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Chamber and biometric flux measurments for upscaling C- budgets: NACP Tier 3 Efforts Peter Weishampel Dept. Soil, Water, and Climate University of Minnesota Randy Kolka USDA/Forest Service North Central Research Station
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Slide Credit: Rich Birdsey Marcell Exp. Forest Chequamegon Nat. Forest
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Three upland cover types Willow Creek - mature hardwood (Stationary EC) Riley Creek – older clear cut Thunder Creek – younger clear cut (Mobile EC)
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Four wetland cover types Conifer swamp near WLEF (no EC) South Fork Flambeau - Open bog (Mobile EC) Wilson Flowage - Sedge fen (Mobile EC) Lost-Creek Alder swamp (stationary EC)
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General Plot Layout 3 Forest Inventory and Analysis (FIA) plots per site Plots arranged linearly, upwind from EC tower (more or less) Our work mostly at the subplot level N 220-370 m 54 m radius
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Work on FIA Subplots Soil gas fluxes Short-term CO 2 and CH 4 (~tri- weekly) Long-term CO2 flux (~monthly) Closed chamber CH 4 Biomass/Productivity assessments Biometrics Measurements of all trees > 2.5 cm and subset of cores Shrubs, understory, Sphagnum moss (small subplots) Litterfall collections Leaf area – LAI 2000 Specific leaf area, leaf N (model parameterization) Carbon storage Forest floor. peat, and soil coring and analysis Coarse woody debris transects Respiration flux collar 8 meter radius FIA subplot Sampling boardwalks (wetland plots) Litter basket Gas sampling boardwalks – wetland subplots
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Instantaneous Soil Respiration Infrared gas analyzer measures CO2 flux from soil at 36 locations per site. Measurements made on FIA-like plots ~ tri-weekly. CO 2 Flux Regression models with soil temperature and moisture help predict soil CO2 flux.
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Temporal Trends in Measured Soil Respiration Rates – Wetland Sites 2005
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Temporal Trends in Measured Soil Respiration Rates – Upland Sites 2005
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New Toy: LI8100 Automated Soil CO2 Flux System Automated system helps establish diurnal profile of CO 2 flux
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Diurnal profiles of CO 2 flux at Wilson Flowage 5/2-06-5/4/06 5/29/06-6/1/06
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Methane Fluxes Static chamber approach Samples collected from chamber with syringe Injected into sealed headspace vials Analyzed by gas chromatography CH 4 sampling at Wilson Flowage (sedge-dominated fen)
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2005 Methane Fluxes – Wetland Sites
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2005 Methane flux at Wilson Flowage >> than other sites
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2005 Methane Flux – Upland Sites
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Relevance of Methane Virtually imperceptible in terms of the total soil carbon flux Considering that CH 4 is 25- 30x more effective at trapping heat than CO 2, CH4 is still important to the greenhouse gas picture
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