Modeling Impacts of Potential Climate Change and Associated Wildfire
Occurrences on the Levels of Sustainable Resources
Wildfire
The Forest
80000
Percent of Potential Old Growth Communities
60000
40000
20000
0
18702002
50s - 2000 + 2000+ 2000+ current
90s cycles cycles cycles
- 5% - 10%
upper
20
50s-90s
15
2000 + cycles
2000 + cycles 5%
10
2000 + cycles 10%
current trts
5
increased trts
0
1
4
7
10 13 16 19 22 25 28 31
decade
•Simulated fire levels resulting from climate scenarios representative of the 1950s – 1990s were
comparable to actual fire events that occurred between 1879 and 2002.
•Addition of warm and dry cycles every 4th decade resulted in a minor increase in fire levels.
•Increased probabilities of fire events under extreme wind conditions resulted in significant
increases in the total acres burned.
•The current and increased levels of treatments reduced total acres burned, but not to the
historic level.
Insect and Disease
•Increased levels of fire resulted in a significant reduction in the percent of plant
communities with potential as old growth on the Forest.
•Treatment scenarios resulted in minor gains in potential old growth communities.
•Potential old growth plant communities were considered to be those that had a
quadratic mean diameter of 15 inches or greater.
Watershed
Accummulated Acres Impacted by Insect and Disease Activity
MONTANA
No Treatments
Current treatments
30
25
acres
SIMulating
Patterns and
Processes at
Landscape
scaLEs
Potential Old Growth Conditions
percent of total Forest
The potential impacts of changing climate on sustainable natural resource goals is
examined in the context of a National Forest over a 300 year planning horizon using
a spatially explicit, stochastic, landscape level simulation model. Spatial and
temporal changes are simulated using data representing a National Forest located in
the Northern Rocky Mountains to examine the influence of wildfire, insect and
disease activities as they occur at various levels resulting from warm and dry
climate cycles and higher probabilities of extreme fire events over a planning
period. Differences in the long term sustained yield for wood products, acres that
have the potential to provide old growth conditions, the frequency of wildfire with
significant impacts on water quality, and the acres of wildfire in a wildland-urban
interface are compared. Fuel reduction treatments are examined at 2 levels for
the scenario with the highest occurrence of wildfire over the planning period.
Barry Bollenbacher, bbollenbacher@fs.fed.us
Northern Region
100000
hectares
Abstract
The Model
Christine Stalling, cstalling@fs.fed.us
Rocky Mtn Research Station
BITTERROOT NATIONAL FOREST
350000
300000
250000
200000
150000
100000
50000
0
percent
Jimmie D. Chew, jchew@fs.fed.us
Rocky Mtn Research Station
20
15
10
Increased treatments
5
0
50s-90s
2000 +
cycles
2000 +
cycles - 5%
IDAHO
2000
cycles +
10%
2000
cycles +
10%
current
2000
cycles +
10%
increased
Increased fire resulted in reduced levels of insect and disease activity. Insect and
disease levels increased when treatments reduced levels of fire on the Forest.
2000+ cycles - 10%
current treatments
increased
treatments
•Potential for watershed damage was based on 300 year
simulations.
•Damaged watersheds were those with more than ten percent
of their area impacted by stand replacing fire.
Total decades of stand
replacing fire occurring on
more than 10 percent of
drainage
http://www.fs.fed.us/rm/missoula/4151/SIMPPLLE
• Five sets of simulations were run with warm, dry cycles every fourth decade.
•
The probability of an extreme fire event occurring along with the warm and dry
cycles were set at 2, 5, and 10 percent.
• Two sets of simulations were run with treatments, warm, dry cycles, and a 10%
probability of extreme fire.
Poster Presenter, Elizabeth Bella
Ecologist, Seward Ranger District, Chugach NF
2500
2000
16
14
12
10
8
6
4
2
0
hectares
• Climate representing conditions of the 1950s – 1990s and a 2 percent probability
of extreme fire events.
Wildland Urban Interface
Long Term Sustained Yield Level
MM BdFt / Yr
The Simulation Scenarios
Long Term Sustained Yield
1500
1000
500
50s-90s
2000+
cycles
2000+
cycles 5%
2000+
cycles 10%
2000+
cycles 10% current
2000+
cycles 10% increased
• Increased fire resulted in a reduction of long term sustained yield.
• Reduction of fire through treatments increased the long term sustained yield.
• Harvest levels were set at 1% per year of the 15 inch DBH and larger size
classes on land allocated for forest production.
0
2000+
2000+ current
treatments
2000+ increased
treatments
•Fuel reduction treatments were applied to polygons with probabilities of stand replacing fire
greater than zero following 300 year simulations.
•Comparison of treated to non-treated scenarios showed a reduction in fire due to treatments
but little difference between the 2 treatment scenarios.