Squirrels are common in urban and suburban environments, but their natural behaviors can threaten the health of trees. These agile rodents cause damage by stripping bark to access the nutritious inner cambium layer, consuming developing buds, and pilfering ripening fruits and nuts. Understanding how squirrels access a tree is the first step in developing a comprehensive strategy to protect your landscape. This article details the most effective physical, chemical, and environmental adjustments to safeguard your trees.
Physical Exclusion Methods for Tree Trunks
The most reliable approach involves installing physical barriers to prevent squirrels from climbing the trunk and reaching the canopy. A smooth metal baffle or collar is highly effective because it exploits the squirrel’s inability to grip slick, vertical surfaces. These baffles should be constructed of sheet metal or smooth plastic and installed at least five to six feet high on the trunk, since squirrels can jump four to five feet vertically.
The baffle must be wide enough to prevent squirrels from leaping around its perimeter, typically extending at least two feet in diameter. Ensure the baffle is not attached snugly to the trunk; allow a small gap for future tree growth and secure it with a flexible mounting system. This method only works on isolated trees that do not have branches extending to within ten feet of any nearby structure, such as a fence, roof, or utility line, which squirrels could use as a launching point.
For young trees, a different barrier may be necessary to prevent bark stripping and gnawing damage near the base. Trunk guards made from durable, galvanized hardware cloth offer chew-proof protection. This mesh should be secured around the trunk, forming a cylinder that allows air circulation, and should be embedded slightly into the soil to stop squirrels from digging beneath it.
To protect the harvest of fruit or nut trees, covering the canopy with wildlife-safe netting is practical during the ripening season. The net must be secured tightly around the trunk or base of the tree to prevent squirrels from accessing the fruit by crawling up underneath the mesh. Using fine mesh netting reduces the risk of entanglement for birds and other small wildlife.
Taste and Scent-Based Deterrents
Repellents relying on unpleasant taste or smell offer a supplemental defense, especially when applied to vulnerable areas. Capsaicin, the compound that gives chili peppers their heat, acts as a taste aversion deterrent by irritating pain receptors in mammals. It is often applied as a liquid spray to surfaces squirrels chew, such as bark, buds, or bird feeder poles.
These capsaicin-based solutions are humane, causing only temporary discomfort, but their effectiveness is limited by environmental factors. Frequent reapplication is necessary, especially after rain, because the active ingredients wash away easily. Squirrels may also learn to tolerate the spray or simply move to an untreated part of the tree if it is not thoroughly and consistently applied.
Some commercial products attempt to deter squirrels using the scent of predators, such as fox or coyote urine. The smell of a natural enemy creates an environment of perceived danger, causing squirrels to avoid the area. However, results from these scent-based repellents are mixed and often temporary, especially where squirrels may not associate the scent with an actual threat.
Naphthalene, found in mothballs, is sometimes recommended as a scent-based deterrent, but its use around trees should be avoided. The chemical is classified as a pesticide, is hazardous to human and pet health, and its outdoor use is often illegal or regulated. Furthermore, mothballs are largely ineffective against determined squirrels and can contaminate soil and water sources.
Modifying the Environment and Intervention Strategies
A long-term prevention plan requires altering the surrounding environment to eliminate easy access points and food sources. Squirrels are accomplished jumpers, capable of leaping several feet horizontally. Trimming tree branches to maintain a horizontal clearance of at least seven to ten feet from fences, utility lines, and house eaves is an effective way to cut off aerial access routes.
Removing ground-level food sources is a powerful deterrent, as squirrels are less likely to frequent an area with limited rewards. This includes regularly sweeping up fallen nuts and fruits, and securing or removing bird feeders, which are a major attraction. If bird feeding is desired, switching to safflower or niger seed can help, as squirrels generally find these less palatable than sunflower seeds or corn.
In cases of severe property damage, intervention strategies like live-trapping may be considered. Humane traps can be baited with nuts or seeds and placed near the damaged area. Before deploying any trap, contact local wildlife control authorities or state agencies, as trapping and the subsequent release or disposal of the animal are often strictly regulated.
Relocating trapped squirrels is generally discouraged and often prohibited by law because it can spread disease or cause the displaced animal to die of starvation or conflict in unfamiliar territory. In many jurisdictions, captured nuisance wildlife must be released on-site or euthanized humanely. Understanding these regulations ensures compliance and ethical treatment of the animals.