Does reforestation help or hinder soil’s carbon storage?

A project to examine how reforestation affects the soil and its ability to tackle climate change, led by Dr Claire Moulton-Brown, has been awarded funding by the Royal Society of Edinburgh (RSE).

The RSE Spring 2025 Research Awards, worth over £729K, have funded 73 innovative research projects, including 20 at the University of Edinburgh, that span a range of scientific disciplines.

Claire’s project aims to reveal if planting trees and woodland restoration helps or hinders the ability of soil microbes to capture and store carbon dioxide (CO2) from the atmosphere.

Whilst reforestation can play a part in helping to mop up more CO2, planting the wrong type of trees, in the wrong place can interfere with soil microbes.

The planting process also disturbs the physical soil, and in some circumstances the resulting disruption to soil microbial communities may drive them to release rather than store CO2.

Capturing Carbon

Every gram of soil contains an enormous diversity of over a billion microbes which feed on decaying plants - taking the carbon they have captured from the atmosphere and locking it underground.

The process is so effective that microbes allow the soil to capture and store more CO2 than all the plants and trees on the planet combined – making them essential in tackling climate change.

However, there is currently a lack of long-term data on how microbes and the levels of carbon in the soil change as a result of woodland restoration.

Pine forest

Soil analysis

The project, which also includes Professor Thorunn Helgason and Professor Sarah Reece, will use advanced DNA analysis, known as meta-barcoding, to pinpoint how microbial communities change after trees are planted.

The analysis, which will take place for three years after initial planting, will also quantify the levels of carbon through regular sampling of the soil.

The project ‘Source or sink: Unearthing microbial carbon cycling in afforested woodland’ is based at Roamers Wood, a community woodland in West Linton in the Scottish Borders.
 

Roamers Wood sign

Impact

The results could lead to better land management strategies that protect the soil. Over the last few decades changes in land use and unsustainable practices have rapidly increased soil degradation.

The project could also lead to a deeper understanding of the vital interactions between soil microbes and the environment, which holds the key to all life on earth. 

Soil and its microbial communities form one of the most important and biodiverse habitats on the planet, with an essential role in nutrient cycling, supporting plant growth and purifying water.

The project, a collaboration with Roamer’s Wood, combines this unique long-term study, with local community engagement to increase awareness of the importance of soil ecology.

About the Funding

The RSE’s Research Awards Programme runs twice a year in spring and autumn. 

It aims to support Scotland’s research sector by nurturing promising talent, stimulating research in Scotland, and promoting international collaboration.
 

My colleagues, Professor Thorunn Helgason, Professor Sarah Reece, and I are delighted to receive a prestigious RSE Small Grant Award. We are excited to investigate this unique, long-term dataset to understand key microbial changes linked to afforestation and their effect on soil organic carbon.

Dr Claire Moulton-Brown Postdoctoral Research Associate, Institute of Ecology and Evolution

The RSE's Research Awards Programme plays a vital role in strengthening Scotland's dynamic research community. I do not doubt that the recipients of these prestigious RSE awards will advance knowledge and make meaningful contributions to Scottish society. On behalf of the RSE, I congratulate these exceptional researchers and their international partners, and I eagerly anticipate the impact of their work.

Professor Anne Anderson OBE FRSE RSE Vice President, Research
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