Tree-centered spot firing to protect special trees
Savanna burns can present problems when special trees are present within lush prairie grass. Flame heights may often be high, and may seriously damage even upper tree branches. Under such conditions, the technique of tree-centered spot firing can be used.
Tree-centered spot firing was described in 1989 by Weatherspoon et al. of the U.S. Forest Service. See link
With tree-centered spot firing, the bases of trees to be protected are lighted by a crew member moving ahead of the flaming front. A few drops of fire is all it takes to blacken the base of the tree. When the flaming front reaches that tree the flames drop and the tree is unharmed.
Our burn crew has been using this technique for the past several years. It takes an additional crew member but perhaps saves mop-up time at the end of the burn. Also, once the trees are protected, this crew member can proceed to interior lighting, which is almost always necessary on a savanna burn.
One might ask whether this precaution is necessary for bur oaks, which are generally quite fire resistant. We use this mainly for smaller specimens, which are less fire tolerant, as a precautionary measure.
|Spot firing around some small bur oaks creates a black area and protects the trees|
C. Philip Weatherspoon, George A. Almond, and Carl N. Skinner. 1989. “Tree-centered spot firing---a technique for prescribed burning beneath standing trees.” Western Journal of Applied Forestry, Vol. 4: 29-31.