A hazel tide, ebbing and flowing

On its way to the shore the boreen tilts down beside a creggan, a sandstone outcrop like a last, rocky toenail of the mountain. Abruptly steep beside the lane, the ridge sometimes offers a wild silhouette between me and the morning clouds: a sitting hare, a wind-blown ewe with a mane like a wild Apache. And couched in the slope between rock and fence – an old one, tilting and bound with honeysuckle – is a miniature hazel wood.

The little trees, perhaps 20 crowding together, are spikily shorn by sea winds to a height that might just hide a man, and each is a dense bundle of vertical stems, none a lot thicker than a broomstick. Hazels grow naturally in this multistemmed way, so reliably renewed that it lends itself to coppicing – the cutting of straight, smooth, durable lengths for all kind of human uses.

My own few hazels on the acre, planted 20 years ago, now yield lightweight two-metre poles to make frames for vertical growing in the polytunnel: winter squashes, mangetout peas, climbing beans. In its many years as a stony track from the strand, busy with cartloads of shell sand and seaweed, the boreen offered stout hazel wands to brace the weave of willow in cliabhs, pardogs and lobster pots. To think the boreen’s bushes were planted there, however, is almost certainly wrong, for hazels also survive in other ungrazed reaches of the hillside.

Classed so often as an "understorey" shrub, happy in the shade of oak trees or others, hazel is actually a light-demanding species, quite capable of growing six- metre-high canopies of its own. It was, after all, the second tree into Ireland after the post-Ice Age juniper, rapidly covering much of the island and helping to house and feed the earliest human settlers. Viking Dublin was a midden of nutshells and hazel wattle, and the Old Irish tree list, rating economic value, put hazel second only to the oak.

Once, as volunteer rod-carrier for Dr Pete Coxon, the Trinity College Dublin palaeobotanist, I watched his coring tool bring up a gem of prehistory from deep below the mud of a little peaty lochan on Clare Island. It was a flawless, golden-brown nut, embedded, magically whole, in a core of twiggy fragments as thick as your thumb. Its place below a band of charcoal (left by early forest-burning) dated it to 8,000 years at least. The nut, too, was soon blackening in the air, but its time shift filled me with wonder.

Left uncoppiced, a hazel can spread ever outwards in a ring of shoots while the core of the tree dies off. Such a “stool” on the Finnish coast has been put at an astonishing 990 years old.

Thousands of years
On the western coasts of Ireland and Scotland old-growth hazel woods have survived, in whatever patterns of succession, over thousands of years. Yet, unlike the old Atlantic oak woods, so valued for their "rainforest" wealth of oceanic lichens, mosses and liverworts, the comparable treasures of these ancient woodlands have earned them no place in the EU's all-seeing habitats directive.

In Scotland this has prompted an Atlantic Hazel Action Group, a partnership of consultants, government agencies, NGOs and ecologists. Their first concern has been protection of a very strange-looking fungus called hazel gloves ( Hypocreopsis rhododendri ). In Paul Whelan's Lichens of Ireland this clasps with many pale orange fingers (eerie, indeed, as he says) the branch of a hawthorn growing among some of the oldest hazels of the Burren, in Co Clare.

The Burren’s hazel scrub, as it gets called these days, has ebbed and flowed across the limestone hills with historic changes of population and farm husbandry. Today’s clearances are aimed at the younger invasions of the uplands; the ancient heart of the hazels, on boulder-strewn slopes never cleared or grazed, remains shadowy and safe. In the State-backed Burren Farming for Conservation Programme, Atlantic hazel woods are recognised as “very rare in Europe and merit special attention”.

They form an enchanting, Tolkienesque tangle: an intimate, three-dimensional maze, furred in bright greens and dappled with sun. The hazel branches, the oldest ones brittle and breaking at a touch, are chequered and studded with lichens and sleeved and muffed with mosses, often up to the highest twigs. The rocks, too, are cushioned and rounded with mosses and ferns and a special retreat of rare helleborines.

This is the terrain of wood mice and shrews, and rustling red squirrels in autumn. It is not, to be clear, an adventure ground for humans. As I write, the Burren is in glorious flower, its high rocky terraces and pastures starred at last with spring gentians, drifts of mountain avens, ranks of early orchids. Go to burrenbeo.com for the closing events of this month’s Burren in Bloom festival, and leave the whiskery hazels to the privileged, fairy footsteps of the lichenologists.