had created their own microclimate, one that was hospitable and welcoming to human beings with no price of admission at all.
These ash trees, along with others on the mainland are now in danger from a small iridescent green insect, ominously named the Emerald Ash Borer (Agrilus planipennis). These insects have already begun killing trees in two counties in Maine. The state is aware of this and is doing what it can to prevent the further destruction of ash trees but the borer is tricky and mature trees are almost always beyond saving before the beetles’ destruction is discovered since much of the damage occurs during the larval feeding stage inside the tree trunk, over many months. Maine has tried to educate the public and to designate several counties as “buffer” zones in an attempt to curtail the spread of the EAB. Knox County is one such area, currently insect free but in potential danger.
We can do a few things to help the ash trees, starting with prevention. Be sure never to bring firewood or bundles of camp wood from other states where the borer has already wrecked its destruction. Purchase your firewood or camp wood in Knox county and you will help contain that nasty beetle. Urge friends and visitors to do the same and to spread that practice as far as possible. If you have ash trees, monitor them closely for any visible damage, such as brittle bark or thinning canopies.Natural biological controls are also effective and can be important in suppressing EAB larval development. Both woodpeckers and native ground nesting wasps feed on EAB larvae.Improving habitat for birds and bees provides benefits across the ecosystem.
As a last resort, and best applied by a professional, there are chemical drenches that one mixes with water and pours on the ground around the tree’s trunk. The problem, of course, is that these drenches, taken in by the tree’s roots and spread through its vascular system to its branches, are strong pesticides that will also harm beneficial insects and may run off into nearby water. Finally, if you do suspect a tree has been infested by the EAB, report it. If we can slow the spread of EAB, perhaps a cure will eventually become available.
When I bought our property on Southern Harbor in the mid 1970’s, it came with one large ash tree. That tree had grown to considerable size because it was in a clearing that had been maintained by Nancy Crockett Howard’s father as a place to dry his fishing nets. It stands alone, not in a grove or group and every Spring I watch carefully to see if it will continue to be healthy. So far, she seems to be doing very well.
(For more detail on the EAB in Maine, see https://www.maine.gov/dacf/mfs/forest_health/invasive_threats/eab/index.shtml ).