Chemicals in Vapors of Smoldering Wood Fires

Chemicals from glowing fires in highly decayed conifer logs may be useful for detection of small fires by spectroscopic methods. Two major chemical constituents were tentatively identified as methanol and furfural (2-furaldehyde). Additional materials tentatively identified were acetaldehyde and either acetone or propionaldehyde, the latter two undistinguishable by the analysis method. The ratio of methanol to wood burned was found to vary from 0.0015 for a wet ponderosa pine log decayed by brown rot to 0.0069 for a relatively dry log (probably Douglas-fir) decayed by white rot. The analysis was performed by gas chromatography on vapor samples collected by cold traps. The presence of significant amounts of gasses having distinctive fine structure in their spectra may prove useful in detecting small fires by remote spectroscopic methods. Forest Sci. 22:81-83.