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rchaeological evidence indicates that deliberate burning of forests and fields has been occurring on the North American continent for at least the past 10,000 to 20,000 years. Here are a few of the reasons native people used fire as an aid to subsistence:
- Forest Treatment. To kill insect infestations, and to diminish shrubs and grasses through which wildfire might spread, and destroy trees.
- Improve Horse Pasture. To make spring grass more easily available, and to eliminate competing species such as brush and tree seedlings.
- Improve Hunting. To thin out dense underbrush, and stimulate growth of good browse. Also used to surround deer herds to make them more accessible to hunters.
- Encourage Food Plants. To favor or increase the growth of one or more of the 200 species of plants used for food and other purposes.
- Campsite Clearing. To improve visibility and eliminate underbrush and tall grass in which attackers could hide.
- Communication. William Clark, August 31, 1805, as the Corps began the climb up to the Bitterroot Divide, wrote:
|This day warm and Sultrey, Praries or open Valies on fire in Several places-- The Countrey is Set on fire for the purpose of Collecting the different bands, and a Band of the Flatheads to go to the Missouri where They intend passing the winter near the Buffalow.|
- Rituals. William Clark, on June 25, 1806, wrote of the three Nez Perce men who had agreed to guide them over the trail from Clearwater country to Travelers' Rest:
|last evening the indians entertained us with seting the fir trees [possibly Engelmann spruce] on fire. they have a great number of dry lims near their bodies which when set on fire creates a very suddon and immence blaze from bottom to top of those tall trees. they are a beautifull object in this situation at night. this exhibition reminded me of a display of fireworks. the natives told us that their object in seting those trees on fire was to bring fair weather for our journey.|
Today it is against federal and state laws to deliberately set a forest or range fire. "Prescribed burns" are carefully designed and monitored by professional foresters. Natural, lightning-caused fires are sometimes allowed to burn, but are closely monitored according to a complex set of interrelated factors, including the density of underbrush and dead or fallen trees.
Content reviewed by: Stephen F. Arno, Intermountain Fire Sciences Laboratory; Mary Horstman, Forest Historian, Bitterroot National Forest; Stan Underwood, Sula Ranger District, Bitterroot National Forest.