2026/06/12 by Mukund Palat Rao, Arturo Pacheco-Solana, Rong Li +26 · 1 voice
Environmental Science · Earth and Planetary Sciences · Agricultural and Biological Sciences · #Plant Water Relations and Carbon Dynamics #Tree-ring climate responses #Plant responses to elevated CO2
paper · pdf · doi:10.1126/sciadv.ady7139
openalex publication_date 2026/06/12 · openalex created_date 2026/06/13 · openalex updated_date 2026/07/27
The magnitude of the terrestrial carbon sink remains a key uncertainty in future climate projections, in part due to poorly understood links between carbon uptake and its allocation to woody biomass in vegetation. Here, in this study, we show that photosynthesis and aboveground growth occur asynchronously across diel to seasonal scales in eight North American oak species. Across 137 tree ring sites, current-year annual growth was insensitive to climate variability after midsummer despite 26 to 36% of annual gross primary productivity (GPP) occurring during this period. Hourly GPP flux and growth measurements at four sites spanning seven site years further demonstrate that wood formation ceases earlier than photosynthesis and is restricted to periods of low atmospheric aridity and temperature. This photosynthesis-growth decoupling intensifies with interannual variability in vapor pressure deficit ( r = 0.86, P < 0.05), suggesting that by assuming tight coupling between photosynthesis and woody biomass, current earth system models may overestimate long-term carbon sequestration in forests.