Deer damage to trees is a common issue for homeowners. The potential for a tree to recover depends entirely on the nature and extent of its injury, especially since deer behaviors can inflict significant harm on young trees and ornamental plantings. A tree’s ability to heal is governed by its biology and the severity of the wound, which directly impacts its internal vascular system. This article provides guidance on diagnosing the damage, assessing the tree’s chance of survival, and taking steps for immediate care and long-term protection.
Identifying the Types and Severity of Deer Damage
Deer injure trees in three primary ways: antler rubbing, browsing, and girdling. Antler rubbing occurs mainly in the fall as bucks remove velvet from their antlers or mark their territory. This results in vertical scrapes on the trunk of young trees, typically one to four inches in diameter. This action strips the bark, exposing the inner wood and causing shredded areas that can extend from one to five feet above the ground.
Browsing damage appears as torn or jagged edges on leaves, terminal buds, and new growth. Unlike rodents, which leave a clean, 45-degree clip, deer lack upper incisors and must tear the plant material as they feed. This damage is most common during the winter when other food sources are scarce, and it tends to affect lower branches up to about six feet high.
Girdling is the most destructive form of injury, resulting from antler rubbing or bark stripping for food. Girdling involves the complete removal of bark and the underlying cambium layer all the way around the trunk or a branch. If the damage fully encircles the tree, it severs the vascular connection between the roots and the canopy, which is almost always fatal.
Assessing the Likelihood of Recovery
A tree’s ability to recover hinges on the integrity of its cambium layer, a thin band of cells located just beneath the bark. This layer is responsible for the tree’s growth and is the main pathway for transporting water, nutrients, and sugars. If antler rubbing or bark stripping removes this layer, the tree can no longer sustain itself.
The most significant factor in predicting survival is the “circumference rule,” which determines the extent of girdling damage. If the cambium layer is removed around more than 50% of the trunk’s circumference, the prognosis is poor because the vascular system has been compromised beyond its capacity for self-repair. If the damage is only partial, the tree can often compartmentalize the wound and slowly grow new bark over the exposed wood.
Browsing damage is generally less severe than trunk injury and is often recoverable unless deer repeatedly destroy the terminal leader, the main vertical stem. Repeated loss of the terminal leader can stunt the tree’s height growth and lead to a deformed shape. Young trees with thinner bark and a smaller diameter are at a higher risk of fatal injury than older, more established specimens.
Immediate Steps for Intervention and Care
Once damage is assessed, prompt intervention can maximize the tree’s chances of survival by minimizing secondary threats. For bark damage, the recommended procedure is bark tracing, which involves using a sharp, disinfected knife to cleanly cut away loose or jagged bark around the wound. This creates a smooth, clean edge that allows the tree to form callus tissue and seal the wound efficiently.
The wound should be left uncovered, as applying tree wound dressings or sealants is generally discouraged. These products can interfere with the tree’s natural healing process and may trap moisture, creating an environment favorable for disease or decay. The primary focus of post-injury care is to reduce stress on the tree.
Adequate watering is important, especially during periods of drought, since a stressed tree has fewer resources for wound recovery. Providing sufficient hydration and appropriate nutrients will support the energy demands of the healing process. For light browsing damage, careful pruning of the remaining shredded branches will encourage new, healthy growth.
Strategies for Future Damage Prevention
Long-term protection relies on installing physical barriers or using deterrents to prevent future access by deer. The most effective method is exclusionary fencing, which must be at least eight feet tall to reliably prevent deer from jumping over it. For individual trees, wire cylinders or tree guards provide a robust defense against antler rubbing.
These protective structures, often made of wire mesh or sturdy plastic, should encircle the trunk and be tall enough to protect the tree up to the height of the first branches (typically four to six feet). The barrier must be far enough away from the trunk to prevent deer from pushing against it and causing damage. Tree tubes, which enclose the entire sapling, are effective for very young trees.
Repellents offer a temporary solution and are categorized as taste-based or odor-based. These products must be applied frequently, especially after rainfall or when new growth appears, since unprotected plant material is quickly exposed. Deer are highly adaptable, so rotating between different types of repellents is necessary to prevent them from becoming accustomed to a single deterrent.