WINTER WORK TO BE DONE.
The most critical elements in managing "deer woods" involve manipulating density of trees and shrubs, diversity of species and stand age-class distribution to produce a more productive landscape. And winter is the best time to inventory the composition and structure of each forest stand.
The leaves are off most deciduous trees and shrubs, in many cases making it easier to get around in the woods and see what's there. In northern climates it's also a great time to harvest timber, as frozen ground permits access for heavy equipment without major soil disturbance.
If you don't already have a recent aerial image of your hunting property and the land surrounding it, get one. High-quality, up-to-date images are readily available from a host of Internet websites and services. There are two general types of aerial and satellite images: leaf-on and leaf-off. Both have utility in assessing deer habitats, but aerials taken in winter are more useful to me. They clearly show where conifers and deciduous trees occur.
My approach is to draw a line around each unique patch of forest habitat. Management starts with a high-altitude view of habitat types and ends with an on-the-ground analysis of what each area does--or could--provide deer.
WHAT WE'RE LOOKING FOR
As light travels from the top of the canopy to the forest floor, layers of leaves trap most of it. So deer forage production in forests is influenced not only by tree density but also by species composition and the number of vegetative layers.
Learn to identify the common trees and shrubs in the forest. Knowing these plants not only improves your understanding of the deer woods but also makes you a better hunter. In most areas, you only need to be able to recognize about 40 species. Less-abundant species most often have little impact on deer.
With few exceptions, conifers yield little quality forage. However, they do offer valuable escape and thermal cover. Deciduous species tend to provide most of the browse and fruits/nuts relished by deer.
I begin winter forest evaluation by examining the amount of use on each species of browse plant. (Your wildlife agency should be able to provide you with a list of these plants for your area.) We biologists divide them into four categories: first, second and third choice and finally, emergency.
First-choice plants, also called "ice cream" plants, are relished by deer. But there are few of these plants, even in areas of low deer density. Plants have spent millions of years trying to not be attractive to plant eaters, developing waxy leaves, thorns, bad tastes and fibrous tissues as defensive mechanisms. Hence, second-choice plants provide the greatest amount of deer food. These are the species I examine in each forest stand. If there's over 50 percent use on these species, I know there's not enough forage. Habitat damage is imminent.
Next, I assess how much total vegetation is present in the "deer zone" (within four feet of ground level). If I have trouble walking through the vegetation, I assume there's enough sunlight for adequate browse production. If not, we need to get more light to the forest floor.
Now look upward. Of course, in deciduous stands, the leaves now are gone, leaving only limbs--but, you still can tell how dense the canopy is. Dense stands are those with individual tree canopies averaging only a few feet in diameter. Competition among trees limits canopy development.
If the trees have limbs that look like umbrellas in a high wind, you probably have too many per unit of area. For young stands of under 25 years, the distance between trees should be no less than 20 feet; in middle-age stands 30-50; and, in mature stands no less than 50. If more crowded, the stand should be thinned.
As you consider thinning, knowing species comes into play. Production of mast (the fruits and nuts of trees) is a key component to consider. A stand with large numbers and diversity of mast-producing trees tends to produce larger, more reliable crops of fruits and nuts seasonally important to deer.
Oaks probably are the most critical species in mast production. In general, they're divided into two major groups: "red" and "white." Red oaks tend to flower in one year and mature fruit the next; white oaks flower and mature fruit the same year. Thus, a stand with an even mix of red and white oaks will have more reliable nut crops than one dominated by one or the other. It also holds that adding other mast producers (persimmon, chestnut, beech, etc.) can increase the usefulness of a stand.
For deer, conifer stands have three utilities: screening cover, summer thermal cover and winter thermal cover. Screening cover is any area with enough vegetation in the deer zone to allow a deer to escape detection after running a short distance. Young conifer stands and even tall grasses supply this need.
Summer thermal cover consists of a stand of trees with a low-density understory and a light overstory canopy, offering air flow and shade during hot weather. Deer tend to eat less when it's hot, reducing body growth and antler development. Winter thermal cover is quite different. This cover type should have at least two vegetative layers, one of which is a dense canopy. This feature reduces air flow and inhibits snow buildup in northern climates.
Visiting a conifer stand will reveal its utility. The next step is to decide whether or not the stand as it exists is needed in that place. Many conifer stands are established for timber, with seedlings planted at high densities (up to 500/acre). These stands quickly serve a screening function, but in under 10 years contain almost no deer food.
If you feel winter thermal cover is needed, you might decide to maintain a relatively high density of trees (100-150 per acre). If, on the other hand, you have greater need of summer thermal cover, begin thinning to gradually reduce tree density to 50-60 per acre at maturity. (Visit NorthAmericanWhitetail.com and search for "deer factory" to learn more about thinning procedures.)
In deer management, winter is an important season. Learn all you can about local trees and shrubs important to wildlife, along with the basics of habitat management. After that, improving your land just takes a good plan and some "elbow grease."
BY DR. JAMES C. KROLL
ABOUT THE AUTHOR > Dr. Kroll is founder and director of the Institute for White-tailed Deer Management & Research in Nacogdoches, Texas.
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|Title Annotation:||DR. DEER|
|Author:||Kroll, James C.|
|Publication:||North American Whitetail|
|Date:||Feb 20, 2019|
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