climate change as a driver in mountain pine beetle outbreaks in eastern washington washington state...
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Climate Change as a Driver in Mountain Pine Beetle Outbreaks in Eastern
Washington
Washington State Climate Change Impacts Assessment Conference
Seattle, WashingtonFebruary 12, 2009
Elaine E. Oneil1, Jeffrey A. Hicke2, Donald McKenzie3, and James A. Lutz1
1College of Forest Resources, University of Washington
2Department of Geography, University of Idaho3Pacific Wildland Fire Sciences Lab, U.S. Forest
Service
J. Hicke
Photo credit: Don Hanley
Photo credit: Don Hanley
MPB and host as co-drivers of MPB epidemics with climate change
Host Susceptibility a function of changes in summer VPD Linked to the likelihood of a tree, or stand, being attacked
as a function of poor vigor. Warmer and drier summers leading to increased moisture stress and
reduced vigor within pine forests Warmer and/or drier winters reducing snowpack and effective moisture
retention into late spring/early summer
Risk of MPB attack linked to changes in annual temperature regimes Linked to the likelihood of MPB attack as a function of MPB
population dynamics and proximity to host trees Climate change enhancing insect survival and reproduction at higher
elevations and leading to asynchronous development at lower elevations
Acres affected by Mountain Pine Beetle in Washington State
YearYearYearYear
19991999
20002000
20012001
20022002
20032003
20042004
00
5050
100100
150150
200200
250250
300300
350350
400400
450450
500500
19101910 19301930 19501950 19701970 19901990 20102010An
nu
al A
cre
s (1
000’
s) a
ffec
ted
by
MP
B i
n E
aste
rn W
ash
ing
ton
Oneil, 2006
Mortality by MPB in ponderosa and lodgepole pine in eastern Washington from 1979-2004 (tallied 1980-2005)
0
500,000
1,000,000
1,500,000
2,000,000
2,500,000
3,000,000
3,500,000
4,000,000
4,500,000
1979 1984 1989 1994 1999 2004Year
Total Mortality (# trees)
0.0
2.0
4.0
6.0
8.0
10.0
12.0
Mortality/acre (Trees/Acre)
# Trees killed by MPB # Trees/acre killed by MPB
1979-1999 Mortality Rate = 2.2 TPA
2000+ Mortality Rate 8.4 TPA
Adapted from Waring and Running (1998)
'Dryness' increases exponentially with increasing temperature
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
0 3 6 9 12 15 18 21 24 27 30
Temperature (C)
Vapor Pressure (kPa)
Humidity
100%
60%
30%
Vapor Pressure Deficit (VPD)
Predictor p-value1) MaxVPD (when exceeds 2 kPa) 0.1672) Pre-growing season PPT 0.3933) Average VPD (Jun, Jul, Aug) 0.0314) DaysVPD exceeds 1.5 kPa 0.0005) First Day VPD (exceeds 1.5 kPa) 0.0006) Interaction of #1 and #3 0.0247) Interaction of #4 and #5 0.000
Climate predictors for MPB attack 2000-03
Summer Water Deficit as a precursor to tree stress
as a percentage of pre-2000 period
Scenario YearAverage Water
DeficitAnnual
PPTSummer
PPTHistorical 1980-99 100% 100% 100% 2 0.1%Historical 2000-03 199% 82% 51% 33 2.0%B1 2020 193% 171% 75% 27 1.7%
2040 236% 187% 60% 18 1.1%2080 326% 235% 25% 116 7.1%
A1B 2020 294% 132% 29% 116 7.1%2040 367% 206% 15% 228 14.0%2080 432% 302% 11% 442 27.1%
# Plots exceeding
deficit of 250
% Plots exceeding
deficit of 250
Higher Elevations get hit harder
Historical 2000-03 B1 2020 MPB attacks
Adapted from: DeLucia, E. H., H. Maherali, et al. (2000). "Climate-driven changes in biomass allocation in pines." Global Change Biology 6(5): 587-593.
Leaf/sapwood area relationships for pine species
Average Summer VPD
MPB and host as co-drivers of MPB epidemics with climate change
Host Susceptibility a function of changes in summer VPD Linked to the likelihood of a tree, or stand, being attacked
as a function of poor vigor. Warmer and drier summers leading to increased moisture stress and
reduced vigor within pine forests Warmer and/or drier winters reducing snowpack and effective moisture
retention into late spring/early summer
Risk of MPB attack linked to changes in annual temperature regimes Linked to the likelihood of MPB attack as a function of MPB
population dynamics and proximity to host trees Climate change enhancing insect survival and reproduction at higher
elevations and leading to asynchronous development at lower elevations
Research Questions • Do Tmax and Tmin increase in lock step?
– future VPD’s are likely underestimated
• Improve predictions of Tdew in increasingly arid environments– future VPD’s are likely underestimated.
• Determine if, and how quickly, leaf area – sapwood area ratios might change in response to changing VPD – Keys into increasing vulnerability to MPB and likelihood
of loss of the species altogether
• Will other phenotypes/genotypes of MPB invade low elevation sites
Blue Print for Management Action
Determine a stress index for lodgepole in their current niches
Refine estimates of future stress based on climate scenarios
Determine if LP can modify its LA/SA ratios in response to the change in VPD (aka research)
Determine how stand carrying capacity changes in response to climate shifts and manage stands to stay within the carrying capacity of the site
• Determine how habitat types will move and change in their constituency with climate change
• Determine how to model that change to increase forest ecosystem resilience
Refine our estimation of disturbance rates