Squirrels chew on tree branches and bark to maintain their continuously growing incisor teeth, gather nesting material, or access the nutrient-rich cambium layer, especially during winter. This behavior can cause significant damage, leading to girdling—where the bark is stripped completely around the circumference—which can kill a branch or the entire tree. Protecting valuable trees requires a non-lethal, multi-faceted approach. Effective strategies involve preventing access, making branches unappealing, and modifying the surrounding environment.
Preventing Access with Physical Barriers
Physical exclusion is the most reliable method for protecting an isolated tree. The primary tool is a tree baffle or collar, typically made from smooth metal or heavy-duty plastic sheeting. This barrier is installed around the trunk to prevent squirrels from gaining the necessary grip to ascend.
For the barrier to be effective, it must be installed at least five to six feet high, as squirrels can leap up to four feet vertically. The collar should be at least two feet wide to ensure the animal cannot jump over the top edge. Secure the baffle loosely with springs or flexible wiring to accommodate the tree’s natural growth without causing constriction.
This method works only if the protected tree is not near other structures that would allow squirrels to bypass the barrier. Squirrels can jump horizontally eight to ten feet, so adjacent tree limbs, fences, power lines, and roof eaves must be trimmed back to maintain a clear perimeter. For young or small trees, a protective wrap made of ¼-inch or ½-inch metal hardware cloth can be wrapped directly around the trunk and lower branches to prevent gnawing damage.
Using Taste and Scent Deterrents
Applying repellents that use taste or scent can make branches unappetizing. Taste-based deterrents are more effective against chewing because they deliver an immediate, unpleasant sensation upon contact. Products containing capsaicin, derived from hot peppers, create a burning sensation in the squirrel’s mouth without harming the tree.
Another common taste repellent is Denatonium Benzoate, known commercially as bitter apple spray, which is the most bitter substance known and discourages gnawing. When using these products, choose formulations safe for plants and ensure complete coverage of the affected branches. These applications are not permanent and must be reapplied frequently, especially after rainfall, as water washes away the active compounds.
Scent-based deterrents, including concentrated oils from garlic or peppermint, are used to confuse or mask the scent of the tree material. Commercial options may also use the scent of predator urine to create a sense of risk. The effectiveness of scent repellents is highly variable and often short-lived, as squirrels are highly adaptable and quickly habituate to the odor.
Environmental Management and Redirection
Long-term success in reducing tree damage often involves modifying the environment to decrease the general appeal of the area to squirrels. Reducing easy access points is a primary strategy, which means pruning any branches that extend within six to eight feet of a house roof, fence, or overhead wire. These pathways allow squirrels to travel directly into the canopy, rendering trunk baffles useless.
Removing readily available food sources, such as bird feeders and pet food left outdoors, can reduce the overall squirrel population density. Fallen fruit and nuts should also be cleaned up regularly, as they provide a strong incentive for squirrels to remain in the immediate vicinity.
A proactive approach involves providing a designated feeding or chewing station away from the protected trees to redirect their activity. Offering an alternative, easily accessible food source, such as an ear of corn secured to a distant fence post, can draw their attention away from valuable trees. This strategy works by satisfying the squirrel’s innate need to forage and chew in a location where their activity is not destructive.