By Tim Baynes

THE role of heather burning to maintain some of Scotland’s most precious habitats can sometimes generate more heat than light.

Critics of the practice – also commonly known as muirburn – claim that burning patches of vegetation on moorland provides few benefits other than to enhance territory for red grouse on Scotland’s rural estates.

Yet, for centuries, gamekeepers, farmers and crofters have used muirburn to reinvigorate land, providing habitat for a wide range of species whilst reducing fuel load in the event of uncontrollable wildfires. But despite opponents claiming that singeing vegetation will increase carbon emissions, a growing body of academic research is finding the opposite to be true.

The latest study, from the University of Cambridge, finds that prescribed burning can lock-in or increase carbon in the soils of forests, savannahs and grasslands.

Without fire, soil carbon is recycled – organic matter from plants is consumed by microbes and released as carbon dioxide or methane. But infrequent, cooler fires can increase soil carbon retention through the formation of charcoal and soil aggregates that protect from decomposition.

So why does the Cambridge research matter when considering the future of Scotland’s land management?

It is the latest research to come to similar conclusions following work by universities including Lancaster, York and Newcastle. Research published in 2020 by Duke University in America concluded high-intensity fires, such as wildfires, can destroy peatbogs and cause them to emit huge amounts of their stored carbon into the atmosphere whilst low-severity fires – including muirburn – spark the opposite outcome.

Despite being regulated through the Muirburn Code, heather burning continues to attract opposition from anti-grouse moor activists who claim halting the practice would be good for the environment. Yet, opposition to muirburn is often confused in its outlook. Some activists choose to disregard recent science, instead opting to call the practice "peatland burning" to imply that it burns the peat – muirburn does not; it only takes off the top layer of vegetation which then regrows and locks up carbon again.

There are undoubted benefits to grouse moors in rotational heather burning but science is demonstrating that cool burns are good for our ecosystem and capturing carbon – especially when it aids the fight against wildfires.

Scotland has witnessed huge wildfires in recent years including the Flow Country blaze in 2019 which is estimated to have released carbon into the atmosphere equivalent to six days’ worth of the nation’s total greenhouse gas emissions (according to WWF).

In higher temperatures countries, such as Australia, USA and Spain, controlled burning has been practised to prevent wildfires and the Scottish Fire & Rescue Service has endorsed here to reduce fuel load.

The latest research from the University of Cambridge demonstrates the value of controlled burning in not just lessening the risk of huge carbon emissions from wildfire but actually increasing carbon storage through use of fire. Whilst that may seem a paradox, if we are to produce the best public policy for our uplands then it would be useful to follow the science on this matter and hopefully enable the heat to be taken out of the debate in the process.

Tim Baynes is Moorland Director at Scottish Land & Estates