How Texans can protect their trees before oak wilt season begins

AUSTIN (KXAN) — As the winter months roll in through Central Texas, so, too is oak wilt season.

Oak wilt is one of the most impactful tree diseases nationally, and is particularly destructive here in Central Texas, according to the Texas A&M Forest Service. Oak wilt involves a fungus that permeates and disables a tree's water conducting system; while all oak trees can be infected by the fungus, some species are more susceptible than others.

Oak wilt season begins Feb. 1, when fungal mats are most commonly set to form and nitidulid beetles — which damage the trees — activate. But that doesn't mean it's too late to prune your oak trees now and mitigate potential infections down the road.

The best time to prune a tree is in late fall or early winter prior to the start of February, according to Dallas-based Landscape Horticulture Services. While it's permissible to trim oak trees between June 30 and Feb. 1, Landscape Horticulture Services recommended January as the best time to prune.

"If the fall and winter months are the best time to trim trees, then you can safely assume that the worst time to cut limbs is during early spring and summer," Landscape Horticulture Services staff wrote. "During these times, the trees are using a lot of energy to put out new growth after being dormant for so long. If you introduce fresh wounds by trimming during this time, the tree may not be able to divert many resources to heal itself."

For those looking to prune, Dallas/Fort Worth-based Treenewal stressed it's best to leave tree trimming and pruning services to professionals who are trained in proper safety techniques. In the event property owners wish to prune their oak trees themselves, the following tips are recommended:

• Using a three-cut method, make an undercut on the branch about 10 inches to 12 inches away from the tree. Moving an inch or two down the branch, cut from the top branch fully through to avoid tearing as the branch's weight is being pulled downward. The final cut should be made closer to the tree.
• With the final cut, experts caution avoiding the "flush cut," or when the branch is removed from a tree as close to it as possible, "making it flush with the trunk or main branch," Treenewal experts said. A flush cut can cause slow or uneven healing that makes the tree more vulnerable to both diseases and pests.
• Paint the wound after trimming an oak tree with an asphalt or latex base to enact a protective layer between the freshly-made cut and insects. Wound paint should be added immediately after making the cut, and should always be made regardless of the cut's size.
• Those suspected an oak tree has oak wilt is advised to call a professional arborist to remove the tree from one's property, in an effort to prevent the spread of the disease.