Tag Archives: conservation

The long-horned bee in Devon – and its endangered friend

South Devon coast looking towards Prawle Point
The south Devon coast looking towards Prawle Point (June 16th 2017)

 

It’s been a good summer. We’ve had some fine weather and I’ve been able to spend time on a beautiful part of the south Devon coast looking for the long-horned bee (Eucera longicornis).  It’s one of my favourite insects and one of our rarest bees and there is a strong colony on the coast between Prawle Point and Start Point where low, soft-rock cliffs meander around headlands, in and out of rocky coves and along seaweed-covered beaches.  I visited this area several times between May and July but my most interesting day was on June 23rd, just after the summer solstice.

It was breezy and warm but partly cloudy when I arrived at the coast.  The sea was a uniform grey-blue although now and then the sun broke through the cloud, creating shimmering areas of white water. I started by following the coast path eastwards along the cliff top from Prawle Point.  The sea-side of the path was fringed with scrub and rough grass along the cliff edge whereas the landward side was fenced and mostly used for arable farming.  Many kinds of wild flower grew along both sides of the path including a few generous clumps of purple tufted vetch scrambling through the scrub. After about a mile of easy walking, the enclosed path reached a gate giving on to a broad, open area, not farmed for some years, as far as I know.

I was completely unprepared for the view that greeted me after I closed the gate.  Here was a meadow where thousands of the small, dandelion-like flowers of cat’s ear moved with the breezes to create a mobile yellow canopy above the grass.  Lower down were many tiny yellow globes of hop trefoil and bright pink semi-circles of common vetch.  This is a paradise for insects and I saw many red-tailed bumblebee workers moving purposefully about the chrome-yellow flower heads.

But that wasn’t all: the area along the cliff edge was a kaleidoscope of purples, yellows and pinks, mostly flowering legumes such as bush, kidney and tufted vetches, bird’s foot trefoil and meadow vetchling, restharrow and narrow-leaved everlasting pea.   The number and variety of flowers was greater than I can remember from previous years, perhaps the warm spring had suited the legumes.

The range of flowers, especially the legumes is ideal for the long-horned bee.  I had seen one or two males back along the enclosed path and now I saw several more, also nectaring on the curving, purple, tubular florets of tufted vetch.   There is something other-worldly, almost primeval about these insects with their yellow mask-like face, orange-chestnut hair (in fresh insects) and their impressively long antennae, resembling stiff black bootlaces and about the same length as rest of their bodies.  They are particularly striking in flight, antennae held so that the bee can negotiate whatever obstacle it meets;  controlling those antennae must involve some impressive micro-engineering.   There were also females about feeding on lemon yellow pea-like flowers of meadow vetchling.  Chunkier than the males, they have shorter antennae and, on their back legs, generous pollen brushes resembling golden harem pants.

I scrambled down a rough track to the main Eucera nest area, a section of reddish, soft-rock cliff, pock-marked with hundreds of pencil-sized holes.  Behind me the sea soughed rhythmically on nearby rocks and an oystercatcher sang its plangent song. Female Eucera arrived at the nest site bringing pollen and nectar to provision their nests but they were not alone and I saw several other bee species that seemed to be using the nest area.

One species I had hoped to see was the very rare Nomada, and I had nearly given up hope when the bee suddenly appeared; I was so surprised, I nearly fell backwards off the rocks.  Like others of its kind, it is wasp-like, with a yellow and black-banded abdomen and orange legs and antennae. It was the pattern of the bands, six yellow bands on a black body that told me that this was Nomada sexfasciata, the six-banded nomad bee, one of Britain’s rarest bees.  This site on the south Devon coast is the only place where it is found in the UK; it is nationally endangered so it was very exciting to see it.

It moved about the nest area furtively as if trying not to be noticed and after looking in to a few of the holes it moved on. Later that day I had more sightings of the Nomada; whether it was the same bee or several I cannot say.  As a nomad, the bee has no nest of its own but lays its eggs in the nest of another bee, in this case the long-horned bee.  The Nomada eggs develop into larvae and take over the nest, killing the host larvae and eating their pollen store.  It depends for its survival on a strong Eucera colony and this one in south Devon is one of the largest in the UK.

Long-horned bees and their Nomada used to be found widely across the southern part of Britain in the early 20th century.  They favour a range of habitats such as coastal soft rock cliffs, hay meadows and woodland rides for nest sites and require unimproved flowery grassland for feeding, being especially dependent on flowering legumes for their pollen sources.  With agricultural intensification leading to a loss of habitat, especially flowers, these bees have been squeezed out and are now confined to a very few sites.

It’s not difficult to see how they could be supported.  At the south Devon site, all that is required is to ensure a consistent source of flowering legumes along the coast, the soft rock cliffs already provide the nest sites.    I recently met Catherine Mitson who is working with Buglife on a project to support the south Devon colony of Eucera longicornis and Nomada sexfasciata  by increasing the number of flowers.  Catherine is very enthusiastic and I have great hopes now for the survival of both the long-horned bee and its nomad.

Yellow meadow Prawle Devon
The yellow meadow

 

Male long-horned bee on meadow vetchling
Male long-horned bee on meadow vetchling (June 16th 2017)

 

Male long-horned bee
Male long-horned bee on tufted vetch (June 23rd 2017)

 

Female long-horned bee
Female long-horned bee on meadow vetchling (June 23rd 2017)

 

Female long-horned bee by nest
Female long-horned bee at the nest site (June 16th 2017)

 

Female long-horned bee 2
Female long-horned bee with pollen on tufted vetch (July 2nd 2017)

 

Nomada sexfasciata
Nomada sexfasciata by Eucera nests (June 23rd 2017)

 

Nomada sexfasciata 2
Nomada sexfasciata by Eucera nests (June 23rd 2017)

 

Female long-horned bee
Very worn female long-horned bee on tufted vetch (July 23rd 2017)

 

The featured image at the top of this  post is a male long-horned bee on bird’s foot trefoil   (May 23rd 2017)

 

 

Have you seen the bee orchids?

There I was, standing up to my knees in the long grass trying to examine a flower, when a woman passing on the nearby path asked, “Have you seen the bee orchids?”  I turned and answered “No, but I was hoping to find them” and she continued “If you go nearly to the end of the reserve by the bridge, there’s a very nice one”.

Bird's foot trefoil
Bird’s-foot Trefoil

 

Common vetch
Common vetch

 

Aller Brook Nature Reserve in Newton Abbott is a place of contrasts.  It might reasonably be called an edgeland for it is on the edge of the town and the reserve starts where the Brunel Industrial Estate ends.  But it’s more urban than even that implies; the other main boundary of the reserve is the A380 trunk road making its presence felt through the continual loud rumble of cars and lorries speeding between Torquay and Exeter.  Between these two urban barriers is an extended triangular tongue of land with the water of Aller Brook running down the middle in a deep scrub-lined channel – this is the Nature Reserve.

Despite all the noise and light-industrial activity, this reserve is a perfect example of how nature can be coaxed in to a space if it is properly managed.  Kingfishers and otters are reported to visit the Brook and, when I was there, birdsong filled the air, at least when traffic noise allowed.  The main path along the boundary with the industrial estate was fringed with typical May flowers: red campion, cow parsley and brambles, all blooming beneath a thick tree canopy.  On the other side of the path, the Brook was occasionally visible through the scrub shield.

Further along the path, I came across several small areas of grassland managed as hay meadows.  Typical meadow plants were flourishing adding splashes of colour to the muted green grasses. Tall drifts of yellow and white ox eye daisies and unruly purple knapweed grew through the thick vegetation.  Common vetch, dotted with pink pea flowers, and buttery yellow bird’s foot trefoil scrambled through the rough cover holding on wherever they could.  A few common spotted and marsh orchids added a little exoticism.  Along the edge of the brook there were stands of dog rose with their floppy, pale pink petals. With all these flowers about, bees were abundant.

The reserve ends at a bridge where the Brook empties into the estuary of the river Teign between huge swathes of tea-coloured reed beds and shiny pillows of brown mud.  The same reeds form a narrow border to the brook.  The bridge area was the part of the reserve where the Bee Orchids were supposed to be, so I looked very carefully within the grass.  They were quite easy to spot, six fine flower spikes standing about 20 cm above the ground with triple propeller-like, pinkish-violet sepals surrounding their complex flowers.

From the bridge, a path returns along the other side of Aller Brook and, at least at the beginning, the vegetation is quite similar.  Compact tracts of grassland sloped downwards to the Brook; common vetch scrambled through the grass accompanied by a few pyramidal orchids.  This side of the reserve, however, felt more contained with stands of brambles and thick tree cover attempting to mask the nearby main road.  It was still slightly unnerving to see glimpses of cars speeding past at 70 mph about 20 metres away.  Incongruously, near here I found another impressive group of Bee Orchids, five spikes in total, with two growing perilously close to the path edge.

As the reserve narrows, so does the path and for some time I walked along a green corridor beneath thick tree cover with relative shade and few flowers.  Eventually the path emerged into the light near a very busy roundabout and the car park of the Toby Carvery.  A ranger I had met earlier told me to look at the grassy area around the car park.  I had to ask a cuddling couple sitting on the edge of this area if they minded if I wandered around the grass but eventually I found thirteen flowering spikes of Bee Orchids looking very fresh, together with one pyramidal orchid.  This unlikely and rather bleak urban spot has a better population of Bee Orchids than the Nature Reserve itself!

There is something very beautiful and rather weird about the flowers of the Bee orchid when you look beyond the three pink sepals.  The most obvious part is the lower petal, the labellum, largely a rich dark red but decorated with variable, yellow horseshoe patterns.  Either side of the labellum are two spurs with a furry surface.  Above the labellum is a pale green arching structure containing two small yellow balls (pollinia) supported by fine threads so that when the wind blows these vibrate.  Above this pale green structure are two horns.

As the name of the orchid suggests, some people see a bee in the complex structure of the flowers.  They imagine the body of a chunky bee (the labellum, complete with furry extensions) with antennae (the two horns) and wings (two of the sepals).  To be honest, I don’t get this – all I see is a complex and idiosyncratic flower but perhaps I am being too literal.  I showed the pictures to Hazel, however, and she immediately saw the bee.

The apparent resemblance of the flowers to bees is also linked with theories of pollination whereby a male bee sees the orchid “bee”, thinks it is a female and tries to pseudo-copulate.  As it does so, it picks up pollen from the pollinia and when it leaves, disappointed, it tries again on another flower pollinating it at the same time.  In southern Europe, the Bee Orchid is cross-pollinated by bees of the Eucera genus but to me none of these bees looks anything like the Bee orchid.  But anyway, who knows what a bee “sees” and it has been suggested that the odour of the flower is more important in attracting the male bees.  To complicate things even more, Bee Orchids in the UK self-pollinate so they manage without bees.

Visiting a place like Aller Brook I can’t help but reflect on our relationship with nature.   I really like the Aller Brook Nature Reserve, there’s something special about the grassland with its profusion of meadow flowers and the Brook with its resident kingfishers and otters.  I love the orchids.  I can’t, however, help feeling troubled by the urban noise, the proximity of traffic and light industry.  This juxtaposition of modern urban life with some of the real glories of nature highlights our dysfunctional relationship with wildlife.  Is this tiny scrap of land the best we can do?  Surely we should be giving nature a higher priority rather than endlessly building roads and houses?

As I thought about this, Joni Mitchell’s song, Big Yellow Taxi kept coming back to me, particularly the words:

“They paved paradise and put up a parking lot”

I visited Aller Brook Nature Reserve on May 30th 2017

Common spotted orchid
Cut-leaved cranesbill and common spotted orchid

 

Bee orchid 1
Bee orchid

 

Bee on knapweed
Bumblebee (male B.pratorum) on knapweed

 

Bee orchid 3
Bee orchids showing pollinia

 

Aller Brook
Aller Brook

 

Toby Carvery Car Park
The car park of the Toby Carvery

 

Perfect poisons for pollinators – available from your local garden centre

We try to make our garden welcoming for bees by growing flowers that provide pollen and nectar throughout the season. We also have some unkempt areas they might want to nest in and we don’t use any pesticides. I enjoy watching the bees foraging on the flowers as they come in to bloom and currently a large cotoneaster bush is full of small bumblebees buzzing loudly as they feed in the sunshine. It’s been very exciting this year to see bumblebees and solitary bees nesting in the dry-stone walls around the garden.

When we need new plants or compost, there is one local garden centre we use. It has a good range of healthy-looking plants and a very nice tearoom! In early spring, it’s also an excellent place to watch one of my favourite bees, the hairy-footed flower bee (Anthophora plumipes), whizzing about in the greenhouses full of flowers. Earlier this year, on a sunny Sunday afternoon in late March, I noticed that these Anthophora had set up nests in the old brick wall of one of the garden centre’s buildings.

Bee 4
A hairy-footed flower bee foraging on plants within the garden centre

……………………………………………………………

About a year ago, I saw a crowd funding request from the well-known bee-defender and researcher, Dave Goulson from the University of Sussex. He wanted the money to test whether plants sold in garden centres in the UK and labelled as “bee-friendly” actually contained bee-toxic pesticides, applied during production of the plants. I remember being quite shocked to read about this possibility – could I have been buying plants to help the bees that were in fact laced with bee-toxic chemicals?

I wanted to find out more so I got in touch with our favourite garden centre and asked whether they were using neonicotinoid insecticides on their plants. They reassured me that they were not. So far so good. I then asked if their suppliers used neonicotinoids in the compost on the plants they sold. The reply came back “I’m afraid I can’t answer that question without phoning every supplier. Also a few companies we deal with import some of their stock from other European countries. I’m happy to ask my local nurseries when I’m speaking to them.” That’s the last I heard.
…………………………………………………………….

Dave Goulson got his money and went ahead with the analyses. The results of his tests have just been published and they don’t make happy reading;  here is a link to his blog on the topic. He and his colleagues bought 29 pots of flowering plants from well-known garden centres around Brighton (Wyevale, Aldi, B & Q, Homebase). Many were labelled “bee-friendly” and some had the Royal Horticultural Society endorsement “Perfect for Pollinators”.

They analysed a range of pesticides in leaves and pollen from the plants and found that most of the plants contained a cocktail of insecticides and fungicides. In the leaf analysis, only 2 of the 29 plants contained no pesticides. 76% contained one or more insecticide and 38 % contained two or more. 70% of the leaf samples analysed positive for neonicotinoid insecticides, well known for their toxic effects on bees. In the pollen analysis, neonicotinoids were found at levels known to cause harm to bees. So much for “Perfect for Pollinators”.

As a result of his work, B & Q announced that from February 2018 their plants would be neonicotinoid-free. Aldi revealed that they had stopped using neonicotinoids in October 2016, a few months after Goulson’s analyses took place. Neither B & Q nor Aldi  addressed the other chemicals found in the Sussex analysis.

The Horticultural Trades Association issued a statement that I believe is both silly and cynical, basically rubbishing Goulson’s analysis. You can read Dave Goulson’s rebuttal here.
……………………………………………………………….

So, it really is true that when we buy plants to help bees in our gardens from garden centres, we may be unwittingly exposing the bees to harmful chemicals, despite the “bee-friendly” labels. Also, any insect that nips into a garden centre for a feed, especially early in the season when garden centres have an abundance of flowers, may be getting a hit of insecticide at the same time.

So, what do we do if we want to have a bee-friendly garden?

Dave Goulson recommends the following course of action: if you must buy plants, buy from an organic garden centre or, failing that, go to B & Q or Aldi. Better still, grow from seed or swap plants with friends and neighbours.
…………………………………………………………

One point that has not been discussed so far concerns potential effects on humans of these pesticides found in garden centre plants. Earlier this year, I bought some fruit bushes from the garden centre and these now have a nice crop of plump berries. If these plants have been treated with pesticides, and of course I don’t know if they have, then the fruit will presumably also contain these pesticides. This possibility makes me very angry. I grow fruit in our garden so that we can eat chemical free, fresh, good quality produce. I don’t want to ingest insecticides and fungicides with poorly defined toxic effects on humans.

The featured image shows a hairy-footed fower bee feeding from plants in a lane adjacent to the garden centre

Golden Cap – a special place in west Dorset

Golden Cap 5
The west Dorset coast with Charmouth to the left. Golden Cap stands out just right of centre.

 

The west Dorset coast contains many wonders but one stands out above all others.  This is Golden Cap, the distinctive steep-sided, flat-topped hill with its golden edge and cliffs falling precipitously to the sea.  Visible for miles around and rising above all its neighbours, it stands 191 metres above sea level and is the highest point on the south coast of England.  It is a local landmark, a place of legend, and an inspiration to writers and artists. 

Golden Cap path
The path from Stonebarrrow leading eventually to Golden Cap. Portland can be seen in the distance.

 

I first climbed Golden Cap nearly thirty years ago.  It was a mild, early spring weekend and I was entranced by the experience.  It’s now one of those places I like to visit periodically so, on a warm mid-July day earlier this year, I set out from the Stonebarrow Hill car park above Charmouth.   The grassy track descended steeply between brambles and bracken towards Westhay Farm with its mellow stone buildings decorated with roses, honeysuckle and solar panels.  I paused in a gateway near the farmhouse to look at one of the hay meadows.  Bees and butterflies enjoyed the thick covering of grasses and colourful flowers while the sun gradually won its battle with the clouds.   Flower-rich hay meadows were once an important feature of the countryside but they have mostly been lost since 1930 as a result of agricultural intensification.  Managed in the traditional way with a late July cut for hay, they support a rich community of invertebrates, birds and flowers. The meadows at Westhay Farm are no exception and rare plants such as the green-winged orchid thrive here.   My gateway reverie was interrupted when a fox suddenly appeared in one of the breaks in the meadow.  We stood looking at one another, a moment out of time, before the fox lolloped off through the long vegetation.

Westhay Farm Golden Cap Estate
Westhay Farm

 

Hay meadow Golden Cap
A flower-rich hay meadow.

 

Beyond the farmhouse, the path descended across open grassland dotted with sunny stands of ragwort and tall, purple thistles populated with bumblebees.  The sea, a pale steely blue, was now ahead of me, dominating the view.  Today it was calm but the slight swell was a warning of its power.  Golden Cap loomed to the east like a steep pleat in the coastline and, when the sun shone, the cliff face revealed some of its geological secrets.  About half way up, a large area of rough grey rock was visible. This was laid down some 200 million years ago and is mainly unstable grey clays of the Middle and Lower Lias prone to rock falls and mud slides.  Towards the summit, tracts of distinctive “golden” rock glowed in the sunshine.  The rock here is Upper Greensand, sandstone laid down about 100 million years ago, forming the “cap”.

Golden Cap 2
Looking towards Golden Cap; the golden sandstone cap and the grey rock below can be seen despite the vegetation.

 

Golden Cap from the east
Golden Cap viewed from the east at Seatown on another day. The golden sandstone cap and the grey rocks beneath can be seen very clearly from this aspect.

 

Fingerpost
A helpful fingerpost

 

solitary bee
A solitary bee on ragwort, possibly Andrena flavipes.

 

beetles
Common red soldier beetles, qualifying for their popular name of “hogweed bonking beetles”.

 

The coast path continued eastwards in a roller coaster fashion.  Prominent fingerposts pointed the way and I passed vast inaccessible coastal landslips and descended into deep valleys with rapidly flowing water, only to climb again on the other side.  In meadows alongside the path, bees, moths, beetles and butterflies flitted among the many flowers including purple selfheal and knapweed, yellow catsear and meadow vetchling.    The final push towards the summit of Golden Cap began very steeply across open grassland before entering a stepped, zigzag track which was easier to negotiate.  As the path rose there was a change in the landscape.  Bright purple bell heather began to show and bracken surrounded the stepped path; a kestrel hovered briefly above.

antrim stone
The Antrim stone

 

Suddenly the path levelled out; I had reached the summit and here were the familiar landmarks:  a low stone marker informing me how far I had walked and the larger stone memorial to the Earl of Antrim.  The dedication told me that the Earl was the Chairman of the National Trust between 1966 and 1977. What it didn’t tell me was that he recognised the importance of preserving our coastline from encroaching development and spearheaded the Enterprise Neptune appeal which led to the purchase of 574 miles of coast saving it for future generations.  Golden Cap was one of two coastal sites purchased in his memory after he died.

Golden Cap view east
The view to the east over Thorncombe Beacon with Portland in the distance.

 

Golden Cap view west
The view to the west towards Lyme Regis and the Devon coastline.

 

I reminded myself of the long views from this high, flat-topped hill:  to the east across Seatown, Thorncombe Beacon, West Bay and Portland, to the west over Lyme Regis and the wide sweep of Devon coastline, to the north across the Marshwood Vale.   Looking down, I saw water skiers carving patterns in the sea surface far below.  The sea now seemed so far away that I felt momentarily separated from the rest of the world.

On my return journey, I headed down and slightly inland to the remains of the 13th century chapel at Stanton St. Gabriel.  Set in meadowland beneath the western slope of Golden Cap, the derelict, grey stone walls and the porch of the old chapel are all that remain.   There is also a cottage nearby and a large building, originally an 18th century manor house, now restored by the National Trust as four holiday apartments.   But why was a chapel built in this isolated spot and why is it now derelict?  A settlement existed here for many hundreds of years and Stanton St. Gabriel was mentioned in the Domesday Book (1086).  There was a farming community of about 20 families in the vicinity until the 18th century and this was their chapel but the settlement was abandoned when some people were lured to Bridport to work in the flax and hemp industry.  Others may have moved to Morcombelake when the coach road from Charmouth to Bridport along the flank of Stonebarrow Hill was moved away from the settlement to its present route.

stanton st gabriel
The derelict chapel at Stanton St Gabriel.

 

The derelict chapel provides a potent reminder of the community that once lived in this isolated but beautiful spot beneath one of west Dorset’s most striking landmarks, Golden Cap.

This article appeared in the September 2016 edition of the Marshwood Vale Magazine.

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.

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.

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.

………………………………………

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.

……………………………………..

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.