by Mark Herwig
Forests and forest creatures, no matter what part of the country they’re in, benefit from more complexity.
If you want more grouse, woodcock and other game and non-game wildlife, don’t treat your forest like your backyard: a few species, mowed to the ground.
A forest with downed trees, fallen branches, tipped trees, stumps, depressions, a mix of tree ages, deciduous and coniferous trees, fruit shrubs and the like offers the complexity grouse and woodcock need to fill all their life cycle needs. This complexity gives wildlife more options for nesting and protecting chicks and adults from predators and harsh weather while providing year-round food options.
“A manicured forest site can look better to some folks, but brush piles, woody debris, standing snags and a wide range of diverse retention provides the structure and diversity that provide habitat for the widest range of forest wildlife,” said Peter Dieser, Great Lakes public lands director for the American Bird Conservancy in Detroit Lakes, Minnesota. “It’s also important to note that sometimes the best management action is to do nothing and preserve unique or later successional habitats where they occur,” added Dieser, who has worked to create young forest habitat on approximately 8,500 acres since 2013. “Maintaining diversity at multiple scales is extremely important.”
A Known Concept
While forest managers have known about the benefits of complexity for decades, that awareness is growing as more research and management are conducted around the county. In one such ongoing study, the University of Minnesota Duluth Natural Resources Research Institute (UMD-NRRI) is making some interesting findings using, among other methods, radio telemetry tags – and Debbie Peterson’s dogs Bradley and Bogie to find the woodcock to tag in the first place.
Leave Those Downed Logs and Large Branches
The study, which began in 2019, is funded by lottery sales revenue distributed by the joint Legislative-Citizen Commission on Minnesota Resources. The study found not only that woodcock use downed logs for cover before spring green-up when there are no leaves for predator cover, but also for shelter from the rain and during snow and ice storms.
“In fact, the woodcock were never in any areas without downed wood before spring green-up,” said Alexis Grinde, Ph.D., research program manager and wildlife ecologist at UMD-NRRI. “In addition, woodcock could also be keying in on larger downed logs and branches to find insects to eat.” In a University of Minnesota Forestry Department webinar in fall 2022, Grinde presented more of the study’s findings from research areas on Blandin Company land near Grand Rapids and in the Chippewa National Forest.
Grinde explained that telemetry found woodcock nesting not just in young aspens, but also in 30-year-old aspen stands. Researchers also found that broods separate during the day, but reassemble later on. Also, when small tree clusters and large singles are left behind after logging, they shed large branches that are used by woodcock and grouse – unlike small trees. These trees may also provide nesting holes for woodpeckers and cavity-nesting ducks such as wood ducks, goldeneyes and hooded mergansers, but also predators such as fishers and raccoons.
“Leave tree clusters – for example, a minimum of a half-acre within a 10-acre cut. This better mimics natural disturbances such as blowdowns, low-intensity fires and tree die-offs from insect infestations,” Grinde recommended. “Young birds, no matter the young forest species, really respond to extra woody forest structure. It’s very important to them.”
Avoid hard edges
Logging operations attempting to increase forest complexity for wildlife will also avoid hard edges between cut and uncut forest. “Feather the edge so the change in height is gradual. Blur the lines between the cut and old forest,” Grinde said.
Dieser agreed. “Soften edges by leaving some trees and shrubs in a cut area and, likewise, cutting out a few trees and shrubs in the adjacent older forest will also create this transition so wildlife has access to all three types of habitat in a small area. Having all life cycle needs close together with a gradual transition between them helps limit a grouse or woodcock’s exposure to predators and harsh weather.”
Grinde’s study is just starting to look at grouse on hunter walking trails in Minnesota’s 666,000-acre Chippewa National Forest. “There, among 30- and 40-year-old aspens, the U.S. Forest Service is doing clump cuts to break up these old stands, not for timber, but for habitat improvement for grouse,” Grinde said, “and we’re monitoring them for grouse drumming, etc. We’ll be doing this for some years.”
Grinde is conducting her study on a site harvested by the Ruffed Grouse Society & American Woodcock Society (RGS & AWS) in 2022 through a shared stewardship agreement with the Chippewa National Forest.
Grinde explained that forest management on a large scale is important, too. “Don’t just think 40 acres. Wildlife need large tracts of old, middle-aged and young forest in the same vicinity. Minnesota does a good job of this. Yes, it only takes a few years to get young forest for grouse, but they also need older forest, which takes a lot longer to grow.”
Managers can also achieve greater forest complexity by using logging slash. “Sure, in a logging operation, chip some of the slash for revenue, but leave the rest in piles and leave some larger branches and logs if you can, and spread them out. Sometimes when you do a cut the saplings and shrubs get destroyed and piled up with slash, but this is too thick for birds to use, so create slash piles in a smart way by spreading it out or just leaving it where it fell. This makes a forest more complex,” Grinde said.
Other UMD-NRRI Study Findings:
• Trail cams show golden-winged warbler eggs and young being predated by weasels, garter snakes, broad-winged hawks and chipmunks.
• When logging, try to avoid filling in or otherwise destroying small depressions, which fill with (usually) shallow water in spring. The water warms quickly and provides habitat and insect food for amphibians and other wildlife.
• Amazingly, a male woodcock fitted with a satellite tracking tag in fall 2021 was found in spring 2022 at the exact same spot where he was tagged. What a memory!
Build a Complex Forest
Jon Steigerwaldt, the RGS & AWS forest conservation director for the Great Lakes/Upper Midwest, said forest owners and managers should try to mimic natural small-scale disturbances such as small fires, beaver activity, wind blowdowns and small disease outbreaks – even something as simple as a single tree falling in a forest.
“One concept that has been around for decades is leaving live or green tree retention within harvested areas,” Steigerwaldt said. “This is something often referred to as ‘standards.’ One example of standards is to do a clear-cut regeneration harvest, but leave a percentage of live trees, say 5 to 25, for seed, wildlife habitat, cavity nesting spots aesthetic value and so on.”
Alternatively, landowners could leave strips of trees as wildlife corridors to connect forest patches for predator-safe wildlife travel, to protect wetlands from sediment runoff or as seed banks for regeneration harvests.
“Leaving large patches of green tree retention can also provide patches of refuge around recent logging sites or in areas that can be harvested in 5-15 years to maximize age class diversity and long-term availability of young forest on a site,” Steigerwaldt explained.
A newer concept is leaving “legacy trees.” Legacy trees are typically individual trees that are left in perpetuity as representatives of what was on the site prior to a timber harvest. “We typically think of legacy trees as large trees with large den cavities, rare species for that particular site, specimen trees with good genetics we want to perpetuate on-site or trees with large crowns and branches that stretch way out. Those make perfect trees for turkey roosting habitat,” Steigerwaldt said.
Legacy trees are those you typically wouldn’t want to cut down anyway. A legacy tree might be one that your grandfather planted and is now part of your family’s legacy. Or perhaps a tree that was left in an old pasture and is now surrounded by younger second- or third-generation forest. Besides, such legacy trees could have barbed wire or other metal in them, and usually make very poor-quality lumber. They might even be hazardous to cut down due to decay or an uneven top.
“Oftentimes their best use is for wildlife,” Steigerwaldt said. “When those trees naturally fall down, they will add important secondary or tertiary benefits such as providing denning sites, drumming logs or places for insects to feed. Insects are important to a wide range of forest wildlife, including young ruffed grouse broods.”
If the wind blows off the top, fine, leave it – this provides pocket cover for grouse to hide from predators because it is snow-free and grouse blend in better.
“Downed tops also protect saplings from deer browsing,” Steigerwaldt said. “These are the small things in a complex forest that we often aren’t aware of, but that matter to grouse and woodcock.”
Talk to a Forester
When all is said and done, Steigerwaldt said, decide how you want your forest managed. Most state forest departments have guidelines for forest owners. Next, talk to a forester to draw up a harvest plan. The forester will then discuss this plan with your logger. You can also advocate the same way for public forest management. Speak up for our forests. The wildlife will appreciate it, and you will to, come hunting season!