Plastic tree guards, also known as tree shelters or tree tubes, are temporary devices designed to protect young saplings during their establishment phase. These polyethylene barriers create a physical shield against various threats in the landscape. They prevent browsing damage from herbivores like deer and rabbits, which can otherwise severely stunt or kill a young tree by eating the tender shoots and leaves. The guards also shield the delicate bark from mechanical injury caused by lawn equipment such as string trimmers or mowers, as well as accidental exposure to herbicide spray drift. By trapping moisture and heat, the tubes create a localized microclimate that can accelerate the initial vertical growth of the tree.
Identifying Growth Signals for Removal
Determining the precise moment for removal requires a visual inspection of the tree’s development. The most important metric is the trunk diameter, or caliper, as the tree must not be allowed to grow to the point where the guard restricts its expansion.
A tree has likely outgrown its need for the guard when the trunk begins to press against the inside wall of the plastic barrier. At this stage, the trunk’s radial growth necessitates removal to prevent constriction. For many newly planted trees, this stage is reached within two to five years, depending on the species and growth rate. Furthermore, the tree should be tall enough that its upper crown is well above the height of the guard, placing its new growth out of reach of common browsing animals like deer.
The tree must also achieve sufficient stem hardening, or lignification, to withstand wind stress without the support of the guard. Tree tubes promote rapid vertical growth, but they can inhibit the development of trunk taper, which is the natural thickening of the stem near the base. The gentle movement caused by wind, known as thigmomorphogenesis, is necessary to build a strong, rigid trunk. If the guard is removed before the tree has developed this structural strength, the stem may be too weak to support the crown, especially in windy conditions. If the plastic itself shows signs of degradation, such as becoming brittle or cracking from UV exposure, it should be removed.
Consequences of Leaving Guards Installed Too Long
Failing to remove a plastic tree guard promptly can lead to severe, often irreversible damage to the tree’s vascular system and overall health. The most serious consequence is girdling, which occurs when the rigid plastic constricts the growing trunk. The guard embeds itself into the bark, effectively cutting off the phloem tissue that lies just beneath the surface.
Phloem is responsible for transporting sugars produced during photosynthesis from the leaves down to the roots. When the phloem is severed, the roots are starved of nutrients, which leads to a slow decline and eventual death of the entire tree, even if the leaves appear healthy for a year or two after the damage occurs. This mechanical strangulation is entirely preventable with timely removal.
Leaving a guard installed too long creates an artificially humid microenvironment around the bark, which is highly conducive to pest and disease development. The trapped moisture can lead to fungal infections, mold, and bark decay, compromising the tree’s natural defenses. The dark, sheltered space between the plastic and the trunk provides an ideal nesting area for rodents and insects. These pests can chew on the tender bark, leading to further girdling damage or creating entry points for pathogens.
Procedure for Safe and Effective Removal
Removal of the tree guard must be executed carefully to avoid injury to the bark, which is delicate even on established young trees. It is recommended to inspect and adjust guards at least twice a year to monitor trunk growth and maintain proper spacing. When the time for permanent removal arrives, begin by taking down any securing ties or removing the stake that supports the guard.
A utility knife or shears can be used to cut the plastic vertically along one side, taking extreme caution to ensure the blade does not score the tree’s bark underneath. Once the guard is cut, it should be gently unwrapped and peeled away from the trunk. After removal, the trunk should be closely inspected for any indentations, abrasions, or signs of insect activity that may have occurred while the guard was in place.
Any trapped debris, leaves, or vegetation that has accumulated between the guard and the trunk must be cleared away from the base of the tree. The plastic material should then be disposed of properly, though many types of guards are durable enough to be cleaned and reused on new saplings. Timely removal and post-inspection ensure the tree can transition successfully from a protected sapling to a healthy, independent young tree.