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Managing woodlands in the St. Louis Moraines and Tamarack Lowlands

The area of north-central Minnesota known as the St. Louis Moraines and Tamarack Lowlands subsections includes all or parts of Aitkin, Carlton, Cass, Crow Wing, Itasca, and St. Louis counties.

These areas have been shaped by the glacial history of Minnesota, just like the rest of the state. Rolling hills in this area are caused by glacial deposits called moraines. Lowlands cover a large part of this region as a result of ancient lake plains, where glaciers previously melted and left behind flat topography with lacustrine (lake drainage) deposits. The Sax-Zim Bog is a great example of this landform.

The low-lying topography and wet conditions led to the accumulation of slowly decomposing vegetative material called peat on top of those lacustrine deposits. These conditions created the large areas of bogs that we see today, characterized by tree species such as black spruce and tamarack and a great diversity of bird species. The Sax-Zim Bog is a very popular destination for Minnesota’s birders.

Creating climate refugia

Models of the state’s future climate may not favor the survival of some species you see in your woods today. However, that doesn’t mean these species don’t hold intrinsic ecological, cultural or economic value. You can work to retain these species in your landscape and protect them from the impacts of climate change by creating forest refugia.

Species in this region that may be most vulnerable to climate change, pests and diseases:

  • Red pine (Pinus resinosa) and jack pine (Pinus banksiana) are projected to be vulnerable to both a warmer and wetter climate in this ecoregion. Consider thinning existing pine stands to promote sufficient growing space. Harvesting in gaps can also promote a diversity of species, age classes, and structures that will improve the resilience of the stand. Learn more about managing red pine and jack pine stands.
  • Black ash (Fraxinus nigra), white ash (Fraxinus Americana), and green ash (Fraxinus pennsylvanica) are projected to do well in warmer and wetter climates but are all extremely vulnerable to emerald ash borer. Black ash is a cultural and ecological keystone species in northern Minnesota and is an essential part of Minnesota’s forests. If ash is present in your woodland, learn more about managing ash woodlands in response to emerald ash borer.
  • Slippery elm (Ulmus rubra) is also projected to do well but is susceptible to Dutch elm disease. With no disease-resistant cultivars of slippery elm currently available, landowners should be cautious in choosing where to encourage this species.
  • Quaking aspen (Populus tremuloides), big-toothed aspen (Populus grandidentata) and balsam poplar (Populus balsamifera) are projected to be vulnerable to a changing climate in this ecoregion. These species regenerate by root suckering (sprouting), and these aspen stands provide many benefits to wildlife throughout their life cycle. Harvesting in gaps can also promote a diversity of species, age classes, and structures that will improve the resilience of the stand. Learn more about managing aspen forests.

Potential future tree species

As our climate changes, some tree species might be able to move into new areas as habitat becomes more suitable. Climate scientists with the USDA Forest Service have identified tree species with migration potential in the St. Louis Moraines and Tamarack Lowlands.

Planting species not historically found in the region does carry some risk. Before you plant, learn more about assisted migration strategies, and work with a forester or another natural resource professional to determine the best options for your land and goals.

Woodlands of Minnesota Handbook

The Minnesota Department of Natural Resources has created a series of woodland handbooks that provide landowners with information on their region’s conditions, frequent challenges, and advice on setting and reaching management goals. The St. Louis Moraines and Tamarack Lowlands handbook includes information on wildlife, plants, invasive species, geology, landscape and watershed management for this special region of north-central Minnesota.

Reviewed in 2024

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