Guest post by Dr Pat Thompson, RSPB Senior Policy Officer (uplands)
Record high temperatures in late February have led to countryside fires in a number of areas right across the UK. Fiery images have made media headlines and led, especially at the time of year when managed burning is allowed, to heated discussion about the role of fire as a countryside management tool. Dry peatlands with a heavy fuel load, such as heather, are clearly a fire risk – so wouldn’t wetland management for moss-dominated blanket bogs be a better way to reduce fire risk in the uplands?
In the summer of 2018, major fires (so called wildfires) occurred throughout the United Kingdom with major vegetation fires recorded in Greater Manchester (Stalybridge) and Lancashire (Winter Hill). The Stalybridge fire encroached onto Dove Stone, an area of land managed by the RSPB on behalf of United Utilities. A major fire-fighting effort was required to bring both fires (declared as major incidents) under control. Even after both fires were out, pockets of peat smoldered for almost 6 weeks after the fires started. Once ignited, peat fires are difficult to extinguish. Whilst both fires generated significant public interest, many other fires occurred across the UK, on a range of habitats.
Degraded bogs tend to be much drier than bogs in good condition. Once dry, the surface vegetation becomes combustible and the peat is at risk of catching fire. Image: Dave O'Hara, RSPB
The Stalybridge and Winterhill fires had a significant impact on air quality and local people, with homes evacuated and residents reported suffering from respiratory and other problems associated with the inhalation of smoke and ash particles. At the height of the fires, exposure to particulate matter (PM10) in Greater Manchester exceeded the ECs legal limit of 50 ppm on five occasions.
The UK’s climate is changing. The Met Office climate change projections show that all areas of the UK are heading to be warmer (more so in summer than in winter) with hot summers more frequently recorded. As we have seen this winter, these changes in climate could lead to an increase in the frequency and severity of out of season countryside fires posing an increasing threat to the natural environment.
In contrast to managed fires, which occur in the agreed burning season, wildfires often occur outside the burning season, and can burn intensively when a period of prolonged hot and dry weather dry out the highly combustible surface vegetation (e.g. a mix of grasses and shrubs). Whilst some vegetation communities may be tolerant to fire, out of season and unplanned fires often generate much higher temperatures (largely because the fuel load is greater and more combustible) with the result that these fires often burn into the soil resulting in major damage to the ecosystem.
The UK’s blanket bogs are of international importance, storing vast amounts of carbon as peat, which has built up over thousands of years. The restoration and positive management of blanket bogs has a key role to play in making these habitats more resilient to a changing climate and to locking up important stocks of carbon and other pollutants associated with the industrial revolution. Heathland and peatland habitats may be especially vulnerable to fire, particularly when in poor condition. For example, peatlands are more vulnerable when the water table is low and the surface vegetation has dried out. Under such circumstances, fire may damage sensitive peatland vegetation, including peat-forming mosses, and even ignite the peat. These fires are difficult to extinguish and are likely to exacerbate climate change through the direct loss of carbon into the atmosphere as CO2 and in other forms (e.g. as Dissolved and Particulate Organic Carbon).
Wet bogs can definitely help halt the spread of a fire. Here, the fire has stopped at the edge of a Sphagnum rich and wet area of bog. Image: Dave O'Hara, RSPB
Spring and early summer fires also pose a major threat to wildlife, particularly to breeding birds, and animals unable to get out of the way of an advancing fire e.g. reptiles, amphibians, small mammals and invertebrates.
In the UK, whilst there is evidence that some wildfires start as managed fires, most vegetation fires start accidentally, or a result of a malicious act (e.g. arson), typically during hot dry periods or periods of drought which are associated with increased visitor numbers. Research in the Peak District found that the risk of fire was greater in April-May and July-August reflecting the interplay between visitor numbers and the changing flammability of moorland vegetation associated with periods of hotter, drier weather and build-up of increasingly combustible older grasses and shrubs (e.g. heather).
Despite the international importance of our peatlands, land managers are still using fire to burn blanket bogs and other peatland habitats, largely to generate young heather for red grouse to feed on. Defra and Natural England are now taking steps to end routine, rotational burning of peatland vegetation. The cessation of burning would help these important habitats to recover and make them much more resilient to the impacts of wildfires. At Dove Stone, where the RSPB has been working to re-wet and revegetate areas of dry and sometimes bare peat, the re-wetted gullies helped slow the passage of the wildfire across the bog and caused much less damage to the underlying peat - see more here.
It is increasingly clear that the incidence of wildfire is increasing. Work is now required to raise awareness of the risk of wildfire and to reduce the incidence of fires starting. Even if the number of accidental fires can be reduced by improving public communications (e.g. at times of high risk or in known high-risk areas), some wildfires may start as managed fires or be started maliciously.
There is much debate about how to reduce the impact of fire, particularly out of season and out of control fires, on carbon-rich peat soils, with some advocating that we need to reduce the amount of combustible surface vegetation (fuel load) - if a fire does occur, the reduced fuel means that the fire will not burn too hot. Somewhat ironically, those arguing for the need to reduce fuel load to protect against fire, believe that fire is the best way of reducing the fuel load. Using fire to manage the fuel load locks the land manager into a cycle of burning. The RSPB believes that re-wetting has a key role to play both in protecting existing stores of peat (carbon) and to create the conditions for peat-forming mosses to recolonise bogs. Healthy bogs should be wet underfoot at all times of year - our bogs need water not fire!
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