I’m sitting in Exeter. I’m nowhere near Dartmoor. I’m not really sure where the fire actually is, I don’t how it started, but am I surprised? Ok, yes, I’m surprised it was last night, because I thought Dartmoor was covered in snow, but apparently it is not. However, this was an event which has been waiting to happen for many years.
There are those who will tell you that Dartmoor is overgrazed and as a result there is little wildlife left; some even described it as sheep-wrecked. Without doubt in the 1980s and 1990s grazing pressures from sheep and cattle did get out of hand. Far too many animals overgrazing the vegetation, reducing the abundance of heather, poaching the peat, generally making a mess – all driven by Government-funded subsidies – the so-called headage payments, where the more animals you pastured on the Commons, the more money you received as a hill-farmer.
Well, that era had to be ended and from 1995 schemes, initially the Environmentally Sensitive Area scheme (ESA), were brought in to reduce the grazing pressure and limit the frequency and extent of swaling (moorland burning) activities. I haven’t spoken to a Dartmoor hill-farmer who said everything in the 80s and 90s was fine and nothing needed to change.
However, the specific farming prescriptions that were introduced with the ESA, whilst popular with conservationists, were very contested and unpopular with Dartmoor’s hill-farmers. Cattle and sheep numbers were cut by 50% and more in some cases. Cattle were prohibited from over-wintering on the Commons and swaling areas were reduced to two hectares in extent. These changes were well intentioned and plausible at the time but led to a series of unintended consequences.
The reduction in stock numbers led to a reduction in the grazing pressure, however, the banning of the over-winter of cattle changed the nature of hill-farming on Dartmoor – sheds had to be built to house the cattle from the end of October, which meant that the hardy moorland cattle became soft and after that when bad weather rolled in, they left their lears (their ancestral places on their Common) early and headed for their home farms. The economics for hill-farmers of keeping hill cattle collapsed as costs increased and as a result cattle numbers reduced further still.
Then in 2001, Foot and Mouth Disease massively impacted Dartmoor and many herds were culled and a season’s grazing was missed. This allowed the vegetation to really get away, in particular a grass known as Purple Moor Grass, also known by its Latin name as Molinia. This species will be well known to Dartmoor’s high moor walkers as it forms large tussocks, sometimes referred to as ‘babies’ heads’ that are extremely difficult and arduous to walk through. Today there are very extensive (thousands of hectares) of un-grazed or undergrazed Molinia. I call it the Molinia jungle and it seems to me that each year it expands in its extent.
Molinia is a palatable grass between May and July for cattle, after that it doesn’t get eaten and the sheep hate it and avoid areas dominated by it. The cattle, particularly Galloways, have attracted an additional payment (as a rare breed) and hill-farmers have favoured cattle over ponies and as a result pony numbers have declined significantly. Finally, Dartmoor is subject to high levels of atmospheric pollution from nitrogen compounds (because it rains a lot) and that combined with climate change has favoured the growth of Molinia. In other drier areas, the same combination of factors has led to an increase in the abundance of gorse.
All the hill-farmers I have spoken to talk about the ‘fuel load’ on the moor, and by that they mean the dead Molinia leaves and the tall straggly gorse. When the Molinia and the gorse are dry, they become very flammable.
The time when hill-farmers prefer to swale (a legal activity which burns gorse on peats which are less than 40cm deep) is when there are cold dry winds from the east. Such conditions allow the gorse to be effectively burnt off and thus provide new fresh areas of palatable grasses for their livestock.
The Molinia jungle tends to grow on peat which is greater than 40cm in depth and here swaling is quite rightly no longer permitted as burning on deep peats can easily damage the Sphagnum mosses. The situation is further complicated by the fact that over the centuries much of Dartmoor’s blanket bog has been drained, for peat cutting for example, and as a result it is no longer hydrologically functional and has converted itself into wet heath rather than blanket bog. This is the place where the Molinia flourishes and expands making the Molinia jungle grow in extent.
Last night a series of weather conditions combined: a strong, cold, dry wind from the east / south east, very low temperatures which froze the peat surface, the wet conditions of the moor were eliminated by the ice and the cold wind dried out the Molinia and the gorse, the perfect conditions for a large fire.
I have no idea how the fire was started but it is unlikely it was a spontaneous event! Interesting to note that under similar conditions a Cornwall Wildlife Trust nature reserve went up in flames and last night there were also moorland fires on Bodmin Moor and on Exmoor.
With such a fuel load on Dartmoor, it was an ‘accident’ waiting to happen. With the parlous nature of hill-farm economics, the reduction of stock numbers, particularly cattle and ponies, it is difficult to see how this fire will be the last.
And to those who suggest that re-wilding is the answer, the Molinia jungle is what 25 years of re-wilding on Dartmoor’s wet heaths looks like. Given time (decades) the degraded deep peat soils will hopefully recover and additional funding will be made available to re-wet areas, but that option is eye-wateringly expensive on Dartmoor as around 50% of the costs are required to remove unexploded military ordnance … there are no easy, cheap or quick fixes.
My hope is that as the ground was frozen this was a surface burn and as a result the peat is largely unaffected. Hopefully one day I will get a chance to go and have a look.
Adrian Colston PhD
Researcher on hill-farming and conservation on Dartmoor at the Centre for Rural Policy Research, University of Exeter