Rain falls on a forested hillside in the mountains of western Maine, 2,000 feet above sea level. Water collects in the narrow valley surrounded by a forest of pine, hemlock, oak, beech, and birch. The water forms a channel quickly on the steep terrain, cascading over boulders and through crystal pools in wild, curving steps. Tree roots help stabilize the banks. Stems and trunks shield against the wind, and leaves keep the water shaded and cool throughout the growing season.
Come autumn, temperatures cool and the hardwoods drop their leaves, just as the rains arrive, raising water levels in the stream and flushing leaves, twigs, and other forest bits into the water. More will enter the stream with snowmelt in the spring.
An American toad (Anaxyrus americanus) discovered along a pathway in the McCoy-Chapman Forest. Photo by Carol Bourque.
The leaves settle to the bottom, or collect in eddies behind rocks and fallen logs. As soon as they get wet, the leaves begin to leach out sugars and tannin and become covered by bacteria and moldy fungi that are food for crayfish, snails, amphipods, and larval forms of insects including stoneflies and craneflies, each with its own preferred kind of leaf.
As they eat, they shred the leaves into smaller fragments that drift to downstream riffles, where a fascinating array of stream creatures have evolved sophisticated ways to catch their forest food: they weave nets of silk, use their legs to form baskets, pump water through pipes of knit sand grains, or direct the current to open mouths. These mayflies, caddisflies, black flies, freshwater mussels, and other “filter feeders” consolidate small and dispersed food particles, keeping energy within the stream reach by concentrating it in their bodies, which become food for fish and other predators, or putting it back into the current as waste.
In the pools, “collector-gatherers” – copepods, worms, mayflies, midges, minnows – consume the fines that have settled on the bottom.
As the stream flows downhill, it gains more water and gets larger, and receives less forest material relative to its area, but more sun. Light and heat stimulate the growth of diatoms and other algae, which are scraped off rocks and wood by grazers that keep the stream looking “clean.”
Snails and brook trout move the nutrients upstream and downstream; insects not eaten by fish hatch and fly into the forest, feeding birds and bats.
Some 52 species of birds and mammals have strong connections with forest lakes and streams. Deer overwinter in dense conifer yards along streams and lakeshores. Eagles and osprey nest in the tallest pines next to the water. Wood duck, common and hooded mergansers, and common goldeneye nest in waterfront tree cavities. Woodpeckers are everywhere, and northern long-eared bats use their feeding holes. Otter, mink, and raccoon eat fish, crayfish, and mussels. Salamanders and frogs migrate into forested pools each spring.
What is left of the leaves that fell last autumn? The smallest particles and shreds have flowed downstream; the organic compounds have dissolved, staining the water like tea; the forest, transformed, is moving out into the Androscoggin River and, eventually, the sea.
The more one learns about forests and water, the clearer it becomes that they are not two separate things, but connected in so many ways that eventually it becomes difficult to distinguish one from the other.
Painted trillium (Trillium undulatum) blooms on the forest floor, representing the diverse flora that thrives in the forest and along the brook. Photo by Carol Bourque.
By some estimates, more than 90 percent of the energy in a stream comes from the terrestrial environment. From a single acre, thousands of pounds of forest material enter rivers, wetlands, and lakes every year.
Change occurring in the forest, such as trees being removed, can be reflected in the water. At its worst, logging can widen streams, expose soil, erode sediment into the water, increase sunlight that warms water temperature, and starve the stream food web of leaves and wood.
In the 50 years since the Clean Water Act, “best management practices” to reduce water pollution have been developed and refined and are now in widespread use, reducing water-quality impacts from forestry operations by more than 90 percent, according to scientists with the National Council for Air and Stream Improvement. Key among these practices is filter areas or buffers – zones of protection around water bodies.
A 2014 study of buffer effectiveness published in the Journal of the American Water Resources Association concluded that, in general, buffers of at least 100 feet are needed “to protect the physical, chemical, and biological integrity of small streams.”
In Maine, buffer requirements vary by town, but are not required for streams draining watersheds less than 300 acres, such as the upper branches of Chapman Brook.
Yet, such headwater streams are the most abundant across the landscape. They provide a continual supply of fresh, clean water to larger rivers and lakes. They tend to be flashy, their flow varying with precipitation, their path easily disrupted by landslides and tipped-over trees. The inhabitants of headwater streams are adapted to turbulent conditions, but still require shade, cool temperatures, and forest surroundings.
“As long as water quality is maintained, they can handle changes in flow, etc., and quickly return after disturbances, especially if the landscape and soil around the site is intact,” said Hamish Grieg, associate professor of Stream Ecology at the University of Maine, who has studied the impacts of timber harvest on small streams. “These are quite resilient organisms to begin with.”
At Chapman Brook, old stumps are visible next to the water, but some limbs and trees have fallen into the channel. The water is clear, and moss grows thick on streamside boulders.
Mahoosuc Land Trust acquired the 493 acres that include Chapman Brook from the McCoy family, who had farmed and logged and cared for the land since the early 1800s.
Healthy streams in the Androscoggin watershed abound with life, from the secretive filter feeders, crayfish, and other invertebrates, to the wildlife that prey on them. Photo by Mac Davis.
In mid-December, the land trust was getting ready to harvest timber from the property. Executive Director Kirk Siegel was a little nervous, but mostly excited about telling the story behind the decision – only the second timber harvest in the land trust’s 31 years of owning thousands of acres of forestland.
“The visuals of logging can be troubling to people who aren’t familiar with it,” said Siegel. “We want to demonstrate how ecological forestry can enhance wildlife habitat while producing profitable timber, and set an example for other landowners. We want to show people we are proud of this.”
Another goal is to ensure the McCoy Chapman Forest is resilient to a changing climate. The project is supported by a grant from the USDA Natural Resource Conservation Service.
Carla Fenner, an ecologist with New England Forestry Foundation, a partner in the project, drafted the habitat-restoration plan. The plan promotes harvesting techniques meant to mimic characteristics of an older forest – a greater abundance and diversity of tree types and ages, with foliage in all levels of the canopy – to support a greater abundance and diversity of wildlife. Most of the McCoy-Chapman woods are either all one age with little new growth in the understory or “two-aged” with older pine, hemlock, and oak, as well as a second layer of birch, moosewood, aspen, and beech saplings.
Even on a well-tended property like the McCoy-Chapman forest, “management practices of the recent past have simplified forest habitats,” according to Fenner. “To reintroduce a diversity of forest age and stand-size classes creates as many niche habitats that our flora and fauna are known today to need.”
Sherman Small is leading the harvest. He grew up in South Paris, graduated from the University of Maine forestry program in 1980, and immediately went to work as a logger. “By the time I started, there were already buffers on streams,” he said. “It’s just common sense. If there’s a stream, buffer it.” He has surveyed and managed forests across western and northern Maine, and now works for New England Forestry Consultants.
Small planned patch cuts and selective harvests to remove the aspens and smaller diseased beech, “releasing” the red oaks into sunlight so they can grow and bear acorns. He marked some large hardwoods, hemlock, and pine for cutting (especially double-topped softwoods, which drive him nuts), while others will be allowed to grow larger. “We are cutting the ones that are ready to go,” he explained, pointing out weak crowns and struggling beeches.
Boston College geomorphologist Noah Snyder walks along a stream channel eroded by an extreme rain event on July 3, 2018, upstream of Kennebago Lake. A boulder- and leaf-covered terrace defined the streambed prior to the rain event; channel deepening was likely caused by the failure of a downstream culvert. Climate change is leading to more frequent intense precipitation events in the Northeast. Photo by Tim Cook.
He marked a “W” on trees with woodpecker holes, or snags with dead and broken tops, or beeches with bear-claw marks. These “wildlife trees” will be left standing so they can provide habitat for birds, bats, and other small mammals. Downed trees stay unless they’re in the way of the skidder or are a safety hazard.
“The idea is to create as diverse a mosaic of structural conditions as possible,” said Fenner. Adequate leaf cover, both on the trees and on the ground, allows forest birds to forage and safely move through the woods. Leaves and wood provide burrowing areas for reptiles and amphibians, and keep the ground cool and wet so they can travel to and from vernal pools and the stream.
No cutting will take place within 150 feet of Chapman Brook. “The current condition of the brook is pretty good now,” said Fenner, “and going into the future, larger and larger inputs of organic material will go into the stream.” In this “natural habitat zone,” the forest will grow as it will, creating what Fenner describes as “messy, woody, brushy structure.”
Water has always been an important link between people and forests. For the Anasagunticook, the Abenaki people whose homeland included the Androscoggin, the river and its tributaries were the route to hunting and gathering grounds of the great woods. Their waterside settlements, from the Magalloway to Canton Point to Merrymeeting Bay, are among the largest and oldest Indigenous historic sites in the region.
European colonists added another layer of relationships as they used rivers to access and process timber, beginning a legacy that persists on the landscape to this day. It is evident in the old-growth white pine forests reduced to scattered groves; in river flows altered by log drives and constrained by highways and railways; and in the reservoirs and large lakes created by dams that also blocked Atlantic salmon and other migratory fish from bringing their marine nutrients into the uplands. A century of making paper from the forest is evident in persistent water pollution: dioxin, mercury, and other chemicals. The patchwork pattern of forest ownership and history is visible in satellite images, as are the thousands of miles of logging roads and skid trails.
Today, it is the roads associated with forestry that have the most impact on these rivers. Road construction disrupts and dislodges soil, exposing sediment that is then vulnerable to erosion. Maine Forest Service has found that erosion controls were effectively applied at 88 percent of monitored harvest sites and 78 percent of monitored road-stream crossings in 2018 and 2019. But when bridges and culverts at stream crossings are too small, broken, or improperly installed, they can interrupt natural drainage patterns and block fish and other animals from moving up and down streams.
Culvert failure. Photo by Tim Cook.
Such movement is especially important for brook trout, which seek out the cold water of headwaters, deep lakes, and groundwater seeps in the summer months. The mountains of western Maine are the only parts of the state projected to stay cold enough for brook trout in the future – as long as the land stays forested, and riparian habitats are accessible. Fish advocates say wider buffers around wetlands and stream channels are needed, and are working with forest landowners to install larger bridges and open-bottomed arched and box culverts. These “stream smart” crossings protect fish and give streams plenty of room to flow naturally. Extra room is becoming critical as precipitation in the region has become more frequent, erratic, and intense.
In July 2018, 50 miles north of Chapman Brook, six inches of rain fell in two hours. The deluge washed out three bridges as well as culverts in the Pingree forests in the Cupsuptic River watershed, which are managed by Seven Islands Land Company. Repairing the damage cost more than $100,000, according to Alex Ingraham of Pingree Associates. Upstream of Kennebago Lake, two culverts were eroded away as a small flooded tributary carved a chasm six feet deep.
“Here in the western part of Maine, the steep terrain causes water from large rain events to move at fast velocities,” said Mike Richard of the Maine Forest Service. Richard’s job includes conducting harvester certification trainings, where large rain events are a topic of discussion. “I often recommend sizing culverts larger, anticipating that 25-year events may be happening more often,” said Richard. “I am seeing more roads built with check dams in ditch lines as well as retention pools being used to help slow down and filter water.”
Older forests store more carbon, and riparian woods like the Riverlands, where the floodplain is wide and the channel complex, accumulate even more carbon – as much as some tropical forests. Photo by Katie Stuart.
Trees, too, help prevent flooding: forested land soaks up between half and one-third of the precipitation that falls on it, and the rest finds its way to bodies of water, either over land or, mostly, through the soil. Wetland forests absorb even more precipitation.
Chapman Brook flows out of the McCoy woods, beneath North Road and the Portland-Montreal Pipeline, through level terrain, curving between sandy banks. Trees lean this way and that, and some have broken and lain across the channel, which braids around patches of gravel. The clear brook merges into the wide, dark current of the Androscoggin River, a great moving mass of water collected from the northeast flank of Mount Washington; Aziscohos, Rangeley, and Umbagog lakes; and the Magalloway, Swift Cambridge, and Dead Cambridge rivers.
The Androscoggin has already passed through nine dams and impoundments. It’s easy to forget them, standing thigh-deep in ferns beneath great arched galleries of silver maples, or following bear and moose tracks through the mud of drying oxbow pools.
The river forest includes wooded islands, flat lowlands, and terraces. The silver maple forests are rare, because so much of the silt-rich floodplain has been cleared for agriculture. The Anasagunticook Tribe took advantage of the fertile ground and grew corn along the river thousands of years ago.
Seven miles upriver from the mouth of Chapman Brook, Mahoosuc Land Trust recently preserved “The Riverlands,” 18 distinct wetland areas across 34 parcels within and along the Androscoggin River, preserving connectivity for wildlife moving between the White Mountains and Mahoosuc Range. The river itself is the cause of disturbance in floodplain forests, eroding and undercutting banks, causing trees to die and fall.
Historical records, and the evolved ecology of aquatic life, suggest our rivers once contained massive quantities of wood that are difficult to imagine now. Centuries of logging, industrial use and navigation, and a human tendency to want to keep woods and streams “clean” have eliminated many forest-river connections. The emptiness ripples through the system. Without wood, a river supports fewer fish.
The decline of dead and dying wood in Northern Forest watersheds also means the woods are storing less carbon than they could.
Dead wood represents about one-tenth of forest carbon; living trees are another quarter to one-third; but most carbon resides in the soil, in the mass of roots and fungus and decaying organic matter beneath the trees. Older forests store more carbon, and riparian woods like the Riverlands, where the floodplain is wide and the channel complex, accumulate even more carbon – as much as some tropical forests.
All of the various forest-based approaches to removing carbon from the atmosphere, including planting trees and preventing loss of forest land, also protect water quality, according to a synthesis of recent findings from Northeast Wilderness Trust. The U.S. Forest Service agrees. Keeping watersheds forested and in good condition is the best way to ensure a plentiful supply of clean, cold water.
At Chapman Brook – now protected by a wide buffer and soon to be surrounded by a diverse and messy forest – the shredders, filter-feeders, scrapers, and collector-gatherers; the birds and the bats; the deer and the trout will find their place in their great continuum of woods to water.
This article and the accompanying infographic were made possible by grants from The Betterment Fund and Maine Timberlands Charitable Trust.
Web Extras
by Catherine Schmitt
Science writer Catherine Schmitt is the author of three books, including The President’s Salmon: Restoring the King of Fish and its Home Waters. Find more of her work at catherineschmitt.com.
This article is part of the Forests to Water Series, a Northern Woodlands magazine special series exploring the various connections between forests and water, with a focus on watershed ecology and collaborative, community-based efforts that support watershed health and community resilience to climate change. See the accompanying infographic, A Connected Landscape, which also appeared in the Spring 2021 issue.