The health of the iconic evergreen trees that define the Pine Tree State is at risk from climate change.
Researchers across the state have begun planting tree species from mid-Atlantic states to replace these trees as temperatures rise, extreme weather intensifies and pests spread.
They believe this practice, called assisted migration, will keep Maine’s forests functioning amid climate change. The migration would happen over time without human planting, but moving trees now will prevent ecosystems from collapsing if weather conditions get more extreme, researchers said.
Pine, spruce, cedar, ash and beech are some of the softwood tree species expected to decline here in coming decades. Hardwoods such as poplar, maple and oak are poised to take their places.
How Maine people adopt these new species on their land — if they do — will make a big difference for the country’s most forested state, researchers said. Here, the future depends partly on small landowners, unlike in other states where more land is publicly owned and managed by the government.
For now, most private foresters and loggers in Maine know conditions are changing, but they aren’t bringing in new species. It’s a big investment, and a lot of the research is still new, according to Matt Russell, a forestry analytics consultant based in Pittsfield.
“Until there’s a big earthquake within the industry, foresters, at least for the short term, are going to continue the way they are,” he said. “There’s an ‘If it ain’t broke, don’t fix it’ mentality.”
He works with larger landowners, but some small woodlot owners are interested in trying to grow these new species. More than 90 percent of Maine’s forest land is privately owned, and in 2018 a third of that was owned and managed by families. Maine forestry and forest products had $5 billion in sales overall in 2021, according to the state’s department of economic and community development.
Hardwoods tend to be more valuable, but they can take 100 years to be ready for harvest, compared with 50 years for some firs. There aren’t reliable large markets for hardwood here either, and it would take a lot of work to develop them, Russell said.
In Augusta, researchers at the Viles Arboretum think that in 50 years our forests will look like the current woods of New Jersey and Maryland. Those states have more oak and hickory hardwood trees. The loblolly pine grows there, but not yet in Maine.
Staff began planting what they call the “forest of the future” using some of those species last year, including tulip poplar, chinkapin oak, sweetgum and redbud. When it’s completed, the survival and spread of 120 trees will be monitored for decades.
The group chose species partly based on value to people and animals, according to Lauren Kircheis, director of research and education at the arboretum. Persimmon trees provide food, for example, while tulip poplar is a faster-growing timber.
These newcomers are not considered invasive because they grow elsewhere in the country, would likely end up here eventually and don’t take over existing ecosystems, she said.
In Hiram, a similar demonstration forest run by the Oxford County Soil and Water Conservation District also advocates for a variety of tree types to make forests more resilient. Losing species could leave a “gaping hole” in a forest’s ecology that would take a long time to fill, project manager Michele Windsor said.
While some native species will likely adapt to change, losing too many would create forests that are less diverse, less healthy and less productive, also reducing wildlife habitat, she said.
Across the state, the Bangor area is between habitat types, so change will be visible faster there. Some species such as spruces are at the southern end of their range, while others such as oaks are at the far north, a balance easily tipped by small changes in the climate.
Maine’s north woods are less likely to change soon because they are in a solidly colder zone, according to Jay Wason, a University of Maine professor who researches northeastern forests and climate change.
The university is also studying how Maine woodland owners respond to the idea of planting new species and managing them differently. Jennifer Leahy, a researcher of human relationships with forests, is part of a study at the Penobscot Experimental Forest investigating those questions.
There’s still a lot to learn about how research might be used and how people will respond, she said. Researchers like her, Wason and Kircheis are optimistic about assisted migration, and feel that planting new species is an empowering option for people worried about the future.
Still, many landowners they speak to are anxious about their woods.
“A lot of people have a connection to the idea of a dark evergreen forest, whereas the science has told us it won’t always be there,” she said.
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