THE EFFECT OF FIRE ON NUTRIENT LOSSES AND CYCLING IN A QUERCUS-COCCIFERA GARRIGUE (SOUTHERN FRANCE)

The effects of burning on plant nutrient budgets and rates of carbonic gas and particulate matter emission during fires were evaluated in a Quercus coccifera (garrigue) shrubland. Nutrient levels were determine d in field-collected pre-fire vegetation and combustion residues. The losses (increased elemental transfer) were calculated as the differenc e between the quantity of an element in the fuel (combustible standing vegetation plus litter) before burning and that present in the postfi re residues lash). Weight losses of elements are correlated with weigh t losses of burnt plant biomass. The relative order of nutrient losses was: N>C>Na>Ca>P>K>Mg. Estimated losses of N, C and P from combustibl e plant matter exceeded 98, 97 and 79% respectively. Copious N, C and P volatilization during burning was promoted by high concentrations of these elements in foliage and fine woody biomass of the aboveground v egetation and leaf litter of the garrigue. Elements were principally r emoved in the smoke. The quantities of gaseous emissions of CO2, CO an d particulate matter produced were estimated.