New research on oak trees shows that during hot, dry summers, photosynthesis continues but actual wood growth stops early. This means trees absorb CO2 but do not store it in long-lasting wood. Instead, much of the carbon is released back into the atmosphere within a short time. The study used satellite data, CO2 measurements, and tree sensors across the United States. It found that 30 to 70 percent of captured carbon goes into short-lived compounds or is respired away. This challenges climate models that assume a direct link between photosynthesis and long-term carbon storage. For carbon markets and forest management, the findings matter. Relying on forests as permanent carbon sinks may be overoptimistic if drought events become more frequent. Policymakers and project developers should consider species selection and water availability when estimating sequestration potential.
