Buck Up! Protecting Young Trees from Deer Rubbing this Fall
There’s now a chill in the air and days are growing shorter. And for deer, fall is mating season! Many of us love seeing deer in our backyards, but even the most dedicated lovers of wildlife probably get really frustrated when they discover that young (and old) bucks have rubbed the bark off the trees in their yards. Not only does this behavior cause unsightly damage, it can permanently disfigure or kill young trees.
Male deer (bucks) clean the velvet off their newly grown antlers from early September through November, while also marking their territory during the breeding season. Bucks repeatedly strike trees for noise effect to show dominance, and to coat the twigs and bark with scent from glands in their faces and underbodies to mark their territory and intimidate competing males. This rubbing typically starts in early fall, with male deer running the surfaces of their horns against tree saplings that are anywhere from one to four inches in diameter. Damage to the tree trunk can extend from one to five feet above ground level and be extensive enough to permanently damage or even kill a tree.
According to Tim Johnson, Director of Horticulture for the Chicago Botanic Garden, young trees that are 1 to 6 inches in diameter with smooth bark — such as dogwood, maples, lindens, birch, and magnolias — are most likely to be damaged by deer rubs. Larger trees with smooth bark, as well as clump-form trees, can also be damaged.
Young trees have very thin bark which is easily damaged. A tree’s vascular system, which transports water, nutrients, and carbohydrates between the roots and shoots is situated just below the bark. When deer rubbing is localized to a small portion of the trunk, the wound may heal and callous over in time with little lasting effect. However, if the damage is more extensive, especially if it encircles the entire trunk thereby impacting the vascular transport of water and nutrients within the tree, the trunk will be “girdled” and die within a short period of time.
Trees can heal after a surprisingly large amount of damage. To encourage healing, trim off any loose, shredded bark where it’s not tightly connected to the trunk. If possible, cut wound locations into an elliptical or football shape to help the tree recover more quickly, but do not dramatically enlarge the wound. Smooth edges heal better than the ragged edges left from the deer rubbing. There is no need to use a wound dressing or wrap the trunk damage.
Tree with deer rub damage
Credit: Brandon Novotny
Protecting Trees from Deer Rubs
Since deer usually return to the same location, it’s important to know how to protect trees from deer, especially if the trees have previously been damaged. Although there are a number of popular ways to scare deer away from gardens, a determined male deer in rut is not going to be bothered by ultrasonic noise deterrents or scented repellents. Wrapping the trunk with burlap or paper tree wrap may not provide enough if any protection from deer rubs.
The best thing to do to protect young trees is to prevent deer from getting close to the tree trunk or branches. This can be done by surrounding trees with deer fencing or using other protective methods. A highly effective method is to create a barrier around the tree trunk with sturdy wire fencing or thick plastic mesh with ½-inch or smaller openings. Welded wire fence and thick plastic mesh is available at hardware stores and may be available online. Flimsy plastic mesh typically used to protect flower beds is not stout enough to provide protection from deer rubbing.
Thick plastic tree guards made of sturdy mesh plastic and welded wire fencing work well, since they allow the tree trunk to grow and allow air flow, which is important to reduce pest infestations. The advantage of using welded wire fencing is the material can be cut to size for various sized trees. Protective fencing should be cut to allow for tree growth and to reduce potential rubbing on the bark. The sturdy plastic tree guards are available in different widths. The wire fencing or plastic mesh guards should be secured to the ground using one or two stakes with a wire tie attached to the protection, to reduce chances of deer tearing it off the tree. Make sure the protection is about five feet off the ground and leave it up through the winter.
Plastic tubes or drain pipe that have been cut down one side (lengthwise) and installed around the tree trunk can also work for smaller diameter trees. Corrugated 4-inch drainage pipe is a cost effective and easy to install protection device. Simply cut it to the length needed, split the pipe down one side and slip it onto the trunk. A few problems with the use of dark colored tubes or drain pipe is the black tube heats up and can cook the bark of a tree, so it should be removed in late winter to avoid damage to the trunk from excessive heat. A light-colored tube is better as it does not produce heat against the tree trunk from the sun. These lighter colored tubes can also protect the tree trunk from sunscald caused by intense sun reflecting off snow, which has been known to blister or crack the bark. Another problem with tubes and drain pipe is that it creates a good environment for fungal growth or insects and birds to nest in, as leaves and grass can build up inside the trunk protection tubes that surround the bark. So, it is best not to leave the tubes or pipes on the entire year.
Rutting season starts in early September and can continue to mid-December, so it’s a good idea to install deer protection in early Fall to avoid the worst damage. The time and expense invested in deer protection is well worth the effort as deer can wipe out an expensive tree planting project.
From the City's Tree and Landscape Board
Deer Protection Wire Cage
modify diameter as needed; typical fence is 4' (H) and 6" - 8" (w)