As part of Lake Appreciation Month, today’s MI Environment story by Rachel Coale of the Michigan Department of Natural Resources examines the connection between healthy forests and clean water.
Whether you’re sitting at your desk, having a cup of coffee at a local coffee shop, or taking a walk in a nearby park, look around and try to count how many things you see that are made from wood. trees. Everything from furniture to paper to the homes we live in are made from renewable forest materials.
One that doesn’t always come to mind? Clean water.
Trees are an essential part of this equation. They recycle water – most of it. In fact, a healthy 100 foot tree can absorb 11,000 gallons of water from the ground, filter it, and release it into the air in a single growing season.
Trees also increase groundwater filtration. At the landscape scale, forests are an important source of drinking water for millions of people in the United States, with 749 million acres of forest land providing more than half of the national water supply, according to the US Forest Service. In Michigan, 20 million acres of forest, covering about half the state, cleans and recycles rainwater through the watershed — about 6 trillion gallons a year — that eventually ends up in your home. in the form of clean drinking water.
“Almost all of Michigan is part of the Great Lakes watershed, which means every drop of rain on the landscape and in our water systems will make its way to the Great Lakes, and eventually the ocean,” Emily said. Finnell, Senior Advisor for the Great Lakes. and strategist at the Michigan Department of Environment, Great Lakes and Energy.
Healthy trees and forests not only provide clean water for Michigan residents, but also help maintain fish habitats by keeping the water clean, fresh, and covered.
To cool off, fish need trees
Walking barefoot on hot pavement in summer is a direct way to experience the “urban heat island effect,” in which concrete and asphalt paved surfaces heat up in the sun, raising temperatures in urban areas at scorching levels.
Planting trees can reduce this effect. The U.S. Environmental Protection Agency estimates that shady areas under trees can be 20 to 45 degrees cooler than the maximum temperatures around them, and the water that trees transpire through their leaves can cool areas further. surrounding. Forested landscapes also provide more groundwater to streams, which has a cooling effect in the hot summer.
Trees along a shore or bank have the same cooling effect on water as on a driveway. Rivers not protected by trees are more exposed to the sun’s rays and, therefore, are warmer than their forested counterparts.
Warmer waters may seem like a good thing for swimmers, but even the smallest increase in surface water temperature can have devastating effects on fish and wildlife.
“Water temperature is the most important factor that determines what kind of fish can live in a stream,” said Jan-Michael Hessenauer, a fisheries research biologist with the Michigan Department of Natural Resources. “Trout species in particular require cool, stable water temperatures during the summer months and benefit greatly from forested landscapes.”
The link between healthy trees and water
Trees keep the waters cool, and by simply keeping the soil in place, they also keep the waters free of sediment.
Most trees do not grow a long downward taproot. Instead, the roots spread outward, covering the landscape like a net. A network of interlocking roots in a forest holds the soil together and prevents it from being washed away by heavy rains or melting snow.
Tree roots also increase water storage in the soil, helping to reduce runoff from rural agricultural fields and urban parking lots. In a contest of areas planted with trees versus those paved with asphalt, the trees reduce runoff by 80% more.
By moving upward, the leaves of the forest canopy help slow down rainfall, letting it run off the land instead of splashing heavily, reducing rapid runoff that could lead to erosion.
You might ask, “Why is erosion important?” Isn’t that just dirt in the water?
The answer is – not exactly.
“A small amount of sediment in the water is natural,” said MNR fisheries resource analyst Joe Nohner. “But large-scale erosion from poorly managed sites can reduce water quality, cover fish spawning grounds and damage aquatic vegetation.”
Tree roots help hold soil that would otherwise erode into a stream and eventually end up in a lake. When soil nutrients exceed natural levels in the water, they can lead to excessive algae growth, which can be detrimental to fish that live in the lake.
For example, ciscoes are known as indicator species in lakes because their health is closely linked to the temperature and quality of the water in which they live. Without plants to absorb nutrients before they enter the water, algae growth can explode and eventually create areas deprived of vital oxygen. Lake cisco populations have completely disappeared in some inland lakes, due to rising temperatures, declining water quality, and other environmental factors.
“The cisco is an increasingly popular fishery in its own right, but it also supports trophy fishing for walleye, northern pike and muskellunge,” Nohner said. “We expect to lose even more cisco populations in lakes across the state as the waters continue to warm.
“Our strategy is to identify populations that we can save through water quality protection and encourage the planting and protection of forests in those areas.”
Similarly, the decline and local extinction of the Arctic grayling – a beautiful, blue-spotted trout-like fish with a sail-like dorsal fin, that once lived in rivers across northern Michigan – is attributed to unsustainable logging practices that cause erosion. a century ago, habitat loss and competition. MNR and its partners are now working to restore this fish to Michigan waters through the Arctic Grayling Initiative.
But with Michigan’s $21 billion forest products industry, is that possible?
“Modern methods of harvesting are very different from what they were in the 1800s,” said Keith Kintigh, MNR’s forest certification specialist, who ensures responsible harvesting and management techniques are used in state forests.
“A century ago, logging was the Wild West, but today we use tools like portable bridges and crane mats to minimize environmental impacts, and need techniques like replanting or the regeneration of seed trees to renew the landscape after harvest.This protects the landscape and the waters.
Large, mature trees along lakes and rivers provide a steady supply of organic matter like woody debris and leaves that serve as habitat and food. When trees fall into the river, they also help create important habitat features such as pools and small rapids.
Forests are essential for maintaining the clean, fresh waters necessary for grayling, trout and cisco, and for keeping lakes and rivers enjoyable for all of us.
“The same things that fish need to stay healthy that we also need for good swimming, drinking and boating waters,” Nohner said.
Protecting forests and freshwater for the future
Want to help keep Michigan’s forests and waters healthy? Whether you’re more comfortable in the woods or on the beach, you can lend a hand. Host an Adopt-a-Forest cleanup to remove illegal dumpsites in the forest that threaten fish and wildlife, or head to shore to host an Adopt-a-Beach event and pick up debris from the shore.
Closer to home, you can plant a tree to bring erosion control, shade, and water purification benefits to your neighborhood. Check out a local Conservation District sale or seedling nursery to find the best picks for your area, and be sure to pin it on the DNR’s interactive tree planting map when you do.
Tree cover projects in Michigan’s watersheds and school forest planting supported by MNR and the Great Lakes Restoration Initiative are also making a difference in local communities.
If you are a forest owner, you can take steps to sustainably manage your forest and achieve goals such as better fishing, improved wildlife habitat, sustainable wood production and more. Visit ForestsForFish.org to learn more about opportunities, explore educational videos and see examples of landowner projects.
A suggested list of trees to plant near rivers and lakes includes species like yellow birch, balsam fir, peachleaf willow, and sycamore that will thrive in moist conditions.
For those who live on the shores of a lake or river, a good place to start is to maintain a natural shoreline with native trees and plants instead of mowing the lawn right to the water’s edge. It will also help deter Canada geese, natural grazers that are attracted to manicured lawns.
The Michigan Natural Shoreline Partnership shares solutions and maintains lists of suggested native plant species to plant and renew shoreline health to protect lakes and rivers. A well-planted shoreline resists erosion and natural changes in water level and can replace the need for a man-made dike.
As you head to the beach, whip out your fishing rod, or water your garden during Lake Appreciation Month, think about the surprising source of some of that water: trees! Responsibly managed forests are essential for vibrant Great Lakes.
Legend: An aerial view of the headwaters of the Manistee River in the northwest Lower Peninsula.