The Dartmoor Fire – an inevitable event

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 2ha 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 early (their ancestral places on their Common) 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’ which is 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 last week 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 …… they 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.

40 thoughts on “The Dartmoor Fire – an inevitable event

      • “won’t be long before it’s back to where it was” I know too little about the dartmoor ecosystem but in that window are there not other plants and animals which might temporarily thrive? Once it gets back to where it was it would be time (it seems whether we like it or not) for it to burn again. I saw an arial photograph of a nature reserve in Ireland where maybe 1/4 of the gorse had burnt in a wildfire. Lots of comments about how terrible this was for the habitat – but if fire promotes gorse and gorse is a good habitat then surely the fire is good for the plants and animals that depends on it. It also strikes me that really thick gorse isn’t actually that good for a lot of plants and animals so again it periodically burning down maybe a good thing because you get a transitional and more dynamic ecosystem with increased biodiversity.

  1. There was also a gorse fire at Altikeeragh Nature Reserve, Co ‘Derry, NI last night, maybe for similar reasons.

  2. This is an insightful article, though I don’t think it is at all accurate to say that the Molinia jungle is the result of 25 years of rewilding! Dartmoor has been continually grazed by livestock over that time, thus not rewilded by any real definition of the word. A reduction in stocking density is bound to have led to an increase in some grasses and gorse, but this is a temporary transitional state, not the end-result of something. In truth I think rewilding any part of the moor would need to incorporate a rather unwild degree of management such as tree protection and planting if any great changes were to be seen in our lifetimes, precisely because succession is slow.

    I hope money can be found for a larger rewetting project – I am surprised to hear there are so many unexploded ordnances left on the moor. Surely the cost of clearup is the military’s responsibility?

    • There are problems with rewetting Dartmoor after 8000 when the mires looked after themselves and i understand that there was no sphagnum
      1000 yrs ago but wood in the mires.
      There is no doubt in my mind and Dr Tom Greeves that it’s better to leave them alone . Creating wood or stone blocks with digging stops natural regeneration. The wet areas soon dry out in a hot summer and the idea that the mire is wet means liver fluke and worm burdens grow. Wetting areas can restrict areas from stock and leers that allow new born stock to be resistant to red water and other tick born disease . Geoff Eyre will tell you that a good storm can remove all or part of the dams !

  3. “this is a temporary transitional state, not the end-result of something” – is it? If gorse, bracken, Molinia and other fire adapted plants manage to repeatedly suppress competitors by promoting fires with the help of arsonists, swalers, lighting strikes, BBQs etc. then surely they would count as fire-climax vegetation? I’m also not sure if putting artificial plantations on Dartmoor counts as ‘rewilding’. That’s not to say it would or would not be a good idea but I’m not sure it makes sense to justify it on ideological grounds because trees = rewilding.

    • I agree that plantations are not ‘rewilding’, I referred to them as ‘unwild’ and wasn’t partcularly advocating for them. I do suspect molinia dominance on the moor is transitional because we know Dartmoor was more diverse a few thousand years ago, prior to large-scale grazing by humans. A plant community relying on anthropogenic inputs such as grazing and fire would be classed as a plagioclimax community – a community ‘delayed’ from reaching it’s climax by human activities. But I think what you were pondering is if molinia dominance has become the new steady state? Have human activities on the moor permanently altered the species dynamics towards molinia grasslands? This is a really interesting question. Pollen records show Dartmoor’s more diverse pockets of natural vegetation and woodlands that existed prior to the arrival of a significant number of humans. It seems likely that grazing and climate have the main agents of change. If we withdrew ourselves and our livestock completely from the landscape, what would it look like in a few thousand of years? We can’t know, but I think in that scenario, whether molinia remained dominant across such vast areas would depend on climate and wild grazing extent and grazing species. Ultimately, it is long term climate patterns that are the strongest influence on plant community evolution over vast timescales, but human use of the moor for grazing has played a huge part as well.

      • Yes a lot of woodland was lost during the Iron Age and I suspect some of that will return over the coming years as hill-farming re-structures itself, I think the presence of bracken indicates the most likely places. With regards to Molinia the pollen record suggests that it yo yos with heather depending on the level of grazing pressure. I’m sure that the jungle is just a phase which will remain while the peat recovers from the hedge days and atmospheric pollution but it will probably take decades

  4. Surely an increase in pony numbers would be the answer for the Mollina, which would be the cheapest way to a degree of rewilding if subsidised?

  5. We could get some of the young farmers to work together, build a mob of Galloways, leer them, (the moorland farmers have horses/quadbikes, they would just need to dedicate time to training), put the mob to work. I think we could do that. There is still hardy Galloway stock around the Okehampton area and out towards Chagford, there’s hardy stock up in Cumbria, etc etc. Put together a breeding plan, encourage young farmers to work together, provide a few cattle each and share the work leering them. The young farmers know each other really well, they’re quite a strong network … find a way to make it pay, set them to work.

    • And at the same time, address over grazing of sheep around the edges. Its lazy farming, that idea you just dump all your stock out the nearest gate to clear your fields … and leave it there. Most farmers know that has to stop and they’re right.

      • We graze sheep on Dartmoor all year around. We try to keep them away from the edges, as you put it, but they come bck for shelter and the sweeter grass. We haven’t been able to swale our common for 2-3 years now because of no insurance, wet spring the covid last year and Molina grass and overgrown areas dont encourage sheep so stay away from the edges! Is catch 22 !

  6. Again you right ….. it has been discussed over and over ….. economics gets in the way … with regards to leaving stock by the moor gate ….. they get away with it …. no easy answers at the moment but the end of the Basic Payment Scheme will focus minds …

  7. The process described doubtless explains hill fires in February – however really misrepresents rewilding. The vast majority of Dartmoor is a million miles from rewilded. It’s a very damaged human landscape which we have decided looks pretty. Possibly substantial peat restoration (re-wetting) would amount to restoration as a basis for recovering some kind of “wild”, combined with facilitated re-afforestation and refaunation depending on local conditions – which would of course require some thinking about more natural grazing – Galloways being a good candidate “in the mix”. What you describe is replacement of one problematic human-sponsored system with another – characterised by dried out peat and military ordinance. Restoration may be eye-wateringly expensive but then we’ve been living on ecological credit for centuries and maybe the piggy bank is nearing empty? Re-wetting has potential to offset some of its cost in carbon storage and biodiversity gains providing we can find a way of accounting for that properly.

    • Thanks for your comments. I accept my comment around re-wilding was a little clumsy and you are not the first to point it out. There are a lot of folk in and around Dartmoor who use the phrase re-wilding as a proxy for ending farming – my comment was aimed at them. As a bit of background about myself, I used to work at Wicken Fen and am the architect of the Wicken Fen Vision, where we introduced Konic ponies and Highland cattle as the agent of the re-wilding work. I will be writing more on the Dartmoor fire in the next few days and I will make it clear that the Wicken Vision without Koniks and Highlands would not have delivered what it has and that Knepp without Longhorns, Exmoors, deer and pigs would not have made the headlines. Best wishes Adrian
      Here’s a bit on Wicken I wrote

    • With regards to re-wetting – massive supporter of it – I’m just making the point it is doubly expensive on Dartmoor because of the ordnance issue and as the hydrologists tell me only so much of the blanket bog is actually amenable to re-wetting now as a result of historical activities such as peat cutting.

  8. Restoring hydrological function to those areas should be an absolute priority, which will result in more bidiversity, more carbon sequestration and more fire resilience.

  9. Thanks for expanding my knowledge and I’m very surprised at how much unexploded ordnance is on the Moor, I’m presuming the military know where it is and how safe is this Ordnance.

  10. …… if only…. the cost is that they have to check out all the areas where the diggers will be working … the MOD have no idea, so it involves specialist teams coming in to search and yes these do find some and those then have to be de-activated …. done by private company not the MOD … £££

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  13. So informative, Thankyou. Regarding re-wetting I wish the science behind this was made available. So difficult to find evidence of benefits, but certainly plenty of money available for it. I also wish they would stop using heavy plant as SWW currently doing on White Horse Hill. So near the 3,500 year old cist and potentially undiscovered archaeological features in this landscape that is so rich in prehistoric remains. A spade and wheelbarrow in these sensitive areas would be less invasive.

    • I don’t have a problem with small scale swaling carried out on shallow peat to get the gorse into a rotational mosaic, assuming it is well before the bird breeding season. The problem with swaling Molinia on the deeper peat is firstly there are obviously now not enough animals to graze the re-growth and there is a danger the peat will be damaged as part of the process. The Catch 22 is that wildfires are very likely to occur and these are much more likely to damage the peat compared to planned limited scale cold burns. It is a big muddle and mess!

      • I appreciate such a detailed response.

        If I may ask one more – Is this because the ground can’t be rewilded/ become woodland?

        Or because its too costly and time consuming so it’s better to keep it in astate that has little or no wildlife just because its a carbon store?

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