Inferno at Yellowstone
The wildfires at Yellowstone National Park during the
summer of 1988 burned with a ferocity seldom seen before.
There were actually eight fires, two started by humans,
helped by nine storm fronts that brought lightning
and high winds but no rain. Mature trees burned completely
in 15-20 seconds, and firefighters watched "javelins
of fire" jump over a mile as the blazes spread.
Before the winter snows extinguished the last of the
fires, some 740,000 of the park's 2.2 million acres
had been burned.
Since then, more than 250 research experiments in the
park have provided a lesson in ecological succession,
the natural process of establishment or reestablishment
of an ecosystem. The burned parts of Yellowstone are
now going through several stages of recognizable, repeated
patterns of change caused by this natural disturbance:
- Wildfires burn in a mosaic, destroying some areas,
singeing others, and leaving some untouched. The lightly
burned or unburned areas provide most of the seeds
that revitalize the heavily burned areas.
SAmong the first species to return to Yellowstone were
the grasses, which burn on top but regenerate from
roots below ground, surging back using the nitrogen
and phosphorous released by the dead plants.
- The park's famous lodgepole pines are also among the
early species to return, growing from seeds in pinecones
whose waxy coating was melted by the fires, enabling
them to germinate under these fire-ravaged conditions.
The lodgepole pines are now as high as 18 feet.
SAspen have been observed in most of the burned areas,
establishing themselves in places they had not been
before. However, as the lodgepole pines grow taller
and create canopies, many aspen will likely die from
- Before 1988, Yellowstone was roughly 70 percent old
forest, where the moose fed in winter. Those moose
in burned areas had to expand their range or risk starving,
and one study showed that almost half the affected
moose died within the year. Hundreds of elk were asphyxiated
during the fire, and some 5,000 died within the year
as well (drought was almost certainly also a contributing
- Hawks fared well even as the fires were burning and
their prey was scurrying for cover, which was being
destroyed. Nesting birds also have thrived; boring
beetles and other insects feasted on the dead trees
and were feasted on by the woodpeckers, mountain bluebirds,
and tree swallows.
- The dead trees provided cover for the snowshoe hare,
voles, and deer mice, which have increased in numbers.
The lynx, which feed on the hares, are also expected
- Ash, burned trees, and mud flow from the fires created
a slurry that poured into park streams, redirecting
and/or widening many of them, and killing many fish.
However, the woody debris then created pools where
fish could spawn, and with the old forest canopy gone,
algae bloomed as well as sunlight fell on the pools.
This has helped increase the size and number of insects,
which has increased the size and number of fish. So,
as the pulse of burned material has washed out, the
streams have recovered and even flourished.
As wildfires rage each summer in our national parks
and forests, many of the lessons on what to expect
and how to manage them will have come from the Yellowstone
fires of 1988.
Barker,Rocky.1996."Yellowstone Fires and their
Robbins, Jim. 2001. "In Fires Afterglow, Nature
Runs Its Course, for Good and Ill," New York Times,
April 10, pp D1, D4.