Effects of MPB on hydrology and post-attack vegetation dynamics

Principal investigators: Uldis Silins and Ellen Macdonald,

Ph.D. projects: Anne McIntosh and Pablo Piña

Lead field technician: Pete Presant

Annual hydrograph

Waskahegan River

0

20

40

60

80

100

120

Str

ea

mfl

ow

(m

3/s

)

1997

1998

?

Time

Re

lative

im

pa

ct

Approach

Don’t wait for MPB (issue of “control”; B.C.)

Simulate MPB attack – variable density herbicide treatment

Stand level research – processes affected by MPB

Forest water balance – how much extra water is produced ?

Short term vegetation responses – potential for compensation, recovery

Combination of

1. Before-After: Treatment:Control approach: Water balance research

2. Replicated stand level: Understory vegetation dynamics research

Treatment

Control

After Before

Main Plots = 120 x 180 m (2.2 ha) 4 treatments (below) x 2.2 ha = 8.8 ha total

Stand water balance subplot (80 x 80 m; 0.64 ha)

Vegetation subplot (80 x 60 m; 0.48 ha)

Control (undisturbed) 50% MPB kill 100% MPB kill Salvage logged (harvested) plot

- no trees left standing

* 1 tree height (20m) exterior buffer between measurement plots & adjecent stand in all plots

Additional replicated plots for vegetation work = 120 x 100 m (1.2 ha ea) 4 treatments (below) x 2 replicates = 9.6 ha total

Control (undisturbed) 50% MPB kill 100% MPB kill Salvage logged (harvested) plot

- no trees left standing

Study duration 3 yr. (1 yr pre-treatment, 2 yr. post-treatment)

Main Plots = 120 x 180 m (2.2 ha) 4 treatments (below) x 2.2 ha = 8.8 ha total

Stand water balance subplot (80 x 80 m; 0.64 ha)

Vegetation subplot (80 x 60 m; 0.48 ha)

Control (undisturbed) 50% MPB kill 100% MPB kill Salvage logged (harvested) plot

- no trees left standing

* 1 tree height (20m) exterior buffer between measurement plots & adjecent stand in all plots

Additional replicated plots for vegetation work = 120 x 100 m (1.2 ha ea) 4 treatments (below) x 2 replicates = 9.6 ha total

Control (undisturbed) 50% MPB kill 100% MPB kill Salvage logged (harvested) plot

- no trees left standing

Study duration 3 yr. (1 yr pre-treatment, 2 yr. post-treatment)

1 year pre-treatment measurements

2 years post-treatment measurements

x 2

x 1

12

stands

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

• Pure pine 120 yrs.

• Medium site index

• 24-26 m height

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

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

Post-attack hydrologic response

1. Changes in overstory rainfall interception.

2. Changes individual tree & stand level transpiration

- Can surviving trees compensate (use more water)

3. Changes in forest floor and soil moisture storage

4. Changes in water table level, groundwater

How much extra water is produced after different levels of “red attack” ?

Gross precipitation + Evaporative demand

Overstory transpiration

Canopy interception

Rainfall interception

Rainfall event size

Inte

rce

ption (

mm

)

Rainfall interception

66 %

= 633 mm

Stemflow

Throughfall

6 m

Litter interception

Rainfall interception

Rainfall interception

Rainfall interception

43%

Individual tree & canopy transpiration

Individual tree & canopy transpiration

20%

Individual tree & canopy transpiration

On a daily basis an average tree

transpires 5.5 liters, that is about 0.7

liters per ground square meter.

During the growing season:

• ≈ 57% of precipitation is

intercepted by the canopy

• 20% of precipitation leaves as

transpiration

• Forest floor interception?

• Understory evaporation?

•Soil moisture storage?

What will happen when the MPB kills the trees?

Stand level (canopy) transpiration

0

0.5

1

1.5

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2.5

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3.5

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4.5

5

1 6 11 16 21 2 7 12 17 22 3 8 13 18 23 4 9 14 19 24 5 10 15 20 1 6 11 16 21

235 236 237 238 239 240

mm

/day

50k

100k

control

Stand level (canopy) transpiration

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

1 6 11 16 21 2 7 12 17 22 3 8 13 18 23 4 9 14 19 24 5 10 15 20 1 6 11 16 21

235 236 237 238 239 240

mm

/day

50k

100k

control

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

1 6 11 16 21 2 7 12 17 22 3 8 13 18 23 4 9 14 19 24 5 10 15 20 1 6 11 16 21

220 221 222 223 224 225

mm

/day

Julian day

100 Kill

50 k

clearcut

Post-attack vegetation response

1. Changes in overstory forest structure.

2. Changes in understory plant community composition (shrubs, seedlings, vascular plants, bryophytes).

3. Recruitment of downed woody debris (DWD).

4. Changes in below-ground processes (nutrient availability, microbial community, decomposition).

What is the early trajectory of post-attack response (advanced growth, understory

vegetation) after different levels of “red attack” ?

23

Objective 1: Overstory

Characterize the overstory forest structure (0.02 ha plots)

• Species

• Live status

• Dbh

• Height

• Crown Vigor

• Cover (hemispherical photos)

24

Pre-treatment - Overstory Basal Area vs Block

Block

HTL NRH PSH

Ba

sa

l a

rea (

m2

/ha

)

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10

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60

Live

Dead

Basal Area

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Pre-treatment - Overstory TPH vs Block

Block

HTL NRH PSH

Tre

es p

er

Hecta

re

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500

1000

1500

2000

2500

3000

Live

Dead

Trees Per Ha

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Pre-treatment - Overstory

Mean dbh vs block

Block

HTL NRH PSH

Me

an

db

h (

cm

)

0

5

10

15

20

25

All

live

dead

Mean DBH

27

Objective 2: Understory

Quantify differences in the understory

plant community composition

Seedlings/Saplings (pine)

Vascular plants (shrubs, forbs, graminoids)

Non-vascular plants (bryophytes, lichens)

Abundance (% cover) and richness by

species

Mean Cover by Block (+/- SE)

Block

HTL NRH PSH

Me

an

co

ve

r o

f q

ua

dra

t

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60

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100

120

140

160

Pre-treatment - Understory

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Cover

Mean Richness by Block (+/- SE)

Block

HTL NRH PSH

Me

an

sp

ecie

s r

ich

ne

ss o

f q

ua

dra

t

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2

4

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8

10

12

14

Pre-treatment - Understory

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Quadrat Richness

Pre-treatment - Understory

Block

HTL NRH PSH

Sp

ecie

s R

ich

ne

ss

0

20

40

60

80

100

Quadrats

Species census

Total Richness

31

Objective 3:

Downed Woody Debris

Quantify DWD

Transects: biomass

estimates

(Megagrams/ha)

32

Mean Fuel (+/- SE) by Block

Block

HTL NRH PSHDead w

oody d

ebris (

Megagra

ms/h

a)

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50

60

Pre-treatment – Downed Woody Debris

Fuel Biomass

33

Objective 4: Below-Ground

Quantify differences in below-ground attributes

Decomposition (cellulose paper in mesh bags)

Microbial biochemical activity & biomass

Community-level physiological profiles (CLPP)

Phospholipid fatty acid (PLFA) analysis

Nutrient availability (PRS probes)

Soil moisture (TDR)

Stay Tuned!

The Future?

Support for the work

Foothills Research Institute

FRIAA / AB SRD

West Fraser Timber Co. Ltd.

Milo Mihajlovich

…Thank you for listening

Coming years …

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