Key to Cadillac plant restoration still elusive 



ACADIA NAT’L PARK — When French explorer Samuel de Champlain sailed into Frenchman Bay in September 1604, he wrote in his journal that mountains on the large island to the west had no trees at the summit. 

That observation led him to name the place l’Isle des Monts-deserts, which means the island of barren mountains.  

Of course, they weren’t completely barren; there likely have always been patches of small plants, grasses and shrubs around the summit. But those that grew at the top of Cadillac Mountain were burned by the great fire of 1947. The subsequent erosion caused by rain and wind left only shallow soil, if any at all. And millions of visitors tramping around have taken a heavy toll.  

“The ferns, flowers, shrubs and grasses of Cadillac Mountain have a tough enough time surviving the elements, but the biggest threat of all may be the pounding of constant foot traffic,” began an “Acadia National Park On my Mind” blog post two years ago. 

Acadia officials have long been concerned about the loss of vegetation at the summit.  

Over the years we have brought in a number of folks to give us advice on how we might approach this,” said Abe Miller-Rushing, Acadia’s science coordinator. “They all said we needed to take an experimental approach.” 

So, that is what a team led by botanist Jill Weber and plant conservation specialist Bill Brumback has been doing for the past seven years. First, they took an inventory of plants on and around the Cadillac summit.  

“That greatly facilitates planning, because if you know what you have you can plan how to manage it,” Weber said. “We documented 151 species at the summit.” 

In deciding which species to try to grow in areas that had been bare, they looked at the types of plants in existing patches nearby. Then they experimented with different methods of restoring those species.  

“Our restoration plots are in the most open, exposed areas that get the most disturbance,” Brumback said. “We have been using plants [started in a nursery] and seeds in various combinations of soils to try to figure out which method was the best for generating plant cover. 

“You can look at which method is cheaper, which one is quicker and which one gives you the better cover.” 

Volunteers working with Weber collected the seeds of about 20 plant species on Cadillac, and seeds of 11 of those were sown in experimental restoration plots. 

The researchers experimented with different types of soil and with soil augmented with material such as compost, peat and loam.  

They presented their findings in an online forum in late March. 

“We found that adding soil to degraded areas increases plant numbers and percent cover,” Weber said. “In plots where we added soil, the depth of soil was a factor in how good the germination was, but it didn’t really translate into increased percent plant cover after four or five years. And the planting medium we used didn’t affect cover. 

“Most of the vegetative cover at the end of the study was due to species that weren’t intentionally planted,” Weber said. “Once the soil was down in our plots, habitat was created for any [naturally deposited] seeds.” 

Brumback said the plots where plants from a nursery were grown achieved a much higher percent of cover than those planted with seeds.  

“We are at 47 percent with plants and 20-something percent with seeds after four to five years,” he said. “We’re trying to get to 62 percent, but it’s not quite clear how long it’s going to take to reach that.” 

Along the apparent advantage of starting with plants instead of seeds, there is a significant downside. Planting plants costs about 12 times as much as planting seeds.  

So, what do Brumback and Weber recommend? 

“We think continued monitoring of this is essential,” Brumback said. “We realize that there can be small experiments going forward. But it would be interesting to stand back and watch a little longer before making large efforts up on top of Cadillac. 

“We don’t know what the final composition of the revegetation plots is going to be. In three or four years, at least, it will be very interesting to see what that composition is.” 

Working on or supporting the Cadillac revegetation project were Acadia’s vegetation management crew, Schoodic Institute staff, Friends of Acadia and Native Plant Trust. Brumback worked at the Trust for four decades before retiring as conservation director in 2019. 

Staff at the Trust’s Nasami Farm in Whately, Mass., propagated the plants that were used in the revegetation project. 

Dick Broom

Dick Broom

Reporter at Mount Desert Islander
Dick Broom covers the towns of Mount Desert and Southwest Harbor, Mount Desert Island High School and the school system board and superintendent's office. He enjoys hiking with his golden retriever and finding new places for her to swim. [email protected]
Dick Broom

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