Twice a week, from June through September, volunteers at Acadia National Park haul bags of soil — each of which are between 5 and 20 pounds — to the summits of Sargent and Penobscot mountains.
Some of the hikers are repeat locals and others are first-time visitors. All, however, have the same mission: to help reverse years of erosion on Acadia’s highest peaks, a consequence of visitors trampling native vegetation.
The trek is part of a volunteer program run by the park, Friends of Acadia — a local conservation group — and the Schoodic Institute, a nonprofit research hub. The hike aims to address years of human-caused damage to Acadia’s fragile summit ecosystems.
It’s one of several programs under Friends of Acadia’s “Wild Acadia” initiative, which focuses on conservation projects that will prepare the park for future climate conditions.
A portion of the restoration project relies on experimental science, in part because researchers don’t yet know how to restore an ecosystem as unique as Acadia’s summits. There are 145 plant species on the park’s summits, according to Chris Nadeau, a lead scientist on the project.
Vegetation loss is a problem across the Northeast, but Acadia’s sub-Alpine ecosystem requires an innovative approach that hasn’t been done before.
“We’re constantly trying to learn how to improve summit restoration, and we do that using a learning-while-doing approach,” Nadeau said. “We don’t wait to restore until we have all the answers because we will never have all the answers. We restore in such a way that we can learn what’s working, what’s not working and then we continually adapt based on that science.”
Acadia’s peaks are exposed to high winds and severe cold. To cope with these conditions, the native vegetation that lives along the summit tends to grow close to the ground. But with thousands of visitors summiting some of Acadia’s most popular mountains, trekkers have destroyed those low-growing native plants over time.
“Those two things don’t combine well,” Nadeau said. “We’ve got a lot of people and this really low-growing vegetation, so, inadvertently, a lot of visitors will step on vegetation. It only takes a couple times for that to happen before the plants die. Once the plants are dead, the soil that they were holding in with their roots just washes off the mountain in a heavy rain event or a heavy windstorm.”
The park service first recognized the need to restore Acadia’s summits in the late 1990s and early 2000s, Nadeau said. At that time, park officials began limiting visitors from walking on certain parts of Cadillac Mountain summit. As the park’s highest peak and the only one with a public road that leads directly to the top, Cadillac has become one of Acadia’s most popular destinations.
But soon park officials noticed that the native vegetation wasn’t returning to Cadillac, and scientists pivoted to a more active approach to restoration. In 2016, researchers launched experiments on the summits to find out what combination of soil, seeds and erosion fabric would best revegetate the park’s granite-covered peaks.
In 2023, scientists added two remote summits to their restoration efforts: Penobscot and Sargent mountains. Yet, unlike Cadillac, the only way up those two mountains is by foot.
Before settling on humans to carry up the soil, researchers weighed other means of transportation: by mule, helicopter and highline systems. Since those means would require trail closures and more complicated planning, experts determined the most efficient way to bring the soil up the mountain was by foot.
That’s where the volunteers come in.
Last year, volunteers carried 5,049 pounds of soil up the mountains — all of which was used during the subsequent fall to find new ways to restore native plants in the sub-Alpine ecosystem.
There are about 200 restoration plots split between Cadillac, Penobscot and Sargent mountains, Nadeau said.
On a Wednesday morning hike up Sargent — the park’s second highest peak — led by Ameri-Corps fellow Lauren Knierim, roughly 20 volunteers summited the mountain with a total soil load of 311 pounds.
The Wednesday group consisted of a mix of first-timers — including a couple from Florida who learned about the hike from the park website — and area locals who summit the mountain monthly, one of whom shared homemade blueberry ice cream with fellow trekkers on a previous trip.
During this week’s hike, volunteers were hauling soil from Portland-based Coast of Maine Organic Products, which donated 100 bags of enriched soil mix to the project. The soil was loaded and delivered to the carriage roads — the hike’s starting point — by Frost Farms, a Bar Harbor garden center and plant nursery.
The trek also teaches park visitors about leave no trace principles, which are essential to the restoration project as so much of summit decay has come from humans crushing native plants. The need to continue restoring the summits’ delicate ecosystems will continue until “people learn that they can’t step on those plants,” Nadeau said.
“People probably aren’t going off the trail and stomping on vegetation on purpose,” Nadeau said, noting that hikers often don’t realize they’ve strayed from designated paths. “So we are working with the park service to figure out how we can keep people on trail in some of these degradation hotspots.”
Although researchers haven’t yet determined which mountains they will expand to next, subsequent phases of the restoration project will include other peaks, Nadeau said, adding that they will first focus on revegetating rare species, like the Nantucket shadbush and boreal blueberry.
The program will welcome dogs on Sept. 12 for their third annual canine-friendly edition of the summit trek, according to Perrin Doniger, a spokesperson for Friends of Acadia.