Prescribed Fire

What is Prescribed Fire? 

Prescribed fire refers to the controlled application of fire to wildland ecosystems under specified environmental conditions that help restore health to fire-adapted environments.

By reducing hazardous fuel accumulations on the forest floor, encouraging the new growth of native vegetation, and maintaining the many plant and animal species whose habitats depend on periodic fire, prescribed burning helps reduce the catastrophic damage of wildfire on our lands and surrounding communities.

 Prescribed fire is one of the most effective tools we have in preventing the outbreak and spread of wildfires. But because prescribed fire is fire, fire management experts must be extremely careful in planning and executing a prescribed fire.

Benefits of Prescribed Fire 

Only in the last century has fire in the forest been considered “bad.” Though fire is often destructive it is also a catalyst for welcomed and necessary change. Fire changes the composition and density of the forest creating openings for more fire resistant trees and stimulating regeneration. Fire also creates early plant successional stages that benefit many species of wildlife.

The powerful, beneficial role of fire has almost disappeared from the ecosystem it once helped create. The inevitable release of energy is postponed and the probability of a devastating wildfire is increased. When extraordinary amounts of fuel are present, a fire’s intensity may increase beyond the beneficial point. Soils can be overheated and root systems damaged. Living tree crowns may be completely destroyed.

Controlling fires by replicating the natural scheme is accomplished with fuel management. In areas where management objectives require reproducing natural communities, the use of prescribed fire is an effective fuel management tool.

The decision to use prescribed fire is one which should be taken with the advice of a qualified professional. In Oklahoma, fire is used for a number of natural resource management objectives including:

  • Reduce fuel accumulations – Periodic burning reduces the annual fuel accumulation in forests and grasslands reducing fire intensity and creating an ecosystem less susceptible to catastrophic wildfire.
    • Improve wildlife habitat – Periodic burning improves habitat for Oklahoma wildlife by modifying cover, and food quality and volume.
    • Increase biodiversity – Periodic burning induces environmental changes that result in plant and animal communities that are adapted to fire.
    • Control hardwood encroachment – Periodic burning also helps control hardwood encroachment onto old fields and into managed pine stands.
    • Control eastern redcedar – Without maintenance, some Oklahoma landscapes begin to shift towards a juniper forest type. This forest type was historically restricted to north slopes, canyons and rock outcrops where fire didn’t burn regularly.

How to Prepare to Conduct a Prescribed Fire 

Prescribed fire is a very deliberative process.  Careful planning must be undertaken to determine why, when and how a prescribed burn will be conducted. Planning for prescribed fire considers the history and variety of past fire events over the landscape to determine the most appropriate place and time to apply fire to achieve your land management objectives.

Anyone planning to apply prescribed fire must consider many issues before determining the location, extent, timing and prescription parameters for any particular burn. 

Burn Within the Law 

To lawfully burn within the law:

  • You must be legally entitled to burn the property as an owner, authorized tenant or agent of the owner/authorized tenant. (Statutory Reference: O.S. Title 2 S 16-25).
  • You must provide adequate firelines, sufficient manpower and firefighting equipment to contain your fires to the property you are authorized to burn and stay with the fire until it is extinguished.
  • In the protection areas of eastern Oklahoma (generally east of highway 69) you must obtain approval from the Forestry Division at least four hours prior to burning. (Statutory Reference: O.S. Title 2 S 16-28).

Click here for more information on burning within the law

Reducing Liability for Prescribed Fires

REMEMBER . . . You are responsible for your fire.

Title 2, Sections 16-28 and 16-28.2 of the Oklahoma Forestry Code provide some liability protection for landowners conducting prescribed burns under certain conditions. To obtain this protection however, the owner or manager is responsible for planning the burn, providing proper notification to neighbors and local authorities, conducting the burn according to the plan, providing adequate equipment and manpower to control the fire and confine it to his or her property, and preventing impacts downwind from smoke.

OFS makes available a Prescribed Burning Notification Plan for use when utilizing prescribed fire.

Fire Weather Resources 

Weather is the fire behavior factor with the highest variability. Temperature, relative humidity, and wind speed vary greatly throughout the day and are also effected by frontal passage. These weather changes can have a major impact on fire behavior.  Outdoor burning should only be conducted inside of predetermined weather conditions. This will result in the safe use of fire.

Please utilize the following websites (which supply current weather and fire danger) to assist you when preparing to do any outdoor burning.

For current fire weather forecasts go to:

National Weather Service – Southern Region Headquarters

Smoke Management 

When conducting an outdoor burn you are responsible for the smoke that is produced by the burn. As you are responsible for the smoke, you need to develop a smoke management plan for your burns to keep the smoke’s impacts on the environment within acceptable levels. This reduces your risk of conducting the outdoor burn. Remember you are responsible for the impacts resulting from the smoke created by your outdoor burning.

The following are the steps to take in developing a Smoke Management Plan following Oklahoma’s Voluntary Smoke Management Guidelines:

  1. Determine Category Day
  2. Determine Screening Distance
  3. Determine Trajectory
  4. Identify Smoke Sensitive Areas
  5. Evaluate the Results

How to Determine the Category Day

The Category Day is determined by the ventilation rate, which is the afternoon mixing height in meters, times the transport windspeed in meters per second.  Forestry burning activities should proceed according to the table below:

 I < 2,000No Burning!
 II 2,000 – 4,000No burning until 11:00 am and not before surface inversion has lifted. Fire out by 4:00 pm.
 III 4,000 – 8,000Daytime burning only after inversion has lifted.
 IV 8,000 – 16,000Burning anytime.
Night burns use backing fires with surface wind speeds greater than 4 mph.
 V> 16,000“Unstable” and windy.
Excellent smoke dispersal.
Burn with caution!

You can obtain a Fire Weather Forecast, including Category Day, from the National Weather Service.

How to Determine the Screening Distance

Screening Distance is the downwind distance you should examine for possible smoke sensitive sites such as airports, highways, communities, recreation areas, schools, hospitals, nursing homes, etc.

The type of burn coupled with the Category Day determines the number of miles downwind to apply the screening process.

Identify your burn in one of the following four types:

  1. Backing fire less than 1,000 acres
  2. Head fire less than 1,000 acres
  3. More than 1,000 acres
  4. Piles/Windrows

Using the following table, find the block that represents the type of burn and Category Day, The number in the block is the minimum number of miles downwind to screen for smoke sensitive areas.

 Type of Burn III  III IV V
Backing Fire
Less than 1,000 acres
Head Fire
Less than 1,000 acres
Fire > 1,000 acres in sizeNo

Anticipated Smoke Plume Trajectory Determination

Locate the burn on a map and draw a line representing the centerline of the smoke plume. The length of the line should be greater than the screening distance. If the burn will last over a long period of time, draw another line showing predicted wind direction at the end of the burn.

To allow for horizontal dispersion of the smoke, as well as shifts in the wind direction, draw two other lines from the fire at an angle of 30 degrees from the centerline(s).

Publications: Wildland Fire Effects, Use, and Recovery 

Fire Effects and Ecology

Prescribed Fire Use