Foliar nitrogen content and tree growth after prescribed fire in ponderosa pine.

Abstract

This initial study of prescribed burning in ponderosa pine (Pinus ponderosa Doug. ex Laws.) stands in central Oregon showed that all periodic annual growth increments were reduced for trees alive four growing seasons later. Height growth was reduced 8 percent in areas burned by fires with moderate fuel consumption and 18 percent in areas with high fuel consumption. Basal area growth was reduced 16 percent in the moderate fuel consumption areas and 28 percent in the high fuel consumption areas; volume growth declined 23 percent at both levels of fuel consumption. Foliar nitrogen (N) concentration was not affected by the prescribed fires; however, total foliar N content was reduced immediately after burning, and it remained depressed four growing seasons later after the burned areas had recovered from crown scorch. Foliar N content was significantly correlated with the observed reductions in periodic annual increments. Prescribed fire needs additional evaluation for a longer period and in additional ponderosa pine communities to determine long-term effects.

Citation

Landsberg, J.D.; Cochran, P.H.; Finck, M.M.; Martin, R.E. 1984. Foliar nitrogen content and tree growth after prescribed fire in ponderosa pine. Res. Note PNW-RN-412. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 16 p