The Truth About Controlled Burning: Debunking the 5 Biggest Myths

For generations, controlled, or prescribed, burning has been a cornerstone of traditional land management on UK moorlands. It's a precise tool used to maintain healthy ecosystems and prevent catastrophic blazes.

However, this proven practice often faces strong opposition rooted in common misconceptions. This post will address the main objections to controlled burning, presenting clear, evidence-based rebuttals to set the record straight.

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• Myth 1: "Controlled Burning is Bad for Peatlands and Releases Harmful Carbon Emissions."

• Myth 2: "Controlled Burning Produces Dangerous Smoke and Air Pollution."

• Myth 3: "Controlled Burning Increases Wildfire Risk or is Not an Effective Prevention Tool."

• Myth 4: "Controlled Burning Harms Biodiversity and Natural Ecosystems."

• Myth 5: "Cutting or Rewetting are Better, More Modern Alternatives."

Myth 1: "Controlled Burning is Bad for Peatlands and Releases Harmful Carbon Emissions."

This is perhaps the most frequent and impassioned argument against controlled burning. Critics claim it damages carbon-rich peat soils and releases significant amounts of CO2, contributing to climate change.

Managed burning is fundamentally different from uncontrolled wildfires. Controlled burns are "cool" and "slow," specifically designed to consume only the topmost layer of vegetation, leaving the vulnerable peat soils beneath largely untouched. This is a crucial distinction.

Research indicates that controlled burning can be a carbon-neutral management technique, as the carbon released from the shrub canopy was only recently absorbed by the growing plants.

Furthermore, studies show that controlled burning can even increase carbon storage in the soil by creating charcoal (biochar), which is highly resistant to decomposition, and by promoting the vigorous regrowth of plants, leading to greater carbon gains.

In stark contrast, uncontrolled wildfires pose the most serious threat to peatland carbon stores, often burning deep into the peat layer and releasing immense quantities of ancient carbon that took millennia to accumulate. For example, the Saddleworth Moor wildfire in 2018 released approximately 40,000 tonnes of CO2 and damaged 7cm of peat, which could take 200 years to replace.

UK peat soils hold more carbon than all the trees in Britain and France combined. Peatland fires, despite covering only about 25% of the total burned area, account for up to 90% of annual UK fire-driven carbon emissions, representing a long-term, potentially irreversible loss.

Investing in proactive prevention through controlled burning is far more effective and economically sensible than attempting to recover from the massive carbon debt incurred by wildfires.

Myth 2: "Controlled Burning Produces Dangerous Smoke and Air Pollution."

Concerns are often raised about the smoke from controlled burns, with some fearing it causes similar health issues and air quality degradation as wildfires.

Not all smoke is created equal. The smoke from a carefully managed controlled burn tells a very different story from the thick, dark plumes of a raging wildfire.

Wildfires produce significantly more smoke and pollution per unit of area or fuel burned. This is because wildfires typically occur under hotter, drier, and more erratic conditions that lead to incomplete combustion, generating more soot and fine particles.

Wildfire smoke is notably richer in fine particulate matter (PM2.5), carbon monoxide, methane, black carbon, and hazardous air toxics. A single prescribed burn might produce only about 17% of the PM2.5 smoke that an equivalent wildfire would emit.

Crucially, the duration and reach of wildfire smoke vastly outweigh those of controlled burns. Controlled burns are short-lived, typically lasting a few hours to a day or two, with smoke dissipating quickly due to careful timing and wind conditions. In contrast, uncontrolled wildfires can rage for weeks or even months, continuously producing smoke.

The Saddleworth Moor fire, for instance, burned for seven weeks, continuously affecting air quality over a broad region and exposing over 4.5 million people to unhealthy air, leading to an estimated 14 to 42 premature deaths and releasing industrial pollutants like lead and cadmium. Controlled burns, when properly managed, rarely cause such widespread health crises.

Ultimately, the claim that controlled burns contribute significantly more to air pollution than wildfires is a myth not supported by scientific evidence. Strategic prescribed burning, by preventing the much larger, more intense, and longer-lasting wildfires, is a net positive for air quality in the long term.

Myth 3: "Controlled Burning Increases Wildfire Risk or is Not an Effective Prevention Tool."

Some critics argue that controlled burning can "get out of hand," or that it is an outdated and ineffective method for reducing overall wildfire risk, suggesting it might even make fires worse in the long run.

Controlled burning is, in fact, an essential tool for mitigating wildfire risk by actively reducing fuel loads. The primary aim is to remove the accumulation of dry, combustible vegetation that fuels destructive blazes, thereby limiting their intensity and rate of spread. It also strategically creates firebreaks, which are vital for hindering the spread of larger, uncontrolled fires.

Evidence strongly supports its effectiveness. Research from Scotland shows that an impressive 96% of wildfires occurred outside areas where controlled burning is carried out, highlighting its role in prevention. International examples, including the USA, South Africa, France, Portugal, and Australia, also widely utilize controlled burning to manage fuel loads and reduce wildfire risk.

The G7 leaders and the White House have explicitly called for the use of "controlled burning" as a means of preventing wildfires. Fire chiefs in Scotland and Wales have also endorsed its use as a wildfire combatting tool. The National Fire Chiefs Council identifies burning, along with cutting and grazing, as crucial for dealing with vegetation build-up.

Conversely, unmanaged landscapes with excessive fuel loads are prone to catastrophic wildfires. Reports on the Peak District National Park warn of the "frightening potential of fire... reaching extremes both in the rate of spread and flame lengths far beyond the capacity of control" of fire services, emphasizing that "fuel loading can be addressed".

The 2018 Saddleworth Moor fire, for instance, occurred on land described as "unmanaged in relation to the risk posed by wildfire" due to decades of heather and scrub growth. Policy changes since 2021 have led to a 73% reduction in fuel load management in England, directly exacerbating wildfire risk.

This highlights that restricting controlled burning, not the practice itself, increases the danger.

Myth 4: "Controlled Burning Harms Biodiversity and Natural Ecosystems."

Critics sometimes claim that controlled burning damages sensitive plant species like Sphagnum moss, leads to monocultures, or generally degrades moorland habitats.

Controlled burning, when skillfully applied, is a beneficial practice for biodiversity and ecosystem health. By creating a mosaic of heather patches of varying ages and heights, it fosters a greater diversity of flora and fauna on a landscape scale.

This varied age-structure provides essential food sources and cover for a wide range of moorland species, including important ground-nesting birds. Moorlands managed with traditional techniques are havens for rare native species such as red grouse, lapwing, curlew, golden plover, merlin, and mountain hare.

Far from damaging Sphagnum moss, studies suggest that Sphagnum moss cover can be significantly higher in areas burned eight to ten years prior compared to unburned areas, indicating that controlled burning at regular intervals can favour its growth by reducing competition from heather.

This also promotes the vigorous regrowth of other plants. The slow pace and small scale of controlled burns also allows wildlife ample time to move out of the way, minimizing harm to animals.

In stark contrast, severe wildfires devastate wildlife habitats, destroying precious moorland and often striking during nesting seasons, causing significant loss of young wildlife. They can also sterilize soils, preventing regeneration. Therefore, by preventing these catastrophic events, controlled burning safeguards the very biodiversity that critics claim it harms.

Myth 5: "Cutting or Rewetting are Better, More Modern Alternatives."

Some policies, heavily influenced by environmental groups, advocate for alternatives like mechanical cutting or rewetting as primary solutions for moorland management and wildfire prevention, often pushing for bans on controlled burning.

While cutting and rewetting can play a role in land management, they are not always sufficient or superior alternatives to controlled burning for comprehensive wildfire prevention, especially in the challenging UK upland environments.

Mechanical cutting has significant limitations. Experts warn that cutting can be "worse than not doing anything" because it leaves behind a layer of dead, highly combustible material (known as "brash") that dries out rapidly, creating a "massive bonfire" that can actually help fires spread quickly rather than contain them.

The Scottish Fire & Rescue Service has explicitly stated that mowing excess vegetation can "leave a dry layer that actually encourages the spread of fire," whereas winter burning "is by far the most effective because it removes a fuel in its entirety".

Furthermore, cutting machinery cannot easily traverse the steep or rocky hillsides common in moorlands, limiting its practical application. Current regulations often impose impractical parameters and acreage limits, hindering effective large-scale fuel reduction through cutting.

Rewetting, while valuable for peatland restoration, is not a "silver bullet" for wildfire prevention on its own. Scientific evidence shows that while a higher water table can dampen fire intensity in peat, it does not rapidly re-establish moisture-retaining moss cover without active intervention like Sphagnum reintroduction.

Even "rewetted" sites can dry out seasonally, especially during droughts, leaving surface vegetation vulnerable to ignition. The National Trust's Marsden Moor, despite rewetting efforts, has suffered multiple wildfires because high fuel loads (dead bracken and grass) carried the fire. The Peak District itself has areas unsuitable for rewetting due to topography.

A holistic and adaptive approach is needed, integrating rewetting with active vegetation management, which often includes carefully controlled burning, cutting, and grazing. Relying on a single method, especially without sufficient scientific backing for its wildfire prevention efficacy, is a risky bet that increases the overall threat.

Conclusion

The rising threat of wildfires demands a pragmatic, evidence-based approach to land management. Controlled burning, a time-tested practice deeply rooted in the traditions of moorland stewardship, is a vital tool for preventing catastrophic blazes, protecting precious ecosystems, and safeguarding communities.

The Moorland Association and its members, who live and work on these landscapes year-round, are committed to responsible and effective land management. We urge policymakers to look beyond misconceptions and short-term narratives, to listen to the expertise of those on the ground, and to support the use of all proven tools, including controlled burning, to build a more wildfire-resilient future for our cherished moorlands.

By working together, based on sound science and practical experience, we can protect these vital habitats for generations to come.

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