Guidelines and recommendations for pruning practices pertaining to oak wilt prevention have changed several times since the early ’80’s. The original suggestion was to prune only in January and August, our most extreme temperature months. More recently, the recommendation has been to “avoid wounding” between February and June. Unfortunately, most people would interpret this to mean don’t prune during the period. But, now we have an official recommendation to address some specific pruning implications. In January 2011 the Texas Forest Sevice, Texas AgriLife Extension Service and the International Society of Arboriculture Texas Chapter met to develop the guidelines for oak pruning to help prevent the above ground spread of oak wilt.
The most important part of the new recommendation, in my opinion, addresses the fact that sometimes pruning actually reduces wounding and this risk of oak wilt infection. The cliche example would be pruning back low hanging limbs in a street. A limb that is struck by passing trucks gets re-wounded on a daily basis. This persistently exposed wound is more of a risk than a single pruning cut that will heal quickly. This scenario commonly crops up quickly when spring growth flushes come out and weigh down branches.