Aspen Bibliography

The Effects of Fire on Nitrogen Cycling Processes Within Bandelier National Monument, NM

Document Type

Conference

Editor

Craig D. Allen

Journal/Book Title/Conference

Fire Effects in Southwestern Forests: Proceedings of the Second La Mesa Fire Symposium

Volume

No. RM-GTR-286

First Page

123

Last Page

139

Location

Los Alamos, NM

Publication Date

1996

Abstract

Nitrogen is often the nutrient limiting production in conifer forests. Fire acts as a mineralizing agent, releasing nutrients in available forms. However, nitrogen is lost during fires, which can further deplete this limiting nutrient. Without fire, nitrogen becomes tied up in partially decomposed litter (needles and woody debris). The problems faced by managers of these forest systems are how and when to use fire from a nutrient perspective. A chronosequence of fire intervals in ponderosa pine forests (Pinus ponderosa) was studied to determine (1) if nitrogen cycling processes (mineralization and nitrification) decrease and (2) if concentrations of organics that inhibit these processes increase along the fire chronosequence. Patterns were not statistically significant, but fairly clear trends occurred. Nitrogen mineralization and nitrification patterns were higher in sites recentry burned (within two years) and were lowest in sites without fire since the 1890's. The patterns at intermediate age sites varied, perhaps because of differential usage by elk and variable amounts of needle scorch which resulted in differential needle litterfall after fire. Within a site, concentrations of certain monoterpenes were consistently negatively correlated with rates of nitrification and mineralization. In these systems, fire promotes more rapid cycling of nitrogen, in part through combustion of monoterpene inhibitors.

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