How the ecology of conifers determines an environmental issue

1
How the ecology of conifers determines an
environmental issue
2
Forest fires in natural ecosystems
Yellowstone National Park 1988
Human Concerns economics, timber reserves,
continuing public access, nature
conservation.
Can we develop a policy toward fire that takes
into account the biology of forest species and
the ecology of forests?
3
Forest Fires in the United States
Note the frequency and distribution of lightning
caused fires
4
Lightning never strikes twice?
An estimated 16 million thunderstorms occur each
year on earth, causing some 100 lightning strokes
to the ground per second.

Only a small fraction ignite fires, but suppose
0.1 of the 3,153,600,000 strikes do, that gives
3 million lightning fires/year.
Between 50 and 80 percent of forest fires in
western North America are lightning caused. There
are some 4,871 lightning fires per year on
federally-owned land in the US.
http//www.chaseday.com/lightning.htm
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Fires burning on 18 August 2001
in Washington and Oregon
High incidence of fire on the eastern slopes of
the Cascade Mountains
The total area classified as being on fire is
341, 669 acres
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The Icicle fire
A series of fires of different sizes started
following multiple lightning strikes. The fires
shown are on the tops of ridges and are difficult
to access. Most fires are small.
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Yellowstone 1988
More than 25,000 firefighters served in the
Yellowstone area and represented the largest
firefighting effort in U.S. history
At its height, the Greater Yellowstone Unified
Fire Command fielded 336 fire engines, 57
helicopters, 41 bulldozers, and numerous
retardant bombers.
"How do you put out the Yellowstone fires? Pour
a hundred million dollars on it and wait for it
to snow."
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Forest fires are a natural events
Forest fire is a natural event
Conifer species in the western USA form largely
dry land forests
Many conifer species are adapted to withstand
fire and/or regenerate following fire
Examples?
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Different types of forest ecosystems and their
relationship with fire
Lodgepole pine the Yellowstone type. Dense
stands that burn completely but usually with a
high frequency.
Ponderosa pine ground fires burn with high
frequency and maintain a stand of widely spaced
mature trees.
Douglas fire on the west side of the Cascades
Large old-growth forests that burn at infrequent
intervals (400years).
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8 years after the Yellowstone fire
The burnt lodgepole pine trees remain standing.
Lodgepole pine bears serotinous cones that
require heat before they open.
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Fire in ponderosa pine forest
Prior to 1900 low elevation ponderosa pine
forests burned every 5 to 30 years
Most fires burned only the forest floor reducing
fuel and killing small trees
This produced open stands of large trees with
grassy understories, some shrubs and occasional
thickets of young trees.
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After fire in Ponderosa pine
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450 year old-growth Douglas-fir type forest
What would happen if this forest burned?
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Why are forest fires a problem?
Human requirements from forests of timber,
recreation and dwelling space are at odds with
fire
Fire suppression has resulted in the accumulation
of high fuel loads
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Effects of fire exclusion in Ponderosa pine
Fire exclusion has produced a dense understory of
young Douglas fir
Deep woody debris and duff give hotter longer
lasting fires and poor germination
Since the advent of fire fighting some forests
have missed 8 to 10 fire rotations
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The consequences of fire protection in Ponderosa
pine
These photos were taken at Lick Creek in the
Bitterroot Valley of Montana over an eighty-year
period. Notice how the old growth ponderosa pine
stand is replaced by dense Douglas-fir after fire
suppression begins in the 1920s.
Exit PowerPoint
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Pinus palustris
The longleaf pine, or Pinus palustris grows in
warm, wet temperate climates in the south east US
characterized by hot summers and mild winters.
A healthy longleaf pine forest needs fire.
Without it hardwoods and other pines encroach.
Thick bark of mature trees makes them fire
resistant. Its seedlings are resistant to grass
fires.
Prescribed fire in the Okefenokee Forest
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Controlled burning
Ground fire
East side of the Cascades set in late fall
What conditions of fuel load, moisture content,
temperature and wind produce a fire that burns
the excess undergrowth and small trees without
burning the dominant trees?
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The effect of a controlled burn
After
The effect of a controlled burn
in a Pinus ponderosa forest
Before
Crater Lake, lower elevation forest burnt in
early spring
Has sufficient material been removed to prevent a
major conflagration?
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Research and Policy Problems
Research establishing a prescribed burn
procedure for forests that are overstocked and
with greater fuels loads than usual in a fire
regime, establishing effective regimes for
different fire types.
Policy gaining acceptance for a prescribed
burning policy, the smoke problem, defining
regulations for urban forestry.
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Is there such a thing as a natural forest?
If we define natural as not influenced by humans
then
wherever there has been an effective fire
suppression policy is it reasonable to conclude
that forests there are not natural?
If we define natural as a forest that is in
equilibrium with its environment then, because
fire suppression has altered that equilibrium, is
it reasonable to establish a prescribed fire
regime to restore that equilibrium as much as
possible?
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Sections you need to have read
17.9, 34.17, 36.6 36.7
Courses that deal with this topic
ESC322 Forest Ecosystems
ESC320 Natural Resource Issues Old-growth and
Forest Management

FM324 Forest Health and Protection