Tree wrapping is a preventative maintenance measure designed to shield the delicate bark of newly planted or young trees from harsh winter conditions. The primary goal of this temporary covering is to moderate the trunk’s temperature, preventing injury that commonly occurs during the cold season. By applying a protective layer, you help ensure the tree’s underlying vascular tissues remain healthy until spring growth begins. This practice focuses on providing a stable environment for the bark of younger, thin-barked species.
Reasons for Trunk Protection
The effort to wrap a tree trunk is necessary to combat several distinct threats that emerge during the winter months. One of the most significant dangers is sunscald, often called southwest winter injury, which affects the bark on the sunniest side of the tree. Intense sunlight warms the dark bark on clear winter days, causing dormant cells to become active. When the sun sets and temperatures rapidly plummet below freezing, these newly activated cells in the cambium layer are killed. This freeze-thaw cycle results in sunken, discolored bark that eventually splits and peels away, leaving a wound that can take years for the tree to compartmentalize.
The wrap also provides a physical barrier against gnawing rodents like mice and rabbits, which feed on tender bark when other food sources are scarce. Rodents can completely girdle a young tree, severing the flow of nutrients and water. Furthermore, a protective trunk wrap offers defense against accidental mechanical damage throughout the year. Lawn equipment, such as string trimmers and mowers, frequently inflict wounds at the base of the tree, creating entry points for pests and disease.
Selecting Materials and Application Timing
Selecting the correct wrapping material is important to ensure the tree receives protection without suffering unintended harm. Commercial tree wraps made from crepe-paper or breathable polypropylene fabric are highly effective and designed to reflect sunlight. Burlap strips or corrugated cardboard are also acceptable options, as they allow for air circulation and moisture evaporation. Avoid non-porous materials like plastic sheets or duct tape, as these can trap excessive moisture against the bark, creating an environment for fungal growth or pest infestation.
The timing of application is just as important as the material selection for maximizing benefits. The wrapping should be applied in the late fall, generally around November, after the tree has entered full dormancy but before the first hard frost. This timing ensures the trunk is shielded when the sunscald risk is highest. Tree wrapping is generally recommended only for young trees, typically those in the first two to five years after planting, until their bark naturally thickens.
Step-by-Step Wrapping Technique
The wrapping process begins at the base of the trunk, just above the soil line, ensuring the material is started on a slight upward angle. The material should then be spiraled up the trunk, maintaining a constant, slight overlap with each revolution, similar to how shingles are laid on a roof. Overlapping by about one-third of the material’s width is usually sufficient to ensure continuous coverage and allow precipitation to shed away from the bark. Starting at the bottom and overlapping upward ensures that rain or melting snow is directed away from the trunk.
Continue wrapping until you reach the lowest main scaffold branch, completely covering the smooth, thin bark susceptible to sunscald. The wrap must be kept snug against the trunk to prevent it from slipping down or blowing open in the wind, but it should not be so tight that it restricts the natural expansion of the trunk. Once the desired height is reached, secure the end of the material using specialized tree tape, twine, or a small piece of flexible wire. Avoid attaching the securing material directly to the bark with tacks or staples, which can damage the underlying tissue.
Seasonal Removal and Maintenance
The protective trunk wrap must be removed in early spring, typically around late March or early April, before the tree breaks dormancy and sap begins to flow. Leaving the material on for too long can create significant problems for the tree’s health. A wrap left on throughout the growing season can girdle the trunk, causing a constriction that chokes the flow of water and nutrients between the roots and the canopy.
Prolonged wrapping also harbors insects and moisture, which can lead to diseases or pest infestations that damage the bark. Once the risk of severe, fluctuating winter temperatures has passed, the wrap should be taken off completely and discarded or recycled. Mature trees with rough, thick bark typically possess sufficient natural insulation and do not require this annual protective measure.