Great Lakes forests
Great Lakes forests encompass a diverse range of forest ecoregions located in North America, primarily around the Great Lakes and the St. Lawrence River. These forests are characterized by three main types: the Northern Forests, the Eastern Great Lakes lowland forests, and the Southern Great Lakes forest ecoregion. Once rich in biodiversity, these regions have faced significant fragmentation due to industrialization and agricultural development, which has drastically reduced original habitats. The Northern Forests remain the most intact, primarily consisting of boreal forests, while the Eastern and Southern ecoregions have seen severe habitat loss, with over 95% of the Eastern Great Lakes lowland forests impacted by development and pollution.
The climate of the Great Lakes Basin is influenced by various air masses and the lakes themselves, resulting in unique weather patterns and ecological phenomena. Conservation efforts are in place to restore these vital ecosystems, with initiatives and collaborations across both the U.S. and Canada aimed at addressing the challenges posed by climate change and habitat degradation. Despite the ecological pressures, some wildlife, including mammals like the moose and birds such as the bald eagle, continue to thrive in these forests, highlighting the importance of ongoing restoration and protection efforts.
Great Lakes forests
- Category: Forest Biomes.
- Geographic Location: North America.
- Summary: Three distinct types of forest ecoregion are spread across a vast section of North America and are anchored by the Great Lakes and the St. Lawrence River. Fragmented now, the habitats here are making a slow recovery.
The Great Lakes drainage basin covers more than 200,000 square miles (518,000 square kilometers) and contains more than 11,000 miles (17,700 kilometers) of shoreline. Here, once-vast stands of boreal forest around the north of the lakes, transitioning to deciduous forests along the southern shores, are highly fragmented today because of the effects of industrialization and agriculture. Reforestation efforts in the twenty-first century, however, have resulted in the slow increase of forest area, extending positive effects on local habitats and biodiversity.
Climate and Ecoregions
The climate of the Great Lakes Basin is affected by three factors: air masses from other regions, the location of the basin within a large continental landmass, and the moderating influence of the lakes themselves. In the winter, the Great Lakes region is affected by two major air masses, which contribute to the characteristically changeable weather here. Arctic air from the northwest is very cold and dry when it enters the basin, but is warmed and picks up moisture traveling over the comparatively warmer lakes. When it reaches the far shore, the moisture condenses as snow, creating heavy snowfalls on the lee side of the lakes in areas frequently referred to as snowbelts. The temperature of the lakes continues to drop during winter; ice frequently covers Lake Erie, but seldom fully covers the other lakes. Less frequently, air masses that are warm and humid enter the basin from the Gulf of Mexico.
The basin encompasses a variety of distinct ecoregions, including prairies, savannas, woodlands, and wetlands. The Great Lakes forests have been further subdivided into more specific forest ecoregions. The Northern Forests ecoregion is wide and crescent-shaped, extending from northern Saskatchewan, Canada, east to Newfoundland and south to the northern shores of the Great Lakes. The region is hilly and lies on the Canadian Shield-Precambrian granite bedrock that is among the oldest on Earth. The hills are morainal deposits left by the most recent glacial retreat, more than 10,000 years ago.
Boreal forests consisting of large stands of black and white spruce, balsam fir, jack pine, tamarack, and other conifers cover more than 80 percent of this region. Many small lakes and areas of exposed bedrock also dot the landscape. Along the southern reaches of the Northern Forests region, there is a transition to a mix of white birch; aspen; and varieties of poplar, sugar maple, beech, spruce, and oak.
Immediately south of the Northern Forests ecoregion lie the Eastern Great Lakes lowland forests. This ecoregion is highly fragmented, with more than 95 percent of the habitat lost to development and pollution in the watershed of the St. Lawrence River. Numerous rare ecological phenomena can be found in this transitional zone, separating the boreal forests to the north from the broadleaf deciduous zones to the south. A mosaic of freshwater marshes, dunes, bogs, fens, and both hardwood and conifer swamps exist. Very rare and unique alvar (limestone plain) communities—also called pavement barrens—support a suite of prairie communities that are globally endangered. Rare stands of ancient white cedars, some determined to be almost 800 years old, grow on the exposed limestone cliffs of the Niagara Escarpment. The wide variety of forest types and habitats makes this region one of the richest in animal species in continental North America.
The Southern Great Lakes forest ecoregion covers much of the industrial heart of the Midwest, including southern Michigan, much of Ohio and Indiana, and extreme southwestern Ontario. The area is so heavily populated and developed that essentially no large blocks of the original habitat remain. The topography ranges from very flat to low rolling hills. Once dominated by deciduous forests of sugar maple and beech, the onrush of agricultural, industrial, and urban development has altered or eliminated nearly 100 percent of the original landscape here. Wetland losses in this region have been severe. Ohio has lost 90 percent of its wetlands, and 80 percent of the tamarack swamps of southern Michigan have been eliminated.
The fourth Great Lakes forest ecoregion is the Western Great Lakes forest. Reaching across the northern portions of Michigan, Wisconsin, and Minnesota into southeastern Manitoba and northwestern Ontario, this entire ecoregion was once covered entirely by glaciers. Characteristic vegetation is a mixed forest influenced by the topography and drainage of the area. The Western Great Lakes forest includes northern coniferous forest, northern hardwood forest, boreal hardwood-conifer forest, swamp forest, and peatland. Approximately 20 percent of this region remains as intact habitat. Most of the original mature pine forests have been logged and replaced by birch and aspen, with only scattered pine; this alteration has made a deep impact on the biodiversity of the region.
Human Interaction
Indigenous people first settled the Great Lakes Basin about 10,000 years ago, establishing hunting and fishing communities around the lakes and their tributaries. The population of the entire region is estimated to have been perhaps 100,000 in the 1500s, when the first Europeans arrived looking for a passage to Asia. By the early 1600s, Europeans had explored the St. Lawrence Valley as far as Georgian Bay, and developed a thriving fur trade. The British maintained control through the American Revolution, resulting in the Great Lakes marking the boundary between the new United States republic and the remainder of British North America; the population grew on both sides of the border as each side attempted to settle and develop the area first.
While the initial settlers had a modest effect on the ecosystem, limited to the exploitation of some fur-bearing animals, the following waves of immigrants logged, farmed, and fished commercially, turning the lakes and their waterways into major trade highways and bringing about profound ecological changes.
The southern and eastern Great Lakes forests have been the most heavily affected by human activity. Pockets of original habitat are rare and remain highly isolated, limiting the species they can support. About 20 percent of the Western Great Lakes forests, in contrast, remain as intact habitat. Forest coverage is greater here, but the intense harvesting of the original pine forests has resulted in the conversion to forests of aspen and birch. While adequate for supporting wildlife, these younger trees are dramatically changing the biodiversity of the area. The boreal Northern Forests ecoregion remains the most unchanged and is 80-percent forested today.
Conservation Efforts
The Great Lakes Basin is a mix of public and private lands, containing portions of two sovereign nations, two Canadian provinces, and eight American states. As a result, hundreds of local, regional, and private special-purpose groups have jurisdiction over the management or protection of some aspect of the basin or the lakes themselves. The U.S. Forest Service, the U.S. Environmental Protection Agency (EPA), and a multitude of private industry programs promote stewardship of public and private lands. Forested lands can also be enrolled in sustainable forestry certification programs such as the Sustainable Forestry Initiative, the Forest Stewardship Council, and the Canadian Standards Association.
These programs require participants to manage the quality and distribution of wildlife habitats and to contribute to the conservation of biological diversity in their regions. Cooperation between and among agencies of the United States and Canada is also necessary to confront the issues of climate change. Climate in the Great Lakes region is already changing: Shorter winters, warmer annual average temperatures, heavier rain and snowstorms, and extreme heat events are occurring more frequently. Air and water temperatures are increasing; lake ice cover is decreasing. These changes are expected to alter lake snowpack density, evaporation rates, and water quality. As a result, jurisdictions in Canada and the United States are studying how to adapt to the anticipated impacts on both lake and river water and across the numerous habitat types here. The EPA has released four versions of its Great Lakes Restoration Initiative, which by 2024 had already funded over 7,500 restoration projects for a total of more than $3.7 billion. The initiative has been in place since 2010.
Wildlife
Some of the wildlife that still thrives in parts of the Great Lake forests include such mammals as the gray wolf, Canada lynx, coyote, marten, little brown bat, beaver, moose, and river otter. Among the birds that breed, nest, or feed here are such predators as the bald eagle and northern harrier, as well as the double-crested cormorant, loon, tern, least bittern, bobolink, common merganser, and Kirtland's warbler, an endangered species. Characteristic reptiles and amphibians here included salamanders, frogs, toads, and snakes. The fish population runs from brook trout and walleye to lake sturgeon and lake trout.
Bibliography
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Bowie, Taylor. “EPA Drafts New Plan Addressing Threats to Michigan’s Great Lakes.” Michigan Public, 14 Aug. 2023, www.michiganpublic.org/environment-climate-change/2023-08-14/epa-drafts-new-plan-addressing-threats-to-michigans-great-lakes. Accessed 4 Nov. 2024.
Bowler, Sydney. "Study Finds Need for Public to See Connection Between Forests and Clean Drinking Water." Great Lakes Echo, 26 May 2022, greatlakesecho.org/2022/05/26/study-finds-need-for-public-to-see-connection-between-forests-and-clean-drinking-water/. Accessed 4 Nov. 2024.
Davis, Mary Byrd, ed. Eastern Old-Growth Forests: Prospects for Rediscovery and Recovery. Washington, DC: Island Press, 1996.
Flader, Susan L., ed. The Great Lakes Forest: An Environmental and Social History. Minneapolis: University of Minnesota Press, 1983.
Grady, Wayne. The Great Lakes: The Natural History of a Changing Region. Vancouver: Greystone Books, 2007.
Stearns, Forest W. “History of the Lake States Forests: Natural and Human Impacts.” In J. Michael Vasievich and Henry H. Webster, eds. Lake States Regional Forest Resources Assessment: Technical Papers. St. Paul, MN: U.S. Department of Agriculture, 1997.