Nature Notes From Crater Lake
Volume 26, 1995
Fire as an Agent of Change
By Doug Lowthian
In 1994, Crater Lake National Park
experienced 44 forest fires. These fires occurred throughout the park,
from the Boundary Springs area to Sharp Peak and Annie Creek. Contrary
to the widely held belief that fire in the forest is devastating and
destructive, the fires at Crater Lake were beneficial products of a
natural process eons old.
The vast majority of these fires during
the 1994 fire season were under one tenth of an acre. A few grew to an
acre or two, but less than five surpassed ten acres. One event, known as
the Agee fire, was particularly interesting. This fire took nearly a
week to find as the lookouts kept losing sight of the furtive smoke.
Rugged topography south of the lookouts at Watchman and Mount Scott
prevented a clear pinpointing of the smoke. It would pop up in the
afternoon for a short time and then disappear, laying down in the tree
canopy. When the smoke could be seen, it seemed to be on the southwest
flank of Crater Peak.
A team of two firefighters were sent to
locate the source of the elusive smoke. After four hours of climbing up
and down the steep slopes, pushing through thick stands of snowbrush,
Ceanothus velutinus, and sliding down scree, they stopped for lunch.
In casually scanning the northern skyline, they saw something that made
the drop their sandwiches and pick up their binoculars. They found the
smoke, but it was not on Crater Peak. Although in line with the lookout
tower on Watchman, the fire was on a ridge above the East Fork Annie
Creek--over a mile and a half away! Since a deep canyon lay between them
and the fire, they ate while hiking out. This turned into a near run so
that they could get back to East Rim Drive and revealed itself, less
than one and a half mile from headquarters. In an ironic twist, this
fire turned out to be one of the closest to home.
Locating this fire on the park map is
easy. Place your finger at Park Headquarters and follow East Rim Drive
until it crosses the east fork of Annie Creek. Turn south and go about
three quarters of a mile. On the west side of the creek, a steep slope
runs up from the canyon bottom to the 6,000 foot level. You will see a
ridge dividing the middle and east forks of Annie Creek. Along this
ridge the fire burned slow but steady through a mature forest consisting
of Mountain hemlock. Tsuga mertensiana, and Shasta red fir
Abies magnifica-procera. Upon discovery, the fire covered less than
half an acre. The decomposing layer of needles and twigs smoldered and
smoked heavily. Occasionally the crackling of burning live needles broke
the quiet. Small seedlings, with their branches near the ground, were
torching. This sent flames up as high as three or four feet, dying out
as quick as they started.

Map by Susan Marvin.
There have been fires around what is
now Crater Lake National Park for many thousands of years. Chances are,
however, that what became known as the Agee Fire was the first in this
part of the forest for quite some time. Far from being static and
seniscent, the forest is constantly changing. Agents of change such as
wind, precipitation, and fire alter species composition and stand
density in the forest. These processes occur with varying frequency,
depending on the type of forest. The frequency of fire in a given locale
can be averaged to obtain its Fire Return Interval. This number can vary
greatly throughout a forested area depending on the species makeup,
altitude, aspect, topography, and prevailing weather patterns.
The forest where the Agee fire burned
has a mean fire return interval of approximately 40 to 50 years. This
means that the fire was burning on land that probably had not burned in
the last 50 years or more. The variability among fire return intervals
is usually very broad. For example, one researcher may find evidence of
fires within the last decade, while another might find that a similar
area had not burned for 120 years. The accuracy of these numbers usually
depends on the extent of the survey.
The Agee fire burned for about eight
weeks before being extinguished by snowfall in early November. During
this time, firefighters made efforts to contain the fire within a fixed
perimeter. With many other fires burning throughout the park at the same
time, people and equipment were stretched thin. The weather remained hot
and dry for several weeks after the fire started. Temperatures in the
80's and humidity as low as 13 percent pointed to conditions normally
associated with high fire danger. For the most part, however, the fire
burned slowly through the underbrush and duff layer.
To study the effects this fire would
have on the forest, plots were established in the path of the spreading
flames to measure various components of the stand structure. These plots
quantified the amount of burnable material, or fuel, and the quantity
and density of live trees and shrubs. By reading the plots before and
after the fire the change caused by the fire could be measured.
The results of these measurements point
to the fact that fire is rarely a devastating event. Even the massive
fires at Yellowstone in 1988 were agents of change that led to massive
regeneration of the forest. The Agee fire, burning through a period of
high fire danger, altered the forest in ways that were not as dramatic
as all-consuming fire storms. This fire killed just 13 percent of the
trees over ten feet tall, and only 41 percent of the trees under ten
feet tall. The fire thinned out the young trees, providing better
conditions for the growth of those that remained. What few large trees
that were killed now allow for more sunlight to reach the forest floor
where grasses and shrubs will sprout next year. During the fire many
signs of elk were present an should be again once the forage returns.
The large dead trees will also provide valuable habitat for birds, bats
and insects. In topping out at 30 acres, the Agee fire left a forest
changed but far from devastated.
Another change documented at the Agee
fire involved deduction of the fuel load. This is composed of dead and
down sticks and logs, as well as duff and needles. From a pre-burn level
of 17.96 tons per acre, the fire consumed 14.53 tons per acre of fuel.
This 81 percent reduction accomplished several things. Stored nutrients
were released, making them available for future plant growth. In
addition, such reduction can prevent the unnatural build up of fuels
(which can lead to high intensity fires) that results from overzealous
suppression of all fires.
Suppression of all fire at Crater Lake
National Park was practiced for roughly 75 years. During that time much
natural change in the forest has been stymied. When the snow began to
fall in early November, there was still heat in the Agee Fire. By this
time the fire crews were long gone and the fire cache was closed for the
year. Snow fell gently and the temperature hovered around 30 degrees.
Standing in the midst of the burn, I warmed my hands over embers in a
slowly burning log. I thought about the regrowth, elk, and more fires in
the summer of 1995.
Further Information
James K. Agee, Fire Ecology of the
Pacific Northwest Forests.
Washington, D.C.: Island Press, 1993.
C.B. Chappell, Fire Ecology and
Seedling Establishment in Shasta Red Fir Forests of Crater Lake National
Park. M.S. thesis, University of Washington, Seattle, 1991.
Doug Lowthian is a seasonal
firefighter at Crater Lake National Park.

Phantom Ship from Kerr Notch in 1936. Homer Marion
photo, NPS files.