Why Well-Managed Aspen is the Best Grouse Habitat
If you hunt ruffed grouse on the southern fringe of its range, aspen forest may not be all that relevant to you. But if you’re an upland hunter in the Great Lakes states or Northeast, it’s almost guaranteed that one of your favorite hunting spots includes an aspen stand. Throughout its lifecycle, it provides everything a grouse needs: dense cover and food.
Managed properly, aspen stands are excellent habitat for ruffed grouse. If you’re unfamiliar, here’s some more information about aspen and its importance for upland birds and other early successional species alike.
Description and Identification
Quaking aspen (Populus tremuloides), also called trembling aspen or simply “popple” by many seasoned hunters, is a beautiful and under-appreciated member of the willow family. When mature, quaking aspen can grow to be 100 feet tall, but rarely get so big before succumbing to storms or timber harvests.
Its bark is generally white-gray and very smooth when young, but it becomes darker and rougher as it ages (USFS 2019). Its rounded leaves are pale green in the summer (but turn bright yellow in the fall), and are attached via flattened stalks that cause it to shimmer in the slightest breeze (hence, why it is called “quaking” aspen) (Minnesota Wildflowers 2019). In the early fall woods, listening to these leaves rustling in the wind is the definition of relaxation.
Quaking aspen is shade-intolerant, meaning it can’t compete well without full sunlight reaching its uppermost canopy. It is what’s known as a pioneer species – one of the first tree species to colonize a disturbed area.
While aspen does establish from seed, it grows primarily by spreading from root sprouts, which can reach lateral lengths of up to 100 feet (USDA NRCS 2019). Each bud that grows off this root is essentially just a clone of the parent tree, and what many might see as a forest is actually just a bunch of clones of the same tree. In fact, the largest living organism on Earth is the Pando clone – a clonal colony of an individual tree that is over 100 acres in size and has been aged at 80,000 years (USFS 2019).
Young aspen stands tend to grow very densely, with several thousand stems per acre. As they reach the sapling or pole stage, it can be a real challenge to navigate through a pure stand. This is the exciting and frustrating part about hunting grouse in these habitats. But as they get older, they start to self-thin, which frees up more soil resources and sunlight for the remaining trees to get bigger. Maturing aspen stands also allow other tree and shrub species to establish a foothold.
Where Does It Grow
As far as distribution, quaking aspen is one of the most extensively scattered tree species in North America. It grows from Alaska and northern Canada down through parts of Mexico, avoiding only a handful of southeast states (USDA NRCS 2019). It can grow in a variety of different conditions too, as indicated by this vast range – everything from dry rocky soils at high elevations to swampy lowlands is fair game provided there is enough sunlight. The Great Lakes states, Colorado, and Utah represent some of the best aspen stands in the United States.
While it is the dominant species in larger stands, they also tend to support white birch, balsam fir, maples (e.g., sugar, red, mountain), and some pines (e.g., white, red), while various hazel species or speckled alder fill in the understory of mature aspen stands.
Importance for Upland Birds
Aspen provides habitat for many different wildlife species across the continent, including ruffed grouse, American woodcock, deer, black bear, elk, moose, snowshoe hare, and numerous smaller animals and migratory birds (USFS 2019). As mentioned above, it is especially important for grouse.
- Young stands provide the dense cover that hens and broods need to protect them during the spring (i.e., nesting) and summer (i.e., brood-rearing). The thick canopy cover protects them primarily from raptors such as northern goshawk and great horned owls.
- In many aspen stands, there are felled logs, brush piles, or rocks that serve as perches for drumming males. A male will find a drumming log (or similar structure) within his territory and aggressively defend it throughout its life. These sites must be in habitats that offer good visibility (for predator detection) but are thick enough to provide cover.
- As aspen trees mature, their flower production also increases. Throughout the winter and early spring, grouse depend on these dormant male flowers (called catkins) as a survival food.
Management of Aspen Forests
Aspen forest management is the critical part as far as grouse and many other early seral/successional wildlife species are concerned. While aspen trees can live to be 50 or 60 years old in the Great Lakes, the forest structure starts to break down well before that (USDA NRCS 2019). Mature trees start to give in to fungal diseases and rot, or storms may take them down. Because its own canopy shades out young aspen, shade-tolerant species (such as northern hardwoods, balsam fir, etc.) start to take over instead. A clearcut is the best way to restore aspen communities on a large scale.
For ruffed grouse, aspen stands that are anywhere from 5 to 20 years old represent good habitat. More importantly, grouse need access to a range of forest ages throughout the year. Since they have small home range sizes, the more you can provide those different ages in close proximity, the better. For example, you might manage your private land in a mosaic pattern. Depending on the size of and access to your property, cutting a series of 1- to 5-acre patches every 5 years could create just the right mix for grouse. In 20 years, you would have four different aspen forest ages all within a checkerboard or grid pattern to maximize grouse habitat. Larger and more infrequent clearcuts may be more economical, but the resulting even-aged stands don’t provide as much forest diversity.
As always, feel free to reach out to one of RGS’s biologists to seek local guidance for your aspen stands.
Sources:
Minnesota Wildflowers. 2019. Quaking Aspen. Accessed at: https://www.minnesotawildflowers.info/tree/quaking-aspen
USDA NRCS. 2019. The PLANTS Database. Quaking Aspen. Accessed at: https://plants.usda.gov/plantguide/pdf/cs_potr5.pdfUnited States Forest Service
(USFS). 2019. How Aspens Grow. Accessed at: https://www.fs.fed.us/wildflowers/beauty/aspen/grow.shtml
