Hydrologic and mineral budgets of New Jersey Pine Barrens upland forests following two intensities of fire

Abstract

The hydrologic and mineral budgets of upland forest sites in the New Jersey Pine Barrens exposed to different fire intensities were determined. Inputs from bulk precipitation and outputs to groundwater were monitored in an unburned control site, two sites burned by severe wildfire, and two sites burned by light prescribed burning. Fluxes of water, calcium, magnesium, and potassium to groundwater were highest in wildfire sites, intermediate in prescribed burn sites, and lowest in the unburned control. At all sites, outputs were the greatest during late-winter snowmelt. In the unburned site, outputs were essentially absent during the growing season, whereas in the wildfire sites outputs to groundwater were present year round. Rates of mineral and water output were inversely proportional to biomass and forest floor mass, which in turn depended upon fire intensity. Relative increases in output were similar to those reported following fire in other ecosystems. However, absolute rates of mineral output both before and after fire were lower in these sandy soils than those reported elsewhere, probably due to the low total mineral storage and variety of fire adaptations present in the Pine Barrens ecosystem.