The importance of termites and fire to dead wood consumption in the longleaf pine ecosystem

Abstract

Microbes, insects, and fire are the primary drivers of wood loss from most ecosystems, but interactions among these factors remain poorly understood. In this study, we tested the hypothesis that termites and fire have a synergistic effect on wood loss from the fire-adapted longleaf pine (Pinus palustris Mill.) ecosystem in the southeastern United States. We predicted that the extensive galleries created by termites would promote the ignition and consumption of logs by fire. We exposed logs from which termites had or had not been excluded to prescribed fire after 2.5 years in the field. We found little support for our hypothesis as there was no significant interactive effect of termites and fire on wood mass loss. Moreover, there was no significant difference in mass loss between burned and unburned logs. Termites were responsible for about 13.3% of observed mass loss in unprotected logs, a significant effect, while microbial activity accounted for most of the remaining mass loss. We conclude that fire has little effect on wood loss from the longleaf pine ecosystem and that termite activity does not strongly promote wood combustion. However, longer term research involving multiple burn cycles, later stages of decay, and differing fire intensities will be needed to fully address this question.