Nitrogen mineralization in aspen/conifer soils after a natural fire

We measured the effects of the 1996 Pole Creek fire, Fishlake National Fore st, Utah, on available soil N and net N mineralization for three summers af ter the fire using an ion exchange membrane (IEM) soil core incubation meth od. Fire in mixed aspen/conifer increased the amount of available NH4, and a subsequent net increase in soil nitrification was observed. Release of NH 4 from the ash and a net increase in soil nitrification were still observed 3 years after the fire. The fire-caused increase in available soil N provi des a source of N for aspen regrowth.