Enhancing Browse: A Better Way to Feed Deer

It is understandable to feel the need to feed deer in winter, but deer biologists discourage it for numerous reasons. Decades of research have shown that supplemental feeding leads to increased risk of disease, long-term habitat destruction, habituation to humans, alteration of other deer behavioral patterns, and a decline in the value of deer-related recreation (Please Don’t Feed the Wildlife, PA Game Commission 2012). With chronic wasting disease now prevalent in the state, the increased risk of disease transmission from feeding in a concentrated area is one of the most significant reasons not to feed.

Deer are extremely well-adapted animals and in general, don’t need supplemental winter food. A deer’s metabolism slows down in winter, and they are able to get by on what natural foods are available. In good habitat, deer enter winter with 2–3 months of fat reserves and conserve energy by being less active. During harsh weather, deer may not move for days, or even to eat. This is made possible by their stored fat reserves. In fact, feeding deer may lure them away from natural wintering areas, increasing energy loss. In addition, it can take up to 4 weeks of feeding on a new food source for deer to establish the microorganisms in their stomach necessary to obtain nutrients from that food. Studies in Pennsylvania have documented the death of wild deer from supplemental feeding in winter, a condition known as rumen acidosis.

Deer are referred to as "browsers," meaning they feed upon twigs, buds, and leaves of trees and shrubs. Browse makes up a primary component of their diet and is an important source of nutrition. Deer easily digest woody browse and feed on it year-round. During winter and early spring, access to browse is especially important as most other food sources are unavailable. Deer depend on browse to get them through the lean winter months.

What is a concerned landowner or hunter to do? Act like a logger and fire up the chainsaw! Felled trees, especially in winter, provide deer with a much-needed food source. If you want to improve habitat for deer and other species, consult with a forestry or wildlife professional and plan how best to achieve results. Loggers can be of assistance. Once a tree hits the ground, deer have access to its tender buds and twigs, which are generally nipped off within a matter of weeks. Not only will deer feed on the felled tops of trees, but they will also browse on the sprouts that grow from the stump the following spring as well. Where there are chainsaws, there's browse.

Deer are "selective" browsers and have distinct foraging preferences. Preferred foods are eaten first, marginal foods are eaten only after preferred foods become scarce, and starvation foods, those that have little nutritional value or palatability, are eaten when no other choices are available. In Pennsylvania, work compiled by the Bureau of Forestry and others has shown that blackgum, oak, basswood, maple, tulip poplar, aspen, hickory, ash, and pin cherry provide preferred browse. Of the shrubs, dogwood, viburnum, elderberry, hawthorn, winterberry, sassafras, and raspberry and blackberry briars are most preferred by deer. Most invasive plants are not preferred browse and should be controlled to allow for desirable plant growth.

On average, a deer will consume one ton of forage annually. Wooded habitats must have large quantities of preferred browse available to support deer numbers, and not all woodlands offer the same amount or quality of browse. A mature forest provides far less browse than the young brushy stage that occurs shortly after a disturbance, such as logging, where a significant number of trees are removed. Mature forests only produce 50–100 pounds of browse per acre, while young forests, or early successional habitat, can produce 1,000–2,000 pounds of browse per acre. Mature forests are important for providing hard and soft mast, such as acorns and nuts. Deer need a variety of habitat types and a diversity of tree age classes, both young and old. Woodland habitat changes as it ages; the same site that may have been good deer habitat 15 or 20 years ago may be poor habitat today.

Enhancing browse to improve deer habitat should be integrated into the specific management activities scheduled in a forest management plan. One important practice to consider is to thin overcrowded trees. This is a great practice to do in woodlots that are still relatively young, from age 15 to 50 years of age. The purpose of thinning is to free the most desirable trees from neighboring trees competing for growing space. Trees are thinned to a more desirable spacing by removing poor quality and less desirable species.

Thinning trees in winter puts tops on the ground that deer can browse on during lean times. Cut trees will also produce stump sprouts the following year, creating additional browse. Thinning overcrowded trees allows sunlight to reach the forest floor, providing conditions for understory plants and seedlings to respond, further increasing available browse. An added benefit of thinning overcrowded trees is that it improves the overall health and condition of the woodlot and concentrates growth on the remaining trees.

Another management practice that increases the amount of woody browse available is to cut and regenerate mature forests, referred to as a "regeneration" harvest. In this case, a new forest is started from seedlings and sprouts. There are a number of specific, recommended practices utilized by foresters to regenerate mature forests, so be sure to consult with a forestry professional before proceeding. Regeneration harvests provide an abundance of herbaceous vegetation and new succulent sprouts that flourish in the increased sunlight immediately following cutting. This new growth provides not only an abundance of browse but also cover deer can use for years, even after the browse has grown above the deer’s reach.

Forest management actions must balance multiple factors and benefits. In regeneration harvests, what’s good for the deer (many seedlings and sprouts to eat) can be detrimental to the seedlings trying to grow into a new forest. In many areas, deer populations exceed the carrying capacity of the habitat and regeneration failures can and do occur, where browsing deer overwhelm the developing young forest. It may be necessary to first reduce the overall deer population before implementing these management practices. The Deer Management Assistance Program or DMAP is a useful tool that forest landowners can utilize to harvest additional antlerless deer from a property during the regular hunting seasons. Balancing deer herds with habitat is best accomplished through a two-pronged approach consisting of harvesting the appropriate number of does while simultaneously improving habitat through practices like thinnings and regeneration harvests.

Consult with a forestry or wildlife professional and make a plan to enhance browse by thinning overcrowded trees or regenerating mature forests to create young forest habitat on your property. Deer and many other wildlife species will benefit from your efforts.