Wildfires affect 40% of the earth’s terrestrial biome, but much of our
knowledge of wildfire activity is limited to the satellite era. Improved
understanding of past fires is necessary to better understand how
wildfires might change with future climate change, to understand
ecosystem resilience, and to improve data-model comparisons.
Environmental proxy archives can extend our knowledge of past fire
activity. Speleothems, naturally occurring cave formations, are widely
used in palaeoenvironmental research as they are absolutely dateable,
occur on every ice-free continent, and include multiple proxies.
Recently, speleothems have been shown to record past fire events
(McDonough et al., 2022). Here we present a review of this emerging
application in speleothem palaeoenvironmental science. We give a concise
overview of fire regimes and traditional palaeofire proxies, describe
past attempts to use stalagmites to investigate palaeofire, and describe
the physical basis though which speleothems can record past fires. We
then describe the ideal speleothem sample for palaeofire research and
offer a summary of applicable laboratory and statistical methods.
Finally, we present four case studies which detail  the
geochemistry of ash leachates,  how sulphur may be a proxy for
post fire ecological recovery,  how a catastrophic palaeofire was
linked to changes in climate and land management, and 
demonstrate that deep caves can record past fire events. We conclude the
paper by suggesting that speleothem δ18O research may
need to consider the impact of fire on δ18O values,
and outline future research directions.