Trees that have been burned in a fire have varying degrees of wood damage depending upon the duration and intensity of the fire. Trees that are killed by a low intensity ground fire often retain their bark for 12 to 24 months and may have minor damage to the wood. Trees that have been scorched 20 to 40 feet from the base, but still have the needles attached can also have minor damage to the wood. If the duration and intensity of the fire is greater, the trees will check and lose bark shortly after the fire. If the checks extend deeply into the wood, the tree may not be useable for studs and boards within the damaged length.
When trees have been severely burned with black bark, with the needles burned off and some branches burned, they often will check soon after the fire. Some of these trees have deep cracks to the heart of the tree that may spiral up to the top of the tree. These trees have been cooked to the point of drying the sapwood. This type of damage makes these logs unfit for lumber, and most pulp facilities do not want burned bark or wood in their processing operation.
When considering selling burned timber, assessing the degree of damage caused by the fire and selling the burned timber as soon as possible are two important factors. Generally, the wood of fire killed trees begins to deteriorate shortly after the fire and may become un-useable within 12 to 18 months. Douglas-fir may show signs of sap rot after 12 months. The pines and spruce will often blue stain within 6 to 10 months resulting in a decrease in value of the burned timber to fall to less than half of the value of the un-blued timber. In some situations larger Douglas-fir and larch that have minimum damage can retain value for up to 24 months after the fire.