Maureen McGlinchy1, Ron Neilson2, Jim Lenihan2, Ray Drapek2 and John Wells2
1Oregon
Introduction and climate projections
We use MC1, a dynamic vegetation model, to evaluate the potential
effects of climate change and augmented carbon dioxide on ecosystem
dynamics in northern California and Nevada. This project is one of a
three-part case study implementing MC1 in the western states using
newly-available high-resolution climate
datasets. We incorporate three global
circulation models—MIROC-medres,
HadCM3 and CSIRO Mark 3.0 – that we
have downscaled to a 30-arcsecond
(approximately 800
meter) grid. For this
poster, we limit discussion
to the A2, or “business-asusual”, carbon dioxide
emission scenario.
State University, Department of Forest Science (maureen.mcglinchy@oregonstate.edu), 2USFS, Pacific Northwest Research Station
Vegetation Distribution
Fire Regime
MC1 projects a decrease in cover by vegetation types that have historically
occupied higher elevations or mild coastal regions. There is a large relative
increase in cover by the mixed forest type, replacing both maritime and
temperate forest. Grassland replaces shrubland as fire increases on the
Modoc Plateau.
MC1 projects an increase in acreage burned and biomass consumed by fire
under all future climate scenarios.
Comparison between observed vegetation map and model output
CWHR Aggregated Veg Type
MC1 Vegetation Type
Compiled in 2002
1971-2000 Modal Output
Alpine
Subalpine Forest
Maritime Forest
Conifer Forest
Mixed Forest
Woodland
Shrubland
Grassland
Desert
These smoothed averages illustrate an increasing trend in area burned. Interannual
variability in burned area also increases, with more frequent “big fire years.”
Change in annual biomass consumed:
1971-2000 versus 2071-2100
http://frap.cdf.ca.gov/
Increase in fire
Decrease in fire
California Wildlife Habitat Relationships. Note that MC1 is a potential
vegetation model so does not simulate the effects of human management.
An urban mask has been placed on the model output for easier comparison.
Future vegetation distribution
e use MC1, a dynamic vegetation model, to evaluate the potential effects of
climate change and augmented carbon dioxide on vegetation distribution in
northern California and Nevada.
When averaged across the study area, the MIROC and HADCM3 models predict
similar extents of change. However, the models differ in how that change is
projected across the landscape.
Comparison between observed and predicted climate:
A lengthened growing season allows the
expansion of temperate conifer forest into the
subalpine zone.
Increases in minimum winter temperature
remove restrictions on the northern and
upper elevational boundaries of the mixed
forest range.
MC1 Historical:
1971-2000
2071-2100 versus 1961-1990
MIROC
A2
Relative Change in
Annual Precip
Relative Change in
RH (May – Oct)
8 C/14 F
+30%
+25%
1 C/2 F
-30%
-25%
MIROC A2:
HADCM3 A2:
CSIRO A2:
2071-2100
2071-2100
2071-2100
MIROC A2
HADCM3 A2
CSIRO A2
Relative change in annual maximum All climate scenarios result in increased
biomass consumption at the upper
snow depth:
elevations of the Sierra Nevada. Decreased
1971-2000 versus 2071-2100
MIROC A2 HADCM3 A2 CSIRO A2
snow pack allows a longer period for drying
0
of coarse fuels above 8000’. Early analysis
of model output supports a relationship
-20
between biomass consumption and the
-40
fuel build-up index (BUI) in the Sierra
Nevada. This index is a proxy for fuel
-60
moisture in coarse woody fuels and the
-80
deep, compacted duff layer and can be
used to indicate drought conditions.
-100
% Change
Absolute Change in
Temp (May – Oct)
The graph below uses smoothed averages to demonstrate this increasing trend; there
is also considerable interannual variability.
Percentage Change in Total Cover by Vegetation Class
Subalpine Forest
Maritime Forest
Conifer Forest
Mixed Forest
Woodland
Shrubland
CSIRO
A2
Grassland
-100
0
100
200
% Change
300
400
Biomass consumed by fire and fuel build-up index
MIROC A2 Sierra Nevada
80
60
400
Carbon consumption
Maximum Annual BUI
300
40
200
20
0
2010
BUI (unitless)
HADCM3
A2
MIROC A2
HADCM3 A2
CSIRO A2
Annual Biomass Consumed (Tg)
Tundra
100
2020
2030
2040
2050
2060
2070
2080
2090
2100
The authors would like to acknowledge Chris Daly and the PRISM group, Brendan Rogers, Dominique
Bachelet, Dave Conklin and Lauren Hahl for various contributions to this research.