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Abstract Climate change has increased the frequency and severity of drought and large wildfire events across western North America. Despite the increasing concurrence of drought and wildfire events and the importance of forests as a global carbon sink, the impacts of fire on tree drought and carbon acquisition traits are not well understood, particularly on multi‐year time‐scales.In 2022–2024, we leveraged a natural experiment at a large 2018 wildfire in southwestern Colorado, comparing leaf and xylem functional traits related to drought resistance and carbon acquisition in burned and unburned ponderosa pine, quaking aspen, subalpine fir, and Engelmann spruce trees.Relative to unburned trees of the same species, we found reduced xylem vulnerability to embolism (P₅₀) in burned ponderosa pine and subalpine fir; decreased leaf heat tolerance (T₅₀) in burned quaking aspen and ponderosa pine; and increased investment in leaf structural over photosynthetic components (leaf C:N isotopic ratio) in burned quaking aspen, subalpine fir, and Engelmann spruce.In contrast to previous studies, our results suggest that wildfire positively impacts functional traits related to drought resistance and water movement in surviving burned trees. However, generally negative impacts of wildfire were found with respect to leaf physiological and photosynthetic traits, suggesting divergent water and carbon responses to fire. Read the freePlain Language Summaryfor this article on the Journal blog. 

Abstract Increases in the frequency and severity of climate-sensitive disturbances like wildfire, drought, and insect outbreaks pose an imminent threat to Earth’s forests, including their status as a net carbon sink. Forest treatments including thinning and prescribed fire are increasingly viewed as key tools for mitigating disturbance impacts, but their efficacy in stabilizing carbon stocks and reducing mortality, especially for drought and insect outbreaks, remains uncertain. Moreover, we have limited understanding of whether the moderating effect of forest treatments provides a net benefit to vegetation carbon stocks, or if the initial carbon loss required to implement treatments outweighs potential reductions in carbon losses during subsequent disturbance. Here we conduct a systematic meta-analysis of published literature to understand how thinning, prescribed fire, and combined treatments impact survival and carbon stocks following wildfires, droughts, and insect outbreaks. We found that treatments improved survival following wildfires, but had only marginal impacts on survival following drought and insect outbreaks. While thinning had a modest positive effect on carbon stocks following wildfire, treatments generally reduced carbon stocks following drought and had no impact following insect outbreaks. Overall, our findings suggest that the benefits of forest treatments for vegetation carbon stocks are limited, especially following drought and insect disturbances. These findings have important policy implications for carbon credit programs.