Monday, 28 August 2017

Week 47: (21st August to 27th August 2017) or 'Punctures in Somerset'

Muddy boots. Shropshire sands and Herefordshire clays, which had stowed away in the soles since woodland fieldwork, became married with Somerset soils. This week, I planned to extract cores down a field in Shepton Beauchamp; cores which would stretch down 4m underground, to bedrock. The principles remained the same - the need for saprolite (weathered bedrock) and overlying soil samples - but there the similarities grew distant. The farmland posed many interesting and novel challenges, one of which being the deeper soils at the base after decades of soil deposition, two deep alas to manually dig a soil pit. The issue, fortunately, was relieved. A lorry reversed into the farmland forecourt; strapped within it was a solution.



The mouth of the lorry yawned and the animal awoke. Emerging over the lip, a large metal dinosaur roamed steadily towards the ground. It's neck, locked in contortion along its own back, was set free and it elongated out, doubling its height to survey the area. Minutes of adjustment passed; a menacing sustained groan rumbled from within. It had neither legs nor arms, but a belt underneath its belly, conveying itself sluggishly over the furrows. And then, when it assumed its rightful position over one of my proposed coring sites, it dipped its neck, picked up a long tubular corer and prepared to beat it into the ground. First, silence. Then... Bang! In an abrupt execution, it recoiled its head and sent it with merciless fury back down to beat the corer, puncturing the soil. Then, again, and again... fifty, perhaps one hundred times, each seemingly as violent as the previous.

The acupuncture became more arduous; the metal corer now 2m deep underground began to argue against the prolonged beating, resisting further incision. It's demands were ignored and the beating continued. Bang! And then, silence was draped over the area once more. The corer was clawed out of the ground and with it an in-tact core of soil.


What I have just described, albeit perhaps with animalistic qualities, is the Dando Drilling Rig, operated by the drilling team at the BGS, and often employed in borehole projects. Despite the name, its more of a large, mechanical hammer than a drill, and with the correct use of multiple extension rods, it can stretch down to over 10m. My ambitions to puncture only 4m of Somerset, I imagine, did not exhibit its full potential but what I saw justified its usage. In 6 hours, a total of 10m of Earth were entombed within plastic. Soon after, they were kidnapped.

The rocks that lay at the depths of my core have not seen daylight since dinosaurs roamed the Earth, over 180 million years ago. The Bridport Sandstone that underlies much of my study field was formed when sediment settled at the bottom of warm, shallow seas that once inundated the area. 180 million years later, the sandstone lays underneath a duvet of silty, loamy soil. Once, the region may have been swarming with giant, plant-eating dinosaurs. Today, it grows potatoes and maize to be sold in supermarkets and bought by hungry humans. With the Dando Drilling Rig, the sandstone, asleep in the dark for 180 million years, was awoken in a matter of minutes.

The Bridport Sandstone has travelled thousands of miles. It was laid down when the UK was enveloped within one large super-continent. Where precisely it was formed from, I nor anyone can state for sure, but I can confirm, with extraordinary accuracy, that its final hundred miles were spent aboard a lorry, cruising with satisfying ease up the M5 to Birmingham, where they encountered the first 'delays' in their 180 million year history. Their final hundred miles in jams were hellish, but I imagine even the punctuated journey up the M69 and M1 was relatively speedy compared to the tortuously slow migration they've been subjected to these last hundred million years.

In a rather vacuous, dusty basement at the BGS, the teeth of a saw bite through the cores. They are sawn length ways, revealing the profile in preparation for sub-sampling. Then the knife is wielded, and as if one is segmenting a fig roll, the cores are partitioned into 5 cm increments and bagged. Although the samples are yet to be analysed, the knife is an informative tool. The pressure required to slice through the core suggests its density, whilst the ability for the sliced piece to sustain its shape following the cut is testament to its soil structure. What's interesting is that there are bands where the core, overwhelmed by the knife, reduces to a mound of crumbs. In catering, this missing ingredient would be a binding agent. In Soil Science, it's clay. But further tests will no doubt reveal all.




Sunday, 13 August 2017

Week 45: (7th August to 13th August 2017) or 'If you go down to the woods today..."

The Earth - a planet skewered onto an axis like a kebab - slowly spins under the grill of the Sun. For all the magical splendour that summertime may bring, for most of us it amounts to spending a few months on the galaxy's largest Rotisserie. Round and round we gyrate on the spit, each country roasted to varying degrees.

Somewhere deep in the heart of the cosmos, I can imagine a few refined aliens sitting down to dinner, selecting their country from the Rotisserie menu.
"I'm partial to a smouldering forest fire", the first alien will admit to the waiter. "I often find it's best served with a couple of buckling roads and side dish of dried-up lakes... have you anything like that?".
"Oh, well in that case, may I recommend the 'Congo' or perhaps, the 'Mexico', served 'Well-done'?"
Alien One eagerly nods and the waiter pivots to the second alien. "And for you, Madame?"
"Oh, I'll have the 'Norway', please."
"And how would you like your country cooked, Madame? The 'Norway' is often best served rare."
"Oh, indeed, most definitely 'rare'... just so that a few glaciers may melt down the valleys."
"Absolutely, Madame," the waiter scribbles, turning to the final alien, who cannot make up his mind at all. The waiter proffers a menu from his waist, in assistance.
"Allow me to recommend our pièce de résistance; the 'Summertime England' is our chef's speciality! It's best served 'medium'." But the third alien sits unconvinced.
"What does the 'Summertime England' consist of?" he asks.
And then we realize the waiter was once resident in England himself, for his eyes, suddenly enchanted with a nostalgic romance, gaze up to the sky as if his memories float in a heaven of their own, and he passionately recalls the splendour of 'Summertime England'.

And, oh, to be in England during the Summer! Neither chargrilled, nor rare, Summertime England is a pièce de résistance!

Summertime in England! The unhurried opening of a wicker picnic basket; the graceful placing of a freshly baked scone on blue china; the effortless transmission of jam onto a miniature pillow of clotted cream; the curious scrutiny by tomorrow's clotted cream donors, peering through the neighbouring hedgerows, their hooves buried in the rich grassy meadows. Long afternoon shadows outstretched across sleepy hollows and sunken lanes; the golden-brown shortbread of the parish church; a small plume of dust ascending to the sky at the tails of combines. Every Summer, the seeds of an old England - an English ancestry of simplicity and tranquillity - germinate in hamlet and parish, far and wide.

At the end of a country lane in Herefordshire sits a thatched, sandstone cottage. Generations of farmers have taken their wellingtons off under the small archway beside the wooden door. Once a toddler learning to ride a bike down the country lane is now a grey-haired father sitting amongst the Dahlias digesting the broadsheets whilst his own son is out harvesting a field of barley. The gardens are festooned with blood-red roses and breathe out a sweet perfume to the bees. Swifts playfully sweep the air. A lady is inside, kneading some dough and surveying her beauteous garden. Her father-in-law has fallen asleep in the deckchair, which draws from her a warm smile and she turns to gaze off into the far distance. The view from the sash windows of the kitchen boasts the best view of the house! There, in the far distance, she can make out a speck, a boy - a young man, perhaps - perched on the trunk of a fallen Oak. Though too far away from her to see, the 'young man' is writing about her cottage, her gardens and her father-in-law asleep in the deckchair. Indeed, that 'young man' is I.

Down in the valley that separates my notebook and her dough, is an early chapter of England's history: an ancient woodland. From my oak-trunk bench, it is a bowel of Broccoli. In the far distance, the woodland is nothing but a smudge on the horizon, as if a band of low-lying clouds had been dunked into a pool of dark green paint. Closer, I can detect a brigade of individual trees, and closer still, their interlocking branches wearing green sleeves. In the foreground, these sleeves are not sleeves at all, but little green palms, some lobed and serrated, some more refined. I run my hand over the roughened bark of the fallen Oak upon which I perch, and then the smooth page upon which I write and realize both are different verses in this requiem to an old England.



At first glance, the woodland is passive. Notwithstanding the threat of the saw, or some similarly fateful disease which might beset it, the tree holds a life-long loyalty to its home, often not a place of its own choosing. There is neither an Estate Agents nor a passport for a tree. Belowground, however, the tentacles of the trunk are on the move; stretching out, burrowing their way through the earth, sometimes rising to the surface like a Dolphin might come up to breathe, and then diving back down again, vacuuming nutrients and water. The community of trees that sit between that little thatched, sandstone cottage and myself are their own villages, sharing space and resources just as we do.

When a sapling emerges and casts its first shadows onto the mossy carpet, they are but infants at the toes of their elders. They must equip themselves with centuries of perseverance if they are to reach those dizzy heights. But if trees had the capacity to feel emotionally, I imagine they would be cautious to be so hopeful of climbing the great ladder of air, for they know their life may begin in a woodland, but may not always end there. The British woodland used to be a duvet, cloaking the body of the British Isles. It still does, but much of it is disguised as coffee tables, breadboards, paperback books and picture frames. It is, of course, a great shame and our weakness that we result to cutting these columns of history down but at least when I write on paper, as I do now, I know that my inked page is only a fraction of a long history, and I can imagine the page not as A5 and lined but as columnar, stretching 200 feet into the air, with roots outspread for miles. I can imagine the branches - the playgrounds of squirrels - and the leaves, the luncheons for caterpillars, and the twigs, the currency of birds. The plastic pen or the metal stapler can never boast this history.

An ancient British woodland is, itself, an important artefact in Britain's history just as much as British history is preserved in handheld, leather-bound woodlands but for many parents, this history is kept alive in their child's imagination. The woodland is where Robin Hood assembles his Merry Men and where Teddy Bears gaily gad about. Indeed, I have very fond memories of a cassette tape with the 'Teddy Bear's Picnic' on, and singing it when I used to 'go down to the woods'. Little did I realize at the time that a line in that familiar tune would come back to pull on the strings of my curiosity.

"Beneath the trees where nobody sees,
They'll hide and seek as long as they please,
'Cause that's the way the
Teddy Bears have their picnic"

Though it may well be a nursery rhyme to carry a child into a dream, there is a mystery in every woodland: the mystery about what, indeed, lies "beneath the trees where nobody sees". No playful teddy bears, alas. Soil, definitely. But how much soil? What kind of soil? And how did it get there? Sitting on a small fallen Oak in Herefordshire, espying an ancient woodland, I began to think about the formation of soils in our British woodlands. How might this formation compare to the arable farm? Do woodland soils erode as quickly as our cultivated soils? What were the lifespans of the British woodland soil? Gathering up these thoughts, along with a bag of equipment, I alighted from the trunk, took one final look at the thatched cottage, and strolled down to begin a fortnight of woodland fieldwork. 


***


"In long-range planning for a trip, I think there is a private conviction that it won't happen."

(John Steinbeck 'Travels with Charley: In Search of America')

The very first line of Steinbeck's novel had haunted me, in Lancaster, for many weeks. I had spent weeks planning the fieldwork in copious detail, but at the back of my mind, I still had lingering doubts that it wouldn't actually take place. This may, at first, seem perhaps a frightful silly. But the truth is that almost every plan was falling into place a little too easily. The National Trust had granted me permission, encouraged the study no less, and I had arranged access. The weather appeared to be bright. Each item of desirable equipment had either been acquired successfully from Lancaster Environment Centre, or otherwise purchased without incident, and I had managed to secure a relay of field assistants. Paul would take me down to complete the first few days of drilling (explained later), John would take the baton for a while before finally handing it over to Andy. On the page, it sounded too seamless. 

My two woodland sites, whilst not naming them specifically here, are in Shropshire and Herefordshire. They were selected based on a promise made by a few unknown geologists that underlying them - indeed, "beneath the trees where nobody sees" - is sandstone bedrock. To calculate Soil Production Rates from sandstone bedrock, the first task would be to acquire some of this weathered sandstone. Many weeks back, I was recommended the employment of a Percussion Corer. Very simply, this is a metal tube which is pushed into the ground by a petrol-driven drill. The tube (or, to be precise, a bag within the tube) slowly fills up with soil. Persist with the corer, and the almost maddening vibrations that surge through your hands and up your arms, and the tube finally hits bedrock, at which point some of the sandstone is grounded up and squeezed into the bag. The drill is then removed, and a mechanism to manually 'jack' the core out of the ground is assembled. I cannot adequately describe to you how quiet this 'jacking' mechanism was, in comparison to the deafening fury of the drill. Although I'm sure a motorized machine could have removed the core in double the time, I protest that this was surely the cleanest and most satisfying aspect of the challenge.





The satisfaction didn't prolong. Two problems, of varying severity, transpired. Firstly, the volume of material extracted from one coring session was by no means enough. At least three cores would be required at each of my four sampling points to amass the volume of sandstone necessary for calculating soil formation rates. Another means by which to collect the material would be to manually dig soil pits, but would this take longer than coring thrice? Alas, the rip-cord of the drill severed, and pit digging very quickly transformed from a contingency plan to the main order of the day.

How deep would one have to dig to reach sandstone? One morning, a car rattled down to the bottom of the wood, and out emerged Andy with a Panda Penetrometer. Both Andy and the Penetrometer are two very interesting subjects to write about, but as knowledgeable as Andy is of sandstone, the penetrometer would perhaps provide more reliable information. Again, in layman's terms, this is a long metal rod which is manually hammered into the ground. Extension rods are subsequently screwed on and hammered in until the first rod 'hits' bedrock. The force that is required to hammer the rod through a known depth of soil is then used to work out the penetration resistance or the strength of the material. As the bedrock is stronger than its soil overburden, one can establish the approximate depth of the sandstone.


"Beneath the trees, where nobody sees"... A jovial line to the toddler becomes a tease to the Soil Scientist. How can one resist the temptation to dig through the soil, this earthy underworld which as the tune quite rightly describes, is forever unseen. It is still quite bemusing to think that we justify space exploration whilst satisfying our minds with simply 'imagining' what might lie beneath the trees. These thoughts were encircling my mind whilst I dug, dug, dug... deep into the heart of another one of Earth's undiscovered, unseen worlds. 

Theory states that soils should be thickest on plateaus, and thinnest on slopes. My woodlands abide by these theories, I am happy to state. On the steep, arduous wooded slopes where the brambles and nettles attempt to retard your efforts, the soils are about 50-80cm deep. Beyond these depths, little purchase is made with the spade, and you wield your knife into one of the pit walls to extract a piece of saprolite (weathered bedrock). At the summit, I dug continuously: 80cm, 1m, 1.2m... 1.5m before finally making a satisfying noise with my spade that informed me I was hitting rock, not soil. It is then a matter of collecting enough samples, not only of the rock itself, but of the overlying soil. I collected soil samples every 5cm down three columns in each pit.



There is an unspoken delight in digging soil pits, arduous as the task may be. You may gaze hard at the soil; this mysterious world 'beneath the trees where nobody sees'. You may collect and bag as many samples as you please, but a bag of soil on its own will not whisper the secrets to the mysteries of the woodland. There may be an urge to quickly re-fill the pits, and to scamper to the laboratory, but speaking personally, there is an overwhelming and slightly surreal experience about sitting still, six feet below ground.

We often speak of the 'woodland floor' as that which we stroll down, casually on Sunday afternoons with the dog; that surface where roots become trunks and saplings take their first breath. But as any curious dog, or root for that matter will demonstrate, in reality, the woodland floor we know is not a floor, but a rooftop and the tree trunks are merely chimneys, breathing out oxygen in exchange for our CO2. Below the rooftops are many floors, home to millions of species. The top floor, that rich, organic horizon with freshly decomposed litter, a thick middle floor full of light sandy soil, and the ground floor, the bedrock - the true woodland floor - and the foundations for all that exist in the storeys above.

If you dig down in the woods today, you're sure of a big surprise; a surprise that would make any Teddy Bear's picnic seem fairly commonplace.