Restoration at the Arboretum

At the Arboretum, more than 900 acres are managed as natural areas.

On these lands, staff and trained volunteers work to restore and conserve plant communities that naturally occur in the upper Midwest, including oak-dominated woodlands, grasslands, and wetlands.

The land is home to magnificent oaks and other native species that have been there for centuries. The natural landscapes at the Arboretum have been marked by their history of human settlement.

The Arboretum was created in 1922 from farmland and wood lots. For nearly 100 years, it had been used to raise wheat, corn, and hay; for cattle grazing; for lumber; and to harvest firewood. Prairies and some woodlands had been cleared and plowed, and wetlands had been artificially drained to create farm fields.

Today, the goal for the Arboretum’s natural areas is to recover healthy populations of native plant and animal communities on the land and to foster as much native biodiversity as possible.

Although management strategies are informed by historic land use records—as well as by current research and monitoring—they do not aim to recreate the earlier ecosystems of a specific era, such as the period before non-Native settlers inhabited the Midwest in the 1830s and 1840s. Conditions have changed too much and the future is too uncertain.

Ecological restoration at the Arboretum now aims to assist the recovery of the native ecosystems, while remaining alert and adaptive in the face of new challenges—such as ongoing climate change, surrounding development, and invasive plants, pests, and pathogens.

Restoration means adjusting conditions and processes to allow native species to recover. In some places, it means removing plant species that are considered harmful to native biodiversity, or opening up shady woodlands to allow more sunlight. It may mean allowing water to flow naturally through the site, reintroducing fire into communities that depend on it, or recreating prairies from farm fields.

In the more than 50 years since the Arboretum’s Schulenberg Prairie became one of the first efforts to return farmland to a prairie ecosystem, restoration work at the Arboretum has informed and inspired conservation efforts throughout the Midwest and the world.

Research, knowledge, and multiple strategies are being used to conserve and restore the Arboretum’s natural areas.

It takes knowledge, planning, adaptation, and time to conserve and restore natural areas. Natural areas face challenges, including invasive plants insects, diseases, and groundwater and surface water flow that has been altered by development.

Restoration work is combined with the Arboretum’s research to improve techniques and expand knowledge. Meanwhile, careful monitoring of trees, plants, animals, and other organisms provides important information about the ecosystems’ health.

Strategies

Canopy thinning for oak woodland restoration
Prescribed burning in woods and prairies
Fostering native species
Invasive species control
Wildlife monitoring
Wetland restoration

Locations at the Arboretum

Schulenberg Prairie
East Woods
Crowley Marsh
Meadow Lake
Bur Reed Marsh

Explore natural areas volunteer and training opportunities at the Arboretum.

The Natural Resources Program has more than 200 invaluable volunteers who carry out important restoration work at the Arboretum. The program is open to the public, and anyone can get involved. You do not have to be a botanist, and scheduling is flexible. Contact the Volunteer Office to find out how to become a volunteer with the Natural Resources Team.

The team works throughout the Arboretum’s natural areas, including the wetlands, prairies, and woodlands.

Volunteer crews carry out many different restoration activities essential for maintaining healthy habitats at the Arboretum. Volunteers assist with controlling invasive species, monitoring wildlife and plant populations, implementing prescribed fire, collecting native seeds, planting native species, and other activities.

The team is composed of several Restoration Groups. Please check with the Volunteer Office to find out which groups are currently accepting new volunteers or view current volunteer opportunities.

Natural Areas Conservation Training Program (N-ACT)

Interested in learning more about the maintenance and restoration of natural areas? Through classroom study and practical field experience at The Morton Arboretum, the Natural Areas Conservation Training Program (N-ACT) provides the knowledge and experience necessary to be a thoughtful caretaker.

The training is not required to volunteer at the Arboretum, but it is available for those who would like to learn and grow their skill set.

To explore the Natural Areas Conservation Certification requirements, browse available restoration and conservation courses, and find other details, see Get Involved: N-ACT.

Video: “What is the Natural Areas Conservation Program?“

Conservation and Restoration Courses

Learn more about conservation and restoration from the experts at The Morton Arboretum. Plant trees and restore our urban forest and woodland treasures. Expand your knowledge of invasive plants, or learn to develop a conservation site plan.

Natural Areas Conservation Training classes are easy to fit into a busy lifestyle and include online, classroom, and field components. Natural Areas Conservation Training is open to anyone involved or interested in the stewardship of our natural heritage, regardless of prior experience. You’ll make meaningful connections with like-minded people and learn from leading experts.

View current restoration and conservation class offerings at the Arboretum.

Natural Areas Conservation Training Online Orientation

Natural Areas Conservation Training Program Enrollment Form

Revitalizing the Arboretum’s East Woods

If you walk along the Heritage Trail in the East Woods of The Morton Arboretum, you may come across areas where many trees have been cut down.

These areas are being restored through a restoration effort aimed at revitalizing the Midwest’s native oak woodlands and securing their future. It uses what foresters call the shelterwood method. Its goal is to create open, sunny areas where oak trees can naturally grow from acorns and mature into trees.

Other trees that hamper the growth of oaks—such as invasive species, those that create too much shade, and species that can tolerate more shade than oaks can—have been thoughtfully removed between large, mature oak trees that will produce plenty of acorns and provide shelter for oak seedlings. This creates open, sun-filled areas where the acorns can sprout and where tiny seedlings are far more likely to survive long enough to become established trees that grow into tomorrow’s magnificent oaks.

New oaks needed

The Arboretum’s shelterwood project is addressing a major problem for the oak-dominated woodlands of the Chicago region: Although many great oak trees still stand after a century or more, new oaks are not growing to replace them when they eventually reach the end of their natural lifespan. Oak seedlings, which need abundant sun to grow, die because they are shaded and out-competed by more shade-tolerant species such as sugar maples. Unless ways can be found to foster new generations of oak trees, the Arboretum’s East Woods and other forests in the Chicago region will gradually lose their oaks, one by one.

Oaks are at the center of many forest ecosystems around the world. In the Chicago region, hundreds of species of animals and other plants depend on oaks for food and habitat.

Before Illinois became heavily settled, Arboretum scientists have found, the forest was kept in balance by frequent fires that cleared competing species and kept woodlands open and sunny, favoring oak seedlings. After settlement, the fires were suppressed to protect nearby farms and towns. As a result, the woods have become much more dense and shady, making it nearly impossible for young oaks to thrive without help.

In 2010, the first Chicago Region Tree Census identified the lack of young oaks as a major problem for natural areas, leading to the establishment of the Oak Ecosystems Recovery Project. The project is led by the Chicago Region Trees Initiative, managed by the Arboretum.

The shelterwood process

In commercial forestry, shelterwood cutting is a proven method of making sure that valuable kinds of new trees will grow up to replace trees that have been logged. The technique has been successfully adapted for restoration of natural oak woodlands in the East, but the Arboretum’s shelterwood project is the first of its kind in the Chicago region.

It is part of the Arboretum’s ongoing work to restore and maintain its natural areas and ecosystems. For example, every fall and spring, the staff conducts carefully controlled prescribed burns. However, previous oak regeneration projects that created smaller openings in the woods were not sufficient to foster the trees’ regrowth, so the Arboretum has turned to shelterwood cutting.

The process can take more than a decade before young oak trees are successfully launched toward the sky. At the Arboretum, the shelterwood method was first tried on a five-acre plot in the East Woods beginning in 2014. In 2018, it was expanded to 28 plots. Some of these areas can be seen from the Heritage Trail, which can be reached from the Big Rock Visitor Station.

First, the mature trees that will be kept to provide acorns and shelter for future oaks are chosen. Then the unwanted trees are removed. The work is done in winter when the ground is frozen. Over the next several years, oak seedlings sprout abundantly, but so do many trees of other species whose seeds were in the soil. About five to eight years after the first cutting, the plot is cut again to eliminate young trees and shrubs that are competing with the oak seedlings. To thin the canopy overhead and reduce shade, trees are removed. This allows the young oak trees the space and sun they need to firmly establish themselves for the long term.

The Arboretum’s shelterwood project is being carefully monitored to assess its prospects as a tool for restoring oak ecosystems. Since trees grow slowly, it will take researchers many years to fully judge the success of the effort.