Earlier this year I removed a fire damaged pecan tree from my farm. This gave me the opportunity to cut a cross section of the trunk to reveal the fire damage and how the tree responded to that damage (photo at right).
The tree was located in a field of tall native grasses. When a grass fire moved through this field, it was pushed along by a strong southern wind. The south side of the trunk was exposed to such intensely high temperatures that the bark was singed and the cambium underneath was killed. The red arrow in the photo points to the burned portion of the trunk.
In response to fire damage, the tree attempted to grow over the wounded area. Note how wide the wood growth rings are in the areas that are attempting to grow over the wound (marked A and B). This tree was moving quickly to seal over the wound. If this tree was left standing, it would have taken just a couple more years before these two fingers of wood growth to meet and grow together to completely seal over the burned portion if the trunk.
Young pecan trees, with their relatively thin bark, are especially prone to fire damage. Older, mature trees with decades of bark thickness are more resistant to fire, however, these tree can also be severely damaged by fire. Keeping the pecan orchard mowed, thus minimizing the potential for a run-away grass fire, is the best method for preventing fire damage to you pecan orchard.