Deer can damage tree trunks by rubbing or scraping their antlers against the bark to remove the velvet and polish. Bucks also rub against trees to mark territory and attract females. Unfortunately, this causes enormous tree damage. Young trees are especially vulnerable because the scraping can damage the systems needed to transport water and nutrients from the roots.
Deer further damage trees by chewing on low branches as well as pawing at the soil below a tree, and urinating around it to mark territory. Compounding the problem is the fact that deer are creatures of habit. They will return to the same trees and repeat the same behavior, so it's important to protect tree trunks. This can be done in a variety of ways.
Tip: A hungry deer will eat almost anything. However, there are a few preferred trees that even a deer who is full might go after. These include the common lilac, Russian olive, oak, hackberry, apple, hawthorn, walnut, white pine, and dogwood. If you have any of these trees, you may want to consider protecting them even if damage has never occurred before.
Protect Tree Trunks with Fencing
The simplest way to protect trees is with fencing placed around a single tree or an entire stand. While fencing is the most expensive way to deter wildlife, it is also the most effective. The fence must be at least six to eight feet tall and tilted at an angle of 30 degrees, as deer are champion jumpers.
Tip: If you notice deer have been chewing on the lower branches of your trees, consider pruning all low branches off completely. If the deer cannot reach a branch for chewing, they may lose interest and move on.
Tree Care with DIY Materials
If fencing is not suitable, protect individual trees by wrapping any number of materials around the trunk, including chicken wire, plastic mesh netting, spiral wraps, paper tree wraps, plastic piping, or corrugated drain pipe. You can even cut plastic bottles open and tie them around the trunk stacked on top of each other. Any of these options, while they may not be the most aesthetically pleasing , can be easily cut to size and secured around any tree trunk.
When using any of these do-it-yourself materials, measure the tree trunk from the ground to just under the first branch. Cut a section of your chosen material to this length. For corrugated drain pipe, an extra cut will be required to split the material open in order to wrap it around the tree trunk. Use care when installing a corrugated drain pipe around the tree so as not to damage the bark or injure your fingers. The material is difficult to maneuver open. To install the chicken wire or netting, simply wrap it around the tree securely and close with zip ties. Any protective material should be kept a few inches from the bark of the tree to allow for proper air circulation.
Firm material, such as the spiral wraps, drain pipes, or plastic pipes are most effective when the bottom four inches are secured in the ground. Dig a trench around your tree and wiggle the bottom of your guard into the soil, tamping it down firmly.
For material such as plastic bottles, use taut twine to attach them to sturdy bamboo stakes a few feet from the tree. The extra support will go a long way during storms and high winds. For maximum tree care, monitor growth annually and widen the protective material as needed.
Tip: To learn more about different types of tree guards, visit this article!
Limit Tree Damage with Repellents
Two types of repellents exist to limit different behavior. Contact repellents taste bad, while area ones emit foul odors that may encourage deer to stay away. With a contact repellent, the tree trunk should be treated to a height of six feet. Commercial preparations of both types exist but many people choose to make their own.
One method is to cut slices of deodorant soap, enclose them in cheesecloth, and hang them from the branches of the tree. Deer don’t like the smell of the soap, but it must be replaced monthly and after every rain to remain effective. I have personally heard wonders about Irish Springs soap. Keep in mind that if food is scarce the deer may well ignore the scents and chow down regardless.
Other less savory options include mixing egg and water to spread around the base of the tree, or mixing dried blood meal (purchased in gardening centers) with any number of items designed to give off a scent to repel deer. Human or pet hair, chicken feathers, egg, garlic, hot sauce, and cayenne pepper are all effective. Mix your choice of ingredients, strain if necessary, cook under the sun to get it really smelly, and spray or pour around tree trunks. Rotate ingredients each season as deer can become accustomed to tastes or smells.
Plant Different Trees
Some types of tree are known to be deer resistant. If you are bothered by these animals and are thinking about planting another tree, consider American holly, bottlebrush buckeye, Alberta spruce, the black, red, or pitch pine, mimosa, or the paper birch, among others. Keep in mind that no tree is 100 percent resistant to wildlife damage and that a hungry deer will eat almost anything.
Tip: To deal with damage already done to your tree, acquire a pair of sharp garden shears. If deer have been rubbing up against your tree and shredding the trunk, use the shears to trim away all of the loose bark. Also prune broken branches back to a main branch or trunk. Over the growing season new bark should develop to cover any exposed wood. However, if the damage is severe, the tree may die.