Half a century ago, summertime in Blue Hill was shaded by hundreds of American elm trees forming a canopy over its downtown streets.
Though hundreds of them are gone now, victims of widespread disease, Blue Hill and nearby Castine still maintain some of the last populations of 19th-century elms in Maine.
They remain alive through some combination of chance and increasingly expensive disease prevention efforts; other elms bred to resist the disease have been planted in both towns in the last 25 years.
But as the original elms are approaching the ends of their natural lifespans, new pests and diseases raise some questions about what future tree-lined streets may look like.
“We are mortal, and the trees are mortal too, and so they’ll always be dying,” said Phil Norris, Blue Hill’s tree warden, who on Tuesday oversaw the all-day process of removing yet another large, historic elm amid a recent outbreak of dying trees. “You know, they all have to come down sooner or later.”
American elms were planted rapidly on downtown streets across America in the mid-1800s, valued for their majestic, sweeping canopies. Norris still sees them as one of the best street trees because of their tolerance for salt and traffic.
But the disease that got a foothold in the state decades ago has wiped out most of the American elms outside of forests, according to the state. The fungus that causes it is spread by small beetles and their larvae under the bark; fungicide injections can help prevent it, which is generally what towns rely on.
There aren’t signs of increase in the disease across Maine, according to Allison Kanoti, state entomologist with the Maine Forest Service. The state’s tracking mostly involves casual observations and reports from members of the public.
It’s not exactly clear why Blue Hill and Castine’s trees escaped that decimation, but in the decades since, they have invested significantly in continuing to fight off the disease.
In Castine, the elms are part of the town’s identity, referenced in the town’s motto and an attraction for summer tourists. It runs a “robust” program to care for about 75 elms along village streets, according to Tree Warden Don Tenney.
“We’re pretty happy with how things are going,” he said. “And we know these trees are old.”
Voters there approve about $25,000 for elm care each year, which combined with fundraising creates a roughly $45,000 annual budget. It covers trees within 35 feet of the center line of roadways, most of them in the village, which the town is responsible for by ordinance. Roughly 175 other elms in town are cared for by private owners.
For the “streetscape” trees, the town funds a rotating three-year schedule of “root flare” fungicide injections and cutting back limbs once they start showing signs of disease.
The injections aren’t a guarantee, though, and generally don’t protect against disease spreading underground, which recently took out one tree and appears to have weakened another.
In Blue Hill, about 400 trees were removed from the 1970s to the 1990s, said Norris, who has been the town’s tree warden since 2001. Until recently, the disease appeared to abate somewhat, with a tree or two removed every five years or so.
The town once covered all costs for elm maintenance and later moved to a 50-50 split with property owners when Norris took the role. Now, the costs are the property owners’ responsibility.
That hasn’t appeared to dampen enthusiasm for preserving the trees, Norris said – partly because residents are proud of their elms, and partly because the trees now cost about $4,000 to remove.
In his tenure, the cost of arborist work has risen from $35 an hour to $250, spiked by pandemic demand. Having an experienced arborist on hand has been critical for Castine, Tenney said.
Other new tree diseases and pests working their way into Maine also complicate the choices for replacements as towns consider ways to diversify species for more resiliency.
“It’s tough to pick one that isn’t disease-prone at this point,” Tenney said.
He would have once planted beech trees to replace elms, but those are threatened by the rapid spread of beech leaf disease. Norris is relieved his town didn’t rely too heavily on ash trees; Blue Hill is preparing for the arrival of the emerald ash borer beetle by choosing 75 trees it will try to save with insecticide injections.
Castine’s newer street trees include maples, oaks, lindens, birch, some beeches, a tulip tree and a black gum. In Blue Hill, Norris has added more disease-resistant elms, along with sugar maples, white oaks and bur oaks.
Both towns have also planted other types of elms within the last 30 years, bred to be resistant to disease and sold under names like Liberty, Valley Forge, Princeton and Jefferson.
Blue Hill’s town hall is shaded by one legacy elm whose days are numbered by old age, Norris said. Younger elms in an array of sizes surround it in an arc, ready to replace it. And across the street, American elms have sprung up on their own in the parking lot of the defunct Merrill and Hinckley store.
He’s focused more heavily on replanting elms than Castine has, and would like future generations to see a canopy over Union Street again.
Other trees in downtown Blue Hill show browning or thinning leaves – certainly signs of Dutch elm disease in some cases.
“They don’t live forever, none of them,” Norris said. “You know, they all have to come down sooner or later.”
