Oak Wilt Prevention and Management

oak wilt vein banding (courtesy Texas A&M Forest Service)

What is Oak Wilt?

Oak wilt is an infectious disease caused by the fungus Bretziella fagacearum, which disables the water-conducting system (xylem) in oaks and leads to the eventual death of the tree. All oaks can be infected by the fungus that causes oak wilt; however, some oak species are affected more than others. Successful management of oak wilt depends on correct diagnosis and an understanding of how the pathogen and different oak species interact.

To learn more about the identification and management of oak wilt, visit TexasOakWilt.org.

Oak Wilt Management Ordinance

The City of Boerne’s Oak Wilt Management Ordinance (Chapter 8.3 Section E of the Unified Development Code) establishes rules and regulations for the planting, maintenance, and treatment of these trees in the City.

  1. Ordinance Highlights

Prohibited Trees

The planting of Texas Red Oak (Quercus buckleyi) aka Spanish Oak, Shumard Oak (Quercus shumardii), and similar thin bark red oaks is prohibited. These trees are potential sources of inoculum for the Oak Wilt fungus, Ceratocystis fagacearum. Fungal spore mats formed on these types of trees are attractive to insect vectors, which results in long range dissemination of the fungus.

Trimming Restrictions and Regulations

Trimming or cutting of any oak species should not occur from the first day of February to the first day of July. Regardless of season, all pruning cuts or other wounds to oak trees, including freshly cut stumps and damaged surface roots should be treated immediately with paint to prevent exposure to contaminated insect vectors.

Contractors or individuals identified pruning any oak(s) without a demonstrated ability to seal all wounds greater that 0.75 inches within 30 minutes of the time of cutting will be required to cease all work until a wound sealant is onsite and utilized on the project. Contractors or individuals identified pruning any oak without sealing wounds with an acceptable wound dressing within 30 minutes of pruning will be assessed a $500 fine per occurrence.

Removal and Disposal of Infected Trees

Upon verification of an oak wilt infected red oak species the City urban forester will provide written notification to the tree owner advising of the proper methods and timing for removal and disposal. Infected red oaks that die in late summer, fall, or early winter should be cut down and burned (when allowed), buried, or chipped soon after discovery to prevent fungal mats that may form on these trees the following spring.

Oak Wilt Incentive Program

The City of Boerne’s Oak Wilt Incentive Program is a fund available to Boerne residents for assistance with tree removal and treatment due to oak wilt. It is incorporated into the City’s annual budget and funded through the Tree Restoration Fund.

The goal of the incentive program is to stop the spread of oak wilt by helping residents treat the trees that can be saved and remove those that can’t before they become a safety hazard.

Learn more about the program.


For questions about Oak Wilt Prevention and Management, please contact Ryan Bass, Environmental Planner and Urban Forester with the City of Boerne.