The abundance, dry weight, and species of weeds found in the wet sclerophyll forests of northern New South Wales were determined by whether fire or tractor was used in seed bed preparation. Acacia, Dodonaea, and Kennedia whose seeds were stored in the ground were regarded as the most serious weeds and were germinated in great numbers by fire. The maximum depth of emergence and soil temperature range for increased germination of each of the three species was determined. Acacia was restricted by prolonged soil heating, whereas Kennedia produced maximum germination but was reduced under light flash fires. Intensity and duration of fire was therefore found to influence the abundance of such weed species, and could be used to some extent in their manipulation.© CSIRO