Oak Wilt and Land Clearing in Texas: The Calendar That Matters

Most land clearing decisions are about money and equipment. This one is about a calendar, and getting it wrong can cost you the trees you were trying to keep.

Oak wilt is a fungal disease that kills oaks, and Central Texas is one of the hardest-hit regions in the country. If your clearing project involves live oaks, and around San Antonio it usually does, the month you do the work matters as much as how you do it.

The Rule in One Paragraph

Texas A&M Forest Service advises avoiding pruning or wounding oaks from February through June, and recommends painting every oak wound immediately, regardless of the time of year. The best time to prune is the dormant window, roughly November through January, when fewer insects and diseases are active. Those are the two facts that drive everything else in this article, and they come straight from the agency’s prevent the spread of oak wilt guidance.

Why February Through June

The disease moves two ways, and one of them is seasonal.

Above ground, small sap-feeding beetles carry fungal spores from infected trees to fresh wounds on healthy ones. Texas A&M Forest Service explains that oak wilt spreads most easily February through June because fungal mat production, insect populations, and oak susceptibility all peak in that window. A cut made in March is an open invitation delivered at exactly the moment the messengers are most active.

Below ground, oaks of the same species share interconnected root systems, and the fungus travels through them from tree to tree. That is why oak wilt tends to move outward through a stand rather than appearing randomly, and why a single infected tree is a neighborhood problem rather than a one-tree problem.

The Forest Service increased funding to combat oak wilt spread in 2026, which tells you how seriously the state takes it. Texas Oak Wilt publishes a pruning calendar and FAQ worth bookmarking if you own oaks.

Paint Every Wound, Every Time

This is the part people skip because it feels like folk advice. It is not.

The guidance is to paint oak wounds immediately, and the agency is clear that any paint will do. The paint is not treating the tree; it is a physical barrier that keeps spore-carrying beetles off a fresh, attractive wound. What matters is speed. A wound painted twenty minutes later is far better than one painted the next morning.

That applies to pruning cuts, to bark scrapes from equipment, and to root damage where a root is exposed and cut. Which brings us to clearing.

What This Means on a Clearing Job

A mulcher does not prune oaks, but a clearing project can wound them in three ways: contact with the trunk, bark damage from material being thrown, and root damage from tracks running over the root zone or from trenching nearby.

Practically, on a Central Texas clearing job with live oaks in the scope:

1. Flag the keepers first. Before anything runs, the oaks you want kept get marked, and so does the working boundary around them.
2. Sequence oak work to dormancy. If limbs actually need to come off a live oak, that portion of the project belongs in the November-to-January window wherever the schedule allows.
3. Cedar and understory are not restricted. Ashe juniper, mesquite, huisache, and brush carry no seasonal restriction. This is why a spring project around San Antonio often starts with the juniper work and holds the oak work for later in the year.
4. Keep tracks off the root zone. The area under the canopy is where the roots are. Working around it rather than across it costs a little time and avoids the wound you cannot paint.
5. Carry paint on the machine. Accidents happen on any site. The response to bark damage on an oak is paint, right then.

If You Already Have It

Symptoms usually show first in the canopy: leaves developing veinal necrosis, where the veins yellow or brown while tissue between them stays green, followed by rapid leaf drop and decline. Live oaks tend to decline over months; red oaks can die within weeks and are the species most likely to produce the fungal mats that start new infections.

This is not a clearing contractor’s call to make. If you suspect oak wilt, the right next step is a certified arborist or the Texas A&M Forest Service, both of whom can confirm a diagnosis and talk through management, which can include trenching to sever root connections and removing red oaks that are producing mats. What we can do is avoid making it worse, which is most of what the calendar above is for.

Where This Fits With the Other Rules

Oak wilt is guidance rather than a permit, but it sits alongside rules that are enforceable and can affect the same trees.

Inside San Antonio city limits, the Unified Development Code protects significant trees from 6 inches diameter for most species, with a higher 10-inch threshold for Ashe juniper, mesquite, huisache, Arizona ash, and hackberry, and heritage trees from 24 inches preserved at 100%. Completed single-family, two-family, and three-family homesites are exempt. In other words, the live oaks you are protecting from oak wilt are often the same trees the city counts. Our San Antonio permits guide covers the tree ordinance, the Edwards Aquifer program, and county permits together.

The Short Version

• Avoid pruning or wounding oaks February through June.
• Prune in the dormant window, November through January, where possible.
• Paint every oak wound immediately, in any month, with any paint.
• Cedar, mesquite, and understory clearing is not seasonally restricted, so most projects can start regardless.
• Suspected infection is a job for a certified arborist or Texas A&M Forest Service, not a contractor.

If you are planning clearing work around live oaks anywhere near San Antonio, Boerne, Bulverde, or New Braunfels, we will sequence it around this calendar as part of the quote. Book a free walk-through, or start with what the work itself looks like on our land clearing page.