The presence of deer often leads to damage on valuable pine trees, especially younger specimens. Deer are primarily attracted to pines in two distinct ways: browsing on the foliage for food and rubbing their antlers against the trunk. Young trees are particularly susceptible because their thin bark offers less resistance to antler rubbing, and their lower branches are easily accessible for feeding. Protecting pine trees requires a proactive, multi-faceted approach that addresses both feeding and territorial behaviors throughout the year. The successful defense depends on implementing physical barriers and deterrents tailored to the specific type of damage you are trying to prevent.
Physical Barriers and Exclusion Methods
Physical exclusion remains the most reliable method for protecting pine trees from deer damage. For large areas or high-value plantings, perimeter fencing is the gold standard, though it must be at least eight feet tall to prevent deer from jumping over it. Woven-wire or high-tensile plastic mesh are effective materials for constructing such a barrier.
Protecting individual young trees requires constructing a robust cage around the trunk and crown. Temporary enclosures made from galvanized wire mesh or concrete reinforcing wire should be at least six feet high to deter browsing and rubbing. These enclosures must be sturdy enough to withstand the force of a buck rubbing its antlers against them, which is a powerful territorial behavior. Ensure the cage is staked securely into the ground and positioned a few feet away from the tree’s dripline so the deer cannot push past the mesh to reach the foliage.
To specifically prevent antler rubbing on the trunk, which can fatally girdle a tree, a protective wrap is necessary. Plastic tree guards, spiral wraps, or sections of corrugated plastic pipe can be placed around the main stem, covering the bark from the ground up to the lowest branches. These wraps must be light-colored to prevent excessive heat buildup, which can damage the bark underneath. For winter protection against browsing, especially on smaller pines, you can loosely wrap the entire crown in burlap or protective netting.
Chemical and Scent-Based Repellents
Chemical repellents offer a non-physical defense by making the pine trees unappealing through taste or smell. These products are broadly categorized into taste-based contact repellents and scent-based area repellents. Taste repellents are applied directly to the needles and stems, requiring the deer to take a bite to experience the deterrent effect. Common active ingredients in taste repellents include capsaicin, which causes pain or irritation, and thiram, a fungicide that acts as a conditioned aversion agent.
Scent-based repellents work by emitting a sulfurous odor that mimics the smell of a predator or decaying matter, triggering an avoidance response. Highly effective ingredients in this category are putrescent egg solids and dried blood products. Unlike physical barriers, all repellents require diligent reapplication to maintain effectiveness, especially after heavy rainfall or when new growth emerges. During the active growing season, reapplication every two to four weeks is often necessary.
Deer are intelligent and adaptable, meaning they can become accustomed to a single repellent over time. To counteract this, it is recommended to rotate between different products or active ingredients every few weeks. Alternating between a taste repellent and a fear-inducing scent repellent can keep deer wary and enhance the overall protection strategy. Chemical sprays, however, are not effective against antler rubbing, as the behavior is territorial and requires a physical barrier for prevention.
Timing Protection for Seasonal Vulnerabilities
Effective protection depends on understanding the two primary periods of vulnerability for pine trees: winter and fall. Browsing damage occurs primarily during the winter months, typically from late fall through early spring, when natural food sources are scarce. Protection against browsing, such as the application of taste repellents or the installation of protective netting, must be in place before the first hard frost sets in.
The second period of heightened risk is the fall, which is when bucks rub their antlers against tree trunks to remove the velvet covering and mark their territory. This destructive activity, which can remove the bark completely around the trunk, peaks from late August through October. Protective trunk wraps and sturdy individual cages must be installed well before this period begins to prevent catastrophic damage to the main stem. Timing the installation of appropriate barriers to coincide with these seasonal behaviors significantly reduces the likelihood of damage.
Assessing and Treating Deer Damage
If a pine tree has already been damaged, a careful assessment is necessary to determine the tree’s chances of survival. Browsing damage, characterized by the torn and jagged ends of needles and twigs, is generally the least severe. In these cases, cleanly pruning the damaged branches back to a healthy lateral branch or bud can help the tree recover and encourage new growth.
Damage to the trunk from antler rubbing is more serious because it compromises the tree’s vascular system located just beneath the bark. If the bark and the underlying cambium layer have been removed completely around the trunk, a condition known as girdling, the tree will likely die because nutrients and water cannot travel between the roots and the crown. For partial bark damage, cleanly trimming the ragged edges of the wound can help the tree compartmentalize the injury. Avoid applying wound dressings or pruning tar, as these materials can trap moisture and inhibit the tree’s natural healing process.