Physiological Effects of Smoke Exposure on Deciduous and Conifer Tree Species

Abstract

Smoke from forest fires can persist in the environment for weeks and while there is a substantial amount of literature examining the effects of smoke exposure on seed germination, the effects of smoke on leaf function are nearly uninvestigated. The objective of this study was to compare growth and primary and secondary metabolic responses of deciduous angiosperm and evergreen conifer tree species to short smoke exposure. Twenty minutes of smoke exposure resulted in a greater than 50% reduction in photosynthetic capacity in five of the six species we examined. Impairment of photosynthesis in response to smoke was a function of reductions in stomatal conductance and biochemical limitations. In general, deciduous angiosperm species showed a greater sensitivity than evergreen conifers. While there were significant decreases in photosynthesis and stomatal conductance, smoke had no significant effect on growth or secondary defense compound production in any of the tree species examined.

Experimental evidence for heat plume‐induced cavitation and xylem deformation as a mechanism of rapid post‐fire tree mortality

“…The impact of desiccation on g s and K leaf varies considerably between species (Brodribb & Holbrook, 2006;Sack & Holbrook, 2006;Brodribb et al, 2009), and is caused in part by the cavitation of leaf veins (Kikuta et al, 1997;Salleo et al, 2000;Nardini et al, 2001Nardini et al, , 2003Cochard et al, 2002;Brodribb & Holbrook, 2003;Johnson et al, 2011), as well as differences in vein architecture (Scoffoni et al, 2011). There is also the intriguing possibility that smoke may provide a cue for stomatal closure that might mitigate the impact of a fire plume (Gilbert & Ripley, 2003;Calder et al, 2010;Bell et al, 2013;Aerts, 2015). However, our simulations were based on an assumption of a constant cuticular conductance that was unaffected by the heating of the leaf.…”

Influence of fire on a rare serpentine plant assemblage: A 5‐year study of Darlingtonia fens

“…First, the dense smoke that covered much of the region from late July 2002 until well into the autumn could have temporarily reduced cover in the unburned fens. Smoke has been shown to have significant effects on plant productivity, even in areas outside of the immediate fire (Davies and Unam, 1999; Calder et al, 2010). Second, 2001–2003 included notably dry summers in the study region as measured by the Palmer Drought Severity Index (PDSI), an index of soil moisture, temperature, precipitation, and evapotranspiration, where higher PDSI indices indicate low moisture stress (Palmer, 1965).…”

Air Phytoremediation

“…In the cocktail of air pollutants, sometimes it is difficult to determine exactly the negative action of BC itself since it is also a carrier of many others, often more toxic compounds. Also during forest fires, BC is one of the predominant components of the aerosol with its negative impacts on photosynthesis [22]. Coniferous compared to deciduous plant species better withstand the stress conditions as in the first smaller reduction of photosynthesis is noted [22].…”

“…Also during forest fires, BC is one of the predominant components of the aerosol with its negative impacts on photosynthesis [22]. Coniferous compared to deciduous plant species better withstand the stress conditions as in the first smaller reduction of photosynthesis is noted [22].…”