Nutrient Cycling: The Ash-bed
Despite the losses (which may be as high as 400 kg/ha for N in eucalypt forests) during fire,
nutrient availability in topsoils is, at least temporarily, increased. In addition to the nutrients added in ash,
surface soils are heated, which releases nutrients from soil organic matter. Heating also 'sterilises' the soil,
resulting in a changed soil microflora.
Each of these changes contributes to increased plant growth following fire.
This photo, taken in a recently burnt logging coupe, shows the result of a hot regeneration burn which has completely consumed the litter layer and all but the largest logs and branches. The surface soil has been 'baked' to a bright reddish colour.