A dusting of crushed basalt rock may give young forests a stronger start.
Scientists from Imperial College London say a new study from the largest field experiment on “enhanced weathering” and soil microbiome enrichment found the rock treatment helped newly planted forests develop faster and absorb more carbon.
The work is part of the Glandwr Forest Carbon Study in Wales, a partnership involving the Royal Botanic Gardens Kew, the Carbon Community, Imperial College London and the University of Sheffield.
At the site, 25 acres of reforested woodland have seen 26,000 trees planted and monitored across 72 plots. Researchers are building a case-control dataset on how trees respond to different reforestation methods, especially crushed basalt spread on the soil and the addition of soil microbes from mature forests.
The basalt treatment is intended to work as silicate rock fragments weather into dust, releasing minerals and changing soil pH in ways that enhance the supply and uptake of nutrients including nitrogen and phosphorous.
Researchers found the technique significantly improved above-ground carbon storage potential in the soil and tree roots by 27 percent, according to early results.
The team also tested microbes and fungi from nearby natural woodland to see if they would speed up root system development in the Glandwr trees. Some plots, particularly oak and spruce, showed a measurable benefit, but variation across the site meant the result was not statistically significant.
Researchers then tested combining the two methods. That result was also insignificant.
The team said it may still be too early in the forest’s life for those interventions to take effect, and that longer monitoring could yet show a benefit.
“Healthy new woodlands are essential for biodiversity, climate mitigation and resilient landscapes,” said Dr. Bonnie Waring, senior author of the paper presenting the results of two growing techniques.
“Our findings show that relatively simple, nature-based interventions can improve tree establishment and increase the carbon uptake of new woodlands during their earliest years.”
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