Ire­land’s his­toric hedgerows the es­sen­tial cor­ri­dors of na­ture

The Irish Times - Weekend Review - - OUTDOORS - Michael Viney

Look­ing out from my desk through a skele­tal weave of branches, I glimpse the white blur of a graz­ing ewe mov­ing closely be­yond the hedge, the patch of azure sprayed on her back as sud­denly bright as blue­bells. Her lamb comes fol­low­ing, a lit­tle blob in a whiter shade of pale.

On this windy, small-farm hill­side, striped with earth banks and fences a cen­tury ago, a hedge is rare but worth its keep for shel­ter. In Ire­land’s wider land­scape, the green net­work some­times seems to sep­a­rate farm­ing life from proper care for na­ture,

It is quite a few springs since the Ir­ish Farm­ers’ As­so­ci­a­tion be­gan lob­by­ing to shorten the closed sea­son for cut­ting or grub­bing out hedgerows and burn­ing up­land habi­tats. A com­pli­ant min­is­te­rial re­sponse from Heather Humphreys, in the new Her­itage Bill of 2016, has brought out­rage from en­vi­ron­men­tal NGOs, a pub­lic pe­ti­tion and tren­chant re­sis­tance in the Seanad. A gen­eral elec­tion and a change of her­itage min­is­ter both de­layed the progress of the Bill, still to be given Dáil ap­proval.

Ear­lier this month, the Na­tional Parks and Wildlife Ser­vice (NPWS) took care to warn that the old pro­vi­sions of the Wildlife Act are still in force; there must be no de­struc­tion of hedges or burn­ing of veg­e­ta­tion from March 1st to Au­gust 31st. Its web­site asked the pub­lic to re­port of­fend­ing ac­tions to lo­cal NPWS of­fices.

When, at some point, the Bill gets its fi­nal Dáil dis­cus­sion, one change might be per­mis­sion to cut road­side hedges (on the rel­e­vant side) dur­ing Au­gust, what­ever the wor­ries for late-nest­ing birds. An Taisce, out to grant the pos­i­tive, thinks this would leave three-quar­ters of our hedges safely in­tact through the crit­i­cal months for wildlife.

Scrawny bases

At some 300,000km, Ire­land’s hedgerows are the es­sen­tial cor­ri­dors of na­ture, for all the gaps and scrawny bases of so many. Their con­di­tion and ecol­ogy are un­der close as­sess­ment – even of their abil­ity to ab­sorb tonnes of CO2. But their value to bio­di­ver­sity is paramount and still has much to do with their his­tory.

Most were planted from the mid-1700s up to the mid-1800s, the years of the coun­try­side’s en­clo­sure, but our old­est hedges are me­dieval or even ear­lier. In Gaelic Ire­land, strips of wood­land were kept for tim­ber and fuel. Hedges were planted on earth banks as de­fences and ditches dug to mark town­land bound­aries. Some still sur­vive as trea­suries of rare and species-rich ecosys­tems.

Banks and ditches are of­ten syn­ony­mous in Ire­land’s ver­nac­u­lar us­age.

“The age of a ditch” was the ti­tle for an email from a Co Tip­per­ary reader, Rachel Vaughan. She won­dered how to date the age of a nearby town­land boundary where a hedge­bank is grow­ing ash, sycamore, holly, hazel, beech, hawthorn, black­thorn and wil­low, all within quite a short dis­tance.

Wasn’t there, she asked, some sort of for­mula that said if you counted, say, five woody species in a spec­i­fied length of hedge, this meant it had been there for five cen­turies? What was the cru­cial dis­tance?

Rachel was re­call­ing “Hooper’s Rule”, the rough-and-ready mea­sure of age de­vised late in the last cen­tury by Bri­tain’s Dr Max Hooper.

In an ex­ten­sive sur­vey, he found that the num­ber of trees and shrubs in 30m of hedge did, in­deed, seem to match the cen­turies, as con­firmed by lo­cal and doc­u­men­tary ev­i­dence.

Ru­ral his­tory

With such a dif­fer­ent ru­ral his­tory, Hooper’s Rule made slow head­way in Ire­land. But as coun­ties na­tion­wide em­barked on hedgerow sur­veys of their own, as­sess­ment for con­ser­va­tion came to need con­sis­tent meth­ods and clas­si­fi­ca­tion. The re­sult­ing Hedgerow Ap­praisal Sys­tem de­scribes and ranks the cur­rent con­di­tion of hedgerows, and their age brings the greater po­ten­tial as refuge and source of species.

The sys­tem is the work of ecol­o­gists in Wood­lands of Ire­land and al­lied NGOs, funded by the Her­itage Coun­cil and backed by Na­tional Bio­di­ver­sity Ire­land. Hedge-

Hedges were planted on earth banks as de­fences and ditches dug to mark town­land bound­aries. Some still sur­vive as trea­suries of rare and species-rich ecosys­tems

rows there are rated for “sig­nif­i­cance”, and the high­est score de­fines “her­itage hedgerows” of great­est con­ser­va­tion pri­or­ity. They tend to be on an­cient bound­aries shown on the old 1-inch maps and have a dou­ble-bank struc­ture and a stream or river run­ning by.

Bor­row­ing the 30m mea­sure from the UK, “high sig­nif­i­cance” is gained by strips with 10 or more species of tree, shrub and climber, half a dozen plants from a long na­tive list, and per­haps five kinds of fern. If the hedge has links to a des­ig­nated wood­land, so much the bet­ter.

The sys­tem will be dis­cussed by one of its au­thors, Dr Jan­ice Fuller, at a ma­jor con­fer­ence on Ire­land’s na­tive wood­lands next Mon­day and Tues­day at the Glen­view Ho­tel, Del­gany, Co Wick­low (see wood­land­sofire­land.com).

The event cel­e­brates 20 years of work by Wood­lands of Ire­land to man­age ex­ist­ing na­tive woods and cre­ate new ones. Their value, with that of hedgerows, to flood man­age­ment is one of the lead­ing top­ics for the con­fer­ence, with more than 20 ex­pert speak­ers.

Hedgerow black­thorn blos­som – early nec­tar for pol­li­nat­ing bees. ILLUSTRATION: MICHAEL VINEY

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