Clearing the Air: Understanding the Differences Between Smoke from Controlled Burning and Smoke from Wildfires
- Rob Beeson
- Mar 21
- 5 min read
We’ve all seen the devastating images of wildfires raging across the globe, and closer to home. But did you know that fire, in a carefully managed form, plays a crucial role in protecting these very same landscapes?
This might sound counterintuitive, but not all smoke is created equal. Understanding the difference between the smoke billowing from a raging wildfire and the wisps rising from a controlled burn is key to appreciating the complex relationship between fire and moorland management.
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The Terrifying Tale of Wildfire Smoke
When wildfires erupt on our moorlands, the consequences can be catastrophic. These are not your gentle, managed burns. Wildfires are often fuelled by an unchecked accumulation of dry vegetation, turning our precious landscapes into tinderboxes. Add dry weather and strong winds, and you have a recipe for disaster, mirroring the horrific events seen in places like Australia, Portugal, and California.
The smoke from these uncontrolled blazes is a dangerous cocktail, carrying a multitude of threats:
Harmful Pollutants: Wildfires release a cocktail of harmful pollutants into the air, posing a significant risk to human health. The 2018 Saddleworth disaster exposed five million people to dangerous pollution.
Loss of Life: Tragically, wildfires can lead to loss of life, both directly from the flames and indirectly from the harmful smoke inhaled. Scientists even linked the Saddleworth Moor fire to dozens of premature deaths due to fumes.
Deep Peat Combustion: Wildfires burn with intense heat, often reaching down into the carbon-rich peat soils. This not only destroys this vital carbon store but also releases vast amounts of carbon dioxide into the atmosphere, exacerbating climate change. The Saddleworth Moor wildfire alone released an estimated half a million tonnes of carbon dioxide.
Long-Lasting Pollution: Because wildfires can ignite deep peat layers, they can smoulder and release poisonous smoke for months, long after the surface flames are extinguished.
Toxic Fallout: Historically, industrial pollution has deposited substances like lead and cadmium on our moorlands. Wildfires can release these toxins back into the environment through smoke.
Scale and Intensity: Wildfires can spread rapidly across vast areas, becoming too intense for fire and rescue services to control. They can even generate their own unpredictable and dangerous winds, causing flames to leap huge distances.
The lack of proper vegetation management, often due to restrictions on controlled burning, is a significant factor contributing to the increased fuel load that feeds these devastating wildfires. As vegetation grows unchecked, the risk of these intense, uncontrollable fires escalates.
Controlled Burning: A Carefully Orchestrated Approach
In stark contrast, controlled burning is a carefully planned and executed land management technique used traditionally by gamekeepers and moorland managers. This is not about letting fire rage; it’s about using it as a precise tool under specific conditions.
The smoke from a controlled burn tells a very different story:
"Cool" and "Slow" Burns: Controlled burns are conducted when conditions are right, often in winter, and are designed to be "cool" and "slow". This means the fire burns at a lower intensity and spreads gently across the vegetation.
Reducing Fuel Load: The primary goal of controlled burning is to reduce the build-up of dry heather and other vegetation – the very fuel that wildfires thrive on. By creating a mosaic of vegetation of different ages and heights, controlled burning breaks up the continuity of fuel, making it harder for wildfires to spread.
Preserving Peat: Done correctly, controlled burning targets the top-most vegetation, leaving the vulnerable carbon-rich peat soils largely untouched. This is a crucial difference from wildfires, which can incinerate the peat layer.
Potentially Carbon Neutral: Because controlled burns primarily consume the shrub canopy, they release carbon that was only recently absorbed as the plants grew. This process can be carbon neutral, especially when it encourages the growth of mosses, which can lead to greater carbon gains. Research even suggests that biochar produced by controlled burning can be an effective way of locking up carbon in peatland soils.
Wildlife Can Escape: The slow pace and small scale of controlled burns allow wildlife ample time to move out of the way, minimizing harm.
Mimicking Natural Processes: This approach shares similarities with the traditional land management practices of indigenous people in fire-prone regions like Australia, who use "cool" burns to manage their landscapes.
Endorsed by Fire Chiefs: Fire chiefs in Scotland and Wales have recognized and endorsed controlled burning as a valuable tool in combating the threat of wildfires.
Smoke Signals: Key Differences at a Glance
To truly understand the distinction, let's break down the key differences in the smoke from these two types of fires:
Wildfire Smoke:
Intense and Hot: Indicates combustion of large amounts of vegetation and potentially deep peat.
Heavy and Dark: Contains a high concentration of pollutants, carbon particles, and potentially toxins.
Long-Lasting: Can persist for weeks or months if peat layers are burning.
Unpredictable: Driven by uncontrolled fire behaviour and weather conditions.
Environmentally Damaging: Leads to significant carbon loss from peat and habitat destruction.
Health Threat: Poses serious risks to respiratory health and can lead to premature deaths.
Controlled Burn Smoke:
Cooler and Less Intense: Arises from a lower intensity burn targeting surface vegetation.
Lighter and More Transient: Smoke dissipates relatively quickly as the burn is small and controlled.
Short Duration: Limited to the period of the controlled burn.
Predictable: Managed by experienced practitioners under specific weather conditions.
Potentially Carbon Neutral: Primarily releases carbon recently absorbed by vegetation.
Habitat Management Tool: Helps to create a mosaic of vegetation and reduce wildfire risk.
Why Understanding the Smoke Matters
The debate around moorland management is often heated, with strong opinions on both sides. However, understanding the fundamental differences between wildfire smoke and the smoke from controlled burning is crucial for informed decision-making.
Restrictions on controlled burning, often driven by concerns about emissions, can inadvertently increase the risk of far more damaging wildfires. When fuel loads build up, the inevitable fires will be much larger, hotter, and will release significantly more carbon and pollutants into the atmosphere.
As wildfire experts have warned, the growth in fuel load on our moorlands means that future fires could be beyond the capacity of our fire and rescue services to control. The consequences for biodiversity, carbon storage, and even the safety of urban areas downwind could be severe.
Many argue that a pragmatic approach is needed, one that recognizes controlled burning as an essential tool in a comprehensive wildfire mitigation strategy. This doesn't mean uncontrolled burning; it means skilled practitioners using fire judiciously to protect our moorlands from the far greater threat of devastating wildfires.
Conclusion: Let's Have an Informed Conversation
The smoke signals from our moorlands tell a complex story. While the thick, acrid smoke of a wildfire spells destruction and danger, the lighter, more transient smoke from a controlled burn can signify proactive management aimed at preventing a larger catastrophe.
By understanding these crucial differences, we can move beyond simplistic narratives and engage in a more informed conversation about the best ways to protect our precious moorland landscapes for future generations.
We need to equip land managers with the necessary tools, including controlled burning, to reduce fuel loads and safeguard our environment and communities from the true menace of catastrophic wildfires.
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