Restoration Methods

Invasive Brush Removal & Burn Piles

In some areas, restoring prairie and oak woodland means removing trees. That may sound counterintuitive—but many of these trees are aggressive, non-native species that crowd out light and suppress native plants. 

One of the most damaging is European Buckthorn, which now dominates millions of acres in the Midwest. Buckthorn has become invasive in the U.S. because it: 

1. shades out other plants
2. contains a chemical, emodin, that prevents germination, growth, and survival of other plant species
3. the bacteria, viruses, insects and animals that would harm, eat, or kill it are not present in the United States

Removing buckthorn and other woody invasives restores sunlight to the forest floor, allowing remnant wildflowers, grasses, and sedges to rebound.

Many of our Poplar Creek Prairie Stewards volunteers are trained and certified through the Forest Preserves of Cook County to operate chainsaws and supervise the burning of cut wood—the most effective and ecologically sound methods of disposal at our scale. All burns are coordinated with the FPCC and local emergency services to ensure safety and compliance with local regulations.

Manual Removal & Scything

Not all restoration requires heavy equipment. Much of our work is done by hand.

Volunteers hand-pull garlic mustard, Japanese hedge parsley, and other invasive species before they set seed. In some areas, we use scythes to selectively remove invasive plants while minimizing soil disturbance.

Manual removal is especially important in high-quality remnant areas where native species already exist. This careful, targeted approach protects sensitive habitat while preventing invasive species from gaining a foothold.

Controlled Burns

Fire is not a destructive force in prairie and oak ecosystems—it is a renewing one.

For thousands of years, periodic fire maintained Illinois’ prairies and open woodlands. Fire suppresses invasive woody growth, recycles nutrients, stimulates native plant germination, and creates habitat diversity for wildlife. The Illinois prairie and open woodland plants and animals evolved with fire. For instance, White and Bur Oaks evolved thick bark to withstand fire, flowers germinate better when last year’s growth has burned off, and grassland birds depend on fires to inhibit the growth of trees and shrubs.

PCPS does not conduct controlled burns ourselves. All burns are managed by the Forest Preserves of Cook County and overseen by professional, certified burn bosses under strict safety protocols.

Without fire, prairie becomes shrubland, and oak woodland becomes closed forest. With fire, biodiversity flourishes.

Seed Collection, Processing & Native Planting

Every fall, volunteers collect native seed from across our sites. In November, we host a large community seed-processing event where hundreds of pounds of seed are cleaned, mixed, and prepared for planting. In 2025, more than 70 volunteers participated in this annual event.

Most processed seed is redistributed directly onto restoration sites to increase plant diversity and strengthen native populations. We also partner with the Chicago Botanic Garden and local specialists to grow native starter plants from collected seed. Each spring and summer, thousands of these plugs are hand-planted into restoration areas to accelerate recovery.

This cycle—collect, process, plant, and monitor—is how biodiversity steadily increases year after year.

Monitoring & Adaptive Management

Restoration is guided by data.

We conduct long-term monitoring of plants, birds, butterflies, and dragonflies to measure ecological response. Bird monitoring alone has been conducted for more than 15 consecutive years using standardized point counts.

Monitoring allows us to adapt. If a species declines, we adjust management. If biodiversity increases, we build on what’s working.

Restoration is not a one-time action. It is an ongoing process of stewardship, learning, and refinement.