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Pyrogenic Carbon as a Component of the C cycle in Boreal Forests?

Pyrogenic Carbon as a Component of the C cycle in Boreal Forests? Caroline Preston, Werner Kurz, Greg Rampley, PFC Victoria Martin Simard, U of Wisconsin Madison Charlotte Norris, U of Alberta, Edmonton.

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Pyrogenic Carbon as a Component of the C cycle in Boreal Forests?

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  1. Pyrogenic Carbon as a Component of the C cycle in Boreal Forests? Caroline Preston, Werner Kurz, Greg Rampley, PFC Victoria Martin Simard, U of Wisconsin Madison Charlotte Norris, U of Alberta, Edmonton

  2. Fire is the main disturbance in Boreal regions – major loss of ecosystem productivity JGR 2007

  3. Role of Pyrogenic Carbon in Boreal Regions -ecological role? -direct role of charcoal?? -importance of disturbance remove thick organic layer change vegetation succession -long-term sink of highly stable soil C? -soot emissions into atmosphere

  4. Boreal Pyrogenic C – as produced in the wild

  5. Managed Biochar Soil AmendmentBoreal Wild Char Production efficiency High Low (5% ?) Transformation High Lower (more H, O, N, S, smaller clusters) Recalcitrance Higher Lower Mineral Soil Protection Optimized Limited – mostly on or above surface Environment Warmer, Cold (Frozen), aerobic anaerobic (peatlands)

  6. What is BC (Pyrogenic C)?

  7. Approaches to BC Analysis -visual char/charcoal (black, floats) -resistance to thermal or photooxidation (with many variants) -NMR (also with photooxidation) -BCPA (production of benzenepolycarboxylic acids) For this effort, we just have to live with the results of this rich variety! For field samples, effects often balance out.

  8. How much PyC is produced in boreal fires? How much PyC is in boreal soils?

  9. Production of charcoal and BC from forest biomass burning, on a mass or carbon basis Based on 500 g C kg-1 for biomass and 700 g C kg-1for char, conversion of 1% of biomass to char on a mass basis is equivalent to 1.4% conversion on a C basis. Conversely, 1% conversion on a C basis corresponds to 0.71% on a mass basis.

  10. Charcoal or BC Stocks – boreal typically <3000 hg/ha or <5% SOC

  11. From Charlotte’s Just-completed MSc thesis

  12. Charlotte Norris Location and major ecological zonations of jack pine sites on the Boreal Forest Transect Case Study (BFTCS)

  13. Fire 4 C Content 2.60 kgm-2 Fire 11 C Content 3.93 kgm-2 Fire 29 C Content 3.33 kgm-2 Fire 91 C Content 3.09 kgm-2

  14. Forest Floor A Light Fr (<1 g/cc) CPMAS 13C NMR spectra from jack pine fire chronosequence Soil organic carbon chemistry in the jack pine boreal forest. C. Norris, MSc. Thesis. U of Alberta (Sylvie A. Quideau, Jagtar S. Bhatti) STOJP

  15. CPMAS 13C NMR spectra from mature jack pine sites FF, light Fr. Soil organic carbon chemistry in the jack pine boreal forest. C. Norris, MSc. Thesis. U of Alberta (Sylvie A. Quideau, Jagtar S. Bhatti) 79 y 91y STOJP

  16. Black Spruce Forests, Flat Topography, Without Fire - Paludification

  17. Peat profile, 95 y since fire 40 cm

  18. Jack Pine: 19 High, 1 Low, Median 25 g/m2

  19. Jack Pine: 19 High, 1 Low, Median 25 g/m2

  20. Black Spruce: 15 High, Median 36 g/m2

  21. Black Spruce: 15 High, Median 36 g/m2

  22. Black Spruce: 12 Low, Median 51 g/m2

  23. Black Spruce: 12 Low, Median 51 g/m2

  24. What happens to PyC? How long does it last in soil? Is it a long-term C sink?

  25. How long does PyC last in Boreal Soils? Our prevous best guesstimate: half-life around 5-10 ky, depending on environment – but a portion could go on decade or century timescales The high values are biased by the survivors – maybe k = 0.001 y-1 is realistic (compare 0.0033/y for slow soil C in CFS model)

  26. CO2 Microbial decomposition Chemical oxidation Photo-oxidation Consumption by another fire SOM, humics, DOC How is PyC lost from boreal soils?

  27. Incorporating Charcoal/BC into the C Budget Model of the Canadian Forest Sector -a very preliminary attempt!

  28. Research needs to model soil PyC -data on soil/peat stocks by any method (look for paleochar unpublished data) -production and stocks in non-soil pools, esp. CWD -BC analysis of Mackenzie DOC and Beaufort sediments -incubations and field decomp studies -more attention to abiotic processes -comparison of BC methods relevant to wildfire charcoal -interdisciplinary approaches needed  -ecological effects -separate direct charcoal effects from vegetation succession and forest floor removal

  29. Some Research Needs for CBI -Agronomic (including forestry, pasture) – rates, changes in soil properties, effects on yields, etc. -chemical characterization of char (elemental analysis, including H, nutrients, NMR, PAHs, metals) -how do we track BC/PyC/biochar added to soil? -we need some standard materials and interlab comparisions

  30. Guggenberger et al., GCB 2008, Forest tundra, Siberia BPCA BC = 0.6 to 3.0% of SOC 220-34 400 kg BPCA BC/ha (especially preserved in permafrost) Export of BPCA-BC in streamwater (mostly DOC) during ice-free period, June 1-Oct. 31/03 Total DOC export: 2.6 g/m2 (1143 kg from catchment) BPCA-BC export: 3.9% of DOC (44 kg) 0.1 g BPCA-BC/m2, mostly during snowmelt! In 100 y, loss = 10 g BPCA-BC/m2, similar to estimated production BC contributes to TOC in Arctic sediments For comparison - Moore, GBC 2003 Sites near Thompson MN, DOC export in streams, approx 3 g/m2

  31. Elmquist et al. 2008. Pan-Arctic patterns in BC sources….Global Biogeochem. Cycles 22, GB 2018

  32. Elmquist et al. 2008 Annual Fluxes of Soot BC from Arctic Rivers (Tg) Total Fossil Modern Production Pan-Boreal 0.202 0.159 0.042 0.38 Eurasia 0.101 0.076 0.027 0.31 North Am 0.101 0.085 0.015 0.07 (Gustaffson CTO method)

  33. Global Wildfire Emissions 1960-2000 (Schultz et al. 2008) 2078 Tg/y (1410-3140, higher in more recent years) Pan-Boreal Emissions - Tg (Balshi et al. 2007,1996-2002, simulations without CO2 effect (Charcoal/BC = 5%, Atmos. Soot 0.15%) (Tg) Total Char/BC Soot Pan-Boreal 255 12.7 0.38 Eurasia 209 10.4 0.31 North Am 45.7 2.3 0.069 Canada 32.3 1.6 0.048 Alaska 13.7 0.69 0.021

  34. Boreal Soil C Global: C in boreal peat and soil – 600 Pg Canada: C in peat – 113 Pg, in forest soil 65 Pg, Total 178 (Bhatti) BC (est. as 5% SOC): 5650 Tg in peat, 3250 Tg in forest (8900 Tg) Canada: Boreal BC/Char Production: 1.6-2 Tg BC/y? In 10,000 y = 16,000-20,000 Tg C – how much has been lost? Compare Canada - All Forest and Wetland Soils – 164.5 Pg C, litter inputs 900 Tg C/y (Ju and Chen 2008) How does BC/charcoal production compare with annual transfer of litter to stabilized pool? How do BC/charcoal pools compare with SLOW pool of DOC (Dead Organic C) in C budget models? (k = 0.0033/y, Q10=0)

  35. = > 2 Mg/ha

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