Once installed, some trees or shrubs may need additional safeguards to counter the effects of the sun, prevailing winds, maintenance workers, vandals, or animals. Trunk wraps, various methods of staking and guying, and antitranspirants are materials used to protect and stabilize new transplants.
To protect young tree species that have thin bark and are at risk for injury by extremely hot summer temperatures or drying winds, it has been common practice to wrap the trunks from the ground up to the first set of branches with a protective covering. Rolls of commercial tree wrap are available as burlap stripping or as a crepe-like paper. Except in arid regions, the wraps are applied from the base of the tree upward, with each coil overlapping the one below to prevent moisture from getting in. The trunk wrap is tied at the top using another strip of burlap or twine, but not wire. Despite its long standing acceptance by landscapers and arborists as a proper protective technique, trunk wrapping has garnered only mixed support among researchers. Some studies seem to justify its value; others find no significant benefit. It may be that the value is specific to certain species, of certain ages, and planted into certain locations subject to certain environmental conditions. One thing is definite: all trunk wrap must be biodegradable, even the twine. The wrap and twine should either degrade naturally after two years or be removed by hand. To leave it in place any longer can harm the tree. For protection against animal injury, the trunks may be wrapped with plastic coils. Like the wraps, tree coils should be removed after two years (Figure 10-9).