From the Discussion and Summary ... 'The data and observations presented here are fragmentary and are not adequate to establish that smoke from wildfires or prescribed burns markedly affects microbial activity in wildland plant communities. They suggest, however, that such effects are likely.Fires produce large quantities of smoke that often accumulate under inversions or drift for long periods through forest stands. Surfaces exposed to smoke were found unsuitable for the germination of spores of several kinds of fungi. Mycelial growth of fungi was inhibited on surfaces previously exposed to smoke, and direct exposure of mycelium to smoke arrested growth. Smoked leaf surfaces and pine-disc surfaces showed marked changes in numbers and kinds of microorganisms present. Bean plants and pine seedlings exposed to smoke were protected from infection by certain rust fungi. Cotton seeds exposed to smoke appeared to be less susceptible to damping-off.These data and observations suggest that smoke may have important effects on microbial activities in plant communities. Microbial activities include initiation of disease, deterioration and recycling of dead plant materials, transformation of soil nutrients, mycorrhizal formation, inhibition of pathogens by antibiosis and competition, and numerous other processes that critically influence the development of plant communities. If we are to understand and utilize the capacity of fire to modify plant communities and ecological processes, we should know how fire and smoke affect these microbial activities.The few data and observations outlined here lead to numerous unanswered questions for which data are needed.......If, as available evidence indicates, smoke was a normal feature of many environments, then our present concepts of microbial activies derived from studies in relatively smoke-free ecosystems may not reflect 'normal' conditions.'