Why Is Heather Burned on Moors? Controlled Burning and Wildfire Prevention

Heather is burned on some moors to encourage fresh growth, maintain patches of different-aged vegetation for grouse and grazing, and reduce vegetation that could fuel a wildfire. Carefully planned burning can remove combustible material before it builds into extensive, continuous stands.

The scientific case for retaining controlled burning rests on how it changes fuel loads and fire behaviour. It belongs alongside cutting, grazing and peatland restoration, with the choice determined by the habitat, local risks and legal permissions.

At a glance

• Mature vegetation and dead material can increase the fuel available to wildfire.

• Controlled burning can reduce fuel; protection depends on conditions and treatment design.

• Rewetting can protect peat and support recovery, while surface vegetation can remain flammable.

• Cutting can work well; removing brash differs from leaving it on the ground.

Why do moorland managers burn heather?

On grouse moors, managers traditionally burn small patches to provide young heather for feeding alongside older vegetation offering cover. Burning can also improve rough grazing and serve conservation or fuel-management objectives.

• Prescribed burning means using fire for a defined purpose under specified conditions.

• Rotational burning treats different patches at different times. In Scotland it is commonly called muirburn, under different rules.

• The practical term cool burning describes the intention to burn vegetation while protecting the underlying moss, litter and soil.

How does fuel management influence wildfire?

Heather growth changes the fuel available

Fuel includes living shoots, woody stems, dead vegetation and litter. Its height, moisture and arrangement matter alongside its quantity.

In 27 experimental Scottish fires, Davies and colleagues (2009) found that total fuel and heather height increased across growth stages. Wind interacted strongly with vegetation structure to influence spread. Fine fuel did not rise consistently into maturity: age alone was an unreliable guide to behaviour.

Research across five British wildfires, published in 2016, found that more surface fuel before fire was associated with more being consumed. Burning of ground material depended strongly on drying. Both fuel and moisture therefore need attention.

Controlled burning can remove combustible material

At Glensaugh in Scotland, Fielding and colleagues (2025) found burnt plots had 0.58 kg less carbon per square metre in above-ground plant material than controls. This measured early material removal, rather than subsequent wildfire losses.

Taken together, these findings support using targeted burning to reduce fuel and interrupt continuous vegetation. Suitably placed treatments may give firefighters better opportunities to contain a fire. Their value depends on location, maintenance, access and weather; vegetation regrows, and extreme conditions can overwhelm fuel breaks.

There is a sound reason to manage hazardous fuels.

Can rewetting replace controlled burning?

Rewetting can improve peatland resilience and should be supported where drainage has damaged a site. Raising water tables and restoring moisture-retaining mosses can make peat less vulnerable to deep, smouldering combustion.

Granath and colleagues’ 2016 modelling, concerning drained and mined northern peatlands, supported restoration to reduce deep-burn potential. It explains an important protective mechanism, although it was not a trial of fuel management on British heather moors.

Water in the peat does not guarantee that vegetation above it cannot burn. In 19 experimental fires, Grau-Andrés and colleagues (2018) studied heather-dominated dry heath and a raised bog with saturated peat. Both carried fire, but the wet bog resisted damaging ground heating much better. Drying increased severity, especially at the heath.

Restoration can also change surface vegetation over time. A 2025 survey of 27 Scottish wildfire sites found weaker vegetation changes in wet moorland, supporting the value of wetter habitats. It did not test rewetting treatments.

The unresolved issue is how reliably rewetting reduces established heather fuels across different uplands. A 2025 review led by Andreas Heinemeyer highlighted the lack of adequate direct evidence for assuming this happens generally. That does not prove rewetting fails.

Rainfall, drainage, slope and peat properties influence achievable wetness. Recovery takes time, while drought can dry vegetation and ground layers. The practical implication is to assess remaining fuel hazards during restoration and respond where necessary. Our explanation of rewetting and surface fires explores the distinction.

Is cutting heather a complete alternative?

Cutting can reduce vegetation height without an open flame or immediate smoke. It can be preferable where burning would be unsafe or inappropriate. However, cutting and removing material produces a different result from leaving it as brash.

Fielding’s experiment found that cutting transferred fine heather material into litter: a possible ignition hazard requiring further investigation.

A five-site Pennine experiment reported by Whitehead and colleagues in 2026 found that both burning and cutting reduced heather cover and vegetation height over five years. Cutting produced broadly comparable vegetation outcomes. Leaving brash added litter and slowed Sphagnum recovery; management also initially reduced moss depth.

These findings support keeping both methods available. They do not establish that cutting is always inferior or that all retained brash will burn dangerously.

Practical constraints matter too. Wet or uneven ground, steep slopes, rocks and restricted access can limit machinery. Cutting height and vehicle pressure need attention to protect moss and peat.

Collecting and transporting brash adds work and cost. Grazing can influence subsequent growth, but its effect depends on livestock, stocking and habitat.

When is controlled burning appropriate?

Heather occurs on dry heath, wet heath and blanket bog. Their soils, water regimes and conservation needs differ. Burning suitable heathland does not establish that burning a functioning bog is appropriate.

A justified treatment needs a clear objective, small and manageable burns, suitable ground moisture and weather, trained supervision, equipment and a safe means of extinguishing the fire. Timing and return intervals should reflect vegetation recovery and habitat needs, rather than a fixed calendar alone.

The objective is to protect the ground layer. Where that cannot be achieved, or ecological and smoke risks outweigh the benefit, another approach is needed. Monitoring should determine whether treatment actually reduces the identified hazard.

What permissions are needed in England?

Current GOV.UK guidance gives the normal burning season as 1 October–15 April in upland areas and 1 November–31 March elsewhere.

Burning specified vegetation on peat deeper than 30 cm within a Less Favoured Area generally requires a Defra licence, with narrow exceptions. Separate Natural England licences can apply, including outside the season. SSSI consent and other protected-site requirements must also be checked. A wildfire plan does not replace required permissions.

Defra’s application guidance includes reducing wildfire impacts as a licensing ground and requires consideration of alternatives. The season alone does not authorise burning or override wildlife protection.

The Moorland Association’s position

The Moorland Association supports controlled burning where it is suitable, justified and properly authorised, alongside cutting, grazing and peatland restoration.

The evidence supports retaining this option where it can address hazardous fuels that other methods cannot adequately or practically manage. Restricting one method does not establish that its alternatives can perform the same job everywhere. Decisions should account for both immediate fuel hazards and long-term habitat recovery.

Frequently asked questions

Does burning heather prevent wildfires?

It can reduce vegetation fuel and potentially limit spread or intensity. It does not remove ignition sources.

Can wet peatlands still catch fire?

Yes. Surface vegetation can burn above wet peat. Wetter ground generally resists deep burning better, but prolonged dry conditions increase vulnerability.

Is cutting better than burning?

It depends on the habitat and objective. Cutting avoids fire and smoke; removing brash reduces material on site more directly than leaving it behind.