Trees in biochar study near Loch Ness
A large-scale scientific test involving a material called biochar is being conducted on forestry land in hills above Loch Ness.
Biochar is a charcoal-like by-product of the wood processing industry.
Millions of tonnes are generated every year and it is mainly sold as a mulch for horticulture.
In the test, trees have been planted at Trinloist, near Foyers, to investigate how biochar performs as a fertiliser and a "nutrient sponge".
The four-year study is being done by Natural Environment Research Council-funded scientists from the University of Edinburgh in collaboration with Forest Research.
The research team believes biochar could be a "green bullet" for forestry and the wider environment, with the potential to generate income while improving soils, reducing residue and storing carbon.
Mike Perks from Forest Research said forestry was an important industry to Scotland.
He said: "Biochar could help soil carbon recover faster, improve planting success, reduce the need for additional fertiliser during forest establishment and add value to the industry as an additional product.
"If a business model can be developed, this represents a huge opportunity for Scotland's £2bn timber processing industry."
Hamish Creber, the PhD student overseeing the test site's thousands of trees, said: "Over the next four years we'll be monitoring biochar's performance by measuring tree establishment success, growth and tree health.
"Our initial results indicate that seedlings grown in soil with biochar are more effective at capturing and using light, which is an indicator for overall tree health."
Dr Saran Sohi, of the University of Edinburgh, said: "Biochar has a range of benefits for the environment. As well containing nutrients like phosphorus, it contains a high proportion of highly-stable carbon.
"This carbon remains sequestered in biochar for centuries, so its sustainable production could be a powerful tool in the fight against climate change."