There are many forest types in the Pine Tree State
By Joe Rankin
Forests for Maine’s Future writer
The Maine Woods.
Writers use the phrase all the time. As though the entire state was covered with a blanket of spruce and fir and pine, with some maples thrown in. But as anyone who has walked or hiked in the state knows, the time-honored phrase only works if we use it as a plural, not a singular. There is no one Maine Woods, but there are Maine woods. On the ground the blanket looks more like a quilt.
And that’s the beauty of it. There’s variety here. In tree species, understory plants, fungi, mammals, reptiles, birds, wildflowers.
Andy Cutko, a forest ecologist with the Maine Natural Areas Program, marvels at that variety in forest types.
“There is just a geographic breadth to Maine’s forests, ranging from the sub-boreal up in the St. John and Allagash basins down to the temperate central Appalachian forest of oak and pine we find in southern Maine,” he said. “But also from an elevation standpoint we’ve got everything from coastal red maple swamps in southern Maine to subalpine krummholz on Mt. Katahdin.”
Loggers and foresters often divide the state’s forest very simply: softwoods, hardwoods, mixed woods.
The Maine Natural Areas Program goes to the other extreme, parsing it into some 40 different forest ecosystems, said Cutko, the author, with Susan Gawler, of The Natural Landscapes of Maine: A Guide to Natural Communities and Ecosystems. The Program has classified the state’s landscape into 104 distinct natural communities in all, ranging from mountain summits to coastal dunes.
Trying to narrow it down a little might give you around a dozen “forest types,” based largely on the varieties of trees in them. That’s actually quite a lot for one state, experts say.
That’s partly a function of Maine’s size, its position along the coast, and the variation in elevation between its coast and mountains. Soil types and depths vary as well. And south-facing slopes of hills and mountains tend to grow different trees than north-facing slopes, because of the micro-climatic differences. Another factor: is the land swampy or well-drained/ White pines c0mpete well on dry, sandy soils; red maples thrive in waterlogged areas.
“The distance between Maine and Fort Kent is over 300 miles, roughly the same as going from Kittery to Philadelphia. So we really have a lot of variation defined by latitude. In the north we have spruce and fir and the northern hardwoods. But in the very southern part of the state you’re walking through forests that are at home in places like Pennsylvania or Connecticut — red oak with scattered white pines with shagbark hickory and chestnut oak,” said Cutko.
David Field, a professor emeritus at the University of Maine’s School of Forest Resources, says Maine probably has more variation in its forests than most states.
“Maine is really unusual in that it has a great deal of diversity north and south, east to west, because of the ocean, because of the mountains. If you were to go from the coastal plain of North Carolina, where you have an awful lot of loblolly pine, to the mountains, where you would see stuff like you would see in Maine, there’s a lot of diversity there. But Maine, for its size has a bit more diversity than many states.”
Field notes that Maine doesn’t have the mix of hardwood species that you would find in forests in the mid-Atlantic states, all the oaks and hickories, but “it’s still a good mix of stuff.”
And mix is, the right word.
It’s not as though forest types are set out like town boundaries. So many factors are involved in determining what grows where that a simple two-mile hike can take you through several of the forest types in the state. Sometimes what’s on one side of a mountain will be vastly different than what’s on the other side. Cutko points to the Camden hills, where the south sides tend to be dominated by northern red oaks, the north sides by spruce and fir.
Field, an avid hiker who’s been involved with the Maine Appalachian Trail Club for decades and wrote the chapter on plants and animals along the Trail in the current edition of the Appalachian Trail Guide to Maine, maintains that backpacking the 200-plus miles of the AT in Maine will take you through all but a tiny handful of the major forest types in the state.
So, here’s an attempt to break down Maine’s forest types into a manageable handful, or two:
The spruce-fir forest covers a huge swath of northern and eastern Maine. Red spruce and balsam fir are its primary constituents, though often northern hardwoods like maples, birches and beech, and other softwoods like hemlock, white cedar, and pines, are interspersed. Both Field and Cutko recommend a hike along the Four Ponds section of the Appalachian Trail south of Rangeley. Start at the parking lot on State Route 4 and go south.
The beech-birch-maple forest is also one of the most common forest types in Maine. Specifically American beech, yellow birch and sugar maple, though it can include red maples and northern red oak as well. This type covers much of the central part of the state and is the dominant hardwood type of forest. Where it mingles with spruce and fir, it gives rise to the “mixed wood” moniker. Field said a hike on the AT north of Monson toward Lily Pond will give you a look at a forest of large hardwoods like this.
The white pine forest is one where Maine’s iconic evergreen is the dominant tree, though it’s almost always mixed with spruces, hemlocks, red maples and even red pines. While usually one of the tallest, it’s not always the most numerous. It can be found along the coastal plain, where the soil is sandier and well-drained,but also on dry and dry-ish spots inland, especially rocky ledges or sandy ridges. A good example of a white pine forest is Flint Woods in Farmington, where the white pines grow with younger hemlocks. Field recommends taking the AT south from the parking lot on the East B Hill Road near Andover to see another example.
The rich northern hardwood forest, made up of sugar maple, basswood and white ash forest, is usually found in areas with nutrient-rich soils, with maple the dominant tree species. This type of forest is found on hillside benches, along floodplains, or in protected areas nestled at the bases of slopes, so-called “coves.” Cutko said there are many examples of this type along State Route 113 in the White Mountain National Forest.
The oak-hickory forest is found in patches in southern Maine. It is more characteristic of forests farther south. The canopy is made up of black, red, chestnut or white oaks and shagbark hickories. It often is found with oak and pine forests. Public trails traverse through this type at Mount Agamenticus in the town of York.
Pioneer forests are common in the state. The term doesn’t refer to people, but trees that colonize disturbed areas. They’re made up of paper birch and quaking aspen and big-toothed aspen, as well as cherries, all primary succession species. Most of these trees grow fast, but don’t live long and are eventually replaced by other species. This forest type can be found all over Maine, wherever farm fields are returning to forest, wildfires have crossed the landscape, or the land has been logged.
Krummholz. German for crooked wood, is a unique dwarf forest found in the subalpine zone on some of the state’s highest mountains: Notably Katahdin, Saddleback Mountain and Mt. Abraham. It’s made up of stunted and twisted spruces, firs, birches, and, rarely, larches, that tenaciously cling to the thin, acid, gravelly soils above treeline and below the rocky summits. Field says the AT on Saddleback threads through one of the best examples of prostrate krummholz in New England.
Atlantic white cedar swamps. Atlantic white cedar is at the northern part of its range in Maine and is rare. Pockets of this forest type exist from the mid-coast south. To see examples, Cutko recommends going to Mt. Agamenticus or the U.S. Forest Service’s Massabesic Experimental Forest.
Jack pine forests or woodlands (Cutko explains that, in ecological terms a ‘forest’ has a closed canopy, while in a ‘woodland’ the trees naturally grow farther apart and more light hits the forest floor) are found at spots along the downeast coast and inland. The two-needled jack pine’s cones hang tenaciously on the tree, and need fire to release their seeds. To find examples head for the Schoodic Peninsula section of Acadia National Park, Lobster Lake in northern Maine, or the No. 5 Bog area south of Jackman, said Cutko.
Pitch pine forests or woodlands are found in the sandy coastal plains of southern Maine, the midcoast area and on Mt. Desert Island. This three-needled pine grows on sandy barrens or rocky ledges. These woods are generally open, with oaks and other species of pine mixed with the pitch pines. There are also pitch pine bogs and pitch pine barrens. You can see a pitch pine forest at Reid State Park in Georgetown and on Dorr and Champlain Mountains in Acadia National Park, said Cutko.
Northern white cedar forests grow in wet areas in northern and eastern Maine. This cedar species is one that likes to keep its feet wet, or at least damp. A good place to see this type of forest is the Debouille Public Reserved Lands Unit in northern Maine. Field said there are some northern white cedar forests along the AT.
Cutko said the northern white cedar forest type is one of his favorites. “They tend to occur in more alkaline bedrock situations. As a result there are just a number of distinctive orchid species that grow there, the showy lady’s slipper and the yellow lady’s slipper among them,” he said.
Seeking out the state’s different forest types can open your eyes to the myriad factors that go into putting together an ecosystem, from the height of the water table to the elevation of the land to the spot’s orientation to the sun. It’s a particularly good way to teach kids about the natural world because one question generally leads to another, said Field.
“It’s just a wonderful bit of education. If you take the time to look around and see the forest and the trees and study individual trees, look at the branches. Hemlock, for instance, has the finest twig you’ll find in the woods, just a delicate fine twig. Then the bark will vary a lot on different trees.” Field recently took his grandchildren, visiting from Georgia, on a hike on the coast, where he showed them the difference between spruce and fir needles, and how to tell a pine, spruce and fir cones apart.
Cutko said what impresses him is the resilience of Maine’s forests, or forest types. “Whatever happens to them they seem to grow back. I think that’s somewhat distinctive of Maine and not necessarily true of the southeastern U.S. or the Amazon Basin or Indonesia where the soils are a lot more sensitive to activity. It’s really a good place to be managing forests and recreating in them as well,” he said.
For Cutko, the topic of resilience brings him back to the three factors that determine what type of forest occupies a particular site: the physical, such as soils, hills, valleys, and whether it’s a south or north-facing slope; disturbances, such as fire, logging, or insect infestation; and climate.
“If you think about it, only one of those things is fixed: the physical aspects, what we call the enduring features. The bedrock and soils and landform. That isn’t going to change,” he said. “But who knows about the other two. I think with a potentially changing climate and potentially different natural disturbance regimes it will be interesting moving forward.”
Joe Rankin is a writer on forestry topics who can spend hours happily wandering through a forest armed only with a tree identification guide.