Nitrogen and phosphorus cycling following prescribed burning in natural and managed Aleppo pine forests

Two prescribed burnings (downhill and uphill fires) were conducted in two s tands of Aleppo pine (Pinus halepensis Mill.): a natural stand and a manage d stand that was subject to thinning, pruning, and shrub removal. The conce ntrations of nitrogen (N) and phosphorus (P) in the pine needles and regrow th of the main shrub species, Quercus coccifera L., and the quantities of N and P in the needle fall and in the forest floor were measured during the 6 months following the fires. The concentrations of N and P in the pine nee dles and leaves of Q. coccifera increased compared with the unburned contro l after both fires in the natural stand, where there was only a slight redu ction in fuel during prescribed burnings and where there was an abundant fa ll of scorched needles. In contrast, the chemical composition of the foliag e was unchanged after the fires in the managed stand, where there was a gre ater reduction in fuel, and where only small quantities of scorched needles fell. This study showed that first opening prescribed burnings (natural st and) were less severe in terms of nutrient balance than maintenance prescri bed burnings (managed stand) and that the forest floor reduction was a good indicator of fire severity.