Oak Wilt Prevention and City Ordinances

OAK WILT & ITS PREVENTION IN HORSESHOE BAY

By Cynthia Lane


It is difficult to appreciate how devastating oak wilt can be especially since Horseshoe Bay does not have any confirmed oak wilt.  Yet.  Having lived in a small community where oak wilt started from something as innocent as a bundle of infected red oak firewood, I can say with certainty that prevention is the key.  That starts with education, which is the purpose of this article.  We all love Horseshoe Bay, and our trees are such a huge part of the beauty and property values here that we would all feel badly if we allowed it to start here because we did not care enough to take it seriously.  Oak wilt does not respect property lines, wealth or fences - what I do with the oak trees on my property can most definitely affect my neighbor’s oak trees due to their interconnected root systems.  Nathan Abbott, a certified arborist with Certified Arbor Care, states “I would like to stress that prevention is key in Oak Wilt management.  Removing crossing branches throughout oak canopies as well as any branches rubbing on other structures greatly reduces a landowner’s chances of the disease being introduced to their property.”

What is oak wilt? It is a vascular wilt disease caused by a fungus that infects the water-conducting tissues of oak trees and causes them to wilt and die.  It is almost always fatal.  Unfortunately, good health does not improve resistance to this disease.  And ball moss does not increase the risk of getting it.

Oak wilt moves from location to location by the transport of a spore carried on the body of an insect.  It travels from a fungal or spore mat, produced on a red oak under the bark to a fresh wound on another oak.  Once the oak wilt infects a live oak, it moves from tree to tree through the common root system.

The symptoms of oak wilt are quite recognizable.  The veins of the leaves in the live oaks turn yellow or brown with the remaining part of the leaves remaining green.  This is referred to as “veinal necrosis”, which means death of the vein.  Once leaf symptoms do occur, live oaks will usually die within 3-12 months.  There are other leaf symptoms that can indicate other issues so it is always best to get professional advice before taking action.

Robert Edmonson of Texas A&M Forest Service states that “There is no “cure” for oak wilt; only management of the disease including prevention, trenching, fungicide injections and creating species diversity. The only “cure” would be to remove all oaks from the property. “

Prevention of oak wilt is easy, but it is a very difficult disease to manage after it becomes established.  These are the guidelines to follow:

  •  Avoid pruning oaks during the spring ( February - June  in Central Texas) when the beetles are active.
  • Paint all pruning cuts and injuries to the oaks immediately.  If you cannot seal the wound, DO NOT CUT IT!!!  To paint the wound use an inexpensive spray paint in medium gray which matches the bark color nicely; pruning sealers such as Spectracide are almost too thick and can result in other problems.  Oaks are the only trees that need to have the wounds sealed. Remember, the key is to paint the wound upon cutting.  
  • Under no circumstances, buy or bring to Horseshoe Bay any unseasoned firewood.  The firewood needs to be well-seasoned, thoroughly dried and cured.
  • Remove and destroy any red oak suspected/confirmed to have oak wilt.

There are some other things that you can do to help prevent oak wilt.  Make sure tree trimmers sanitize their equipment and paint all wounds immediately.   A good practice is to plant trees other than oaks;  go to www.texasoakwilt.org for suggestions for alternatives.  Also, use a certified arborist for tree trimming and verify that they are familiar with oak wilt.  Mr. Abbott also says “I always tell my clients that with most tree diseases we just need to keep an eye on what is going on with their trees on their property, but with oak wilt, it is important that we keep a vigilant eye on the surrounding properties as well. We have multiple tools we can use to prevent our trees from becoming infected, but once a tree is infected there is a very low chance that we can save it. “

Mr. Edmonson adds that “Creating species diversity is important in your tree composition throughout Horseshoe Bay. The reasons we have chestnut blight, Dutch elm disease, and oak wilt is we favored certain species over others either intentionally or by accident. When one species dominates the stand, we set ourselves up for disease epidemic. I feel creating diversity through supplemental plantings is the long-term solution for managing oak wilt.”

Remember, we are all in this together to protect our beautiful oak trees and property values.  None of us wants to be the one who brings oak wilt to Horseshoe Bay.  The good news is there is currently no verified oak wilt in Horseshoe Bay.  Let’s keep it that way.

For more information on oak wilt prevention please visit www.texasoakwilt.org

Reminder: Beginning February 1st  Oak Tree Trimming is Prohibited Until July 1st


The City’s Development Services Department would like to remind everyone that beginning February 1st, pruning of any type of oak tree is prohibited until July 1st, per Chapter 8, Article 8.09 Tree Trimming Protection.

Section 8.09.004 (Violations, Penalty and Enforcement) reads as follows:

(a) All species and varieties of oak wilt infected oak trees that are dead or substantially dead, and all red oak wood and firewood, which may serve as a breeding place for any carrier of said disease, are hereby declared to be public nuisances.

(b) Pruning or cutting of oak trees shall be prohibited in the spring months of February through June when fungal spore formation and beetle activity are highest unless such activities are completely unavoidable in order to protect the safety of people and property or the health of the tree. Golf courses and resorts are exempt from this prohibition from February 1st through February 14th. Pruning or cutting of oaks is permitted from July through January.

(c) It shall be unlawful to stack firewood taken from red oaks.

(d) It shall be unlawful for any person to transport, store or sell firewood within the city that was taken from red oak trees or unknown sources of firewood. Red oaks may not be retained for firewood under any circumstance due to the high risk of fungal mat formation and insect transmission.

(e) Red oaks that are dead or dying of oak wilt as determined by the city staff or the state forest service shall be cut at ground level, with all firewood and woody debris covered and hauled away or disposed of by burying, burning or chipping within three working days.

(f) Regardless of the time of year that a tree is cut or otherwise damaged by natural disaster and a wound occurs, neutral color paint must be applied immediately to all wounds of any size on susceptible oaks, including the cut surface of healthy oak stumps, pruning cuts, rubbing of branches together or on a roof or other structure creating open wounds, or branches with construction damage, or any spot where the bark has been removed to expose the wood beneath, in order to discourage potential insect/disease contamination. Failure to seal any wound immediately after the wound is discovered or occurs is an unlawful violation of this article.

(g) It shall be unlawful for any person, firm or corporation to knowingly violate the provisions of this article. Any person knowingly violating any of the provisions of this article shall be deemed guilty of a misdemeanor, and each and every day or portion thereof during which any violation of any provision of this article is committed, continued, or permitted, shall be considered a separate offense and upon the conviction of any such violation, such offense shall be punishable by a fine of not more than one thousand dollars ($1,000.00) per day.

(h) The city’s code officer is charged with the enforcement of the provisions of this article.

Please help us protect the City’s oak tree population from this devastating disease. You can report violations to the Development Service Office at 830-598-9959.

Thank you for helping keep Horseshoe Bay beautiful!