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Effects of Simulated MPB Early Red Attack on Hydrology, Postattack Vegetation, Fuels, & Belowground Dynamics

Principal investigators: Drs. Uldis Silins and Ellen Macdonald Ph.D. projects: Anne McIntosh and Pablo Pi単a-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 •

Study processes that govern; • •

2008

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)

2009

2010

2011

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

yout, set up - instrumentation

Pre-Treatment year

Post-Treatment Year 1

Post-Treatment Year 2

Analys


Post-attack hydrology responses Pablo Pi単a, PhD Candidate

Is MPB red attack a threat to the hydrologic regime of these stands?


Forest stand water cycle Gross precipitation + Evaporative demand

Canopy interception

Overstory transpiration

Forest floor interception Soil moisture storage


Typical time series of soil moisture storage availability and precipitation in the Upper Foothills 2009

2008

F

Frozen soil (F)

50

2010 F

Depth (mm)

40

30

20

10

0 September

February

September

March

December

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


Forest stand water cycle Canopy interception

Net precipitation Overstory transpiration

Forest floor interception

Soil moisture recharge


Characterizing rainfall interception


40

Total forest interception 70 % of seasonal rainfall

Total Forest Interception Canopy Interception Forest Floor Interception Recharge

350

280

30 210 20

Rain event (mm)

10 70

0

0

-70 -10

Cumulative interception (mm)

140

-140 -20

30 % of seasonal rain = 97 mm of recharge into the mineral soil -210

-30

-280

-40

-350 133

143

153

163

173

183 Julian day

193

203

213

223

233


Characterizing lodgepole pine transpiration

Thermal Dissipation Probe


Overstory transpiration‌

Fading Rates? Compensatory Response?


Range of seasonal transpiration for live trees: tree scale Control Control Partial attack 50% Kill 100% Kill Massive attack

1.2

mm d-1

mm d-1

0.9

0.6

0.3

0.0 May

Jun

Jul

Aug

Sept

Oct


transpiration (mm day-1) Partially MPB attacked stand Tst 50Kscaled (mm day-1)

Modeled scenarios to scale transpiration using relationships developed in the experimental units: stand scale 0.8

A= 75% alive B= 50% alive C= 25% alive

0.7

A

0.6

B 0.5

C

0.4

Table 4 Control Scenarios mean for stand scale transpiration in a partially MPB

0.3

attacked stand. The reference Tg used was 102 mm, being 77 mm for control conditions. The baseline proportion of the stand conditions followed the distribution found on the 50% Kill site: live 77.5%, fade 13.4%, dead 9.1%. Live trees (%) Fading trees (%) Dead trees (%) Tst (mm) 75 (A) 15 10 85 50 (B) 30 20 67 25 (C) 45 30 50 5 (Not shown) 56 39 36

Totals per season

0.2

0.1

0.0

control conditions = 77 mm 0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Control stand scaled transpiration (mm day-1) Tst Control (mm day-1)

0.8


Forest stand water cycle Gross precipitation + Evaporative demand

Overstory transpiration 16%

Canopy interception 48%

Total forest interception 70%

Forest floor interception 34% Soil moisture storage


Forest stand water cycle Gross precipitation + Evaporative demand

Canopy interception

Overstory transpiration

Is there a clear response in the soil moisture dynamics after an early Mountain Pine Beetle Forest floor interception attack? ‌ come to the workshop to find out ď Š Soil moisture storage


Post-attack vegetation, fuels, & below-ground response

Anne McIntosh, PhD Candidate •How resistant are vegetation, fuels, and

below-ground dynamics to different levels of “red attack”? 1. 2. 3. 4.

Understory plant community composition Future regeneration potential of these stands Recruitment of downed woody debris (DWD) Changes in below-ground processes (pH, decomposition, nutrient availability, microbial community, decomposition)


Understory cover ALDER GRASS SHRUB FORB CLUB-MOSS BRYOPHYTE

180 160

Cover (%)

140 120 100 80 60 40 20 0

Pre Trt Post

Control

Pre Trt Post

50%Kill

Pre Trt Post

100%Kill

Treatment by Interval

Pre Trt Post

Salvage


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


Mean number of germinants counted

5

4

Germinants â&#x20AC;&#x201C; Year Sown Moss Deep litter Shallow litter Wood Mineral

3

2

1

0 Control

50%kill

100%kill

Treatment

Salvage


Mean number of germinants counted

One Yr Post-germination 4

3

Moss Deep litter Shallow litter Wood Mineral

2

1

0 Control

50%kill

100%kill

Treatment

Salvage


Recap & the futureâ&#x20AC;Ś


Main findings – stand hydrology 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

Overstory Trees are dying

Understory *No change… yet? Regeneration? Unlikely… MPB

Below-ground No change …yet?


As we move to grey attackâ&#x20AC;Ś Transpiration Interception

Soil water Soil nutrients Light

Understory cover Species-specific responses

Future forest development

Below-ground communities Below-ground processes Understory community change Recover water balance?


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: uldis.silins@ales.ualberta.ca ellen.macdonald@ales.ualberta.ca ppina@ualberta.ca amcintos@ualberta.ca

Mpbep 2012 04 prsnttn effectssimulatedmbpearlyredattack  

http://foothillsri.ca/sites/default/files/null/MPBEP_2012_04_Prsnttn_EffectsSimulatedMBPEarlyRedAttack.pdf

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