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.
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.