There are two stories to the frequency of naturally caused fires in the Pacific Northwest: the "west side story and the "east side story". Forests of Mt. Rainier, Olympic, and the western portion of North Cascades National Parks are generally moist, fir-dominated regions. The fire cycle at any one point is infrequent here, occuring at intervals of 150 to 700 years.

East of the Cascades, the fire story is quite different. Much of the fire history here at Crater Lake National Park has been documented through the research of James Agee, professor of Forest Ecology at the University of Washington, and other researchers since the mid-70's. For example, the drier, ponderosa pine-dominated region encompassing lower elevations at Crater Lake National Park has a much shorter interval between fire. Here natural fires occurred every 2 to 17 years. Research indicates that historical fire regimes varied according to the forest type in terms of fire frequency and severity. Mountain hemlock/Shasta red fir forest regions have a 42 year mean fire return interval while Lodgepole pine forest areas experience natural fires every 60 to 80 years on average.

Prior to fire suppression activities, these small but frequent fires served to decrease the amount of fuel on the forest floor. In the absence of fire, ground fuels and understory vegetation began to accumulate to unnaturally high levels. This accumulation of fuels presented a serious fire hazard. To lessen this hazard and restore natural forest conditions, resource managers at Crater Lake are prescribing low intensity fires. These burns are set in pre-determined areas usually in the spring and fall so that low levels of fire intensity are assured.

Fire is a natural process - a part of each park's ecosystem of plants, animals, soil, water, and air - and is as much as a part of the forests as avalanches, windstorms, native insect and disease outbreaks, and, certainly evident at Crater Lake National Park, volcanoes. All of these naturally occurring forces have played an important role in shaping the forest landscape we all enjoy today.