Effect of Periodic Burning on Soil Nitrogen Concentrations in Ponderosa Pine

Abstract

Abstract To determine the effects of different burning intervals on soil N status in substands of sapling‐, pole‐, and sawtimber‐sized ponderosa pine ( Pinus ponderosa Laws.) we sampled plots burned at 1‐, 2‐, and 4‐yr intervals by three strata at two depths (0–5 and 5–15 cm). Generally, NH 4 + and NO 3 ‐ concentrations were higher on plots repeatedly burned than on unburned controls. However, plots not reburned for 4 to 5 yr had concentrations similar to controls. No significant difference in total (organically bound) N was found among treatments. We conclude that frequent periodic burning can be used to enhance N availability in southwestern ponderosa pine sites.