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Fire and Its Role in the Watershed

Fire has been a part of the natural ecosystem since the origin of vegetation on earth. Historically, fires have occurred as often as every 2 years to as infrequently as 400 years in most North American plant communities. In Arizona, natural fires in ponderosa pine communities occurred historically every 4 to 12 years. Fires eliminated young pines and other conifer species, and kept the forest open and park like. Fire is responsible for plant distribution and varied vegetative communities. Overall, fires are beneficial because they reduce fuel buildup (for example the Yellowstone Park fire of 1987), reduce dense understories of shrub and trees, and increase plant and wildlife diversity.

Throughout the world, chaparral is thought to be a fire-induced vegetation type. In fact, some chapparal species germinate from seed after a fire. In Arizona, burned chaparral areas that are left to recover naturally can survive for 80 to 100 years. In general, fire helps to keep chaparral communities diverse and productive as long as they do not occur more frequently than 20 to 30 years apart.

Fire has been a dominant force controlling the distribution of juniper, but fire is not the only factor. Fire, drought, competition, and effects of grazing play a role in the distribution of juniper. Prescribed burning is a management technique that has been used in the Beaver Creek Watershed.

Fire is not a cure-all for all forest and range management problems. Poor rangeland condition cannot be improved with fire alone. Rangelands in poor condition must first be restored using other reclamation techniques. However, once the rangeland is in good condition, fire can be used as an effective management tool in special situations during wet weather cycles to control undesirable species such as burroweed, broom snakeweed, creosote bush, cactus species, and young mesquite trees. Desirable species such as native grasses may increase. Fire is effective and inexpensive for many land management problems, if used by people skilled in the use of prescribed burning.
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20 March 2001
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