Oak Tree Carbon Storage Overestimated

A new study published in Science Advances, led by ecoclimatologist Mukund Palat Rao of Lamont–Doherty Earth Observatory (part of Columbia Climate School), reveals that oak trees in the United States continue to photosynthesize for months after their growth has stopped. This finding challenges the long-held assumption in climate models that photosynthesis directly correlates with tree growth and long-term carbon storage in woody biomass. The research, conducted across 137 sites in the eastern United States and United States — California, found that a significant portion of annual carbon uptake occurs after wood production ceases, especially under hot and dry conditions. This suggests that projections of forests' capacity to act as carbon sinks in a warmer, CO2-saturated world may be overly optimistic, as absorbed carbon is often allocated to short-term metabolic processes rather than long-term wood storage. The decoupling is more pronounced in years with extreme wet and dry climate variability, a pattern expected to become more common with climate change. The study highlights the need to revisit climate models and refine estimates of forest carbon sequestration.