Vegetation fires burn over 3 million km2 per year around the globe. They emit substantial amounts of CO2 to the atmosphere, but they also transform some of the relatively labile carbon (C) stored in biomass to environmentally more stable pyrogenic organic matter (PyOM), also termed black carbon, or biochar if man-made.

Whether produced naturally in fires or industrially, PyOM resistance to degradation is viewed by many as an important mechanism for C sequestration, allowing its accumulation in the environment. This issue, however, is currently subject of considerable debate as available data about PyOM production, accumulation and degradation are often conflicting, preventing robust assessments of C budgets and fluxes at local and global scales.

This interdisciplinary session seeks to stimulate exchange and debate on this fundamental issue by bringing together scientists from the diverse fields of soil, water and sedimentary systems; fire management; PyOM characterization, mobilization, deposition, degradation and preservation; and carbon dynamics in the environment.

Evidence-based, as well as more speculative contributions, dealing with the following aspects are particularly welcome:

- Quantification and characterization of PyOM in different matrixes (soil, water, sediments, ash, etc.).
- PyOM in-situ: production, accumulation and degradation rates and mechanims.
- Movilization within the landscape and off site export.
- PyOM in hydrological systems (rivers, lakes, oceans).
- Deposition and preservation: PyOM in sediments and other depositional environments.
- PyOM and biogeochemical cycles: black carbon, black nitrogen and other nutrient cycles.

Keywords: charcoal, black carbon, wildfire, prescribed fire, biochar, soil, sediment, dissolved organic carbon, organic matter, black nitrogen, ocean, river, ash.

SOLICITED SPEAKERS:
P. Ascough (UK)
A. Berhe (USA)
T. Dittmar (Germany)
J. Hatten (USA)
A. Heyvaert (USA)
E. Kane (USA)
H. Knicker (Spain)
Y. Kuzyakov (Germany)
C. Masiello (USA)
M. Ohlson (Norway)
C. Preston (Canada)
C. Rumpel (France)
M. Schmidt (Switzerland, Keynote lecture)

Apart from the session, we will be organising a casual get-together in one of Vienna's famous cellar restaurants to allow further discussion over wine, beer and a hearty meal.