mpbep 2012 04 prsnttn effectssimulatedmbpearlyredattack
DESCRIPTION
http://foothillsri.ca/sites/default/files/null/MPBEP_2012_04_Prsnttn_EffectsSimulatedMBPEarlyRedAttack.pdfTRANSCRIPT
Effects of Simulated MPB Early
Red Attack on Hydrology, Post-
attack Vegetation, Fuels, & Below-
ground Dynamics
Principal investigators: Drs. Uldis Silins and Ellen Macdonald Ph.D. projects: Anne McIntosh and Pablo Piña-Poujol Lead field technician: Pete Presant
Broad research questions
• Is MPB red attack a threat to the hydrologic regime of these stands? (Pablo Piña) • How resistant are vegetation, fuels, and below-ground dynamics to different levels of “red attack” ? (Anne McIntosh)
Approach & treatments
• Simulate MPB attack - issue of “control” (B.C. experience) - variable density herbicide treatment
• [1] Control (untreated)
• Simulated MPB attack ([2] 50% & [3] 100% overstory kill)
• [4] Clearcut - harvested to simulate “salvage logging”
4
Study area & design
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar
2007 2008 2009 2010
Post-Treatment Year 2
2011 2012
Analysis, write-upSurveying-layout, set up - instrumentation Pre-Treatment year Post-Treatment Year 1
• Study processes that govern;
• Forest water balance
• Understory veg. dynamics
• Pre-treatment (1 year)
• Post-treatment (2 years)
• 2.2 ha treatments (water balance)
• + 2 x 1.2 ha replicates (vegetation)
Post-attack hydrology responses Pablo Piña, PhD Candidate
Is MPB red attack a threat to the hydrologic regime of these stands?
Overstory transpiration Canopy interception
Forest stand water cycle Gross precipitation + Evaporative demand
Forest floor interception
Soil moisture storage
September February September March December
0
10
20
30
40
50
Dep
th (
mm
)
Typical time series of soil moisture storage availability and precipitation in the Upper Foothills
Three things here: 1. Periods of frozen soils have considerable length and contribution to
recharge during spring melt 2. Soil moisture has a clear response to rain events larger than ~8 mm 3. Precipitation has a pattern in terms of rain and snow events’ intensity
2008 2009 2010
Frozen soil (F)
F F
Forest stand water cycle
Net precipitation
Canopy interception
Overstory transpiration
Forest floor interception
Soil moisture recharge
Characterizing rainfall interception
133 143 153 163 173 183 193 203 213 223 233
-40
-30
-20
-10
0
10
20
30
40
-350
-280
-210
-140
-70
0
70
140
210
280
350
Cum
ula
tive inte
rcep
tion (
mm
)
Julian day
Ra
in e
ven
t (m
m)
Total Forest Interception
Canopy Interception
Forest Floor Interception
Recharge
Total forest interception 70 % of seasonal rainfall
30 % of seasonal rain = 97 mm of recharge into the mineral soil
Characterizing lodgepole pine transpiration
Thermal Dissipation Probe
Overstory transpiration… Fading Rates? Compensatory Response?
Range of seasonal transpiration for live trees: tree scale
May Jun Jul Aug Sept Oct
0.0
0.3
0.6
0.9
1.2
mm
d-1
Control
50% Kill
100% Kill
Control Partial attack Massive attack
mm
d-1
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
A
B
C
Tst Control (mm day-1)
Tst
50
K (
mm
da
y-1
)
A= 75% alive
B= 50% alive
C= 25% alive
Control stand scaled transpiration (mm day-1)
Part
ially
MP
B a
ttac
ked
sta
nd
sca
led
tra
nsp
irat
ion
(m
m d
ay-1
)
Control mean
Modeled scenarios to scale transpiration using relationships
developed in the experimental units: stand scale
Table4ScenariosforstandscaletranspirationinapartiallyMPBattackedstand.ThereferenceTgusedwas102mm,being77mmforcontrolconditions.Thebaselineproportionofthestandconditionsfollowedthedistributionfoundonthe50%Killsite:live77.5%,fade13.4%,dead9.1%.Livetrees(%) Fadingtrees(%) Deadtrees(%) Tst(mm)
75 15 10 8550 30 20 6725 45 30 505 56 39 36
Totals per season
control conditions = 77 mm
(A)
(B)
(C)
(Not shown)
Overstory transpiration
16%
Canopy interception
48%
Forest stand water cycle Gross precipitation + Evaporative demand
Forest floor interception
34%
Soil moisture storage
Total forest
interception
70%
Overstory transpiration Canopy interception
Forest stand water cycle Gross precipitation + Evaporative demand
Forest floor interception
Soil moisture storage
Is there a clear response in the soil moisture
dynamics after an early Mountain Pine Beetle
attack? … come to the workshop to find out
Post-attack vegetation, fuels, & below-ground response
Anne McIntosh, PhD Candidate
1. Understory plant community composition
2. Future regeneration potential of these stands
3. Recruitment of downed woody debris (DWD)
4. Changes in below-ground processes
(pH, decomposition, nutrient availability, microbial community, decomposition)
•How resistant are vegetation, fuels, and below-ground dynamics to different levels of
“red attack”?
Pre Trt Post Pre Trt Post Pre Trt Post Pre Trt Post
Control 50%Kill 100%Kill Salvage
Treatment by Interval
Co
ve
r (%
)
0
20
40
60
80
100
120
140
160
180
BRYOPHYTECLUB-MOSS
FORB
SHRUB
ALDERGRASS
Understory cover
Germination study (Post-treatment yr)
What is regeneration potential after MPB?
Quadrats on 5 substrates sowed w/ seed:
• LFH < 2.5 cm
• LFH > 2.5 cm
• Mineral soil
• Moss
• Dead wood (decay class 4-5)
Monitored germination
Treatment
Control 50%kill 100%kill SalvageMean
nu
mb
er
of
germ
inan
ts c
ou
nte
d
0
1
2
3
4
5
Moss
Deep litter
Shallow litter
Wood
Mineral
Germinants – Year Sown
Treatment
Control 50%kill 100%kill SalvageMe
an
nu
mb
er
of
germ
inan
ts c
ou
nte
d
0
1
2
3
4
Moss
Deep litter
Shallow litter
Wood
Mineral
One Yr Post-germination
Recap & the future…
Stand evapo-transpiration depended on level of attack reduced by 100% attack & salvage
• 100%kill: Dying trees had decreased transpiration • 50%kill: Living trees can compensate in partial attacked stands
Soil moisture increased • Surface 20 cm clear treatment effect • Surface 5 cm clear gradient with treatment (data not presented - come to the workshop!)
There are regional effects too… come to the workshop!
Main findings – stand hydrology
Overstory
Understory
Below-ground
Trees are dying
No change …yet?
*No change… yet?
Regeneration?
Unlikely…
MPB
Main findings
As we move to grey attack…
Transpiration
Interception
Soil water
Soil nutrients
Light
Understory cover
Species-specific
responses
Understory community change
Recover water balance?
Future forest development
Below-ground communities
Below-ground processes
Support for our work
• Foothills Research Institute
• FRIAA / AB SRD
• West Fraser Timber Co. Ltd.
• NSERC
• Killam Trusts
• CONACYT
• Milo Mihajlovich
• Field Assistants
…Thank-you for listening For further information: [email protected] [email protected] [email protected] [email protected]