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Background: The Problem and Why It Matters
Across the Post Oak Savannah region of Texas, a growing share of rural land has become — or is becoming — dense oak forest choked with yaupon in the understory. At ground level, these forests appear deceptively open: a carpet of leaf litter with several clear feet of space before the canopy closes in overhead. But that openness is a sign of ecological poverty, not health.
Ground-level view of a yaupon-choked Post Oak Savannah forest. The open, shaded understory provides almost no food or cover for wildlife.
Almost no sunlight reaches the ground. Without it, native grasses and forbs cannot establish, and the insects that depend on them — along with the birds and small animals higher up the food chain — have little to eat. The open sightlines also offer poor cover: predators can spot prey from a distance, making these forests nearly useless as wildlife habitat. A recent study further found that this "thicketization" of oak forests suppresses groundwater recharge to near zero.
Some might assume this is simply what land looks like when left alone, but that misunderstands the region's natural history. Before European settlement, this landscape was shaped by bison herds that grazed intensively and by frequent wildfires — both natural and intentionally set by Indigenous people. These forces kept woody growth in check and maintained a diverse mosaic of tall grasses (especially little bluestem) and flowering forbs.
Today, we can't restore free-roaming bison or unchecked wildfire, but we can manage land actively to achieve similar results. The goal is threefold: significantly reduce the woody understory, moderately thin the forest canopy, and encourage native grasses and forbs to reestablish in the thinned areas. The process described here was developed for the Post Oak Savannah but applies broadly to other forest types with dense woody understory problems.
Ground-level view of a yaupon-choked Post Oak Savannah forest. The open, shaded understory provides
A 4-Stage Multiyear Process
Habitat restoration requires sustained commitment. The four-stage process outlined here requires at least two years of active work and ongoing maintenance thereafter — but the results are well worth the effort.
The stages below are illustrated with an ongoing 170-acre restoration project at the Cedar Hill Nature Preserve, conducted in partnership with Texas Parks and Wildlife (TPWD). The project's primary goal is to expand quality habitat for the endangered Houston Toad, but the methods benefit all native plants and animals — and make the land far more enjoyable for the landowner.
This is what we hope to end up with.
Stage 1 – Mulching
Mulching is the foundation of the restoration process and typically the most expensive step. It uses specialized forestry mulching equipment to grind down the woody understory. The objective is not to clear the land entirely, but to reduce shrub cover to a level where a UTV can drive through comfortably.
At the Nature Preserve, approximately 75% of the project area was mulched; the remaining 25% was left as strips and clusters to be reduced gradually by prescribed burns in later stages. Due to the project's Houston Toad protections, mulching was limited to the period of July 1 through December 31, outside the toad's breeding season.
Cost: Approximately $1,200–$1,800 per acre mulched
Contractor (Nature Preserve): Shuffield Land Clearing, Cameron, TX, (254) 482-0697
Shuffield Land Clearing performed the work and has built a strong reputation across projects for private landowners and government agencies alike.
A forestry mulching machine in operation, grinding down the woody understory.
Stage 2 – Seeding
Seeding is the only optional stage, but experience at the Nature Preserve suggests it can make a significant difference. Its purpose is to enrich the soil's seed bank in freshly mulched areas, accelerating the return of native grasses and forbs.
Because mulched terrain is rough and uneven, seed must be broadcast using specialized equipment rather than a standard drill seeder. Timing matters: seeding ideally occurs in the winter immediately following the mulching season. Post-seeding weather plays a major role in germination success, so results can vary from year to year.
At the Nature Preserve, seeding was done at about one-quarter the standard recommended rate, yet it produced striking results — 12-foot-wide swaths of native grass throughout the landscape. These not only expand the seed base for surrounding areas but also create the fine-fuel load needed for effective prescribed burns in Stage 4. Comparison with unseeded mulched areas on the same property confirmed that seeding dramatically improved native grass establishment.
Cost (in 2023): Approximately $57 per acre (labor and seed combined at reduced rate)
Seed Specifications: Tim Siegmund, TPWD Private Lands Program Leader, (903) 426-1834
Contractor (Nature Preserve): Chancey Lewis, Native Texas Wildlife, Cameron, TX, (512) 393-9958
Chancey Lewis has the right equipment for broadcasting native seed across rough, varied terrain, and brings the experience to do it well.
Chancey Lewis broadcasts native seed throughout the mulched area.
Stage 3 – Spraying
Yaupon is remarkably resilient: if simply mulched, it resprouts denser than before. Herbicide treatment is essential to prevent this. Ideally, spraying should occur between May and September of the year following mulching, when resprouts are actively growing and most susceptible.
Two approaches are available — individual plant treatment (IPT) for smaller areas and broadcast spraying for larger projects. At the Nature Preserve we used broadcast The formula used at the Nature Preserve achieved strong top-kill of yaupon (knocking down nearly all visible growth) but is estimated to have completely eliminated only 30–50% of plants. Even so, this top-kill allowed substantial native grass and forb growth and set the stage for more effective prescribed burns. (A TPWD-led research study is currently underway at the Preserve to identify a broadcast formula that achieves more complete kill.)
Individual Plant Treatment (IPT)
Mix: 10% Triclopyr, 90% diesel, with blue dye as needed
Application rate: Approximately 2.6 oz of mix per plant; about 100 plants per labor hour. Requires a diesel-compatible sprayer.
Coverage estimate: ~6 gallons of mix per acre at 300 stems/acre
Cost estimate: Chemical costs exceed $65/acre; labor often adds $100+/acre. Stem density varies widely.
IPT is highly effective — nearly 100% kill on everything sprayed, including large yaupon when applied to trunks. However, the labor intensity makes it impractical to contract for projects exceeding roughly 25 acres. IPT is best suited for smaller projects and follow-up spot treatments.
Broadcast Treatment
Mix: 2.8% Triclopyr, 2.8% Methylated Seed Oil (surfactant), 94.4% water, with blue dye as needed
Application rate: 30 gallons per acre using broadcast spray equipment
Cost estimate (in 2024): Chemical costs exceed $70/acre; labor at approximately $125/hour for equipment and operator yields about 2.25 acres/hour
Contractor (Nature Preserve): Chancey Lewis, Native Texas Wildlife — same contact as Stage 2
Broadcast is more economical per acre but less precise — plants shaded by others can be missed, and the method is ineffective on larger, trunk-dominated yaupon. A follow-up spot treatment is typically needed. Importantly, the formula above does not significantly harm grasses or most forbs. There is some indication that reducing the MSO concentration to around 1.25% could improve complete kill rates; further research will help clarify this.
IPT vs. Broadcast: How to Choose
Use IPT when:
• The treatment area is fairly small
• You need maximum effectiveness, including on large-stemmed yaupon
• Conducting follow-up or spot treatments after broadcast
Use Broadcast when:
• The project area is large and full IPT coverage is not feasible
• Target plants are mostly smaller and bushy
• Budget is a primary constraint
• You plan a follow-up spot treatment for missed plants
Chancey's broadcast sprayer.
Stage 4 – Prescribed Burns
Even the most thorough mulching and herbicide program won't achieve 100% coverage on large acreage — and without ongoing management, woody understory will return over time. Once enough grass has been established to carry a fire, prescribed burning is by far the most cost-effective tool for both improving and maintaining restored habitat.
The first burn should be timed for the second or third winter after herbicide treatment. Multiple burns — often three or more in consecutive years — are typically needed to bring an area into excellent condition.
Prescribed burns require careful planning and execution. Burn-day weather conditions must fall within a narrow acceptable range, and landowners face some liability exposure. Professional burn teams can be contracted, or in some areas burn associations provide cooperative support. TPWD also offers training and limited assistance.
Contractor (Nature Preserve): Acorn Forestry, 7680 FM2497, Lufkin, TX 75904, (936) 875-5400
Professional burn team cost: Approximately $50/acre on large acreage; higher on smaller properties
First Burn Results at the Nature Preserve (December 2025)
Approximately 30–40% of the treatment area burned during the first prescribed burn. Remaining thickets were largely unaffected, due to a combination of factors: some forest areas remained too dense to carry fire effectively, and wind direction shifted during the burn, limiting spread. Advisors expect the second burn to perform significantly better as fuel loads and conditions improve.
The burn was conducted by Acorn Forestry, whose team walked numerous transects across the area and ignited the grass in a methodical pattern appropriate for the fragmented, patchy nature of the landscape.
For landowners who cannot conduct prescribed burns, periodic shredding on a one-to-two-year cycle is a workable alternative for controlling woody regrowth — though it will not achieve the same level of habitat diversity as fire.
A prescribed burn led by TPWD in 2020.
Long-Term Maintenance
Once the woody understory is well suppressed and native grasses and forbs are firmly established, the maintenance burden decreases substantially. Periodic prescribed burns every three to four years are expected to sustain habitat diversity and quality over the long term. On smaller properties, periodic shredding can serve as a substitute, though habitat diversity may be somewhat reduced compared to fire-managed land.
A prescribed burn led by TPWD in 2020.