About

Prescribed burns are conducted as often as possible provided the conditions are appropriate for meeting land management objectives. We set goals each season and hope to conduct between 10 and 20 prescribed burns each year totaling 500-1000 acres, however weather, resources and other constraints often limit what can be accomplished in any given year.

Fire is a normal, natural, and essential process in nearly all Texas landscapes, including those in Travis County. Prescribed burns are implemented to mimic natural fires and are designed to meet specific land management and/or fuel reduction goals. The goals for prescribed burns vary, but they are generally conducted to reduce the amount of fuel as well as to reduce the density of brush (and sometimes trees) and to increase the diversity of grasses and forbs (a flowering plant other than grass). Routine prescribed burns can make landscapes more resilient to disturbances, such as wildfires, by reducing fuel loads and encouraging a diversity of plant species.

A prescribed burn requires a prescription that identifies specific fuel and weather parameters to ensure the fire behavior will meet objectives and can be safely controlled by the resources on-site. This prescription is only a small part of a much larger plan that details how the prescribed burn will be implemented. In contrast, a controlled burn does not require the same level of planning, resources, and coordination.

Travis County Parks manages the prescribed burns. Travis County Parks has qualified fire management staff and has also entered into agreements with local fire departments and land management agencies such as the Texas Forest Service, The Nature Conservancy, and the US Fish and Wildlife Service that allow us to share resources on prescribed burns. All partner agencies meet the same federal standards for firefighter qualifications, fitness and safety requirements.

Prescribed burns can reduce fuel loads over time and routine prescribed burns may make communities more fire adapted by altering the fire behavior from a wildfire (reducing flame lengths, radiant heat and ember production). Prescribed burns are also an important training tool and provide opportunities for individuals and agencies to cooperate, collaborate, and to develop skills in a controlled environment that allows for more efficient fire suppression operations.

Specific fuel and weather parameters are required to meet the ecological and operational objectives. The amount of fuel, fuel moistures, weather conditions (particularly the relatively humidity, wind direction and wind speed) are evaluated closely to ensure the operation is conducted as safely and with as few negative impacts as possible.

Firelines are constructed around the perimeter of the prescribed burn area and may include roads, creeks, or hand lines. Fire personnel are in place along the perimeter of the prescribed burn area to ensure the firelines are reinforced during the burn. The downwind side of the fire is ignited first along the fireline. This fire is backing into the wind and therefore has a lower intensity and can be managed by fire personnel. The crews continue to ignite along both sides of the prescribed burn area and, after the fire has backed into the wind sufficiently to ensure no fire or embers can reach beyond the firelines, the headfire is ignited. This headfire is more intense than the backing fire but, because the backing fire has burned all the fuel downwind of the headfire, the headfire cannot cross the fireline. Contingency crews are in place to manage any unexpected problems with the fire or smoke. After the burn is complete, the crews remain on-site to patrol and mop-up as long as necessary to ensure no embers remain that could cause the fire to cross the containment lines later.

Prescribed burning is generally the cheapest and most beneficial land management treatment available to land managers. The cost is less than half of a comparable mechanical or chemical treatment and the result is generally better with few negative ecological impacts.

Most Texas ecosystems (including the animals that live in them) are well adapted to fire and there is generally very little mortality to animals. Not everything in the burn unit burns-there are places where the fire does not carry and often the canopies of the trees are unaffected. Although some individual animals may be harmed, the populations are not impacted and generally benefit from periodic burns.

There are many reasons for burning in the summer. We conduct prescribed burns in the summer partially because we cannot meet all of our targets by burning in the winter due to limited burn windows and staffing limitations. However, the most important reasons are ecological. A summer burn produces very different fire effects than a winter burn due to the different phenological stage of the plant (growing versus dormant), life cycle (growing, seeding or dormant) or fire intensity. Generally, we impact targeted woody species more heavily, particularly the hardwoods which are actively growing during the summer. Summer fires also encourage forbs and improve the health of native grasses. Finally, summer burn conditions often provide for better smoke dispersion than a winter fire.

A burn ban is recommended by the Travis County Fire Marshal and approved by the Commissioners Court when the Keetch-Byram Drought Index (KBDI) reaches a certain threshold and/or the fire departments are running a high volume of calls. The intent is to prevent the number of unintended ignitions. Essentially, burn bans are implemented when fuels are receptive to ignitions and fires have the possibility of moving across the landscape. These are the same conditions that we require to conduct our prescribed burns and generally we find a close correlation between when our burns are in prescription and when the burn bans are in place.

We consider the KBDI and the general fire situation (number of starts etc.) when we evaluate conditions for our prescribed burns, but we also evaluate a number of other fire danger indexes as well as fuel and weather parameters. The decision to burn is based on a broad range of criteria and may identify good burn days within a burn ban and vice versa. The important thing is that burns are only conducted when certain requirements for fuels, weather and staffing are met.

We obtain the necessary permits and coordinate closely with the local fire departments, fire marshal, emergency management coordinators and other entities before we implement any prescribed burns.

The Keetch-Byram Drought Index is one of many indexes used to track the drought conditions. It is commonly used because it can be easily tracked with limited measuring equipment; all that is needed is an observation of rainfall amounts and the condition of the sky (sunny, cloudy, etc.). In the simplest terms, it is a measurement of the moisture in the top 8 inches of the soil with a number of 0 indicating 8 inches of rain would be necessary to bring the soil moisture back to saturation and 800 indicating saturated soils. A low KBDI has been shown to be correlated with problem fires but it is not a predictor of problem fire conditions and other factors such as recent rains, winds, etc. need to be evaluated as well to determine the fire conditions on any particular day.

Smoke management is one of the key criteria for all of prescribed burns and it is even more critical in densely populated areas. Prescribed burns are conducted on days with good smoke dispersion and with favorable wind speeds and directions to avoid the receptors (schools, homes, roads, etc.) located closest to the burn unit and areas that are densely populated. Light smoke and the odor of smoke can often affect a large area near a burn. This type of smoke is often a nuisance but does not generally pose a health risk. The primary focus is on minimizing smoke impacts in adjacent neighborhoods and along the roadways where the greatest smoke impacts are anticipated.

Through multiple media outlets, sensitive receptors are notified as broadly as possible, particularly those closest to the fire. Signs may be posted in adjacent neighborhoods and sensitive receptors such as schools may be contacted directly. Finally, signs may be posted on roads to alert drivers to the potential for smoke.

Prescribed burns do release significant amounts of emissions, primarily small particulate matter. However, fires are a normal and natural occurrence and by conducting prescribed burns we have greater control on when, where, and how much emissions are produced in comparison to a wildfire. Although emissions from a prescribed fire can be heavy, they last a short time and have fewer negative impacts than the larger volume and continuous emissions from other sources, such as vehicles, power plants etc.

All the regulations identified in the Outdoor Burning Rules are met and notify the Texas Commission on Environmental Quality (TCEQ) is notified before each burn. Prescribed burns are not conducted on Ozone Action Days.