How do you know when a tree has reached its natural life expectancy, or when it has become decayed and presents a public safety issue? And how do you balance that with the joy it brings to humans who enjoy its beauty and appreciate the shade it offers? What about the wildlife it supports? Those are questions we grappled with as we looked at three large, old trees along the access road to our Gilsland Farm Audubon Center headquarters in Falmouth.
Risk tree evaluation is an ongoing process where land managers evaluate tree conditions with regard to public safety and tree health, especially after storm events. As part of this process, property managers and arborists here at Maine Audubon identified three prominent trees along our access drive that display signs of concern—two Siberian Elm trees and a Sugar Maple.
These three large stately trees have graced the viewshed at Gilsland Farm for decades, and have no doubt appeared prominently in countless photos, paintings, and memories in the 50 years the property has been a Maine Audubon sanctuary. The Sugar Maple was almost certainly here when Gilsland Farm was first given to Maine Audubon in 1974, and healthy specimens can live 300-400 years. Maples are incredibly important and invaluable for nearly every taxa of wildlife as a source of food and other ecosystem services. Maples host 282 species of caterpillars here, enabling this tree to provide necessary food for the many species of birds which breed at Gilsland Farm. For humans, this tree has also been tapped for maple syrup, provided leaves and samaras for craft projects, and been climbed and swung from. All this is to say this tree has an endearing legacy for the people and wildlife that visit Gilsland Farm.
The Siberian Elms, which are exotic to Maine, were likely planted around the same time Maine Audubon took on the property. By the 1970s, Dutch Elm Disease was sweeping through the continent destroying thousands of the native American Elm trees, an iconic species that had become commonplace in city parks and promenades. As it does today, the horticulture industry responded to the threat facing our beloved elms by producing alternatives which are resistant to the blight through cultivating and hybridizing exotic species. Our Maine Audubon predecessors clearly wanted big trees fast, and these two Siberian Elms met the challenge. Part of their “resistance” comes from the fact that they are tens of thousands of miles from their home ecosystems, meaning they haven’t ever been part of the Gilsland Farm food web. But we can still love them for the shade they’ve provided, the carbon they have sequestered, and the bird nests and squirrel drays they have no doubt held up through the years.
Tree inspection includes examining all sections of the tree beginning with the root zone, trunk flare, main stem, branches and branch unions, twigs, and foliage depending on the season. While it is easiest to determine the fate of a dead tree, often these risk defects are hidden from casual view in a living tree. This is the case for the Sugar Maple along our access road. It looks fine as you head toward the Visitor Center but it is concerning when you view it from the other direction, as you exit the sanctuary. Unfortunately, decay in the root flare and main stem, and progressive dieback, are serious signs pointing to the need to remove and replace this tree.
Nearby, the two Siberian Elms (which are now on Maine’s invasive species list) are also posing risk resulting from recent storm damage. As a species, the Siberian Elm is often prone to failure. While it can be sad to lose mature trees, the reality of continued decline and increased risk make the remove and replace option the best course of action. As a result, we made the difficult decision to have the trees removed this October.
The circle of life continues; as these three trees live out their life spans and are removed, we look to trees that are emerging and trees we have planted nearby and in other parts of the sanctuary.
For example, another Sugar Maple was planted about 50 yards from the removed one roughly twenty years ago. This tree mimics and matches the fall foliage glory and caterpillar host potential of its older ancestor, but is just now reaching breeding/seed age. The odds are good that this tree will see the year 2200 and do a whole heck of a lot of good for wildlife, people, and the climate along the way.
In 2017, the Maine Chapter of The American Chestnut Foundation planted two chestnut trees just under the Siberian Elms, and another between the Outdoor Classroom and pond. These hybrid trees are immune to the blight that almost wiped out what was once the most abundant tree in North American forests, and were planted by colleagues to celebrate the life of a dear friend and partner to Maine Audubon, Jed Wright. Like the elms they are replacing here, chestnuts once made for huge and iconic presence in pastoral views like this until their demise, decades before Gilsland Farm was gifted to Maine Audubon.
We hope you will join us in honoring and remembering what these trees have given us and the wildlife and habitat here, and embrace and celebrate the new trees taking their place.
