Effects of Experimental Effects of Experimental Burning and Thinning Burning and Thinning on Soil Respiration and on Soil Respiration and

Belowground Belowground CharacteristicsCharacteristics

Soung-Ryoul RyuSoung-Ryoul Ryu11, Amy Concilio, Amy Concilio11, Jiquan Chen, Jiquan Chen11, , Deborah NeherDeborah Neher11, Siyan Ma, Siyan Ma11 and Malcolm and Malcolm

NorthNorth22

11Department of EEES, University of Toledo, Department of EEES, University of Toledo, Toledo, OHToledo, OH

22Department of Environmental Horticulture, Department of Environmental Horticulture, University of California-Davis, Davis, CAUniversity of California-Davis, Davis, CA

ObjectivesObjectives Is there relationship between soil Is there relationship between soil

respiration and root biomass? respiration and root biomass? The relationship is the same under The relationship is the same under

thinning and burning ?thinning and burning ? What controls root biomass ? What controls root biomass ?

The driving factor is the same The driving factor is the same between treatments? between treatments?

What affects soil respiration rate ?What affects soil respiration rate ? Any effects from thinning and Any effects from thinning and

burning ?burning ?

Soil Climatic Factors

Root Respiration (Ra)

Soil Organic Matter

Litter Layer

Available Nutrient

Soil CarbonHeterotrophic

Respiration (Rh)

Soil Chemical Factors

Soil Respiration

Site Description Site Description

Teakettle Experimental Forest Teakettle Experimental Forest 1300ha of area, located in Sierra 1300ha of area, located in Sierra

National Forest on the west side of the National Forest on the west side of the Sierra Nevada range of California. Sierra Nevada range of California.

Altitude: 1980 ~ 2590 m Altitude: 1980 ~ 2590 m Precipitation: 1250mm/year, mostly in Precipitation: 1250mm/year, mostly in

the form of snow the form of snow Mean air temperature: 1°C(January ) Mean air temperature: 1°C(January )

and 14.5°C(July) and 14.5°C(July)

Plot Preparation Plot Preparation Eighteen plots (4 ha each) were Eighteen plots (4 ha each) were

prepared using variogram and prepared using variogram and cluster analysis (North et al. 2002). cluster analysis (North et al. 2002).

California spotted owl (CASPO) California spotted owl (CASPO) thinning, and shelterwood thinning thinning, and shelterwood thinning were applied between August 2000 were applied between August 2000 and Summer of 2001 and Summer of 2001

Prescribed burning followed Prescribed burning followed November 2001 November 2001

Transects (1m spaced) developed atTransects (1m spaced) developed at Burn-CASPO (BC), Burn-Shelterwood Burn-CASPO (BC), Burn-Shelterwood

(BS), Burn only (BN), Unburn-CASPO (BS), Burn only (BN), Unburn-CASPO (UC), Unburn-Shelterwood (US), and (UC), Unburn-Shelterwood (US), and Control (UN) plotsControl (UN) plots

Field Measurement Field Measurement Soil respiration rate (SRR; gCOSoil respiration rate (SRR; gCO22 hr hr-1-1 m m-2-2): a ): a

portable infrared gas analyzer (EGM-2 portable infrared gas analyzer (EGM-2 Environmental Gas Monitor, PP Systems, UK)Environmental Gas Monitor, PP Systems, UK)

Soil temperature at 10cm depth (Ts; ˚C): using Soil temperature at 10cm depth (Ts; ˚C): using a digital thermometer simultaneously with SRR a digital thermometer simultaneously with SRR measurement. measurement.

Soil moisture (Ms; %): Time Domain Soil moisture (Ms; %): Time Domain Reflectometry (TDR) within 0~10cm depth in Reflectometry (TDR) within 0~10cm depth in mineral soil. mineral soil.

Litter depth (LD) Litter depth (LD) Measured at least every other week during the Measured at least every other week during the

growing season of 2002 growing season of 2002

Field Measurement Field Measurement

Total nitrogen (TN) and total carbon Total nitrogen (TN) and total carbon (TC) content in soil: using CN (TC) content in soil: using CN analyzer (analyzer (Carlo Erba NA 1500 Series Carlo Erba NA 1500 Series 2) 2)

pH: soil:HpH: soil:H22O = 1:2 O = 1:2 Fine root biomass (<2mm; FR) and Fine root biomass (<2mm; FR) and

coarse root biomass (>2mm & <2cm; coarse root biomass (>2mm & <2cm; CR)CR)

Soil samples were collected during Soil samples were collected during June 25 to July 3, 2002June 25 to July 3, 2002

Effect of burning and Effect of burning and thinning on the soil thinning on the soil

chemistrychemistry  Source DF SS MS F Value Pr > F

TN (%) burn 1 0.01 0.01 9.11 0.0028

thin 2 0.00 0.00 1.06 0.3475

  burn*thin 2 0.00 0.00 1.54 0.2163

TC (%) burn 1 0.02 0.02 1.24 0.2662

thin 2 0.10 0.05 2.75 0.0655

  burn*thin 2 0.09 0.05 2.56 0.0787

CN burn 1 3.77 3.77 23.97 <.0001

thin 2 4.13 2.07 13.14 <.0001

  burn*thin 2 0.45 0.22 1.43 0.2416

pH burn 1 0.02 0.02 8.46 0.0039

thin 2 0.12 0.06 24.16 <.0001

  burn*thin 2 0.04 0.02 6.95 0.0011

Effect of burning and Effect of burning and thinning on the microclimatethinning on the microclimate

  Source DF SS MS F Value Pr > F

SRR (gCO2 hr-1 m-2) burn 1 1.06 1.06 99.50 <.0001

thin 2 0.13 0.07 6.34 0.002

  burn*thin 2 0.02 0.01 0.96 0.3841

Ts (˚C) burn 1 0.27 0.27 118.58 <.0001

thin 2 0.85 0.43 190.90 <.0001

  burn*thin 2 0.07 0.04 16.45 <.0001

Ms (%) burn 1 55.42 55.42 9.97 0.0018

thin 2 95.35 47.67 8.58 0.0002

  burn*thin 2 0.22 0.11 0.02 0.9805

LD (cm) burn 1 3664.78 3664.78 160.18 <.0001

thin 2 97.84 48.92 2.14 0.1197

  burn*thin 2 171.04 85.52 3.74 0.0249

Effect of burning and thinning on the Effect of burning and thinning on the Root BiomassRoot Biomass

  Source DF SS MS F Value Pr > F

FR010 burn 1 17.89 17.89 9.66 0.0026

thin 2 11.53 5.77 3.11 0.0495

  burn*thin 2 6.06 3.03 1.64 0.2008

FR1020 burn 1 4.89 4.89 5.22 0.0248

thin 2 13.54 6.77 7.22 0.0013

  burn*thin 2 8.80 4.40 4.69 0.0116

FR burn 1 43.91 43.91 12.90 0.0006

thin 2 49.68 24.84 7.30 0.0012

  burn*thin 2 18.01 9.00 2.64 0.0769

CR010 burn 1 1.06 1.06 2.54 0.1144

thin 2 0.33 0.17 0.40 0.6728

  burn*thin 2 0.36 0.18 0.43 0.6504

CR1020 burn 1 3.76 3.76 1.70 0.1955

thin 2 15.49 7.74 3.50 0.0344

  burn*thin 2 10.79 5.40 2.44 0.093

CR burn 1 7.11 7.11 2.77 0.0999

thin 2 11.39 5.69 2.22 0.1152

  burn*thin 2 9.06 4.53 1.76 0.1777

Soil Respiration and Root Soil Respiration and Root BiomassBiomass

SRR = SRR = ff (FR010, FR1020, CR010, CR1020) (FR010, FR1020, CR010, CR1020)

  Regression Coefficientsr2

  FR010 FR1020 CR010 CR1020

UN 0.127 0.199 0.800 0.013 0.063

UC 0.015 0.790 -0.632 2.300 0.233

US 1.472 -0.023 -0.615 1.569 0.390

BN -0.561 -0.250 1.897 1.524 0.428

BC 0.011 -0.280 2.909 -3.326 0.749

BS -1.516 0.112 -1.121 1.751 0.553

Previous Results Previous Results Lee and Jose (2003) found significant Lee and Jose (2003) found significant

((αα=0.05) correlation between SRR =0.05) correlation between SRR and fine root productionand fine root production Populus deltoides Populus deltoides 0.640.64 Pinus taeda Pinus taeda 0.540.54

Pregitzer et al. (2003) showed that root N concentration explained 70% of variance in SRR

FR and Belowground FR and Belowground CharacteristicsCharacteristics

Path Coefficients TN TC pH Ts Ms LD

UN 0.11 0.33 -0.33 0.06 -0.06 0.40

UC 0.66 0.17 0.68 -0.25 -1.15 -0.49

US -0.09 0.09 0.30 0.80 0.44 -0.25

BN -0.15 -0.17 0.37 -0.40 0.26 -0.15

BC 0.86 0.78 0.28 0.23 -0.50 0.44

BS 0.09 0.14 0.06 -0.11 -0.18 -0.48

FR010

FR and Belowground FR and Belowground CharacteristicsCharacteristics

Path Coefficients TN TC pH Ts Ms LD

UN 0.13 0.09 -0.22 -0.07 0.10 -0.10

UC 0.62 -0.04 0.31 0.70 -2.11 0.23

US 0.75 0.90 0.80 -0.01 0.95 -0.88

BN -0.82 -0.48 -0.23 -0.67 -0.58 -0.07

BC 0.38 0.34 0.27 0.12 -0.56 0.15

BS 0.30 0.43 0.28 -0.54 -0.07 -0.46

FR1020

Path Analysis – SRR Path Analysis – SRR

Path Coefficients CN pH FR CR Ts Ms LD

UN 0.22 -0.23 0.20 0.22 0.29 -0.45 0.29

UC 0.05 0.13 0.14 -0.09 -0.73 -0.11 0.45

US -0.38 -0.40 0.46 -0.29 0.96 0.01 0.73

BN -0.06 0.09 -0.08 0.55 0.42 -0.14 0.79

BC 0.00 -0.02 0.22 0.71 0.22 -0.38 0.35

BS 0.19 0.09 -0.53 0.54 -0.05 -0.39 0.15

Conclusions Conclusions Root biomass explained variance in SRR better Root biomass explained variance in SRR better

in burned plots in burned plots Need for N analysis? Need for N analysis?

Factors affecting fine root biomass changed by Factors affecting fine root biomass changed by treatmentstreatments At 0~10 cmAt 0~10 cmMostly climate factors – not clear; test w/ direct Mostly climate factors – not clear; test w/ direct

factors only factors only At 10~20cmAt 10~20cmBurned plots – climate factors/ unburned – nutrient Burned plots – climate factors/ unburned – nutrient

factors factors SRR and Belowground characteristicsSRR and Belowground characteristics Unburn – Climate factors Unburn – Climate factors / Burn only – LD / Burn and cut – Root biomass / Burn only – LD / Burn and cut – Root biomass

Acknowledgements Acknowledgements

Joint Fire Science Program Joint Fire Science Program Teakettle Experimental Forest Teakettle Experimental Forest Forest Service Forest Service LEES Lab, Dept of EEES, University LEES Lab, Dept of EEES, University

of Toledoof Toledo A lot of helpers for the data A lot of helpers for the data

collectioncollection

Questions?Questions? Any suggestions are Any suggestions are

welcome!welcome!If you are interested, you If you are interested, you

are welcome to get involved are welcome to get involved in this paperin this paper. .

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Extra data Extra data This forest has three major patches, This forest has three major patches,

closed canopy by mixed conifer (CC), closed canopy by mixed conifer (CC), Ceanothus cordulatus Ceanothus cordulatus Kellogg. shrub dominant areas (CECO) Kellogg. shrub dominant areas (CECO) open canopy (OC). open canopy (OC).

CC, OC, and CECO occupy the 67.7, 13.4, and 4.7% of the entire CC, OC, and CECO occupy the 67.7, 13.4, and 4.7% of the entire study forest respectively (North et al. 2002). study forest respectively (North et al. 2002).

Major conifer species includes Major conifer species includes Abies concolorAbies concolor Lindl. ex Hildebr, Lindl. ex Hildebr, A. A. magnificamagnifica A. Murr, A. Murr, Pinus lambertianaPinus lambertiana Douglas, Douglas, P. jefreyiP. jefreyi Grev. and Grev. and Balf, and Balf, and Calocedrus decurrensCalocedrus decurrens (Torr.) Florin (North et al. 2002). (Torr.) Florin (North et al. 2002).

Soils are classified as Xerumbrepts and Xeropsamments (North et Soils are classified as Xerumbrepts and Xeropsamments (North et al. 2002).al. 2002).