Photo by Phil Cox.

August 1, 2023

When Hunting Season’s Over, Habitat Season Begins:
Part 2 – Woodland Habitat Management

Part 1 of this story series discusses how the habitat work undertaken off-season has a direct impact on a hunter’s success in the field the following hunting season.

Illinois is home to 14 million acres of forested land. In a state that is 97 percent privately owned, if we hope to move the needle for wildlife habitat management, educating and providing resources for private landowners should be a major priority. Fortunately, many sources of information and assistance exist for anyone who owns a piece of Illinois forests.

Contacting a District Forester from the Illinois Department of Natural Resources is a great first step towards getting the most out of any wooded acreage. Foresters can evaluate your property and help landowners work towards a plan or direct them to a private consulting forester who can. Illinois foresters are often working towards improving conditions to maximize oak regeneration with the future of both timber and wildlife in mind. Many of our woodlands are still dominated by mature oaks but, unfortunately, oaks in younger age classes are insufficient to ensure future generations, or they are absent altogether.

An small oak sapling grows surrounded by wild ginger.
To ensure future generations of oaks, foresters work to maximize regeneration in woodlands having insufficient numbers of younger age class oaks. Photo by Kathy Andrews Wright.

The plans most foresters write utilize management techniques to increase the sunlight to the forest floor to promote oak regeneration. As natural and manmade disturbances such as fire and timber harvest have been suppressed or reduced over time, our woodlands have become denser and more shaded. As a result, species such as maple and beech, which are more shade tolerant and less fire dependent, have been able to gain an advantage. This process is called mesophication. Oak seedlings need sunlight at least 50 percent of the day to thrive and move into the mid-canopy and eventually the overstory. Another benefit of reintroducing disturbance and opening canopies is that native herbaceous plants will rebound, supporting insects and providing structure crucial for wild turkeys and other species.

As with most habitat work, landowners looking to improve their woodlands for wildlife should have a detailed plan before any on-the-ground labor begins. A Forest Management Plan (FMP) will help a landowner become more familiar with their property. Forest inventory metrics such as species diversity and abundance, trees per acre, basal area, board feet, and species position (e.g., oak overstory with a mesic sugar maple understory) are all details a certified forester can provide. The planning phase will also help landowners learn which invasive species are present and what threats they pose, as well as the herbaceous plants occur on site that are beneficial for wildlife.

The plan will spell out management recommendations such as forest stand improvement, invasive species control, prescribed burning, tree and shrub planting, and timber harvest if appropriate. Most FMPs have a ten-year schedule to guide landowners with the timing of suggested activities over the next decade. Foresters will likely suggest controlling invasive species before conducting any forest stand improvement or timber harvest. Cutting mature trees opens the canopy which will allow more sunlight to hit the forest floor. This is typically one of the goals of a plan, however if invasive species coverage is not reduced first, additional sunlight will provide them with an opportunity to further dominate the site. Reducing the coverage of undesirable species upfront will decrease competition for preferred species ensuring more diversity than a stand full of bush honeysuckle, autumn olive and multi-flora rose.

The most technical portion of a FMP involves decisions about which trees to cut as well as when, where and why to cut them. A stand of trees that average 4 to 10 inches in diameter at breast height (DBH) is a prime candidate for thinning. The trees in a stand like this will respond with rapid growth. However, there are many benefits to thinning the larger sized stands and Timber Stand Improvement (TSI) after a harvest may be needed to manage for future timber production and wildlife habitat.

The purpose of TSI is to improve the quality of a stand by removing or deadening undesirable species to achieve desired stocking and species composition. TSI techniques can also be used to create standing dead trees to provide various types of wildlife habitat such as perches, dens, and foraging trees for animals such as bats and birds. Undesirable species and cull trees can also be cut for firewood. Cull trees are those which are not currently marketable and are not expected to be in the future. Thinning trees usually increases nut or seed production of the remaining trees. This provides food for wildlife as well as a seed source for the next generation of trees.

All trees in a stand can be placed in one of three groups.

  • Crop trees are the most important. They will be desirable species and have tall, straight, clear trunks, free from major insect or disease damage, fire scars, decay or mechanical damage. They are typically the top mast producers as well.
  • The second group are often called reserve or trainer trees. These trees may not make it to economic or physiological maturity because they will likely be removed in the next 10 to 20 years. They typically do not have the preferred characteristics of crop trees but aid in proper spacing for the time being.
  • The third category are surplus trees. They will be removed first because they are less desirable species or have poor form.

When selecting the species to leave, foresters will try to select species and individuals that will grow on the sites best suited for them. Some species naturally have a higher commercial and wildlife value than others. Examples of valuable species are black walnut, white oak, black oak, red oak and hickories. Less desirable species include honey locust, blackjack oak, osage orange, and American elm, as well as any nonnative species. One can only work with the species available on the site, but any species will be of higher quality if the site has had some care.

A young male white-tailed deer stands in tall grass  next to a tree in the fall.
A young white-tailed deer buck. Photo by Chris Young.

By implementing an FMP and TSI, landowners can not only increase potential income of the property by well-planned harvest of marketable trees, but also improve wildlife habitat. Forest management practices can improve woodland habitat by controlling invasive species, providing cover through felling or leaving standing dead trees, increasing hardwood stands and nut-bearing trees that provide food, as well as increasing sunlight penetration to the ground that produces herbaceous plants (grasses and forbs) that also provide high quality food and shelter for wildlife.

In the next “When Hunting Season’s Over, Habitat Season Begins,” article we will cover various techniques and equipment used to implement woodland habitat restoration and management practices as well as federal and state assistance programs.

Wade Bloemer currently serves as the District Forester with an office at Stephen A. Forbes State Park. He has been with the Illinois Department of Natural Resources (IDNR) for 10 years. Prior to working with IDNR Wade worked for the National Wild Turkey Federation and Quail Forever.

Luke Garver is the Wild Turkey Project Manager with the Illinois Department of Natural Resources, Division of Wildlife.

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