Released April 14, 2009
MANHATTAN, Kan. – The best treatment for a springtime pruning wound on tree or shrub is no treatment at all.
“Most of us have seen sealers – usually black -- painted onto the open cut where a major branch used to be. Those coatings may have seemed like a good idea, especially since we humans treat and protect our own wounds with a dressing. For plants, however, sealants hurt more than they help,” said Charles Barden, forestry specialist with Kansas State University Research and Extension.
Whether tar, emulsion, or asphalt -- sealants can easily dry and crack in a High Plains-type climate, Barden said. Many sealants also inhibit woody plants’ own ability to develop callus growth over cuts.
“The worst case is probably if and when rain or irrigation water gets behind a sealant crack. That promotes decay,” he added. “It really is best to just keep the wound exposed to the sun and wind.”
In places where the general public expects to see tree wounds treated with sealant, city tree crews can be in a real bind, the forester said. What the public wants is in direct opposition to what the trees really need.
“I heard about one tree crew, however, that decided to deal with this problem by applying a thin coat of grayish-brown latex paint on larger pruning wounds. From a distance, the cuts were much less noticeable,” Barden said. “In any case, the approach really reduced community complaints about the crew’s tree care, while not creating the kinds of risks to trees that a sealant would.”
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http://www.oznet.ksu.edu/news/story/briefs041609.aspx
Contact: Elaine Edwards, elainee@ksu.edu
