Soil Responses to Forest Canopy Disturbance

Soil respiration response to canopy disturbance in a Northern Michigan Forest

Conor Flynn

The Ohio State University

Outline:

Definitions Hypotheses

Methods Results & Discussion

Conclusion Future directions

Soil respiration response to canopy disturbance in a Northern Michigan Forest

Soil respiration response to canopy disturbance in a Northern Michigan Forest

Ryan MG, Law BE. Interpreting, measuring, and modeling soil respiration. Biogeochemistry. 2005.

Aspen/maple/oak

Even-aged

Disturbance/mortality

releases understory

Pine/maple/oak

Uneven-aged

Forest age (yrs)

0 10 20 30 40 50 60 70 80 90 100 110 120

Soil respiration response to canopy disturbance in a Northern Michigan Forest:

Soil respiration response to canopy disturbance in a Northern Michigan Forest:

The Forest Accelerated Succession ExperimenT (FASET)

Nave LE, Gough CM, Maurer KD, Bohrer G, Hardiman BS, Moine JL, Munoz AB, Nadelhoffer KJ, Sparks JP, Strahm BD, Vogel CS, Curtis PS. Disturbance and the resilience of coupled carbon and nitrogen cycling in a

north temperate forest. Journal of Geophysical Research. 2011

Soil respiration response to canopy disturbance in a Northern Michigan Forest

Ryan MG, Law BE. Interpreting, measuring, and modeling soil respiration. Biogeochemistry. 2005.

Soil respiration response to canopy disturbance in a Northern Michigan Forest

Ryan MG, Law BE. Interpreting, measuring, and modeling soil respiration. Biogeochemistry. 2005.

Aspen Oak

FASET (treatment)

GIRDLED

(released from competition)

Ameriflux (control)

no change

no change

Experiment Design: 4 Sites

Aspen Oak

FASET (treatment)

↓ Total Soil Respiration

↓ Rs Sensitivity to Temperature

↑ Total Soil Respiration

↑ Rs Sensitivity to Temperature

Ameriflux (control)

no change

no change

Hypotheses

Aspen Oak

FASET (treatment)

↓ Total Soil Respiration

↓ Rs Sensitivity to Temperature

↑ Total Soil Respiration

↑ Rs Sensitivity to Temperature

Ameriflux (control)

no change

no change

Hypotheses

Aspen Oak

FASET (treatment)

↓ Total Soil Respiration

↓ Rs Sensitivity to Temperature

↑ Total Soil Respiration

↑ Rs Sensitivity to Temperature

Ameriflux (control)

no change

no change

Hypotheses

Aspen Oak

FASET (treatment)

↓ Total Soil Respiration

↓ Rs Sensitivity to Temperature

↑ Total Soil Respiration

↑ Rs Sensitivity to Temperature

Ameriflux (control)

no change

no change

Hypotheses

Methods:

Automated Soil CO2 efflux Measurement

Methods:

Automated Soil CO2 efflux Measurement

FASET Aspen Site (FAS)

Methods:

Manual Soil CO2 efflux

Measurement

Results

Results: Growing Season Soil Respiration - Manual

0

1

2

3

4

5

6

7

8

9

10

153 180 194 208 230 244

Soil

CO

2 E

fflu

x μ

mo

l m

-2 s

-1

Day of Year

AF EFFLUX FASET EFFLUX

Results: Growing Season Soil Respiration - Autochambers

0

1

2

3

4

5

6

7

8

9

10

153 180 194 208 230 244

Soil

CO

2 E

fflu

x μ

mo

l m

-2 s

-1

Day of Year

AF EFFLUX FASET EFFLUX

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0

0.5

1

1.5

129 149 169 189 209 229

Soil

CO

2 E

fflu

x μ

mo

l m

-2 s

-1

Dif

fere

nce

Day of Year

Difference

FAS-AAS

Results: Growing Season Soil Respiration - Autochambers

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0

0.5

1

1.5

129 149 169 189 209 229

Soil

CO

2 E

fflu

x μ

mo

l m

-2 s

-1

Dif

fere

nce

Day of Year

Difference FAS-AAS

FOS-AOS

Results: Growing Season Soil Respiration - Autochambers

Results: Q10: Soil Respiration Temperature Sensitivity

y = 1.3944e0.0592x R² = 0.465

0

1

2

3

4

5

6

7

8

8 10 12 14 16 18 20 22

Soil

CO

2 E

fflu

x μ

mo

l m-2

s-1

15cm Soil Temperature C

FAS Efflux Q10= 1.81

Results: Q10: Soil Respiration Temperature Sensitivity

y = 1.3944e0.0592x R² = 0.465

0

2

4

6

8

8 10 12 14 16 18 20 22Soil

CO

2 E

fflu

x μ

mo

l m-2

s-1

15cm Soil Temperature C

FAS Efflux Q10= 1.81

Control Treatment

AAS AOS FAS FOS

Q10

(r2)

2.93a

(0.68)

2.84b

(0.59)

1.81c

(0.47)

2.39d

(0.75)

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0

0.5

1

1.5

129 149 169 189 209 229

Soil

CO

2 E

fflu

x μ

mo

l m

-2 s

-1

Dif

fere

nce

Day of Year

Difference FAS-AAS

FOS-AOS

Results: Phenoperiod 1

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0

0.5

1

1.5

129 149 169 189 209 229

Soil

CO

2 E

fflu

x μ

mo

l m

-2 s

-1

Dif

fere

nce

Day of Year

Difference FAS-AAS

FOS-AOS

Results: Phenoperiod 2

Results: Soil Respiration Sensitivity:

Phenoperiods

Control Treatment

AAS AOS FAS FOS

Q10

(r2)

2.93a

(0.68)

2.84b

(0.59)

1.81c

(0.47)

2.39d

(0.75)

Phenoperiod 1 Q10

(r2)

2.31a

(0.37)

3.86b

(0.74)

3.12c

(0.68)

2.97c

(0.74)

Phenoperiod 2 Q10

(r2)

2.37a

(0.35)

2.28a

(0.25)

1.27b

(0.04)

1.86a

(0.32)

Results: Soil Respiration Sensitivity:

Phenoperiods

Control Treatment

AAS AOS FAS FOS

Q10

(r2)

2.93a

(0.68)

2.84b

(0.59)

1.81c

(0.47)

2.39d

(0.75)

Phenoperiod 1 Q10

(r2)

2.31a

(0.37)

3.86b

(0.74)

3.12c

(0.68)

2.97c

(0.74)

Phenoperiod 2 Q10

(r2)

2.37a

(0.35)

2.28a

(0.25)

1.27b

(0.04)

1.86a

(0.32)

Aspen Oak

FASET (treatment)

↓ Total Respiration (↑ PP1 ; ↓ PP2)

↓ Total Rs Sensitivity to Temperature

(↑PP1; ↓PP2)

↔ Total Respiration

↓ Total Rs Sensitivity to Temperature

(↓PP1; ↓PP2)

Ameriflux (control)

no change

no change

Conclusions

Aspen Oak

FASET (treatment)

↓ Total Respiration (↑ PP1 ; ↓ PP2)

↓ Total Rs Sensitivity to Temperature

(↑PP1; ↓PP2)

↔ Total Respiration

↓ Total Rs Sensitivity to Temperature

(↓PP1; ↓PP2)

Ameriflux (control)

no change

no change

Conclusions

Aspen Oak

FASET (treatment)

↓ Total Respiration (↑ PP1 ; ↓ PP2)

↓ Total Rs Sensitivity to Temperature

(↑PP1; ↓PP2)

↔ Total Respiration

↓ Total Rs Sensitivity to Temperature

(↓PP1; ↓PP2)

Ameriflux (control)

no change

no change

Conclusions

Aspen Oak

FASET (treatment)

↓ Total Respiration (↑ PP1 ; ↓ PP2)

↓ Total Rs Sensitivity to Temperature

(↑PP1; ↓PP2)

↔ Total Respiration

↓ Total Rs Sensitivity to Temperature

(↓PP1; ↓PP2)

Ameriflux (control)

no change

no change

Conclusions

Aspen Oak

FASET (treatment)

↓ Total Respiration (↑ PP1 ; ↓ PP2)

↓ Total Rs Sensitivity to Temperature

(↑PP1; ↓PP2)

↔ Total Respiration

↓ Total Rs Sensitivity to Temperature

(↓PP1; ↓PP2)

Ameriflux (control)

no change

no change

Conclusions

Conclusions

Soil respiration reflects total belowground activity, and responds strongly to aboveground disturbance: less C in, less C out. Carbon cycle is resistant to natural disturbance as compared to anthropogenic. In undisturbed forests, root-derived respiration can contribute as much as 50% of total soil respiration. Heterotrophic respiration can be more sensitive to temperature than autotrophic, but depends on time of year – different drivers.

Problems and Solutions: Future Directions

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

-3

-2

-1

0

1

2

3

129 149 169 189 209 229

Vo

lum

etr

ic S

oil

Wa

ter

Co

nte

nt

%

FAS

Re

sid

ual

Un

exp

lain

ed

So

il R

esp

irat

ion

Doy of Year

residuals

SM_15cm2

R² = 0.1422

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

3

0 0.05 0.1 0.15 0.2

Volumetric Soil Water Content %

Problem: Soil Respiration Sensitivity to Change in Soil Moisture

Problem: Diurnal time-delay (Hysteresis)

3.5

3.7

3.9

4.1

4.3

4.5

4.7

4.9

5.1

5.3

5.5

17.4 17.6 17.8 18 18.2 18.4 18.6

Soil

Res

pir

atio

n

Soil Temperature (15cm)

Time

Time

Midnight

Noon

6:00 PM

6:00 AM

6:00 PM

0

1

2

3

4

5

6

7

8

8 13 18

Effl

ux

15cm Soil Temperature

8

13

18

23

129 149 169 189 209 229

Soil

Tem

per

atu

re, C

DOY

15cm Soil Temperature AAS ST_15cm2

Continuous Wavelet Transform (CWT)

• Can be interpreted as time-localized power spectra (CF Fourier Transform) • Indicates time, period (i.e. wavelength), and power of signal

8

13

18

23

129 149 169 189 209 229

Soil

Tem

per

atu

re, C

DOY

15cm Soil Temperature AAS ST_15cm2

Continuous Wavelet Transform (CWT)

• Can be interpreted as time-localized power spectra (CF Fourier Transform) • Indicates time, period (i.e. wavelength), and power of signal

Cross-Wavelet Transform (CXT)

CXT indicates time-period domains of shared power between two signals

CXT also includes phase (lag) information with arrows

CXT AAS efflux and ST 15cm:

Continuous Wavelet Transform (CWT)

• Can be interpreted as time-localized power spectra (CF Fourier Transform) • Indicates time, period, and power of signal

0

0.05

0.1

0.15

0.2

129 149 169 189 209 229

Vo

lum

etri

c w

ater

co

nte

nt

%/%

DOY

15cm Soil Moisture

AAS SM_15cm

Cross-Wavelet Transform (CXT)

CXT indicates time-period domains of shared power between two signals

CXT also includes phase (lag) information with arrows

CXT AAS efflux and SM 15cm:

Wavelet Analysis:

CXT can identify: -Hysteresis time-lags

-Variable (episodic, pulsed) controls of soil respiration -CorrelationCausation

Acknowledgments

Dr. Peter Curtis Dr. Gil Bohrer Dr. Richard Dick Jen Nietz Dr. Chris Vogel, UMBS Dr. Valeriey Ivanov, UM Lingli He, UM Alexandra Permar, UNC …and many other collaborators!

Soil respiration is Important

Carbon Neutral?

Questions?

Results: Growing Season Soil Respiration - Autochambers

-1

0

1

2

3

4

129 139 149 159 169 189 199 209 219 230

Soil

Res

pir

atio

n D

iffe

ren

ce

DOY

Soil Respiration Difference AAS-FAS

significant

not significant

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

-3

-2

-1

0

1

2

3

169 179 189 199 209 219 229

residuals

SM_15cm2

Phenoperiod Residual Analysis

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

-3

-2

-1

0

1

2

3

129 139 149 159 169

y = 2.4628x - 0.2188 R² = 0.0112

-1.5

-1

-0.5

0

0.5

1

1.5

2

0 0.05 0.1 0.15 0.2

y = 0.5907ln(x) + 2.0034 R² = 0.1899

-3

-2

-1

0

1

2

3

4

0 0.05 0.1 0.15

Growing Season Soil Respiration Driver: Soil Temperature

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0.2

129 149 169 189 209 229

Soil

Wat

er P

ote

nti

al, K

pa

SWC

%

SM_15cm2

convert 15cm SM toMatric

Growing Season Soil Respiration Driver: Soil Temperature

0

5

10

15

20

25

0

1

2

3

4

5

6

7

8

129 149 169 189 209 229

Soil

CO

2 E

fflu

x μ

mo

l m-2

s-1

Day of Year

FAS efflux

ST_15cm2

Phenoperiods: Growing Season

-2

0

2

4

6

8

10

12

14

129 149 169 189 209 229

AF C Fluxes

Average of REgf

NEE

GPP

AAS efflux

AOS efflux

Substituting Rs for modeled Re in GPP calculations

-4

-2

0

2

4

6

8

10

12

14

16

129 149 169 189 209 229

NEEgf

REgf

GPP (NEE+Regf)

GPP (NEE+Rs)

Soil respiration response to canopy disturbance in a Northern Michigan Forest

Heterotrophic Soil Respiration: Biodiversity

Modified from Smith P, Fang C. Carbon cycle: A warm response by soils. Nature. 2010 March 24

What is the soil respiration response to succession?