Biogeosciences www.biogeosciences.net 1726-4170 1726-4189 3 4 2006 10.5194/bg-3-397-2006 http://www.biogeosciences.net/3/397/2006/ http://www.biogeosciences.net/3/397/2006/bg-3-397-2006.html http://www.biogeosciences.net/3/397/2006/bg-3-397-2006.pdf 397 420 2006-09-19 Black (pyrogenic) carbon: a synthesis of current knowledge and uncertainties with special consideration of boreal regions C. M. Preston cpreston@pfc.cfs.nrcan.gc.ca M. W. I. Schmidt Pacific Forestry Centre, Natural Resources Canada, 506 W. Burnside Rd., Victoria BC, V8Z 1M5, Canada Dept. of Geography, University of Zürich, Winterthurerstr. 190, 8057 Zürich, Switzerland The carbon (C) cycle in boreal regions is strongly influenced by fire, which converts biomass and detrital C mainly to gaseous forms (CO2 and smaller proportions of CO and CH4), and some 1–3% of mass to pyrogenic C (PyC). PyC is mainly produced as solid charred residues, including visually-defined charcoal, and a black carbon (BC) fraction chemically defined by its resistance to laboratory oxidation, plus much lower proportions of volatile soot and polycyclic aromatic hydrocarbons (PAHs). All PyC is characterized by fused aromatic rings, but varying in cluster sizes, and presence of other elements (N, O) and functional groups. The range of PyC structures is often described as a continuum from partially charred plant materials, to charcoal, soot and ultimately graphite which is formed by the combination of heat and pressure. There are several reasons for current interest in defining more precisely the role of PyC in the C cycle of boreal regions. First, PyC is largely resistant to decomposition, and therefore contributes to very stable C pools in soils and sediments. Second, it influences soil processes, mainly through its sorption properties and cation exchange capacity, and third, soot aerosols absorb solar radiation and may contribute to global warming. However, there are large gaps in the basic information needed to address these topics. While charcoal is commonly defined by visual criteria, analytical methods for BC are mainly based on various measures of oxidation resistance, or on yield of benzenepolycarboxylic acids. These methods are still being developed, and capture different fractions of the PyC structural continuum. There are few quantitative reports of PyC production and stocks in boreal forests (essentially none for boreal peatlands), and results are difficult to compare due to varying experimental goals and methods, as well as inconsistent terminology. There are almost no direct field measurements of BC aerosol production from boreal wildfires, and little direct information on rates and mechanisms for PyC loss. Structural characterization of charred biomass and forest floor from wildfires generally indicates a low level of thermal alteration, with the bulk of the material having H/C ratios still >0.2, and small aromatic cluster sizes. Especially for the more oxidation-resistant BC fraction, a variety of mainly circumstantial evidence suggests very slow decomposition, with turnover on a millennial timescale (in the order of 5–7 ky), also dependent on environmental conditions. However, there is also evidence that some PyC may be lost in only tens to hundreds of years due to a combination of lower thermal alteration and environmental protection. The potential for long-term PyC storage in soil may also be limited by its consumption by subsequent fires. Degraded, functionalized PyC is also incorporated into humified soil organic matter, and is transported eventually to marine sediments in dissolved and particulate form. Boreal production is estimated as 7–17 Tg BC y−1 of solid residues and 2–2.5 Tg BC y−1 as aerosols, compared to global estimates of 40–240 and 10–30 Tg BC y−1, respectively. Primary research needs include basic field data on PyC production and stocks in boreal forests and peatlands, suitable to support C budget modeling, and development of standardized analytical methods and of improved approaches to assess the chemical recalcitrance of typical chars from boreal wildfires. To accomplish these goals effectively will require much greater emphasis on interdisciplinary cooperation. Accardi-Dey, M. and Gschwend, P. M.: Reinterpreting literature sorption data considering both absorption into organic carbon and adsorption onto black carbon, Environ. Sci. Technol., 37, 99–106, 2003. Almendros, G., Kgathi, D., Sekhwela, M., Zancada, M.-C., Tinoco, P., and Pardo, M.-T.: Biogeochemical assessment of resilient humus formations from virgin and cultivated northern Botswana soils, J. Agric. Food Chem., 51, 4321–4330, 2003. Amiro, B. D., Todd, J. B., Wotton, B. M., Logan, K. A., Flannigan, M. D., Stocks, B. J., Mason, J. A., Martell, D. L., and Hirsch, K. G.: Direct carbon emissions from Canadian forest fires, 1959-1999, Can. J. For. Res., 31, 512–525, 2001. Andreae, M. O. and Merlet, P.: Emission of trace gases and aerosols from biomass burning, Global Biogeochem. Cycles, 15, 955–966, 2001. Bachelet, D., Lenihan, J., Neilson, R., Drapek, R., and Kittel, T.: Simulating the response of natural ecosystems and their fire regimes to climatic variability in Alaska, Can. J. For. Res., 35, 2244–2257, 2005. Baldock, J. A. and Smernik, R. J.: Chemical composition and bioavailability of thermally altered \textitPinus resinosa (Red pine) wood, Org. Geochem., 33, 1093–1109, 2002. Berglund, L. M., DeLuca, T. H., and Zackrisson, O.: Activated carbon amendments to soil alters nitrification rates in Scots pine forests, Soil Biol. Biochem., 36, 2067–2073, 2004. Bélanger, N., Côté, B., Fyles, J. W., Courchesne, F., and Hendershot, W. H.: Forest regrowth as the controlling factor of soil nutrient availability 75 years after fire in a deciduous forest of Southern Quebec, Plant Soil, 262, 363–372, 2004. Benites, V. M., Mendonça, E. S., Schaefer, C. E. G. R., Novotny, E. H., Reis, E. L., and Ker, J. C.: Properties of black soil humic acids from high altitude rocky complexes in Brazil, Geoderma, 127, 104–113, 2005. Benscoter, B. W. and Wieder, R. K.: Variability in organic matter lost by combustion in a boreal bog during the 2001 Chisholm fire, Can. J. For. Res., 33, 2509–2513, 2003. Bhatti, J. S., van Kooten, G. C., Apps, M. J., Laird, L. D., Campbell, I. D., Campbell, C., Turetsky, M. R., Yu, Z., and Banfield, E.: Carbon balance and climate change in boreal forests, in: Towards Sustainable Management of the Boreal Forest, edited by: Burton, P. J., Messier, C., Smith, D. W., and Adamowicz, W. L., NRC Research Press, Ottawa ON, Canada, 799–855, 2003. Bird, M. I. and Gröcke, D. R.: Determination of the abundance and carbon isotope composition of elemental carbon in sediments, Geochim. Cosmochim. Acta., 16, 3413–3423, 1997. Bird, M. I., Moyo, C., Veenendaal, E. M., Lloyd, J., and Frost, P.: Stability of elemental carbon in a savanna soil, Global Biogeochem. Cycles, 13, 923–932, 1999. Bond, T. C. and Sun, H.: Can reducing black carbon emissions counteract global warming?, Environ. Sci. Technol., 39, 5921–5926, 2005. Brodowski S. B.: Origin, function, and reactivity of black carbon in the arable soil environment, PhD thesis, University of Bayreuth, Bayreuth, Germany, 2004. Brodowski, S., Amelung, W., Haumaier, L., Abetz, C., and Zech, W.: Morphological and chemical properties of black carbon in physical soil fractions as revealed by scanning electron microscopy and energy-dispersive X-ray spectroscopy, Geoderma, 128, 116–129, 2005a. Brodowski, S., Rodionov, A., Haumaier, L., Glaser, B., and Amelung, W.: Revised black carbon assessment using benzene polycarboxylic acids, Org. Geochem., 36, 1299–1310, 2005b. Brown, R. A., Kercher, A. K., Nguyen, T. H., Nagle, D. C., and Ball, W. P.: Production and characterization of synthetic wood chars for use as surrogates for natural sorbents, Org. Geochem., 37, 321–333, 2006. Brun, G. L., Vaidya, O. M., and Léger, M. G.: Atmospheric deposition of polycyclic aromatic hydrocarbons to Atlantic Canada: geographic and temporal distributions and trends 1980–2001, Environ. Sci. Technol., 38, 1941–1948, 2004. Bucheli, T. D., Blum, F., Desaules, A., and Gustafsson, Ö.: Polycyclic aromatic hydrocarbons, black carbon, and molecular markers in soils of Switzerland, Chemosphere, 56, 1061–1076, 2004. Carcaillet, C.: Are Holocene wood-charcoal fragments stratified in alpine and subalpine soils? Evidence from the Alps based on AMS $^14$C dates, Holocene, 11, 231–242, 2001a. Carcaillet, C.: Soil particles reworking evidences by AMS $^14$C dating of charcoal, C. R. Acad. Sci. Paris, Sciences de la Terre et des planètes, 332, 21–28, 2001b. Carcaillet, C. and Talon, B.: Soil carbon sequestration by Holocene fires inferred from soil charcoal in the dry French Alps, Arctic Antarct, Alpine Res., 33, 282–288, 2001. Castro, A., González-Prieto, S. J., and Carballas, T.: Burning effects on the distribution of organic N compounds in a $^15$N labelled forest soil, Geoderma, 130, 97–107, 2006. Certini, G.: Effects of fire on properties of forest soils: a review, Oecologia, 143, 1–10, 2005. Chang, S. and Berner, R. A.: Humic substance formation via the oxidative weathering of coal, Environ. Sci. Technol., 32, 2883–2886, 1998. Chang, S. and Berner, R. A.: Coal weathering and the geochemical carbon cycle, Geochim. Cosmochim. Acta, 63, 3301–3310, 1999. Choromanska, U. and DeLuca, T. H.: Microbial activity and nitrogen mineralization in forest mineral soils following heating: evaluation of post-fire effects, Soil Biol. Biochem., 34, 263–271, 2002. Chun, Y., Sheng, G., Chiou, C. T., and Xing, B.: Compositions and sorptive properties of crop residue-derived chars, Environ. Sci. Technol., 38, 4649–4655, 2004. Clark, J. S. and Royall, P. D.: Pre-industrial particulate emissions and carbon sequestration from biomass burning in North America, Biogeochem., 23, 35–51, 1994. Clark, J. S., Lynch, J., Stocks, B. J., and Goldammer, J. G.: Relationships between charcoal particles in air and sediments in west-central Siberia, Holocene, 8, 19–29, 1998. Cofer III, W. R., Winstead, E. L., Stocks, B. J., Goldammer, J. G., and Cahon, D. R.: Crown fire emissions of CO2, CO, H2, CH4 and TNMHC from a dense jack pine boreal forest fire, Geophys. Res. Lett, 25, 3919–3922, 1998. Conard, S. G. and Ivanova, G. A.: Wildfire in Russian boreal forests – potential impacts of fire regime characteristics on emissions and global carbon balance estimates, Environ. Pollut., 98, 303–313, 1997. Conny, J. M. and Slater, J. F.: Black carbon and organic carbon in aerosol particles from crown fires in the Canadian boreal forest, J. Geophys. Res., 107(D11), 4116, doi:10.1029/2001JD001528, 2002. Cooke, W. F. and Wilson, J. J. N.: A global black carbon aerosol model, J. Geophys. Res., 101, 19 395–19 409, 1996. Cornelissen, G., Gustafsson, Ö., Bucheli, T. D., Jonker, M. T. O., Koelmans, A. A., and Van Noort, P. C. M.: Extensive sorption of organic compounds to black carbon, coal and kerogen in sediments and soils: mechanisms and consequences for distribution, bioaccumulation, and biodegradation, Environ. Sci. Technol., 39, 6881–6895, 2005. Currie, L. A., Benner Jr., B. A., Kessler, J. D., et al.: A critical evaluation of interlaboratory data on total, elemental, and isotopic carbon in the carbonaceous particle reference material, NIST SRM 1649a, J. Res. Natl. Inst. Stand. Technol., 107, 279–298, 2002. Czimczik, C. I., Preston, C. M., Schmidt, M. W. I., Werner, R. A., and Schulze, E.-D.: Effects of charring on mass, organic carbon, and stable carbon isotope composition of wood, Org. Geochem., 33, 1207–1223, 2002. Czimczik, C. I., Preston, C. M., Schmidt, M. W. I., and Schulze, E.-D.: How surface fire in Siberian Scots pine forests affects soil organic carbon in the forest floor: Stocks, molecular structure, and conversion to black carbon (charcoal), Global Biogeochem. Cycles, 17(1), 1020, doi:10.1029/2002GB001956, 2003. Czimczik, C. I., Schmidt, M. W. I., and Schulze, E.-D.: Effects of increasing fire frequency on black carbon and soil organic matter in Podzols of Siberian Scots pine forests, Eur. J. Soil Sci., 56, 417–428, 2005. Dai, X., Boutton, T. W., Glaser, B., Ansley, R. J., and Zech, W.: Black carbon in a temperate mixed-grass savanna, Soil Biol. Biochem., 37, 1879–1881, 2005. DeBano, L. F.: The role of fire and soil heating on water repellency in wildland environments: a review, J. Hydrol., 231–232, 195–206, 2000. Decesari, S., Facchini, M. C., Matta, E., Mireca, M., Fuzzi, S., Chughtai, A. R., and Smith, D. M.: Water soluble organic compounds formed by oxidation of soot, Atmos. Environ., 36, 1827–1832, 2002. DeLuca, T. H., Nilsson, M.-C., and Zackrisson, O.: Nitrogen mineralization and phenol accumulation along a fire chronosequence in northern Sweden, Oecologia, 133, 206–214, 2002. DeLuca, T. H., MacKenzie, M. D., Gundale, M. J., and Holben, W. E.: Wildfire-produced charcoal directly influences nitrogen cycling in ponderosa pine forests, Soil Sci. Soc. Am. J., 70, 448-453, 2006. Dickens, A. F., Gélinas, Y., and Hedges, J. I.: Physical separation of combustion and rock sources of graphitic black carbon in sediments, Mar. Chem., 92, 215–223, 2004a. Dickens, A. F., Gélinas, Y., Masiello, C. A., Wakeham, S., and Hedges, J. I.: Reburial of fossil organic carbon in marine sediments, Nature, 427, 336–339, 2004b. Dreyer, A., Radke, M., Turunen, J., and Blodau, C.: Long-term change of polycyclic aromatic hydrocarbon deposition to peatlands of eastern Canada, Environ. Sci. Technol., 39, 3918–3924, 2005. Duarte, R. M. B. O., Pio, C. A., and Duarte, A. C.: Spectroscopic study of the water-soluble organic matter isolated from atmospheric aerosols collected under different atmospheric conditions, Anal. Chim. Acta, 530, 7–14, 2005. Dyrness, C. T., Van Cleve, K., and Levison, J. D.: The effect of wildfire on soil chemistry in four forest types in interior Alaska, Can. J. For. Res., 19, 1389–1396, 1989. Elias, V. O., Simoneit, B. R. T., Cordeiro, R. C., and Turcq, B.: Evaluating levoglucosan as an indicator of biomass burning in Carajás, Amazônia: A comparison to the charcoal record, Geochim. Cosmochim. Acta, 65, 267–272, 2001. Elmquist, M., Cornelissen, G., Kukulska, Z., and Gustafsson, Ö.: Distinct oxidative stabilities of char versus soot black carbon: implications for quantification and environmental recalcitrance, Global Biogeochem. Cycles, 20, GB2009, doi:10.1029/2005GB002629, 2006. Fearnside, P. M., Leal Jr., N., and Fernandes, F. M.: Rainforest burning and the global carbon budget: biomass, combustion efficiency, and charcoal formation in the Brazilian Amazon, J. Geophys. Res., 98, 16 733–16 743, 1993. Fearnside, P. M., Graça, P. M. L. A., Filho, N. L., Rodrigues, F. J. A., and Robinson, J. M.: Tropical forest burning in Brazilian Amazonia: measurement of biomass loading, burning efficiency and charcoal formation in Altamira, Pará, For. Ecol. Manage., 123, 65–79, 1999. Fearnside, P. M., Graça, P. M. L. A., and Rodrigues, F. J. A.: Burning of Amazonian rainforests: burning efficiency and charcoal formation in forest cleared for cattle pasture near Manaus, Brazil, For. Ecol. Manage., 146, 115–128, 2001. Fernandes, M. B., Skjemstad, J. O., Johnson, B. B., Wells, J. D., and Brooks, P.: Characterization of carbonaceous combustion residues. I. Morphological, elemental and spectroscopic features, Chemosphere, 51, 785–795, 2003. Flannigan, M., Campbell, I., Wotton, M., Carcaillet, C., Richard, P., and Bergeron, Y.: Future fire in Canada's boreal forest: paleoecology results and general circulation model – regional climate model simulations, Can. J. For. Res., 31, 854–864, 2001. Flannigan, M. D., Logan, K. A., Amiro, B. D., Skinner, W. R., and Stocks, B. J.: Future area burned in Canada, Clim. Change, 72, 1–16, 2005. Friedli, H. R., Atlas, E., Stroud, V. R., Giovanni, L., Campos, T., and Radke, L. F.: Volaile organic trace gases emitted from North American wildfires, Global Biogeochem. Cycles, 15, 435–452, 2001. Gavin, D. G.: Forest soil disturbance intervals inferred from soil charcoal radiocarbon dates, Can. J. For. Res., 33, 2514–2518, 2003. Gavin, D. G., Brubaker, L. B., and Lertzman, K. P.: Holocene fire history of a coastal temperate rain forest based on soil charcoal radiocarbon dates, Ecology 84, 186–201, 2003. Gélinas, Y., Prentice, K. M., Baldock, J. A., and Hedges, J. I.: An improved thermal oxidation method for the quantification of soot/graphitic black carbon in sediments and soils, Environ. Sci. Technol., 35, 3519–3525, 2001. Glaser, B. and Amelung, W.: Pyrogenic carbon in native grassland soils along a climosequence in North America, Global Biogeochem. Cycles, 17(2), 1064, doi:10.1029/2002GB002019, 2003. Glaser, B., Haumaier, L., Guggenberger, G., and Zech, W.: Black carbon in soils: the use of benzenecarboxylic acids as specific markers, Org. Geochem., 29, 811–819, 1998. Glaser, B., Balashov, E., Haumaier, L., Guggenberger, G., and Zech, W.: Black carbon in density fractions of anthropogenic soils of the Brazilian Amazon region, Org. Geochem., 31, 669–678, 2000. Glaser, B., Haumaier, L., Guggenberger, G., and Zech, W.: The "Terra Preta" phenomenon: a model for sustainable agriculture in the humid tropics, Naturwissenschaften, 88, 37–41, 2001. Glaser, B., Lehmann, J., and Zech, W.: Ameliorating physical and chemical properties of highly weathered soils in the tropics with charcoal – a review, Biol. Fert. Soils, 35, 219–230, 2002. Golchin, A., Clarke, P., Baldock, J. A., Higashi, T., Skjemstad, J. O., and Oades, J. M.: The effects of vegetation and burning on the chemical composition of soil organic matter in a volcanic ash soil as shown by $^13$C NMR spectroscopy. I. Whole soil and humic acid fraction, Geoderma, 76, 155–174, 1997. Golding, C. J., Smernik, R. J., and Birch, G. F.: Characterization of sedimentary organic matter from three south-eastern Australian estuaries using solid-state $^13$C-NMR techniques, Mar. Freshwat. Res., 55, 285–293, 2004. Gõni, M. A., Yunker, M. B., Macdonald, R. W., and Eglinton, T. I.: The supply and preservation of ancient and modern components of organic carbon in the Canadian Beaufort Shelf of the Arctic Ocean, Mar. Chem., 93, 53–73, 2005. González-Pérez, J. A., González-Vila, F. J., Almendros, G., and Knicker, H.: The effect of fire on soil organic matter – a review, Environ. Int., 30, 855–870, 2004. Graça, P. M. L. A., Fearnside, P. M., and Cerri, C. C.: Burning of Amazonian forest in Ariquemes, Rondônia, Brazil: biomass, charcoal formation and burning efficiency, For. Ecol. Manage., 120, 179–191, 1999. Greif, G. E. and Archibold, O. W.: Standing-dead tree component of the boreal forest in central Saskatchewan, For. Ecol. Manage., 131, 37–46, 2000. Guinto, D. F., Saffigna, P. G., Xu, Z. H., House, A. P. N., and Perera, M. C. S.: Soil nitrogen mineralization and organic matter composition revealed by $^13$C NMR spectroscopy under repeated prescribed burning in eucalypt forests of south-east Queensland, Aust. J. Soil Res., 37, 123–135, 1999. Guo, L., Semiletov, I., Gustafsson, Ö., Ingri, J., Andersson, P., Dudarev, O., and White, D.: Characterization of Siberian Arctic coastal sediments: implications for terrestrial organic carbon export, Global Biogeochem. Cycles, 18, GB1036, doi:10.1029/2003GB002087, 2004. Gustafsson, Ö. and Gschwend, P.M.: The flux of black carbon to surface sediments on the New England continental shelf, Geochim. Cosmochim. Acta, 62, 465–472, 1998. Gustafsson, Ö., Bucheli, T. D., Kukulska, Z., Andersson, M., Largeau, C., Rouzaud, J.-N., Reddy, C. M., and Eglinton, T. I.: Evaluation of a protocol for the quantification of black carbon in sediments, Global Biogeochem. Cycles, 15, 881–890, 2001. Haberstroh, P. R., Brandes, J. A., Gélinas, Y., Dickens, A. F., Wirick, S., and Cody, G.: Chemical composition of the graphitic black carbon fraction in riverine and marine sediments at sub-micron scales using carbon X-ray spectromicroscopy, Geochim. Cosmochim. Acta, 70, 1483–1494, 2006. Hamer, U., Marschner, B., Brodowski, S., and Amelung, W.: Interactive priming of black carbon and glucose mineralization, Org. Geochem., 35, 823–830, 2004. Hammes, K., Smernik, R. J., Skjemstad, J. O., Herzog, A., Vogt, U. F., and Schmidt, M. W. I.: Synthesis and characterisation of laboratory-charred grass straw and chestnut wood as reference materials for black carbon quantification, Org. Geochem., in press, 2006a. Hansen, J., Sato, M., Ruedy, R., Lacis, A., and Oinas, V.: Global warming in the twenty-first century: an alternative scenario, Proc. Nat. Acad. Sci., 97, 9875–9880, 2000. Harden, J. W., O'Neill, K. P., Trumbore, S. E., Veldhuis, H., and Stocks, B. J.: Moss and soil contributions to the annual net carbon flux of a maturing boreal forest, J. Geophys. Res., 102, 28 805–28 816, 1997. Harden, J. W., Trumbore, S. E., Stocks, B. J., Hirsch, A., Gower, S. T., O'Neill, K. P., and Kasischke, E. S.: The role of fire in the boreal carbon budget, Global Change Biol., 6 (Suppl 1), 174–184, 2000. Harden, J. W., Neff, J. C., Sandberg, D. V., Turetsky, M. R., Ottmar, R., Gleixner, G., Fries, T. L., and Manies, K. L.: Chemistry of burning the forest floor during the FROSTFIRE experimental burn, interior Alaska, 1999, Global Biogeochem. Cycles, 18, GB3014, doi:10.1029/2003GB002194, 2004. Harvey, A. E., Larsen, M. J., and Jurgensen, M. F.: Distribution of ectomycorrhizae in a mature Douglas-fir/larch forest soil in western Montana, For. Sci., 22, 393–398, 1976. Haslam, S. F. I., Chudek, J. A., Goldspink, C. R., and Hopkins, D. W.: Organic matter accumulation following fires in a moorland soil chronosequence, Global Change Biol., 4, 305–313, 1998. Haumaier, L. and Zech, W.: Black carbon – possible source of highly aromatic components of soil humic acids, Org. Geochem., 23, 191–196, 1995. Hays, M. D., Geron, C. D., Linna, K. J., and Smith, N. D.: Speciation of gas-phase and fine particle emissions from burning of foliar fuels, Environ. Sci. Technol., 36, 2281–2295, 2002. Hedges, J. I. and Oades, J. M.: Comparative organic geochemistries of soils and marine sediments, Org. Geochem. 27, 319–361, 1997. Hedges, J. I., Eglinton, G., Hatcher, P. G., Kirchman, D. L., Arnosti, C., Derenne, S., Evershed, R. P., Kögel-Knabner, I., de Leeuw, J. W., Littke, R., Michaelis, W., and Rullköter, J.: The molecularly-uncharacterized component of nonliving organic matter in natural environments, Org. Geochem., 31, 945–958, 2000. Hély, C., Flannigan, M., and Bergeron, Y.: Modeling tree mortality following wildfire in the southeastern Canadian mixed-wood boreal forest, Forest Sci., 49, 566–576, 2003. Hicke, J. A., Asner, G. P., Kasischke, E. S., French, N. H. F., Randerson, J. T., Collatz, G. J., Stocks, B. J., Tucker, C. J., Los, S. O., and Field, C. B.: Postfire response of North American boreal forest net primary productivity analysed with satellite observations, Global Change Biol., 9, 1145–1157, 2003. Hille, M. and den Ouden, J.: Charcoal and activated carbon as adsorbate of phytotoxic compounds – a comparative study, Oikos, 108, 202–207, 2005. Hiridate, S., Nakadai, T., Shindo, H., and Yoneyama, T.: Cabon source of humic substances in some Japanese volcanic ash soils determined by carbon stable isotope ratio, $\delta ^13$C, Geoderma, 119, 133–141, 2004. Hockaday, W. C., Grannas, A. M., Kim, S., and Hatcher, P. G.: Direct molecular evidence for the degradation and mobility of black carbon in soils from ultrahigh-resolution mass spectral analysis of dissolved organic matter from a fire-impacted forest soil, Org. Geochem., 37, 501–510, 2006. Hopmans, P., Bauhus, J., Khanna, P., and Weston, C.: Carbon and nitrogen in forest soils: Potential indicators for sustainable management of eucalypt forests in south-eastern Australia, For. Ecol. Manage., 220, 75–87, 2005. Hung, H., Blanchard, P., Halsall, C. J., Bidleman, T. F., Stern, G. A., Fellin, P., Muir, D. C. G., Barrie, L. A., Jantunen, L. M., Helm, P. A., Ma, J., and Konoplev, A.: Temporal and spatial variabilities of atmospheric polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides and polycyclic aromatic hydrocarbons (PAHs) in the Canadian Arctic: Results from a decade of monitoring, Sci. Total Environ., 342, 119–144, 2005. Ito, A. and Penner, J. E.: Historical emissions of carbonaceous aerosols from biomass and fossil fuel burning for the period 1870–2000, Global Biogeochem. Cycles, 19, GB2028, doi:10.1029/2004GB002374, 2005. Jacobson, M. Z.: Control of fossil-fuel particulate black carbon and organic matter, possibly the most effective method of slowing global warming, J. Geophys. Res., 107(D19), 4410, doi:10.1029/2001JD001376, 2002. Jonker, M. T. O., Hawthorne, S. B., and Koelmans, A. A.: Extremely slowly desorbing polycyclic aromatic hydrocarbons from soot and soot-like materials: evidence by supercritical fluid extraction, Environ. Sci. Technol., 39, 7889–7895, 2005. Kasischke, E. S. and Johnstone, J. F: Variation in postfire organic layer thickness in a black spruce forest complex in interior Alaska and its effects on soil temperature and moisture, Can. J. For. Res., 35, 2164–2177, 2005. Kasischke, E. S., Hyer, E. J., Novelli, P. C., Bruhwiler, L. P., French, N. H. F., Sukhinin, A. I., Hewson, J. H., and Stocks, B. J.: Influences of boreal fire emissions on Northern Hemisphere atmospheric carbon and carbon monoxide, Global Biogeochem. Cycles, 19, GB1012, doi:10.1029/2004GB002300, 2005. Kavdir, Y., Ekinci, H., Yüksel, O., and Mermut, A. R.: Soil aggregate stability and $^13$C CP/MAS-NMR assessment of organic matter in soils influenced by forest wildfires in Çanakkale, Turkey, Geoderma, 129, 219–229, 2005. Keech, O., Carcaillet, C., and Nilsson, M.-C.: Adsorption of allelopathic compounds by wood derived-charcoal: the role of wood porosity, Plant Soil, 272, 291–300, doi:10.1007s/11104-004-5485-5, 2005. Keller, C. K. and Bacon, D. H.: Soil respiration and georespiration distinguished by transport analyses of vadose CO2, $^13$CO2 and $^14$CO2, Global Biogeochem. Cycles, 12, 361–372, 1998. Kiem, R., Knicker, H., Körschens, M., and Kögel-Knabner, I.: Refractory organic carbon in C-depleted arable soils, as studied by $^13$C NMR spectroscopy and carbohydrate analysis, Org. Geochem., 31, 655–668, 2000. Kim, E.-J., Oh, J.-E., and Chang, Y. S.: Effects of forest fire on the level and distribution of PCDD/Fs and PAHs in soil, Sci. Total Environ., 311, 177–189, 2003. Kim, S., Kaplan L. A., Benner R., and Hatcher P. G.: Hydrogen-deficient molecules in natural riverine water samples – evidence for the existence of black carbon in DOM, Mar. Chem., 92, 225–234, 2004. Kim, Y., Hatsushika, H., Muskett, R. R., and Yamazaki, K.: Possible effect of boreal wildfire soot on Arctic sea ice and Alaska glaciers, Atmos. Environ., 39, 3513–3520, 2005. Kleber, M., Rössner, J., Chenu, C., Glaser, B., Knicker, H., and Jahn, R.: Prehistoric alteration of soil properties in a central German chernozemic soil: in search of pedologic indicators for prehistoric activity, Soil Sci., 168, 292–306, 2003. Knicker, H., González-Vila, F. J., Polvillo, O., González, J. A., and Almendros, G.: Fire-induced transformation of C- and N-forms in different organic soil fractions from a Dystric Cambisol under a Mediterranean pine forest (\textitPinus pinaster), Soil Biol. Biochem., 37, 701–718, 2005a. Knicker, H., Totsche, K. U., Almendros, G., and González-Vila, F. J.: Condensation degree of burnt peat and plant residues and the reliability of solid-state VACP MAS $^13$C NMR spectra obtained from pyrogenic humic material, Org. Geochem., 36, 1359–1377, 2005b. Kramer, R. W., Kujawinski, E. B., and Hatcher, P. G.: Identification of black carbon derived structures in a volcanic ash soil humic acid by Fourier transform ion cyclotron resonance mass spectrometry, Environ. Sci. Technol., 38, 3387–3395, 2004. Krull, E. S., Skjemstad, J. O., Graetz, D., Grice, K., Dunning, W., Cook, G., and Parr, J. F.: $^13$C-depleted charcoal from C4 grasses and the role of occluded carbon in phytoliths, Org. Geochem., 34, 1337–1352, 2003. Kuhlbusch, T. A. J.: Method for determining black carbon in residues of vegetation fires, Environ. Sci. Technol., 29, 2695–2702, 1995. Kuhlbusch, T. A. J.: Black carbon and the carbon cycle, Science, 280, 1903–1904, 1998. Kuhlbusch, T. A. J. and Crutzen, P. J.: Toward a global estimate of black carbon in residues of vegetation fires representing a sink of atmospheric CO2 and a source of O2, Global Biogeochem. Cycles, 9, 491–501, 1995. Kuhlbusch, T. A. J., Andreae, M. O., Cachier, H., Goldammer, J. G., Lacaux, J-.P., Shea, R., and Crutzen, P. J.: Black carbon formation by savanna fires: measurements and implications for the global carbon cycle, J. Geophys. Res., 101, 23 651–23 665, 1996. Kuhry, P.: The role of fire in the development of \textitSphagnum-dominated peatlands in western boreal Canada, J. Ecol., 82, 899–910, 1994. Kurz, W. A. and Apps, M. J.: A 70-year retrospective analysis of carbon fluxes in the Canadian forest sector, Ecol. Apps., 9, 526–547, 1999. Laird, L. D. and Campbell, I. D.: High resolution paleofire signals from Christina Lake, Alberta: a comparison of the charcoal signals extracted by two different methods, Paleogeog. Paleoclimat. Paleoecol., 164, 111–123, 2000. Langenfelds, R. L., Francey, R. J., Pak, B. C., Steele, L. P., Lloyd, J., Trudinger, C. M., and Allison, C. E.: Interannual growth rate variations of atmospheric CO2 and its $\delta ^13$C, H2, CH4 and CO between 1992 and 1999 linked to biomass burning, Global Biogeochem. Cycles, 16(3), 1048, doi:10.1029/2001GB001466, 2002. Lavoué, D., Liousse, C., Cachier, H., Stocks, B. J., and Goldammer, J. G.: Modeling of carbonaceous particles emitted by boreal and temperate wildfires at northern latitudes, J. Geophys. Res., 105, 26 871–26 890, 2000. Lee, P.: Dynamics of snags in aspen-dominated midboreal forests, For. Ecol. Manage., 105, 263–272, 1998. Lee, K. H., Kim, J. E., Kim. Y. J., Kim, J., and von Hoyningen-Huene, W.: Impact of the smoke aerosol from Russian forest fires on the atmospheric environment over Korea during May 2003, Atmos. Environ., 39, 85–99, 2005. Lehmann, J., Liang, B., Solomon, D., Lerotic, M., Luizão, F., Kinyangi, J., Schäfer, T., Wirick, S., and Jacobsen, C.: Near-edge X-ray absorption fine structure (NEXAFS) spectroscopy for mapping nano-scale distribution of organic carbon forms in soil: Application to black carbon particles, Global Biogeochem. Cycles, 19, GB1013, doi:10.1029/2004GB002435, 2005. Lertzman, K., Gavin, D., Hallett., D., Brubaker, L., Lepofsky, D., and Mathewes, R.: Long-term fire regime estimated from soil charcoal in coastal temperate rainforests. Conserv. Ecol 6(2), 5, http://www.consecol.org/vol6/iss2/art5, 2002. Liousse, C., Penner, J. E., Chuang, C., Walton, J. J., Eddleman, H., and Cachier, H.: A global three-dimensional model study of carbonaceous aerosols, J. Geophys. Res., 101, 19 411–19 432, 1996. Lohmann, R., MacFarlane, J. K., and Gschwend, P. M.: Importance of black carbon to sorption of native PAHs, PCBs, and PCDDs in Boston and New York harbour sediments, Environ. Sci. Technol., 39, 141–148, 2005. Lynch, J. A., Clark, J. S., and Stocks, B. J.: Charcoal production, dispersal, and deposition from the Fort Providence experimental fire: interpreting fire regimes from charcoal records in boreal forests, Can. J. For. Res., 34, 1642–1656, 2004. Machulla, G., Zikeli, S., Kastler, M., and Jahn, R.: Microbial biomass and respiration in soils derived from lignite ashes: a profile study, J. Plant Nutr. Soil Sci., 167, 449–456, 2004. Mackenzie, F. T., Lerman, A., and Andersson, A. J.: Past and present of sediment and carbon biogeochemical cycling models, Biogeosciences, 1, 11–32, 2004a. MacKenzie, M. D., DeLuca, T. H., and Sala, A.: Forest structure and organic horizon analysis along a fire chronosequence in the low elevation forests of western Montana, For Ecol. Manage., 203, 331–343, 2004b. MacKenzie, M. D., DeLuca, T. H., and Sala, A.: Fire exclusion and nitrogen mineralization in low elevation forests of western Montana, Soil Biol. Biochem., 38, 952–961, 2006. Mandalakis, M., Gustafsson, Ö., Alsberg, T., Egebäck, A.-L., Reddy, C. M., Xu, L., Klanova, J., Holoubek, I., and Stephanou, E.: Contribution of biomass burning to atmospheric polycyclic aromatic hydrocarbons at three European background sites, Environ. Sci. Technol., 39, 2976–2982, 2005. Manies, K. L., Harden, J. W., Bond-Lamberty, B. P., and O'Neill, K. P.: Woody debris along an upland chronosequence in boreal Manitoba and its impact on long-term carbon storage, Can. J. For. Res., 35, 472–482, 2005. Masiello, C. A.: New directions in black carbon organic geochemistry, Mar. Chem., 92, 201–213, 2004. Masiello, C. A. and Druffel, E. R. M.: Black carbon in deep-sea sediments, Science, 280, 1911–1913, 1998. Masiello, C. A. and Druffel, E. R. M.: Carbon isotope geochemistry of the Santa Clara River, Global Biogeochem. Cycles, 15, 407–416, 2001. Masiello, C. A. and Druffel, E. R. M.: Organic and black carbon $^13$C and $^14$C through the Santa Monica Basin sediment oxic-anoxic transition, Geophys. Res. Lett., 30(4), 1185, doi:10.1029/2002GL015050, 2003. Menon, S., Hansen, J., Nazarenko, L., and Luo, Y.: Climate effects of black carbon aerosols in China and India, Science, 297, 2250–2253, 2002. Middelburg, J. J., Nieuwenhuize, J., and van Breugel, P.: Black carbon in marine sediments, Mar. Chem., 65, 245–252, 1999. Mitra, S., Bianchi, T. S., McKee, B. A., and Sutula, M.: Black carbon from the Mississippi River: quantities, sources, and potential implications for the global climate cycle, Environ. Sci. Technol., 36, 2296–2302, 2002. Mokma, D. L. and Vance, G. F.: Forest vegetation and origin of some spodic horizons, Michigan, Geoderma, 43, 311–324, 1989. Naydenov, K., Tremblay, F., Bergeron, Y., and Goudiaby, V.: Influence du charbon actif sur la croissance primaire des plantules de pin gris, Can. J. For. Res., 35, 761–767, 2006. Neary, D. G., Klopatek, C. C., DeBano, L. F., and Ffolliott, P. F.: Fire effects on belowground sustainability: a review and synthesis, For. Ecol. Manage., 122, 51–71, 1999. Neff, J. C., Harden, J. W., and Gleixner, G.: Fire effects on soil organic matter content, composition, and nutrients in boreal interior Alaska, Can J. For. Res., 35, 2178–2187, 2005. Ohlson, M. and Tryterud, E.: Interpretation of the charcoal record in forest soils: forest fires and their production and deposition of macroscopic charcoal, Holocene, 10, 519–529, 2000. Park, R. J, Jacob, D. J., Chin, M., and Martin, R. V.: Sources of carbonaceous aerosols over the United States and implications for natural visibility, J. Geophys. Res., 108(D12), 4355, doi:10.1029/2002JD003190, 2003. Payne, N. J., Stocks, B. J., Robinson, A., Wasey, M., and Strapp, J. W.: Combustion aerosol from experimental crown fires in a boreal forest jack pine stand, Can. J. For. Res., 34, 1627–1633, 2004. Pedlar, J. H., Pearce, J. L., Venier, L. A., and McKenney, D. W.: Coarse woody debris in relation to disturbance and forest type in boreal Canada, For. Ecol. Manage., 158, 189–194, 2002. Petsch, S. T., Berner, R. A., and Eglinton, T. I.: A field study of the chemical weathering of ancient sedimentary organic matter, Org. Geochem., 31, 475–487, 2000. Petsch, S. T., Smernik, R. J., Eglinton, T. I., and Oades, J. M.: A solid state $^13$C-NMR study of kerogen degradation during black shale weathering, Geochim. Cosmochim. Acta, 65, 1867–1882, 2001. Pietikäinen, J., Kiikkilä, O., and Fritze, H.: Charcoal as a habitat for microbes and its effect on the microbial community of the underlying humus, Okios, 89, 231–242, 2000. Ping, C. L., Michaelson, G. J., Packee, E. C., Stiles, C. A., Swanson, D. K., and Yoshikawa, K.: Soil catena sequences and fire ecology in the boreal forest of Alaska, Soil Sci. Soc. Am. J., 69, 1761–1772, 2005. Poirier, N., Derenne, S., Rouzaud, J.-N., Largeau, C., Mariotti, A., Balesdent, J., and Maquet, J.: Chemical structure and sources of the macromolecular, resistant, organic fraction isolated from a forest soil (Lacadée, south-west France), Org. Geochem., 31, 813–827, 2000. Ponomarenko, E. V. and Anderson, D. W.: Importance of charred organic matter in Black Chernozem soils of Saskatchewan, Can. J. Soil Sci., 81, 285–297, 2001. Preston, C. M., Shaw, C. H., Bhatti, J. S., and Siltanen, R. M.: Soil C and N pools in forested upland and non-forested lowland sites along the boreal forest transect case study in central Canada, in: The Role of Boreal Forests and Forestry in the Global Carbon Budget, edited by: Shaw, C. H. and Apps, M. J., Natural Resources Canada, Edmonton, AB, pp 155–178, 2002a. Preston, C. M., Trofymow, J. A., Niu, J., and Fyfe, C. A.: Harvesting and climate effects on organic matter characteristics in British Columbia coastal forests, J. Environ. Qual., 31, 402–413, 2002b. Preston, C. M., Bhatti, J. S., Flanagan, L. B., and Norris, C.: Stocks, chemistry, and sensitivity to climate change of dead organic matter along the Canadian Boreal Forest Transect Case Study, Clim. Change, 74, 223–251, doi:10.1007/s10584-006-0466-8, 2006. Randerson, J. T., van der Werf, G. R., Collatz, G. J., Giglio, L., Still, C. J., Kasibhatla, P., Miller, J. B., White, J. W. C., DeFries, R. S., and Kasischke, E. S.: Fire emissions from C3 and C4 vegetation and their influence on interannual variability of atmospheric CO2 and $\delta ^13$CO2, Global Biogeochem. Cycles, 19, GB2019, doi:10.1029/2004GB002366, 2005. Read, D. J., Leake, J. R., and Perez-Moreno, J.: Mycorrhizal fungi as drivers of ecosystem processes in heathland and boreal forest biomes, Can. J. Bot., 82, 1243–1263, 2004. Richter, D. D., O'Neill, K. P., and Kasischke, E. S.: Postfire stimulation of microbial decomposition in black spruce (\textitPicea mariana L.) forest soils: a hypothesis, in: Fire, Climate Change, and Carbon Cycling in the Boreal Forest, edited by: Kasischke, E. S. and Stocks, B. J., Springer-Verlag, New York, pp 197–213, 2000. Rodionov, A., Amelung, W., Haumaier, L., Urusevskaja, I., and Zech, W.: Black carbon in the zonal steppe soils of Russia, J. Soil Sci. Plant Nutr., 169, 363–369, 2006. Rodionow, A., Flessa, H., Kazansky, O, and Guggenberger, G.: Organic matter composition and potential trace gas production of permafrost soils in the forest tundra in northern Siberia, Geoderma, in press, 2006. Rumpel, C. and Kögel-Knabner, I.: The role of lignite in the carbon cycle of lignite-containing mine soils: evidence from carbon mineralization and humic acid extractions, Org. Geochem., 33, 393–399, 2002. Rumpel, C. and Kögel-Knabner, I.: Microbial use of lignite compared to recent plant litter as substrates in reclaimed coal mine soils, Soil Biol. Biochem., 36, 67–75, 2004. Rumpel, C., Skjemstad, J. O., Knicker, H., Kögel-Knabner, I. and Hüttl, R. F.: Techniques for the differentiation of carbon types present in lignite-rich mine spoils, Org. Geochem., 31, 543–551, 2000. Rumpel, C., Alexis, M., Chabbi, A., Chaplot, V., Rasse, D. P., Valentin, C., and Mariotti, A.: Black carbon contribution to soil organic matter composition in tropical sloping land under slash and burn agriculture, Geoderma, 130, 35–46, 2006. Samsonov, Y. N., Koutsenogii, K. P., Makarov, V. I., Ivanov, A. V., Ivanov, V. A., McRae, D. J., Conard, S. G., Baker, S. P., and Ivanova, G. A.: Particulate emissions from fires in central Siberian Scots pine forests, Can. J. For. Res., 35, 2207–-2217, 2005. Sanborn, P., Geertsema, M., Jull, A. J. T., and Hawkes, B.: Soil and sedimentary charcoal evidence for Holocene forest fires in an inland temperate rainforest, east-central British Columbia, Canada, Holocene, 16, 415–427, 2006. Schiffman, P. M. and Johnson, W. C.: Phytomass and detrital carbon storage during forest regrowth in the southeastern United States Piedmont, Can. J. For. Res., 19, 69–78, 1989. Schmid, E.-M., Skjemstad, J. O., Glaser, B., Knicker, H., and Kögel-Knabner, I.: Detection of charred organic matter in soils from a Neolithic settlement in southern Bavaria, Germany, Geoderma, 107, 71–91, 2002. Schmid, H., Laskus, L., Abraham, H. J., Baltensperger, U., Lavanchy, V., Bizjak, M., Burba, P., Cachier, H., Crow, D., Chow, J., Gnauk, T., Even, A., ten Brink, H. M., Giesen, K.-P., Hitzenberger, R., Hueglin, C., Maenhaut, W., Pio, C., Carvalho, A., Putaud, J.-P., Toom-Sauntry, D., and Puxbaum. H.: Results of the "carbon conference" international aerosol carbon round robin test stage I, Atmos. Environ., 35, 2111–2121, 2001. Schmidt, M. W. I.: Carbon budget in the black, Nature, 427, 305–306, 2004. Schmidt, M. W. I. and Noack, A. G.: Black carbon in soils and sediments: Analysis, distribution, implications, and current challenges, Global Biogeochem. Cycles, 14, 777–793, 2000. Schmidt, M. W. I., Skjemstad, J. O., Czimczik, C. I., Glaser, B., Prentice, K. M., Gelinas, Y., and Kuhlbusch, T. A. J.: Comparative analysis of black carbon in soils, Global Biogeochem. Cycles, 15, 163–167, 2001. Schmidt, M. W. I., Skjemstad, J. O., and Jäger, C.: Carbon isotope geochemistry and nanomorphology of soil black carbon: Black chernozemic soils in central Europe originate from ancient biomass burning, Global Biogeochem. Cycles, 16(4), 1123, doi:10.1029/2002GB001939, 2002. Schmidt, M. W. I., Masiello, C. A., and Skjemstad, J. O.: Final recommendations for reference materials in black carbon analysis, EOS, 84, 582–583, 2003. Schulze, E.-D., Lloyd, J., Kelliher, F. M., Wirth, C., Rebmann, C., Lühker, B., Mund, M., Knohl, A., Milyukova, I. M., Schulze, W., Ziegler, W., Varlagin, A. B., Sogachev, A. F., Valentini, R., Dore, S., Grigoriev, S., Kolle, O., Panfyorov, M. I., Tchebakova, N., and Vygodskaya, N. N.: Productivity of forests in the Eurosiberian boreal region and their potential to act as a carbon sink – a synthesis, Global Change Biol., 5, 703–722, 1999. Schuur, E. A. G., Trumbore, S. E., Mack, M. C., and Harden, J. W.: Isotopic composition of carbon dioxide from a boreal forest fire: Inferring carbon loss from measurements and modelling, Global Biogeochem. Cycles, 17(1), 1001, doi:10.1029/2001GB001840, 2003. Scott, A. C.: The pre-Quaternary history of fire, Paleogeog. Paleoclim. Paleoecol., 164, 297–345, 2000. Seiler, W. and Crutzen, P. J.: Estimates of gross and net fluxes of carbon between the biosphere and the atmosphere from biomass burning, Clim. Change, 2, 207–247, 1980. Shindo, H.: Elementary composition, humus composition, and decomposition in soil of charred grassland plants, Soi. Sci. Plant. Nutr., 37, 651–657, 1991. Shindo, H., Matsui, Y., and Higashi, T.: A possible source of humic acids in volcanic ash soils in Japan – charred residue of \textitMiscanthus sinensis, Soil Sci., 141, 84–87, 1986. Shindo, H., Honna, T., Yamamoto, S., and Honma, H.: Contribution of charred plant fragments to soil organic carbon in Japanese volcanic ash soils containing black humic acids, Org. Geochem., 35, 235–241, 2004. Shindo, H., Yoshida, M., Yamamoto, A., Honma, H., and Hiradate, S.: $\delta^13$C values of organic constituents and possible source of humic substances in Japanese volcanic ash soils, Soil Sci., 170, 175–182, 2005. Shneour, E. A.: Oxidation of graphitic carbon in certain soils, Science, 151, 991–992, 1966. Simpson, M. and Hatcher, P. G.: Determination of black carbon in natural organic matter by chemical oxidation and solid-state $^13$C nuclear magnetic resonance spectroscopy, Org. Geochem., 35, 923–935, 2004a. Simpson, M. and Hatcher, P. G.: Overestimates of black carbon in soils and sediments, Naturwissenschaften, 91, 436–440, 2004b. Skjemstad, J. O., Clarke, P., Taylor, J. A., Oades, J. M., and McClure, S. G.: The chemistry and nature of protected carbon in soil, Aust. J. Soil Res., 34, 251–271, 1996. Skjemstad, J. O., Taylor, J. A., and Smernik, R. J.: Estimation of charcoal (char) in soils, Commun. Soil Sci. Plant Anal., 30, 2283–2298, 1999a. Skjemstad, J. O., Taylor, J. A., Janik, L. J., and Marvanek, S. P.: Soil organic carbon dynamics under long-term sugarcane monoculture, Aust. J. Soil Res., 37, 151–164, 1999b. Skjemstad, J. O., Reicosky, D. C., Wilts, A. R., and McGowan, J. A.: Charcoal carbon in U.S. agricultural soils, Soil Sci. Soc. Am. J., 66, 1249–1255, 2002. Skjemstad, J. O., Spouncer, L. R., Cowie, B., and Swift, R. S.: Calibration of the Rothamsted organic carbon turnover model (RothC ver: 26.3), using measurable soil organic carbon pools, Aust. J. Soil Res., 42, 79–88, 2004. Solomon, D., Lehmann, J., Kinyangi, J., Liang, B., and Schäfer, T.: Carbon K-edge NEXAFS and FTIR-ATR spectroscopic investigation of organic carbon speciation in soils, Soil Sci. Soc. Am. J., 69, 107–119, 2005. Stocks, B. J., Fosberg, M. A., Lynham, T. J., Mearns, L., Wotton, B. M., Yang, Q., Jin, J.-Z., Lawrence, K., Hartley, G. R., Mason, J. A., and McKenney, D.W.: Climate change and forest fire potential in Russian and Canadian boreal forests, Clim. Change, 38, 1–13, 1998. Stocks, B. J., Fosberg, M. A., Wotton, B. M., Lynham, T. J., and Ryan, K. C.: Climate change and forest fire activity in North American boreal forests, in: Fire, Climate Change, and Carbon Cycling in the Boreal Forest, edited by: Kasischke, E. S. and Stocks, B. J., Springer-Verlag, New York, pp 368–376, 2000. Stocks, B. J., Alexander, M. E., and Lanoville, R. A.: Overview of the International Crown Fire Modelling Experiment (ICFME), Can. J. For. Res., 34, 1543–1547, 2004. Talon, B., Payette, S., Filion, L., and Delwaide, A.: Reconstruction of the long-term fire history of an old-growth deciduous forest in Southern Québec, Canada, from charred wood in mineral soils, Quatern. Res., 64, 36–43, 2005. Tinker, D. B. and Knight, D. H.: Coarse woody debris following fire and logging in Wyoming lodgepole pine forests, Ecosystems, 3, 472–483, 2000. Topoliantz, S., Ponge, J.-F., and Ballof, S.: Manioc peel and charcoal: a potential organic amendment for sustainable soil fertility in the tropics, Biol. Fert. Soils, 41, 15–21, 2005. Treseder, K. K., Mack, M. C., and Cross, A.: Relationships among fires, fungi, and soil dynamics in Alaskan boreal forests, Ecol. Apps., 14, 1826–1838, 2004. Trumbore, S. E. and Harden, J. W.: Accumulation and turnover of carbon in organic and mineral soils of the BOREAS northern study area, J. Geophys. Res., 102, 28 817–28 830, 1997. Turekian, V. C., Macko, S., Ballentine, D., Swap, R. J., and Garstang, M.: Causes of bulk carbon and nitrogen isotopic fractionations in the products of vegetation burns: laboratory studies, Chem. Geol., 152, 181–192, 1998. Turetsky, M. R., Amiro, B. D., Bosch, E., and Bhatti, J. S.: Historical burn area in western Canadian peatlands and its relationship to fire weather indices, Global Biogeochem. Cycles, 18, GB4014, doi:10.1029/2004GB002222, 2004. Turney, C. S. M., Wheeler, D., and Chivas, A. R.: Carbon isotope fractionation in wood during carbonization, Geochem. Cosmochim. Acta, 70, 960–964, 2006. Wallstedt, A., Coughlan, A., Munson, A. D., Nilsson, M.-C., and Margolis, H.A.: Mechanisms of interaction between \textitKalmia angustifolia and \textitPicea mariana seedlings, Can. J. For. Res., 32, 2022–2031, 2002. Wang, X., Peng, P. A., and Ding, Z. L.: Black carbon records in Chinese Loess Plateau over the last two glacial cycles and implications for paleofires, Paleogeog. Paleoclimat. Paleoecol., 223, 9–19, 2005. Ward, T. J. and Smith, G. C.: The 2000/2001 Missoula Valley PM$_2.5$ chemical mass balance study, including the 2000 wildfire season – seasonal source apportionment, Atmos. Environ., 39, 709–717, 2005. Wardle, D. A., Zackrisson, O., and Nilsson, M.-C.: The charcoal effect in Boreal forests: mechanisms and ecological consequences, Oecologia, 115, 419–426, 1998. Wengel, M., Kothe, E., Schmidt, C. M., Heide, K., and Gleixner, G.: Degradation of organic matter from black shales and charcoal by the wood-rotting fungus \textitSchizophyllum commune and release of DOC and heavy metals in the aqueous phase, Sci. Tot. Environ., 367, 383–393, 2006. White, A., Cannell, M. G. R., and Friend, A. D.: The high-latitude terrestrial carbon sink: a model analysis, Global Change Biol., 6, 227–245, 2000. Wilcke, W. and Amelung, W.: Persistent organic pollutants in native grassland soils along a climosequence in North America, Soil Sci. Soc. Am. J., 64, 2140–2148, 2000. Wirth, C., Czimczik, C. I., and Schulze, E.-D.: Beyond annual budgets: carbon flux at different temporal scales in fire-prone Siberian Scots pine forests, Tellus B, 54, 611–630, 2002. Wolff, E. W. and Cachier, H.: Concentrations and seasonal cycle of black carbon in aerosol at a coastal Antarctic station, J. Geophys. Res., 103, 11 033–11 041, 1998. Wotawa, G. and Trainer, M.: The influence of Canadian forest fires on pollutant concentrations in the United States, Science, 288, 324-328, 2000. Yunker, M. B. and Macdonald, R. W.: Alkane and PAH depositional history, sources and fluxes in sediments from the Fraser River Basin and Strait of Georgia, Canada, Org. Geochem., 34, 1429–1454, 2003. Yunker, M. B., Backus, S. M., Pannatier, E. G., Jeffries, D. S., and Macdonald, R. W.: Sources and significance of alkane and PAH hydrocarbons in Canadian Arctic rivers, Estuarine Coastal Shelf Sci., 55, 1–31, 2002. Zackrisson, O., Nilsson, M.-C., and Wardle, D. A.: Key ecological function of charcoal from wildfire in the boreal forest, Oikos, 77, 10–19, 1996. Zackrisson, O., DeLuca, T. H., Nilsson, M.-C., Sellstedt, A., and Berglund, L. M.: Nitrogen fixation increases with successional age in boreal forests, Ecology, 85, 3327–3334, 2004. Zech, W., Guggenberger, G., Zalba, P., and Peinemann, N.: Soil organic matter transformation in Argentinian Hapludolls, Z. Pflanzenernähr. Bodenk., 160, 563–571, 1997. Zoltai, S. C., Morrissey, L. A., Livingston, G. P., and de Groot, W. J.: Effects of fires on carbon cycling in North American boreal peatlands, Environ. Rev., 6, 13–24, 1998. Zhu, D. and Pignatello, J. J.: Characterization of aromatic compound sorptive interactions with black carbon (charcoal) assisted by graphite as a model, Environ. Sci. Technol., 39, 2033–2041, 2005.