Ojibwe Lifeway: Maple Sugaring and Birch Bark Harvesting (“ziigwan”-spring)

Harvesting birch bark, GLIFWC photo

In this unit you will investigate impacts of a warming climate on sugar maple and paper birch, two trees of special importance to the Lake Superior Ojibwe. Making maple sugar and harvesting birch bark are cultural practices that that occur in the spring. As you work through this unit, think about how climate changes affecting the sustainability of these tree species could be indicators of how climate change might affect the activities and traditions you enjoy.

Key species: sugar maple (Aninantig) and paper
birch (Wiigwaas)

Possible climate change stressors: Higher air
temperatures, changes in precipitation patterns,
shorter winters and less snow cover, drought, increased storm events.

Impacts include: Decline or loss of species due to A geographically defined area in which a specific category of plant life is capable of growing, as defined by climatic conditions. growing zone changes, mortality due to drought, productivity decrease, root damage due to freezing and thawing, storm damage, die off due to insect infestation, increased competition from invasive plants


  • Understand the cultural importance of sugar maple and paper birch to the Ojibwe both historically and today.
  • Understand the importance of these tree species to Lake Superior communities both socially and economically.
  • Identify habitat conditions needed to sustain healthy stands of sugar maple and paper birch trees.
  • Identify three climate change stressors that could impact the sustainability of both sugar maple and paper birch based on an evaluation of scientific climate change trends and Evidence that you can see, feel, or experience based on what you observe around you. place-based evidence.
  • Hypothesize what tree species might make up Wisconsin’s forest under a warming climate and shifting A geographically defined area in which a specific category of plant life is capable of growing, as defined by climatic conditions. growing zones.
  • Develop and test a hypothesis to determine how these climate change stressors are affecting Wisconsin’s ecosystems and cultures.
  • Implement a service learning project to educate others about how to reduce climate change impacts.


Wisconsin’s original forest ecosystems were drastically changed between 1850 and the early 1930s when nearly all of the trees were cut down to provide wood for a growing country. Great, intense fires followed fed by the dry "slash" left from logging. This time period, and the treeless land that was left behind, is called the “Cutover.”

Today, almost 50% of northern Wisconsin is once again covered by forests. Many important tree species grow in a wide range of habitats from coastal wetlands to dry barrens. Many of these tree species play an important role in Ojibwe culture and to all communities because of social and economic benefits they can provide. Warmer conditions have the potential to significantly change the composition of these forests and how we use them. This unit will focus on two tree species that were traditionally used by the Ojibwe that could be significantly impacted by climate change.

Paper birch, sometimes called “canoe birch,” “white birch,” or “wiigwaas” by the Lake Superior Ojibwe. It is a member of the “Northern Boreal Forest Community.”

Paper birch is a medium sized tree. As trees go, it is relatively short lived and reaches “old age” around 60-80 years old. The tree gets its name from its white paper-like bark that is easily peeled into thin layers. Other tree species in this forest community include quaking aspen, white spruce, balsam fir and cedar.

Paper Birch tree, Scott and Ruth Bassett photo
The paper birch tree is culturally important to the Lake Superior Ojibwe who have used its bark to make everything from wild rice winnowing baskets to birch bark canoes that could carry over two tons of cargo. Today the Ojibwe continue these traditions. Birch bark harvesting must be done in a respectful manner and at the right time of the year, so that the tree is not damaged.

Paper birch is an important tree species for lumber and veneer. With its beautiful white bark, it is a popular landscape tree in our yards. It is also an important tree to Wisconsin’s tourism industry because of its strong association with Wisconsin's “northwoods” experience.

Sugar maple, sometimes called “hard maple” or “aninaantig” to the Ojibwe, is Wisconsin’s state tree and no wonder! It is the dominant tree of the maple-beech-basswood forest type common in the Lake Superior and Great Lakes region. This group of tree species is often referred to as the “northern hardwood forest,” also called the “Northern Mesic Forest.” Other tree species in this forest type include red maple, basswood, white ash, red oak, quaking aspen, yellow birch, ironwood, with American beech being found only in eastern areas along Lake Michigan.

Sugar maples can grow to over 200 feet and may live for 400 years or more. Sugar maples can be identified, from other maples, by the “U” shaped notches between the lobes of their leaves. A trick to recall this identifying characteristic is to remember the “U” in sugar maple. The sap of all maples is somewhat sweet, but the sugar maple is the sweetest. Hence the name “sugar” maple!

Sugar maple can be identified from other maple trees by the “u” shaped notch between their leaf lobes. Tip:  Think of the “u” in sugar!

The Ojibwe used “Traditional Knowledge is the total understanding by indigenous people of their relationship to the earth and the universe, and the knowledge inherent within that relationship. This knowledge includes the spiritual, physical, emotional, and mental aspects of a person and related components of the earth and universe to these aspects.”- Stewart Hill, Cree. traditional ecological knowledge and learned from elders to know when and how to tap and process maple sap into a delicious, nutritious food product. They also used inner bark medicinally to create a cough syrup.

Historically, each spring Ojibwe families gathered at sites called “sugar camps” or “sugar bushes” where they stayed for several months to collect and process maple sap. It was hard work, but a festive time as families and friends came together for the yearly event. The sap they collected was not only boiled down to make maple syrup, but was often cooked even longer to make maple sugar. Maple sugar was formed into small cakes which could be preserved longer than syrup and were easier to carry. Maple sugar was traditionally stored in a birch bark container called a “makak.” The sugar was used to flavor and preserve other foods. It was also a valuable commodity that could be traded for other items.

Ojibwe Sugar Camp around 1850
Today many Ojibwe people continue this tradition as families gather together each spring to tap maple trees and enjoy making maple syrup and sugar together.

The sugar maple tree is economically important for many families and businesses that produce maple syrup. The tree provides high grade lumber and veneer used in construction and furniture making. Sugar maple trees are an important landscape tree in our yards and communities. They provide welcome shade in the summer and spectacular fall colors in autumn.

Tapping Sugar Maple today, GLIFWC photo


Paper birch and sugar maple grow in different habitats.

Paper birch is a “pioneer species” meaning that it is among the first tree species able to grow on sites where a disturbance, such as fire, has exposed bare soil. Paper birch can tolerate drier sandy soils. It is a sun-loving tree. Depending on the soil type, over time stands of paper birch eventually shade themselves out and are replaced by shade tolerant species such as sugar maple. This process is called “succession.”

Sugar maple trees can grow on many different soil types, but prefer “ Containing a moderate, balanced supply of moisture mesic” sites meaning locations with moderate soil moisture. Unlike paper birch, sugar maple is a “shade tolerant” species. It can grow in the full sun, but also can also tolerate growing in the shade of the mature trees above it, including the shade of other sugar maples. Because of this, sugar maples make up what is called a “climax forest.” Once it is established, the forest type tends to perpetuate itself unless a disturbance such as fire, storm damage, or logging opens the forest canopy allowing more sunlight to reach the forest floor. When this happens, sun-loving pioneer species, such as paper birch, can get established again.


Paper birch is a “ The subarctic, evergreen forest dominated by coniferous trees such as spruce, fir, and pine. boreal” forest species meaning that it is found between 50-55 and 65-70 degree latitude in the Northern Hemisphere. While paper birch can be found on drier sites in central Wisconsin, the largest volume of paper birch (69%) is located in northern Wisconsin. Northern Wisconsin is the southern edge of this species' A geographical area where an animal normally lives range.

Northern Boreal Forest, WDNR

Sugar maple is found throughout Wisconsin. The greatest concentration of sugar maple is found in northern Wisconsin where it is a dominant species within the northern mesic forest.

Northern Mesic Forest, WDNR

Climate Related Issues

Climate change models project that both sugar maple and paper birch are expected to experience large declines in their current A geographical area where an animal normally lives range due to climate warming. The Climate Tree Atlas suggests that paper birch and sugar maple are among 12 tree species that will show large declines in their current range, especially under climate scenarios where carbon emissions are higher than they are today.

Increased Temperatures: Temperature increase is expected to have the greatest impact on sugar maple and paper birch because of its effect on soil moisture and the ability of trees to get both water and nutrients.

Changing Precipitation: Less precipitation in the form of rain, especially during the critical growing season, can affect the sustainability of sugar maple and paper birch by limiting the amount of available soil moisture. Decline of paper birch is already occurring in northern Wisconsin, especially in drier habitats.

Drought: This variable is linked to rising air temperatures and decreased soil moisture from less precipitation and less frequent precipitation. Sugar maple prefers sites with moderate soil moisture and current habitats could become too dry to sustain it. Although paper birch is adapted to growing on drier sites, drought conditions could make these habitats too parched even for paper birch.

Shorter, Warmer Winters: Both sugar maple and paper birch are adapted to Wisconsin’s long, cold winters. While a shorter, warmer winter might sound good to some people, it will have serious effects on the tree community. Shorter warmer winters reduce the flow and the production of maple sap. These conditions have led to a significant negative impact on Wisconsin’s maple syrup industries. As a The subarctic, evergreen forest dominated by coniferous trees such as spruce, fir, and pine. boreal species, paper birch is well adapted to temperatures as low as -50 degrees F, with a blanket of snow. Warmer winter temperatures give invasive species, insect pests, and plant pathogens a greater chance to survive and expand their range.

Increase Storm and Wind Events: Intense storm events and flooding can impact trees by physically damaging them or by affecting their habitat through erosion and flooding.

Disease, Pests, and Invasive Species Increased stress on trees weakens their ability to recover from disease or pest attacks. For example, paper birch when stressed is susceptible to an insect pest called the bronze birch borer. This pest destroys the tree’s ability to transport food and water between the roots and the leaves. It can cause tree die-back and often death.

As climate change brings longer growing seasons, higher temperatures and more extreme weather events, invasive species and diseases will have greater opportunities to spread. Insect pests like the gypsy moth and emerald ash borer take advantage of stressed trees and recently disturbed areas. They grow and reproduce quickly, giving them the upper hand over native species. Pests and pathogens, in addition to the increased risk of fire posed by hotter and drier conditions, make managing forests an increasingly complex task.

It’s All Connected

Wisconsin’s forests are home to many different species of plants, birds, and other wildlife. As climate changes these forests, it will change the other species that can live there, too. Increases in summer and winter temperatures, changes in seasonal precipitation (more in the winter, less in the summer) in much of the state, and more frequent extreme weather events such as very heavy rainstorms or heat waves will affect wildlife. As their habitats change in response to climate warming, they may need to find new food sources, or cope with new competitors, invasive species, and disease.

Some species, such as the American marten or spruce grouse, may no longer find suitable habitat in the state and will disappear from Wisconsin. Other species, such as white tailed deer, turkey, and opossums may increase in numbers