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Thursday - February 04, 2010

From: New Braunfels, TX
Region: Southwest
Topic: Diseases and Disorders, Pruning, Trees
Title: Should I use wound paint when pruning my live oak tree?
Answered by: Joe Marcus


When trimming live oak branches, is it best to coat the wound on the tree? I have been doing this but have recently heard that it can actually be bad for the tree.


Once upon a time it was standard practice to treat an open wound on any tree with tree-wound dressing.  However, research showed that painting tree wounds inhibited healing and sometimes actually promoted the growth of tree pathogens by providing them with a protected place and ideal conditions to grow beneath the paint.

Today, the general consensus among arborists is to forego the use of tree-wound sealant and allow fresh wounds to remain exposed to the fresh air where they can heal naturally.

However, live oaks and many other species in the genus, Quercus are exceptions to the rule.  The freshly-cut stumps of oak limbs should always be immediately painted with tree-wound dressing as a prophylactic measure against the spread of Oak Wilt Disease.  Oak Wilt is spread by tiny wood-boring beetles that are attracted to the sap of oak trees.  Fresh wounds on oak trees draw these beetles like porch lights draw moths.  The adult beetles carry on their bodies the fungus that causes Oak Wilt Disease wherever they go and in that way spread the disease.  Be sure and use tree-wound dressing especially made for that purpose.  Regular paint often contains ingredients harmful to trees.

Timing is also important in preventing Oak Wilt Disease spread.  The disease-vectoring beetles are active only when the weather is not too hot nor too cold.  So pruning live oaks only in mid-winter and mid-summer is advised.

Please visit the Texas Oak Wilt Information Partnership website more information on Oak Wilt Disease, how you can protect your trees and help prevent its spread.

Finally, proper pruning technique is every bit as important to your trees' health as whether or not you use tree paint.  The US Forest Service has published an excellent on-line article called, How to Prune Trees, that you will benefit from reading.


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