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Effects of Experimental Burning and Thinning on Soil Respiration and Belowground Characteristics. Soung-Ryoul Ryu 1 , Amy Concilio 1 , Jiquan Chen 1 , Deborah Neher 1 , Siyan Ma 1 and Malcolm North 2
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Effects of Experimental Burning and Thinning on Soil Respiration and Belowground Characteristics Soung-Ryoul Ryu1, Amy Concilio1, Jiquan Chen1, Deborah Neher1, Siyan Ma1 and Malcolm North2 1Department of EEES, University of Toledo, Toledo, OH2Department of Environmental Horticulture, University of California-Davis, Davis, CA
Objectives • Is there relationship between soil respiration and root biomass? • The relationship is the same under thinning and burning ? • What controls root biomass ? • The driving factor is the same between treatments? • What affects soil respiration rate ? • Any effects from thinning and burning ?
Available Nutrient Soil Chemical Factors Heterotrophic Respiration (Rh) Root Respiration (Ra) Soil Respiration Soil Climatic Factors Litter Layer Soil Organic Matter Soil Carbon
Site Description • Teakettle Experimental Forest • 1300ha of area, located in Sierra National Forest on the west side of the Sierra Nevada range of California. • Altitude: 1980 ~ 2590 m • Precipitation: 1250mm/year, mostly in the form of snow • Mean air temperature: 1°C(January ) and 14.5°C(July)
Plot Preparation • Eighteen plots (4 ha each) were prepared using variogram and cluster analysis (North et al. 2002). • California spotted owl (CASPO) thinning, and shelterwood thinning were applied between August 2000 and Summer of 2001 • Prescribed burning followed November 2001 • Transects (1m spaced) developed at • Burn-CASPO (BC), Burn-Shelterwood (BS), Burn only (BN), Unburn-CASPO (UC), Unburn-Shelterwood (US), and Control (UN) plots
Field Measurement • Soil respiration rate (SRR; gCO2 hr-1 m-2): a portable infrared gas analyzer (EGM-2 Environmental Gas Monitor, PP Systems, UK) • Soil temperature at 10cm depth (Ts; ˚C): using a digital thermometer simultaneously with SRR measurement. • Soil moisture (Ms; %): Time Domain Reflectometry (TDR) within 0~10cm depth in mineral soil. • Litter depth (LD) • Measured at least every other week during the growing season of 2002
Field Measurement • Total nitrogen (TN) and total carbon (TC) content in soil: using CN analyzer (Carlo Erba NA 1500 Series 2) • pH: soil:H2O = 1:2 • Fine root biomass (<2mm; FR) and coarse root biomass (>2mm & <2cm; CR) • Soil samples were collected during June 25 to July 3, 2002
Soil Respiration and Root Biomass • SRR = f (FR010, FR1020, CR010, CR1020)
Previous Results • Lee and Jose (2003) found significant (α=0.05) correlation between SRR and fine root production • Populus deltoides 0.64 • Pinus taeda 0.54 • Pregitzer et al. (2003) showed that root N concentration explained 70% of variance in SRR
Conclusions • Root biomass explained variance in SRR better in burned plots • Need for N analysis? • Factors affecting fine root biomass changed by treatments • At 0~10 cm Mostly climate factors – not clear; test w/ direct factors only • At 10~20cm Burned plots – climate factors/ unburned – nutrient factors • SRR and Belowground characteristics Unburn – Climate factors / Burn only – LD / Burn and cut – Root biomass
Acknowledgements • Joint Fire Science Program • Teakettle Experimental Forest • Forest Service • LEES Lab, Dept of EEES, University of Toledo • A lot of helpers for the data collection
Questions? Any suggestions are welcome!If you are interested, you are welcome to get involved in this paper.
TN TC CN pH (box-whisker with Anova) ab ab a ab b ab ab ab a ab ab b c b ab ab ab a a a b a a a
SRR Ms Ts LD ab a bc bc ab c c c c ab a b a a b b a c c c c b a ab
0~10 cm FR CR 010 1020 b b ab b ab a a a a a a a 10~20 cm c bc abc bc a ab b ab ab b ab a
Extra data • This forest has three major patches, • closed canopy by mixed conifer (CC), • Ceanothus cordulatus Kellogg. shrub dominant areas (CECO) • open canopy (OC). • CC, OC, and CECO occupy the 67.7, 13.4, and 4.7% of the entire study forest respectively (North et al. 2002). • Major conifer species includes Abies concolor Lindl. ex Hildebr, A. magnifica A. Murr, Pinus lambertiana Douglas, P. jefreyi Grev. and Balf, and Calocedrus decurrens (Torr.) Florin (North et al. 2002). • Soils are classified as Xerumbrepts and Xeropsamments (North et al. 2002).