Acadia forests: Everything is changing.
David Byrne had it wrong; it’s not the same as it ever was. Everything is changing.
The woods of Acadia National Park on Mount Desert Island are amazing. You can hike from a granite-topped bald hill into the trees and in seconds be enveloped in darkness. If you spend some time hiking around this isle of many trails, you will find differences in the forest. Besides the apparent change from woodlands to bald hill tops, the forested zone has some distinct clusters of tree species. There is the dark woodland of conifers, contrasted by the birch and aspen bunches.
Pre-European forests on Mount Desert Island (MDI) were dominated by the cold-adapted spruce-fir forests (Balsam Fir is typical along the Maine coast): these forests housed spruce grouse, red-backed voles, providing food and cover. The squirrels and chipmunks take advantage of the energy packed in the cone. While many bird species, such as the Blackburnian Warbler, Boreal Chickadee, and wrens, take advantage of the food and cover of the forest.
Above are the predators seeking out those that break cover. The Merlin hunts the small birds, while the Saw-whet Owl is listening and trying to hone in on small rodents scurrying in the undergrowth.
Changes to the woods of Acadia have taken place, grace of mankind. The largest, tallest spruce were cut for ship masts in the 1800s. Quicker and more dramatic than the famous fire of 1947, which burned 17,000 acres, the fire decimated the forest. Those regions are now the aspen and birch woodland. Those smaller, faster-growing trees took over the burnt zones.
Other threats:
Outbreaks of moth larvae, the spruce budworm, can impact the spruce coverage. Outbreaks are sporadic. Maine has had outbreaks in the 1910s, 1940s, and a big outbreak in 1967 and 1993. Acadia did not experience the same level of devastation as Northern Maine during those difficult years. Over the last few years, the outbreaks have sparked up again in Maine. The 2023-24 season in Maine was good for the moth, and bad for the Spruce. This peak included the Acadia Spruce.
Other tree species are at risk from the likes of the Emerald Ash Borer, a recently detected beasty on Mount Desert Island. This boring beetle affects ash trees. I bet you figured that out from the name. The Helmock Woolly Adeilgid has also been found in Acadia National Park. This beastly causes needle loss and death of hemlock trees.
There is also a scale insect that damages and eventually causes the loss of Red Pine trees on the island. Noooooooo, I love the Red Pine.
Where the Spruce Still Stands, the best remaining patches in Acadia National Park and MDI Schoodic Peninsula, Cadillac Mountain North Ridge Trail (scattered old trees), and the Western parts of Mount Desert Island
Of course, Climate Change is the oncoming threat.
The cold-adapted spruce will be stressed by milder winters and drought. Long-term shifts will cause the southern edge of the spruce-fir range to move northward. Will Acadia soon become unsuitable? Probably.
These forests are fading but are not gone. A hike through these forests still allows a quiet, often dark foray, even on a bright day, into Acadia’s past. The Acadian views are still here, beautiful, but changing. FYI, the changing forest may attract more pileated woodpeckers, which prefer the deciduous trees over the spruce.
Sources and Further Readings:
Schmitt, C. & Lambert, K. (2014).
Acadia’s Forests: A Century of Change. College of the Atlantic & Schoodic Institute.
US National Park Service – Acadia National Park Resource Briefs.
https://www.nps.gov/acad/learn/nature/resource-briefs.htm
Lorimer, C. G. (1977). The presettlement forest and natural disturbance cycle of northeastern Maine.
Ecology, 58(1), 139–148.
Whitney, G. G. (1994). From Coastal Wilderness to Fruited Plain: A History of Environmental Change in Temperate North America.
NPS Fire History Reports – 1947 Bar Harbor Fire.
Janowiak et al. (2018). New England Forest Ecosystem Vulnerability Assessment and Synthesis. USDA Forest Service, GTR-NRS-173.
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