Many times, when our trees are injured, such as during pruning, we want to help manage the wound to facilitate quick healing. Typically, this means the application of a tree wound dressing. How do you determine if you should apply a wound dressing and what type?
Tree wound dressings have been around for decades and was frequently used by arborists, fruit tree growers and tree owners. However, research has confidently proven that these chemical bandages are not good for your tree and will actually slow natural wound closure. Tree wound dressings do not prevent decay (Collins 1934, Marshall 1950, Shigo and Wilson 1977, Mercer 1979, 1982, Bonneman 1979, Dooley 1980), and are of limited benefit for wound closure (Neely 1970, McQuilkin 1950, Young and Tilford 1937). Many arborists have known this for a long time and have stopped using them, but there are still many of those who care for trees that are greatly uninformed and not current with best management practices.
Why are wound dressing not recommended? First, a lesson on tree biology and the tree recovery process. Trees isolate damage from an injury by forming wound wood in the damaged area, such as a pruning cut. This highly lignified tissue forms at the edge of the wound and gradually seals off the pruning cut or any other injury by forming a specialized wall around the wound to help reduce the spread of decay. This helps prevent wood damaging decay organisms from establishing itself in the tree leading to serious health issues.
So, although the seemingly legitimate advertisements on the wound dressing packaging make claims such as these:
“A clean, easy, simple way to aid in healing cuts and protecting tree wounds, pruned-edges and graft unions of roses, trees, and shrubs”
“Insure your trees, shrubs, and vines against decay, insects, and fungi in any kind of weather”
“An artificial bark for treatment of wounds…made of ALL NATURAL biodegradable materials”
The reality is these petroleum-based products do not inhibit decay but limit the oxidative processes necessary to seal the wound. It has been thought that a wound dressing can be used to prevent wood rot and the entrance of decay organisms.. Actually, tree wound dressings seal in moisture and decay which can make problems even worse.
There may be some benefit for wound treatment with certain diseases such as Oak Wilt with a pesticide application to the wound. However, if pruning is done to susceptible trees when they are in dormancy, the chance of infection is greatly reduced, and wound treatment is unnecessary and should be avoided. The best treatment for wounds especially from pruning, is a proper cut using the proper tools. If you are pruning trees prone to disease such as Fireblight, sterilize pruning tools to help reduce the spread to other plants. Help your tree heal from required pruning with good cuts and good choices. Avoid the application of wound dressings for faster recovery.
For more information on pruning, see Tree Pruning Essentials, FNR-506-W,