Hidden Figures: how tree species shape methane uptake in temperate forests.

Methane (CH₄) is a potent greenhouse gas and the second most important contributor to the Earth’s warming after carbon dioxide (CO₂). Atmospheric methane concentrations have nearly tripled since pre-industrial times, exceeding 1,930 ppb in 2025, and its radiative forcing is approximately 28-30 times greater than that of CO₂ over a 100-year time scale. As a result, methane is at the centre of the climate agenda, led by the Global Methane Pledge (GMP) launched at COP26. Owing to its relatively short atmospheric lifespan ranging from 7 to 12 years, methane concentration is highly sensitive to changes in the balance between its sources and sinks.

Soils have long been recognised as the primary terrestrial methane sink alongside atmospheric oxidation. However, recent observations suggest that trees growing in free-draining soils may constitute an overlooked and potentially significant methane sink. Despite its possible importance, the magnitude, drivers, and global relevance of this tree-mediated methane uptake remain poorly constrained, introducing substantial uncertainty into current methane budget estimates. This knowledge gap is particularly pronounced in temperate forests, where evidence of tree methane uptake is limited to only two tree species (Fraxinus excelsior and Acer pseudoplatanus), leaving the broader sink potential of these ecosystems largely unexplored.

Here, we present preliminary results on spatial and temporal variability of stem methane fluxes measured across multiple UK native and non-native tree species in newly planted forests under contrasting forest management approaches, including monoculture and mixed-species woodlands.  This experiment is conducted at the Norbury Park Estate, Shropshire (central England), close to the Birmingham Institute of Forest Research (BIFoR) FACE facility. These data will provide new insights into potential drivers of tree-mediated methane uptake in temperate forests and help assess the additional climate benefits of forest expansion under different planting strategies.