Strip-Heading Fire

Heading Fire

In strip-head firing, a series of lines of fire are set progressively upwind of a firebreak in such a manner that no individual line of fire can develop to a high energy level before it reaches either a firebreak or another line of fire. A backing fire is generally used to secure the base line and the remainder of the area is then treated with strip-heading fires. Strips are often set 1 to 3 chains apart. The distance between ignition lines is determined by the desired flame length. This distance can be varied within a fire to adjust for slight changes in topography, stand density, weather, or the type, amount or distribution of fuel. Compensation for minor wind direction changes can be made by altering the angle of the strip fire with the base line.

Strip-heading Fire Technique

Major changes in fuel type should be treated separately. An effective method of reducing fire intensity is to use a series of spots or short 1- to 2-foot-long strips instead of a solid line of fire. An added advantage of these short strips or spots is that driptorches will not have to be filled as often. Strip-heading fires permit quick ignition and burnout, and provide for smoke dispersal under optimum conditions. However, higher intensities will occur wherever lines of fire burn together, increasing the likelihood of crown scorch.

Occasionally, on areas with light and even fuel distribution, a heading fire may be allowed to move over the entire area without stripping to better accomplish the objective(s). This method reduces the number of areas of increased fire intensity that occur each time two fires burn together. Caution: Be sure the fire will not escape control. First set a backing fire along the downwind control line and allow it to burn out a strip wide enough to control the heading fire.

Flame Dimensions

Factors associated with strip-heading fires

• Secure the downwind base line before igniting a heading fire.
• Do not use in heavy roughs. Consider alternative techniques if the fire-free interval exceeds 3 years.
• Winter use is best because cool weather (below 60^oF) helps avoid crown scorch.
• Use in medium-to-large sawtimber. May be used for annual plantation maintenance burns after initial fuel reduction has been accomplished.
• Can be used in "flat" fuels such as hardwood leaves.
• Is a good method for brownspot control.
• Because fire movement is fast, large blocks can be burned.
• Can be used with high relative humidity (50 to 60 percent) and high actual fine-fuel moisture (20 to 25 percent).
• Needs just enough wind to give direction (1 to 2 mph in-stand).
• Cost is lower than other linefiring techniques because fire progress is rapid and few plow lines are required.
• The technique can accommodate wind shifts up to about 45 degrees.
• Flame lengths increase whenever heading fire converges with a backing fire, thereby increasing the possibility of crown scorch.
• A single torch person can progressively ignite strips.
• Do not force a burn on a marginal day at the low end of the prescription window. The fire may burn slowly until after the crew leaves, then pick up intensity and escape.