Monday 23 April 2018

On hedges

Whooeee, I just finished a book in hedges [L a plashed hedge from the English MidlandsA Natural History of the Hedgerow: and ditches, dykes and dry stone walls by John Wright ISBN 9781846685538. Well done me because it is 350 small print pages and I don't have the stamina or attention span that I had at school, ploughing through Ulysses and War & Peace. So many distractions: Blob, eat, commute, work, home, sheep, drains, eat, sleep, repeat - that it is difficult to get a good run at a book. A natural history of hedges is clearly related to both parts of my working life - earning an honest crust at the frontiers of science and trying to limit the natural tendency of sheep to die. This has been the longest wettest Winter in this generation. With blizzards of March the grass is at least a month behind itself and the sheep are starvin'. We've been horsing bags of sheep muesli [mmmm good] down their necks at €8.50 a bag but I've also been up and down the field boundaries pulling down hanks of ivy Hedera helix. Those boundaries are hereabouts referred to as ditches, a term reserved exclusively for things running below grade when I was growing up in England: 'drains' is the local term for them. The subtitle of John Wright's book hints at the variety of local terms and local styles of the boundaries between field and field and between field and road.

These differences are driven by local tradition, sure, but the traditions are driven by the local natural history. Building a dry-stone wall L example from Cape Wrath NW Scotland: go to link: that's an order] out of a sedimentary rock like Kilkenny limestone is as easy as building a wall out of Lego: the natural bedding planes give you two flat parallel faces to each stone. Our granite comes in the round and naturally tumbles out of a ditch like marbles. But there is so much of the rock about that you're better off building the stones into vertical walls a) to get rid of them from the fields and b) to keep the sheep separate from the turnips. Our field boundaries are rich in trees: mainly ash Fraxinus excelsior; rowan Sorbus aucuparia; hawthorn Crataegus monogyna with a scatter of blackthorn Prunus spinosa; damson Prunus domestica; and elder Sambucus nigra; with alder Alnus glutinosa and willow Salix spp. down near the river; and plenty of  ivy Hedera helix and gorse /whin / furze Ulex europaeus filling in any gaps. I'm strangely impressed by this diversity because Hooper's Rule states:
Age = (no of species in a 30 yard stretch) x 110 + 30 years.
That's woody species! We're not counting every plant, let alone every beetle and butterfly. I'd guess that we'd have 2 or 3 'trees' in any random 30m stretch which accords with the history of local settlement and hill clearance about 250 years ago.

Wright's book is at pains to big up the smaller constituents of the biota of hedgerows; especially the fungi, lichens and insects which are ignored by Hooper's Rule although not by Hooper or Wright in their books. Wright is a good amateur mycologist and there are some stunning colour photographs of fungi: tiny and delicate or gross and flubbery their fruiting bodies photograph well. We tend to forget that they are just the icing on the cake of a web of mycelia penetrating the substrate, be that soil, leaf-little, dead wood or living tissue. This fungal world is essential for turn-over and maintenance in hedges and their surrounds. We should pay more attention because soil fertility for crops is dependent on the microscopic world for sustainable production. Lurrying on ammonium nitrate shipped from a distant factory is a) expensive and b) not sustainable.

The first part of Hedgerows is about geographic history and the development of the landscape of England. I learned a lot of new (=old) words and concepts. A selion for example is a peasant holding, typically 1 chain wide and 1 furlong long. A chain is 22 yards or 66 feet and the length of a cricket pitch between stumps. 10 chains is 1 furlong. The area 66 x 660 = 43,560 sq.ft is called an acre, which is as near as dammit to 4,000 sq.m. So 1 acre [we have 16 and a whisker on the farrrrrm] is very close to 40% of a hectare - a much more universal unit of area. Depending on the rotation of crops and the inclusion of livestock in the peasant economy, selions would eventually be hedged. Some hedges in England have been there for more than 1,000 years as a living immovable boundary. Regions with hedges were called wooded, to differentiate them from champion [O.Fr. champaign open country] regions of open field systems. The selions and their owners were all written up and recorded in a terrier, (O.Fr terroir as in wine]  some of which have survived to the present day. On the other hand an assart is a piece of farm land carved from the forest. If you look at olde mappes and see fields with rounded edges, then it was likely (part of) an  assart: circles give you the most area for the least effort of clearance.

I have tribbed Oliver Rackham's brilliant Trees and Woodland in the British Landscape before.

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