Tag Archives: climate change

A songbird makes a welcome return

The Cirl Bunting is an attractive songbird once found throughout the southern half of the UK.  Its numbers declined precipitously in the second half of the 20th century following changes in farming practice and, by the late 1980s, it was confined to coastal farmland in south Devon and might have become nationally extinct.  The Royal Society for the Protection of Birds (RSPB) recognised the problem and worked with farmers to support the bird resulting in a dramatic increase in its numbers. In a recent expansion of its range the bird has established itself in East Devon at Stantyway Farm near Otterton having been absent for more than 30 years.  I wanted to find out more so I went to Stantyway to see for myself.

Male cirl bunting (photo generously given by David R White)
Female cirl bunting (photo generously given by David R White)

The Cirl Bunting was first reported in the UK by Montagu in the winter of 1800 near Kingsbridge in south Devon in the west of the country.  It is roughly sparrow-sized and the male, in particular, is very distinctive with its black and yellow striped head and olive-green breast band.  The bird gradually spread across the southern half of the UK, its numbers peaking in the early years of the 20th century.  Since then it has declined and by the late 1980s only 118 pairs remained, confined to coastal farmland between Plymouth and Exeter.

With the Cirl Bunting facing national extinction, the RSPB identified changes in farming practice linked to agricultural intensification as responsible for the precipitous decline.  In the winter, the bird forages for insects and spilt grain in weedy stubble fields.  In the summer, it nests in hedges or scrub and forages on unimproved grassland rich in invertebrates with grasshoppers being important food for chicks.  With agricultural intensification, there was a shift from spring-sown cereals to autumn sowing so that far fewer arable fields were left as winter stubble; grubbing out of hedges took away nest sites and loss of the hay meadows and increased use of pesticides reduced invertebrate numbers and summer food for the bird.

Once the cause of the decline had been identified, the RSPB worked with farmers in south Devon to support the birds by reinstating some traditional agricultural practices, supported by government agrienvironment schemes.  The effect was spectacular and by 2016, numbers of Cirl Buntings had increased to over 1000 pairs. Most of the increase occurred in the bird’s core range but there was some spread along the coast and inland where habitat was suitable.   This was a major conservation success, also benefitting other species.

The coast of south Devon showing the core range of the cirl bunting and the location of Stantyway Farm across the Exe estuary in East Devon (from British Birds).

The bird has a reputation for being sedentary and it had been assumed that the estuary of the river Exe would be a barrier to further eastwards expansion of its range.   So, it was a surprise when, around the end of 2010, a single Cirl Bunting was seen at Stantyway Farm near Otterton in East Devon followed by several more sightings early in 2011.  Since then, the numbers at Stantyway have increased suggesting that the local conditions suit the birds and from 2015 it was clear that a breeding population existed.

Stantyway Farm is owned by Clinton Devon Estates and when the tenant, Mr Williams, retired in 2014, the farm was taken back into Clinton’s own Farm Partnership.   Clinton Devon Estates were keen to support Cirl Buntings and other species on their arable farm at Stantyway so they took advice from the RSPB and applied for agrienvironment support.  This was awarded in 2016 and supports planting hedges to provide more nest sites, leaving wildlife margins around fields to provide invertebrates as summer food, and planting spring cereal crops that are harvested in the autumn leaving weedy winter stubbles with seed as food.  These are all activities shown to be critical in supporting these birds in south Devon.  The farm was also put into organic conversion in 2016; organic farming by its nature supports wildlife and increases invertebrates.  Cirl Bunting numbers at Stantyway gradually increased across this time.

In 2017, Clinton Estates advertised for a new tenant farmer at Stantyway and Sam Walker was appointed.  Although the farm is still mainly arable, Sam keeps 52 cows whose calves are raised and sold on to beef finishers.  About a third of the land is now devoted to grass for silage production for winter animal feed.  Sam has, however, embraced the existing philosophy of the farm in supporting wildlife: he has maintained the organic status and intends to apply for further agrienvironment support when the current scheme runs out in 2021.

I wanted to see the farm for myself so, on a mild early April day, I went to Stantyway.  I left the car on the rough ground across from Stantyway Farmhouse and stood for a few moments enjoying the sunshine.  The air was filled with the endlessly inventive song of the skylark and occasionally a buzzard mewed as it circled lazily overhead.  Sometimes a low buzz cut through all of this and when I looked, I realised this was from all the insects about.

I walked away from the farm along the gentle downhill slope of Stantyway Road with views developing over rolling East Devon countryside on one side and to the hazy mid-blue sea on the other. The lane descended between wide grassy verges backed by luxuriant hedges. Spring flowers grew through the thick grass including stitchwort, celandine, dandelions, violets and white dead nettle.  The dominant flowering plant was, however, alexanders, with its fleshy green stems, copious shiny dark green foliage and pale mop head flowers.  This was proving very popular with many kinds of fly and a selection of solitary mining bees, some collecting large lumps of white pollen on their back legs.

My walk included a long section of the coast path skirting the edge of Stantyway fields.  Thick scrubby hedges, mainly flowering blackthorn, lined the cliff edge along with more alexanders. The occasional hedge break afforded spectacular views along the red cliffs of the Jurassic Coast towards Ladram bay with its crumbling stacks, past the white elegance of Sidmouth and finishing in the chalk of Beer Head (see picture at the top).   Again, there were many solitary mining bees taking advantage of the flowers.    I did not see any Cirl Buntings on my walk but, on two occasions I heard their distinctive, rattling, metallic trill telling me the birds were about.

It’s a beautiful place made all the better by glorious early April weather and I was surprised to see so many insects along the paths.  Perhaps this reflects the methods used at Stantyway, showing that productive farming and wildlife can coexist and prosper. Around the farm, each field gate has an information board giving the crop and some other useful information.  An Honesty Café has been installed near the farmhouse providing continuous hot water for tea or coffee and homemade cakes that I can strongly recommend.  All of this suggests an outward looking, open approach to farming.  When I met Sam Walker, the farmer, he explained that, in addition to the provisions of the agrienvironment scheme, he has put skylark plots in cereal fields, created wild bird seed corridors and put up swift boxes to support wildlife.  I came away feeling that at Stantyway, Cirl Buntings were getting the best support they could.  His methods have already benefitted other farmland birds with numbers of skylarks and reed buntings doubling over the past year and in a further twist to the Cirl Bunting story, some of the birds have now been seen to the east of Sidmouth.

I should like to thank Sam Walker, Doug and Joan Cullen, Kate Ponting and David White for generous help in preparing this article which appeared in the May edition of the Marshwood Vale Magazine.

 

sign
One of the farm gate signs

 

Alexanders and blackthorn
Alexanders (greenish-yellow) and blackthorn (white) along the coast path. The cliff edge is behind the hedge!

 

Solitary mining bee on Blackthorn
A solitary mining bee (probably Andrena flavipes) feeding from blackthorn.

 

Solitary mining bee on Alexanders
A solitary mining bee (probably Andrena nitida) feeding from Alexanders

 

Honesty Cafe
The Honesty Cafe at Stantyway Farm

 

Change is coming whether they like it or not

[This post is dedicated to the 100s of  MPs who  chose not to attend a debate in parliament on climate change in a week when the UK experienced its hottest ever winter’s day.]

 

Blizzards, strong winds, drifting snow, bitter cold – that was the story in early March last year when the “Beast from the East” collided with storm Emma bringing extreme weather and disruption to life across large parts of the UK.  Towards the end of June, by contrast, the sun began to shine and daytime temperatures climbed into the thirties and stayed that way across much of the country until August (the picture at the top of this post shows the effect of the long hot summer on the UK countryside).  Elsewhere across the globe, reports came in of flooding, wildfires, severe tropical storms and unusually high and low temperatures.  Many of these weather extremes can be attributed to climate change and there is considerable concern that the planet is heading for climate catastrophe.  David Attenborough expressed this fear at a climate change conference in Poland:  “If we don’t take action, the collapse of our civilisations and the extinction of much of the natural world is on the horizon.”

 

Heavy snow falling in early March while a great tit continues to feed

 

In the UK, it was the long, hot summer, the joint hottest on record, that made people think most about a changing climate.  The weather here is, of course, notoriously fickle and some will remember that in 1976, we experienced a similar long, hot, dry summer, so how can we disentangle normal weather variation from climate change?  One way of looking at this was shown by Simon Lee, a PhD student at the University of Reading, who shared graphs on Twitter of the global temperature anomalies in June 1976 and in June 2018 (see pictures below).  These show that in 1976 the UK was one of a few unusually hot spots in an otherwise cooler than average world whereas in 2018 much of the world, including the UK, was hotter than the average.   The 2018 picture shows climate change in action: the planet is warmer making heatwaves more likely.

 

The pictures show temperatures across the world in June 1976 (upper panel) and in June 2018 (lower panel) compared to the average across the period 1951-1980. Red and yellow mean higher, blue means lower. Kindly supplied by Simon Lee who generated the images from NASA/GISS data.

Careful measurements of the average surface temperature of the planet show that it is currently about 1oC hotter than in pre-industrial times.  This may not seem very much but it is enough to disturb the complex systems that create our weather.  As a result, heatwaves may be more frequent in summer and, in winter, polar air may be directed southwards bringing abnormal, freezing temperatures.  Also, a warmer atmosphere holds more moisture so that rain and snow may be more severe.  Climate breakdown might be an apt description of these changes.

This global heating is a result of human activity.  The emission of greenhouse gases, particularly carbon dioxide produced by burning fossil fuels such as coal, gas, oil and petrol, traps heat in the atmosphere so the temperature of the world increases.  We have known this for some time and we have also known that the solution is to reduce carbon emissions. Atmospheric levels of carbon dioxide have, however, continued to climb because no government has had the will to introduce the extreme lifestyle changes required to curb emissions.  Some governments, including our own, have even encouraged the continuing extraction of fossil fuels.

It is, therefore, significant that in October 2018, the Intergovernmental Panel on Climate Change (IPCC) issued a report containing a dire warning: we must make urgent and unprecedented changes to the way we live if we are to limit heating to 1.5oC above pre-industrial levels.  To achieve this target, we must reduce net global carbon emissions by 45% by 2030 and to zero by 2050 – fossil fuel use must be drastically reduced by the middle of the 21st century but we must start the reduction now.  Should we fail to achieve this 1.5oC target, the risks of drought, flooding, extreme heat, poverty and displacement of people leading to wars will increase significantly.  The world will no longer be the place we know and love and parts of it will become uninhabitable for humans and the rest of nature.

How do we achieve this reduction in carbon emissions? Voluntary measures such as suggesting people fly or drive less will not work.  The only way this reduction can be achieved is through coordinated government action based on recommendations made in the IPCC report.  These include the planting of more forests and the chemical capture of carbon dioxide to reduce atmospheric levels of carbon dioxide.  There must also be a drastic shift in energy production and in transport away from fossil fuels and this can be driven in part by investment and subsidies directed towards clean technologies.  A carbon tax can also help drive this shift but the tax will need to be high enough to force change, for example by taxing energy companies who burn fossil fuels so that they invest in cleaner technologies.  In the short term, costs to consumers may rise, so politicians would need to keep the public on side, for example, through tax incentives.  If we grasp the opportunity, the scale of change may have the unexpected bonus of allowing us to design more sustainable and equitable societies.

The IPCC report set out very clearly the changes required to avoid damaging global climate change so there was great anticipation when the UN Climate Change Conference convened in Katowice in Poland just before Christmas.  Astonishingly, given the gravity of the situation, the 200 countries represented there failed to agree new ambitious targets for greater reductions in carbon emissions. Four countries (USA, Saudi Arabia, Russia and Kuwait) would not even sign a document welcoming the IPCC report; these countries are of course all oil producers.

It was at this conference that David Attenborough issued his warning about the collapse of civilisations but there was another hugely impressive intervention.  This came from 15-year old activist Greta Thunberg from Sweden.  She had already achieved some notoriety through her weekly climate strikes where she missed one day of school to protest about climate change.  Her actions have stimulated many thousands of young people around the world to do likewise.  Thunberg also spoke in London at the launch of the new grass-roots movement, Extinction Rebellion, which intends to use peaceful protest to force governments to protect the climate.  These new trends offer some hope for the future since it is the young of today that will bear the climate of tomorrow.

Greta Thunberg, 2018 (cropped)
Greta Thunberg

Here is part of Greta Thunberg’s speech given at the Katowice conference:

“For 25 years countless people have come to the UN climate conferences begging our world leaders to stop emissions and clearly that has not worked as emissions are continuing to rise. So, I will not beg the world leaders to care for our future, I will instead let them know change is coming whether they like it or not.”

“Since our leaders are behaving like children, we will have to take the responsibility they should have taken long ago. We have to understand what the older generation has dealt to us, what mess they have created that we have to clean up and live with. We have to make our voices heard.”

I am grateful to Simon Lee for generously supplying the temperature anomaly graphs.

This article was published in the March 2019 edition of the Marshwood Vale Magazine.

Magical midsummer meadows

Last summer, on one of the hottest days of the year, I joined a walk led by Nick Gray of the Dorset Wildlife Trust through some traditionally managed meadows in Dorset’s Marshwood Vale. We found fields filled with lush grasses, colourful wild flowers and a profusion of insects. This outpouring of joyous, exuberant growth seemed to embody the essence of high summer and the walk turned out to be one of my wildlife highlights of 2018.

Marshwood meadow 2
Lush grasses in the meadow

 

We started from Babers Farm below the village of Marshwood and, after a short walk across several fields clad only in a veneer of golden stubble, we crossed a field boundary to enter another world. Here a thick carpet of knee-high grasses dominated the sward, still green despite the long spell of hot weather. Richly coloured flowers were woven into the grassy fabric and many small brown butterflies danced among the seed heads. A transient flash of orange was probably a silver-washed fritillary butterfly. Grasshoppers leapt from the grass in broad arcs as we walked and brightly coloured insects fed from the flowers. As I looked up at the bowl of hills surrounding the Vale, a kestrel, pale brown in this brash light, swept silently across the field. It was the perfect summer moment.

Perhaps it was a reaction to all the doom and gloom I had been hearing about our treatment of the environment and the resulting loss of wildlife? Perhaps it was a deeply buried childhood memory of family picnics among flowers on Dorset hills? Perhaps it was simply all the natural beauty around me? Whatever the reason, it felt, for a few moments, as though this was the only place in the world I wanted to be.

These meadows are managed under a higher-level stewardship scheme which pays for the loss of income incurred through traditional, less intensive land cultivation. The meadow flowers and grasses grow during the warmth and wet of spring and summer and hay is cut and removed in mid-July when flowers have mostly set seed. The aftermath growth is grazed by animals in the autumn after which the land is left until the following spring. It was the last day of June when we visited and high summer sees these meadows liberally studded with the flattened white umbels of corky-fruited water dropwort, a member of the carrot family and a Dorset speciality but rare elsewhere. The flowers were very popular with insects, especially hoverflies which buzzed loudly in small groups while hovering by the flowers in a courtship display. A female would sit on a flower head while a male hovered above her; sometimes another male would hover above the first in a “stack”.

The bright yellow slipper-like flowers of bird’s foot trefoil were also very common in the meadows, sometimes growing so prolifically that the flowers merged into drifts of sunny colour. This is such a common flower that we tend to overlook it but perhaps its very familiarity leads to the many popular names attached to the plant such as eggs and bacon, hen and chickens or granny’s toenails. Nick also told us that the plant may have useful anti-worming properties if consumed by sheep.

Dotted around the meadows, sometimes in large clumps, were the unruly purple flowers of knapweed. These are popular with nectaring insects and I saw a colourful burnet moth and several marbled white butterflies. Knapweed is also one of the plants with the popular name of Bachelor’s Buttons and Nick told us how, in the past, young women played a love-divination game with the flower heads. A young woman wanting to know if her affections would be returned took a knapweed flower head and plucked off the open florets. She placed the flower head inside her blouse and if, after an hour, new florets had opened, then her love would be reciprocated.

Here is the story told by John Clare in his poem “May” from the Shepherd’s Calendar:

They pull the little blossom threads
From out the knapweeds button heads
And put the husk wi many a smile
In their white bosoms for awhile
Who if they guess aright the swain
That loves sweet fancys trys to gain
Tis said that ere its lain an hour
Twill blossom wi a second flower
And from her white breasts hankerchief
Bloom as they ne’er had lost a leaf

A short walk across open countryside took us southwards towards the centre of the Vale, where we found another large traditionally managed meadow. As before, a rich mixture of thick grasses and colourful flowers dominated but I was surprised to find drifts of yellow rattle and a few orchids, looking rather the worse for wear. I began to realise that each meadow has its own character, its own flora, its own colours reflecting the underlying geology and dampness.

Several recent studies have highlighted the decline of insect and bird life in the UK. Factors contributing to this decline include climate change, habitat loss, pollution and pesticide use. For example, the 97% loss of flower-rich hay meadows in the UK during the 20th century linked to agricultural intensification must have seriously affected insect populations as well as birds dependent on insects for food. Some have gone so far as to suggest that unless we modify farming methods, we shall face “Insect Armageddon”. This needs to be taken seriously owing to the important role insects play in, for example, maintaining soil health, digesting waste and pollinating our fruit and flowers.

The meadows that I visited last summer in the Marshwood Vale send a positive message showing that, with careful management, these important habitats can be restored to their former glory, supporting insects and providing food for birds. In more good news, the Magical Marshwood Vale Project (funded by National Grid and coordinated by Dorset AONB and Dorset Wildlife Trust) started in 2018 with the aim of enhancing traditional landscape features and helping to reinstate ecologically important wildlife habitats. This includes the restoration of more wildflower meadows.

I should like to thank Nick Gray for his advice and enthusiasm.

Black and yellow long-horn beetle on corky-fruited water dropwort, The beetle has lost nearly all of one antenna.
Black and yellow long-horn beetle on corky-fruited water dropwort, The beetle has lost nearly all of one antenna.

 

Swollen thighed beetle on corky-fruited water dropwort
Swollen thighed beetle on corky-fruited water dropwort

 

Birds foot trefoil
Bird’s foot trefoil (with a green insect on the upper right hand side of the picture)

 

Marbled white butterfly on knapweed
Marbled white butterfly on knapweed

 

Burnet moth on knapweed
Burnet moth on knapweed

 

Meadow Grasshopper
Meadow Grasshopper

 

This article appeared in the January 2019 edition of the Marshwood Vale Magazine.

Death and destruction at Dawlish Warren

As we stepped off the train at Dawlish Warren station, we had our first glimpse of the river Exe, its waters a sparkling pale blue in the bright sunshine.  The weather was a welcome change after so many cold and snowy days but, during our short journey from Totnes, we had passed bright ridges of snow still piled against field hedges and, in low lying places, large lakes of standing water from snow melt.  Perhaps the weather was giving us a gentle reminder of its power to disrupt life.

We hadn’t intended to visit Dawlish Warren again so soon (see here for a description of our previous visit) but we wanted to get out for a walk and, hearing that some country roads were still snow-blocked, we chose somewhere easily accessible.  We also wondered how the recent extreme weather might have affected this beautiful sand spit.

The view from the promenade quickly told us part of the answer.  Sand was piled up on the retaining wall that slopes to the beach and, along the promenade, some of the benches were partly submerged in sand as if caught by a pale brown snow storm.  On the beach, huge quantities of wooden debris lay in random heaps, along with some very large plastic items; it will be a mammoth task to clear this.  A closer look showed that the debris was a mixture of wood and reeds along with bits and pieces of plastic and many industrial plastic pellets (mostly grey nurdles).  I don’t want to go on too much about these industrial pellets, I’ve written about them several times already, but we found them littering all the beaches at the Warren to a greater or lesser extent.  Near the promenade there must have been thousands.

As we were picking up a few of the pellets, a woman asked Hazel what she was doing.  After an explanation, the woman said:

“I thought you were picking up driftwood,” and after Hazel had shown her some pellets the woman continued “still they might be very nice for decorating a mirror.”

 

We then walked around the Dawlish Warren sand spit following the route I outlined in a previous post, which also gives some background information about this nature reserve.

The central area of the Warren was partially flooded but still passable.  No spring flowers were to be seen yet but small birds were performing florid mating displays while a group of black corvids sat judgementally in a nearby tree.  Vegetation along paths over the dunes was seemingly spray-painted with a coat of rough sand, probably a result of the blizzard sucking up material from the beach.   Near the bird hide, I disturbed a large flock of Brent geese feeding on the golf course.  These imposing birds took off as a group and circled low over us before moving to a quieter spot.

Warren Point at the end of the sand spit was as mysterious and beautiful as always, its pale marram grass covering glowing in the sunshine. A small flock of linnets, the males with their pink bibs standing out, fidgeted in the branches of a low bush.   A skylark rose from the ground, wings flapping frantically as it hovered in mid-air, singing, turning a tune over and over, changing it each time.  Then, without warning, it stopped flapping and deftly descended back to the ground with subtle, steadying wing movements.

The story on the beaches bordering Warren Point was less uplifting.  There was a slew of debris along the strandline, mostly wood and reeds but also many dead birds. We saw at least twenty casualties, mostly lapwings, identified by their largely black colouring combined with russet brown and white undersides.  During the storm there had been a mass movement of these birds across the Warren and a proportion didn’t survive.  We also saw one or two golden plovers with their exquisite pale brown and white herringbone patterns.  On the beach facing up the Exe, the low sand cliffs at the back of the beach had been damaged by high water and when we rounded the point to walk back, there were more signs of storm damage.  Areas of marram grass had been torn out and reddish soil had been deposited on the edge of the remaining marram grass.

The most significant damage, however, had occurred to the taller sand cliffs that abut the groynes on the sea-facing beach.  Sand had been washed away from the back of the groynes and several metres of sand cliff removed exposing, in some places, the old sea defences.  Some of the new fences built on the reinforced dune ridge had been torn out and now lay on the ground in casual heaps or hanging in mid-air, still partly attached.  The groynes themselves seemed to be intact but plastic notices attached to them lay in pieces among the other debris.  In a powerful demonstration of the scale of the storm and the water level reached, small pieces of wood and more plastic pellets lay along the wooden planks of the groynes and on top of the main support posts nearly a metre above the sand.

Despite all this, the Warren itself is intact and ready for the bloom of spring flowers. The scale of the damage to the new sea defences was shocking and a salutary reminder of the power of the sea, but at least the defences did hold.  Elsewhere in south Devon, the coast road linking Torcross and Slapton was almost completely washed away.  As in 2014, when the Dawlish railway line was destroyed, this year’s damage was the result of a combination of high winds and very high tides, perhaps combined with increased sea level.

As we waited at the station for our homeward train, I noticed willow trees by the platform with many plump, pussy willow catkins.  A medium sized buff-tailed bumblebee arrived to collect pollen from the lemon-yellow male flowers.

We visited Dawlish Warren on March 6th 2018

Debris on Dawlish Warren Beach
Sand heaped on the retaining wall and debris piled on the beach at Dawlish Warren

 

Debris on Dawlish Warren Beach close up
Some plastic debris on Dawlish Warren Beach

 

Plastic pellets Dawlish Warren
A selection of plastic pellets found on Dawlish Warren Beach. If you enlarge this picture and look around you will see several clear plastic nurdles, several yellow ones and many cylindrical pellets (grey, pale blue and white). Also a few biobeads noted for the fine ridges around the outside. The larger plastic balls are not nurdles or biobeads.

 

Brent Geese take flight at Dawlish Warren
Brent Geese take flight above the inner bay at Dawlish Warren (photo by Hazel Strange)

 

 

Dead lapwings at Dawlish Warren
Several dead lapwings
Damaged sand cliffs at Dawlish Warren
Damaged dune cliffs and fences

 

Debris on groyne post at Dawlish Warren
Debris on top of groyne post

 

Dune fences destroyed at Dawlish Warren
Damaged dune cliffs and fences

 

A barbecue summer – but what about the charcoal?

 

Sunny days, long evenings, a barbecue at the beach? Sounds idyllic doesn’t it? But as we light the charcoal , do we ever think about where it comes from? I wanted to know, so I went to Higher Halstock in north Dorset to meet woodsman and charcoal burner, Rick Smith.

Halstock Vale
The countryside approaching Halstock

 

From Winyard’s Gap I followed a narrow lane downhill, past woodland and open pasture, between verges full with spring flowers. It was the first noticeably warmer spring day of the year and the low morning sunshine seemed to breathe new life in to the Dorset countryside. At the sign for Winford Rural Workshops I parked and went to look for Rick Smith. I found him leaning over one of his kilns, unloading charcoal in to sacks labelled “British Barbecue Charcoal”.

Rick Smith
Rick Smith by one of his kilns

 

The origins of charcoal

Most people nowadays know charcoal for the richly glowing fire it creates in their barbeque, but the fuel has a long history and enabled one of mankind’s earliest technologies, the smelting of metals. Charcoal is made by heating wood in a low oxygen atmosphere so that it carbonises but does not burn; moisture and other volatile substances are driven off and eventually the large molecules making up the structure of wood are broken down, leaving the carbon and a little ash. Because charcoal is largely carbon, it burns in the presence of oxygen at a much higher temperature than wood and that’s one reason why it’s good for the barbecue.

The big discovery, several thousand years ago was that not only was a charcoal fire hot enough to melt and work metals but that the fire released pure metals such as copper from their ores. This is smelting, a technology that allowed man to move from the Stone Age to the Bronze Age. The same basic technology continued to be used, with charcoal as a fuel, until the beginning of the 18th century when coke took over. Until that time, charcoal was made by skilled itinerant workers, charcoal burners, who lived solitary lives in woods where they could continually oversee their work. The craft of charcoal burning has been revived by a handful of people in Dorset, and Rick Smith is one of these.

Charcoal burning

Kilns

Rick showed me the kilns he uses for making charcoal (charcoal burning). These are large metal cylinders about 3 metres in diameter set in to the ground with several ports at ground level that allow air to enter and escape. Each kiln is filled with wood, dried outdoors for a year before use and arranged in the kiln so that air can circulate. The fire is started by pouring lighted charcoal in to the centre of the kiln and the lid is placed loosely on top. Rick watches the fire spread through the wood and once it is uniform, he seals the lid and places chimneys on half the ports to act as flues. Air in the kiln can be regulated through the other ports and kept at a low level so that the wood is carbonised but not burnt. The experienced charcoal burner knows the state of the fire from the colour of the smoke.

The kilns need to be watched carefully throughout this phase of the burn which lasts 12-18 hours, and Rick stays on site in a cabin for the entire period. I wondered how he felt about this commitment.
“It’s part of the job, but anyway, this is an amazing place to be, especially at night” he explained “no noise pollution, no light pollution, just imagine the stars!”
When the colour of the smoke changes from white to blue, Rick knows that the conversion of wood to charcoal is complete; he seals the kiln completely and allows it to cool for another 24 hours. The fuel is then ready to use, a jumble of pieces of charcoal, still retaining the original shape of the wood but now a mosaic of greys, blacks and silvers.

charcoal

Coppiced woodland

woodland 4
Coppiced woodland in the late spring

 

blackthorn
Blackthorn

 

Most of the wood used in Rick’s kilns comes from woodland adjacent to the site. This is ancient semi-natural broadleaf woodland containing mainly blackthorn and hazel, managed by the traditional technique of coppicing where trees are cut to the ground periodically and the stool left to regenerate. New shoots grow vigorously providing they are protected from browsing deer, forming multiple new stems which are ready to be cut again and used for charcoal burning after 7-10 years. Because there is continuous renewal, coppicing is a sustainable process; it also keeps the wood light and airy, encouraging wildlife among the trees and on the woodland floor. When I visited, the woods were a tapestry of bluebells and celandine, birds were singing and bumblebees were feeding from yellow archangel.

bumblebee2
Common carder bee on yellow archangel

 

Barbecue charcoal – think before you buy

charcoal sacks
British Barbecue Charcoal from Rick Smith’s kilns

 

The British love affair with the barbecue consumes a massive 60,000 tons of charcoal each year, 90% of that being imported. Namibia is the UK’s biggest supplier and much of this charcoal is produced under dismal circumstances using illegally harvested trees leading to deforestation and lack of sustainability; working conditions are deplorable and archaic equipment is used causing damage to both the environment and to workers’ health. Major supermarkets buy imported charcoal in bulk to drive down prices but at least they now require that the product bears the FSC (Forest Stewardship Council) label; this provides some oversight of production methods but the labelling system seems far from watertight. Non FSC charcoal is still imported in to the UK for barbecues and the restaurant trade.

British Barbecue Charcoal, the sort Rick Smith produces, avoids all of these problems: it is produced using sustainable methods that support rather than destroy ancient woodland; it often contains a higher percentage carbon than the imported product so that it burns better and, when you buy locally, carbon emissions from transport are minimal compared with the 5000 mile journey from Namibia. Home-produced charcoal is widely available and buying the local product supports local employment. What could be better?

Lady's Smock
Lady’s Smock growing on the Winford Rural Workshops site at Higher Halstock – Rick leaves these plants to flower to provide food for the Orange Tip Butterfly

 

This article appeared in the July 2016 edition of the Marshwood Vale Magazine. It was chosen by Science Seekers as one of their Picks of the Week.

The surprising story of oil in Dorset.

[Please read the important amendment at the end of this article]

A few months ago, I visited Kimmeridge Bay in Dorset in the south west of the UK.  I went  to look at the oil well on the cliffs above the beach and wrote about my experience.  The Kimmeridge oil reserve is quite small but further east there are huge additional reserves of oil extending for several kilometres under Poole Harbour and Poole Bay.  I wanted to write about these much larger deposits and the environmental effects of extraction: my article, which also takes another look at some of the Kimmeridge story, appeared in the May edition of the Marshwood Vale Magazine. Here is the article:

It’s difficult to believe but one of the most beautiful parts of Dorset in the south west of the UK is home to the largest on-shore oil field in Western Europe. And yet the day to day impact on most residents and on the local environment is minimal. Perhaps the Dorset oil experience can help us predict the potential environmental effects of shale gas extraction by fracking in other parts of the UK? Let’s look at the story of oil in Dorset and see what we can learn.

“Kimmeridge Coal”

Medieval times were harsh for most people but if you lived near Kimmeridge Bay in the Isle of Purbeck, you had one thing going for you; some of the rocks exposed in the cliffs would burn so you had a ready-made fuel for heating and cooking. The locals called it “Kimmeridge Coal” and it didn’t matter that it smelt awful, it was available and it was free. The same logic drove Sir William Clavell in the 17th century to set up alum works at Kimmeridge using the fuel. His efforts came to nothing because of patent restrictions so he turned to making salt by boiling sea water and subsequently he set up a glass works, but neither enterprise prospered.

“Kimmeridge Coal” is found in bands of bituminous shale in the cliffs around Kimmeridge Bay but further exploitation of the material had to wait until the 19th century when it was realised that useful hydrocarbons might be extractable. Processing plants were set up at Weymouth and at Wareham making varnish, grease, pitch, naphtha, paraffin and paraffin wax and in 1848 the street lights of Wareham were lit by 130 lamps powered by gas derived from the shale. The industry never prospered, possibly because the high sulphur content made the gas unsuitable for domestic use.

Kimmeridge oil shale is a useful material but it is not a source of conventional crude oil. Ironically, the first discovery of crude oil in Dorset also occurred at Kimmeridge Bay but it comes from rocks lying well below the shale deposits.

The Kimmeridge “nodding donkey”

Oil pump
The Kimmeridge nodding donkey

The search for oil in Dorset began in the 1930s but it was not until 1959 that the first well producing oil and gas was discovered below Kimmeridge Bay. The well is extracted by a single beam “nodding donkey” pump on the cliffs above the Bay that has worked continuously for more than 50 years; it is the oldest working oil well in the UK and the “nodding donkey” is now part of the local scenery. The Kimmeridge well produced 350 barrels of oil a day at its peak but this has now declined to a fifth of that level. Although the Kimmeridge reservoir is not large, the discovery prompted the search for other oil deposits in Dorset.

The largest on-shore oil field in Western Europe – hidden near Poole Harbour

The energy crises of the 1970s led to further exploration in Dorset and in 1974, oil and gas were discovered by the Gas Council at Wytch Farm on the southern side of Poole Harbour. Production started in 1979 and nowadays the Anglo-French company Perenco owns the majority stake in the oil field. There are three large reservoirs of oil 1-2 km below the sea, extending up to 10 km under Poole Harbour, Brownsea Island, Sandbanks and to the south of Bournemouth. Peak production was in 1997 at 110,000 barrels of oil per day; current levels are about 18,000 barrels per day. The field also produces natural gas (for domestic use) and liquid petroleum gas.

nodding donkeys Wytch Farm
Some of the Wytch Farm nodding donkeys (photo courtesy of Perenco)

 

Furzey Island
Furzey Island in Poole Harbour showing the “hidden” oil wells (photo courtesy of Perenco)

 

There are 12 well sites distributed around Wytch Farm, the Goathorn Peninsula and Furzey island from which more than 100 wells have been drilled. There is also a gathering station where the products of the wells are collected, processed and distributed. This is a large industrial enterprise, the largest on-shore oil field in Western Europe and the second largest consumer of electricity in the South of England (after Heathrow Airport).

Hengistbury Head looking west
Poole Bay viewed from Hengistbury Head – oil reservoirs and long distance drills extend under the sea 1-2 km below the surface (from Wikipedia).
The paradox is that this industrial complex operates in an Area of Outstanding Natural Beauty so the site has been developed with this is mind. Buildings are on sites that have been excavated to reduce height and are screened by trees. Facilities are painted a dull brown and the number of well sites has been minimised by drilling long distances horizontally away from the well site in to the oil deposits; until 2008 Wytch Farm held the world record for the longest drill extending 10.1 km under Poole Bay. In consequence, this large industrial complex has minimal impact on the surrounding countryside and most people are unaware of the activity.

Goathorn Peninsula
An oil rig on the Goathorn Peninsula used for long distance directional drilling (Photo from Wikipedia, taken in 2006) .

 

Lessons from Dorset oil

Wytch Farm is a great success story, both in terms of the oil and gas produced and the minimal environmental impact. Some have used the Wytch Farm experience to suggest that fracking (hydraulic fracturing for shale gas) in other parts of the UK will also have a minimal environmental impact, even suggesting, incorrectly, that fracking has already occurred at Wytch Farm.

Although similar drilling technology is used to extract crude oil and to release shale gas, fracking uses large volumes of high pressure liquid (mostly water) to create fissures in low permeability rock and this has not been carried out at Wytch Farm. Also each potential fracking site is likely to be unique and different from Wytch Farm in terms of the density of wells required, the density of population and the nature of the countryside. Dorset oil has been managed to minimise environmental impact but it would be wrong to use the Dorset oil experience to predict the general environmental impact of fracking elsewhere.

There is, of course, one important issue I have not considered here:  should we continue to extract and use oil given the need to prevent global climate change?  Take a look at the complementary article for my views on that.

Important amendment:  In September 2018 it was revealed that the Kimmeridge oil pump has been legally  leaking the powerful greenhouse gas methane into the atmosphere for nearly 60 years.  The story is covered here.  This disclosure changes very considerably my view of the environmental impact of the Kimmeridge oil pump.

Renewable energy from a Devon river – the new Totnes Weir Hydro

About a mile upstream of the south Devon town of Totnes, the tree-lined tranquillity of the river Dart is interrupted by a weir. Water cascades over this concrete barrier and after heavy rain there is a spectacular display of power with swirling whirlpools and foamy white water. Slate-grey herons and sparkling white egrets stand sentinel by the weir and the occasional grey seal lurks below, waiting to feast on fish that linger too long. There has been a weir at this bend in the Dart since the 16th century, built originally to harness the power of the river; the present rather bland construction dates largely from the 20th century.

Totnes weir
The Totnes Weir viewed from the upstream pool. The picture shows the concrete weir after the installation of the new Hydro (off the picture to the right) and after a period of low rainfall so that water flow across the weir is quite low. The gulls are enjoying the calm conditions.

 

The weir is a downwards-sloping concrete barrier that interrupts the flow of the river so that a large pool of water accumulates upstream, isolated from the tidal downstream water about three metres below. This pool of water is a store of potential energy that was used in the past to drive several water mills in the town a mile away. A channel, the leat, ran from the pool all the way in to Totnes and providing the leat stayed above the level of the river it contained the energy to drive a water wheel. Only one mill building now survives: the Town Mill dating from the 17th century but with 19th century additions. This was used as a water mill until 1945 and currently houses the Tourist Information Centre. The leat is still intact and can be viewed along much of its path, through an industrial estate, under the main railway line and passing near the front of Morrisons superstore. The leat is celebrated in the name of the town’s large medical centre, the Leatside Surgery.

Water Mill
A water mill at Dartington in Devon showing the principle of the leat. The leat takes water from the stream and providing the leat stays above the stream it can drive the mill wheel.

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Turbine Building exterior
The turbine building of the Totnes Weir Hydro. The Archimedes Screws can be seen on the right.

 

Hydro and weir
The two Archimedes Screws alongside the weir

 

Over the past year, a neat, stone-clad, turf-roofed building has materialised by the side of the weir. This is the turbine house of the new Totnes Hydro which once again harnesses the power of the Dart. On the downstream side of the building are two tube-like structures roughly aligned with the descending surface of the weir, each tube containing an Archimedes Screw. Water from the pool behind the weir passes under the turbine building to enter the tubes, pressing on the blades of each Archimedes Screw causing them to turn and driving the turbines. The Archimedes Screws can be viewed from the downstream side and I find them mesmerising – turning steadily, water splashing, feeling almost alive – as they transform the potential energy of the water in to kinetic energy and subsequently electrical energy.

turbine in action
Renewable energy in action: a close up of water emerging from one Archimedes Screw.

 

When there is a good head of water, the turbines generate about 250 kW of power.  Output will depend on flow in the river (higher power after heavy rain) and the head across the weir (typically about 3m but reduced by spring tides).   Generation may cease altogether for about two weeks in a dry summer when water flow in the Dart is low.   Currently, the electricity generated is powering the local comprehensive school and an aluminium foundry on the nearby industrial estate and any surplus enters the grid.  To put this in to perspective the overall energy produced is enough to power the equivalent of about 300 homes. In time, the hydro will also provide electricity for the new ATMOS project.  This is a community-led development of homes and businesses on the former Dairy Crest site in Totnes.

The river Dart is an important route for migrating fish and the weir already contained a fish pass to help sea trout and salmon overcome the barrier. The pass was, however, in poor condition so that fish were having difficulty moving up the weir leading to losses to hungry herons and seals. The new Hydro project includes renovating the existing fish pass and building an additional modern fish pass alongside the turbine building. These should help migrating fish so that, in time, the piscine population on the Dart increases; new fish counters have also been installed to help monitor traffic.

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So far so good, but if equipment is installed to capture the energy of the river it is bound to alter the flow over and around the weir.   You can see this clearly on the upstream side of the turbine house where water in the pool flows towards the new building to enter the Archimedes Screws, eventually discharging in to the river below.   Although water flow through the turbines is carefully regulated by sluices to make sure that the weir does not dry out, less water now flows across the weir than before.  This redistribution of water has remodelled islands in the river downstream and night fishermen have had to relearn safety on the river.    We should not forget, however, that when the weir was first built and water was directed down the leat to power the Totnes mills some 500 years ago, water flow in the river must have been changed to a much greater extent.    There is also the question of noise.  The new Archimedes Screw turbines do emit noise as they turn and there is some splashing of water.  The turbine building is insulated and the current level of noise from the new installation is no more than I can remember coming from the weir on a full flood.

Water enters hydro
The pool of water behind the weir showing water preferentially entering the turbine building.

 

The Weir Hydro project was developed by the owners of the weir, Dart Renewables, working closely with the Totnes Renewable Energy Society (TRESOC). TRESOC was set up by local residents to enable the community to develop renewable energy and to retain control of the resources. On a practical level TRESOC aims to supply local homes and businesses with “local” energy. If everything works to plan, the Totnes Weir Hydro should generate 1.35 GWh of electricity each year, saving 550 tonnes of carbon dioxide. The majority of this electricity will be used to power local enterprises.

Disclaimer: I am a member of TRESOC and have invested in some of their projects.