Waring, B.G., Averill, C., Bidartondo, M. et al. Microbiome manipulation and enhanced weathering influence tree growth in reforestation. Commun. Sustain. 1, 102 (2026).
Findings from a major forest peer-reviewed study, published on 30th June 2026 in Communications Sustainability, show how simple nature-based interventions can increase tree growth in the earliest stages of reforestation. These interventions have the potential to boost carbon capture by 13% to 27% in the first four years of native woodland establishment.
Key findings:
The project is the result of a long-term collaboration between The Carbon Community charity and researchers from Imperial College London, the Royal Botanical Gardens, Kew, and The University of Sheffield.
The research is investigating carbon sequestration in two types of forest – broadleaf and conifer – with two interventions.
The results are based on the first four years of the study, focusing on the carbon stored aboveground in the trees.
Applying crushed basalt (a by-product of mining) to the soil increased carbon removal significantly, with native woodland areas found to store up to 27% more aboveground carbon after four years. This approach likely improved tree nutrition through two mechanisms: directly releasing calcium as the basaltic minerals weathered, and increasing soil pH, which made existing nutrients (nitrogen and phosphorus) more available to trees.
Microbial enrichment showed the greatest impact during the crucial first year after planting, with some species benefiting more than others, particularly spruce and oak. The results highlight the potential to harness soil microbial communities in the early stages of reforestation and ecological restoration, particularly by optimising inoculum selection. After four years, the broadleaf native woodland areas with microbial enrichment tended to store more carbon, with aboveground biomass 13% higher than those without this intervention.
Read moreWhat is enhanced rock weathering and how does it improve tree nutrition?
Silicate rock weathering is a natural geological process that removes CO2 from the atmosphere. The ‘enhancement’ of rock weathering is done by crushing silicate rocks into smaller particles and spreading them over large areas, which accelerates their dissolution (i.e. weathering).
Enhanced rock weathering (ERW), in this case with crushed basalt, can boost tree growth via improved tree nutrition. There are two pathways for this: 1) directly releasing nutrients into the soil; and 2) increasing soil pH, which can make existing nutrients more available to the trees.
The Carbon Community wishes to express special thanks to the volunteer supervisors and the over 200 volunteers from The Carbon Community’s community science program who have contributed their time, care and dedication to the data collection process during the annual Big Tree Measure as well as maintaining the integrity of the field site throughout the year.
Thank you
