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Abstract Few studies have investigated how mature trees recover physiologically from wildfire damage, and none have comprehensively linked tree hydraulics with belowground function. Uncovering mechanistic links between rates of above‐ and belowground recovery is necessary for improving predictions of forest resilience and carbon dynamics following wildfire. We coupled continuous measurements of tree water flow and soil CO₂efflux with detailed physiological measurements of above‐ and belowground function following a mixed‐severity wildfire. We found that maturePinus ponderosatrees with up to 85% canopy and stem damage resumed physiological functioning by the second growing season post‐fire. However, these trees also exhibited delayed peak water uptake (relative to less‐burned trees) that coincided with summer heat and drought. Our results suggest fire damage may prevent the critical timing in which peak physiological function overlaps with optimal growing conditions (e.g., moisture and nutrient availability). As a result, we suggest the degree of root and microbial damage should be assessed along with observed aboveground damage to more effectively predict tree recovery potential. While significantly damaged trees resumed typical hydraulic function within two years, observed delays in peak water uptake could require higher water and nutrient use efficiency to maintain carbon sequestration rates. 

Abstract Although the 16S (and 18S) rRNA gene has been an essential tool in classifying prokaryotes, using a single locus to revise bacteria taxonomy can introduce unwanted artifacts. There was a recent proposition to split the Methylobacterium genus, which contains diverse plant-associated strains and is important for agriculture and biotechnology, into two genera. Resting strongly on the phylogeny of 16S rRNA, 11 species of Methylobacterium were transferred to a newly proposed genus Methylorubrum. Numerous recent studies have independently questioned Methylorubrum as a valid genus, but the prior revision has left discrepancies among taxonomic databases. Here, we review phylogenomic and phenotypic evidence against Methylorubrum as a genus and call for its abandonment. Because Methylobacterium sensu lato forms a consistent and monophyletic genus, we argue for the restoration of the former and consensual Methylobacterium taxonomy. The large genomic, phenotypic, and ecological diversity within Methylobacterium however suggests complex evolutionary and adaptive processes and support the description of the most basal clade of Methylobacterium (group C) as a distinct genus in future work. Overall, this perspective demonstrates the danger of solely relying upon the 16S rRNA gene as a delimiter of genus level taxonomy and that further attempts must include more robust phenotypic and phylogenomic criteria. 

In an increasingly flammable world, wildfire is altering the terrestrial carbon balance. However, the degree to which novel wildfire regimes disrupt biological function remains unclear. Here, we synthesize the current understanding of above- and belowground processes that govern carbon loss and recovery across diverse ecosystems. We find that intensifying wildfire regimes are increasingly exceeding biological thresholds of resilience, causing ecosystems to convert to a lower carbon-carrying capacity. Growing evidence suggests that plants compensate for fire damage by allocating carbon belowground to access nutrients released by fire, while wildfire selects for microbial communities with rapid growth rates and the ability to metabolize pyrolysed carbon. Determining controls on carbon dynamics following wildfire requires integration of experimental and modelling frameworks across scales and ecosystems.