mpbep 2012 04 prsnttn effectssimulatedmbpearlyredattack

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


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%



34%


Total forest

interception

70%

Overstory transpiration Canopy interception




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]

mpbep 2012 04 prsnttn effectssimulatedmbpearlyredattack

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