Another Life: Scots pines pass the native species test

On the other side of the mountain, Doo Lough Pass is a spectacular glacial valley between Mweelrea and the Sheeffry Hills, its stretch of the Wild Atlantic Way twisting narrowly beside the lake. Setting out for Galway in a southerly gale, we are sometimes greeted by waterspouts spinning across the dark water. Coming back in whatever the weather, a special clump of trees on a promontory of the shore is reassurance that we’ll soon be home.

This group of statuesque Scots pines, much photographed for the picture they make, with a fishermen's jetty curving at their feet, were planted by a Scottish sheep rancher in the middle of the 19th century. William Houstoun's operation, spread over some 40,000 acres, from the Sheeffrys to the sea, displaced 180 of Lord Sligo's peasant families (iti.ms/1NqgwmG).

Most of Ireland's ageing stands of Pinus sylvestris were originally planted by colonial settlers, often for commercial timber, using pine saplings raised from Scottish seed. Houstoun's trees would have sprung from the cones of Scotland's native forest. Houstoun may even have known that the remnants of Ireland's ancient pines lay buried in many of the bogs around him. In my turf-cutting days, on what used to be some of his land, the slean would sometimes strike a root while cutting the lowest spit, gashing the spongy red timber.

Our native P sylvestris colonised Ireland from Europe soon after the last ice melted. Their decline began as climate changed with the rise in sea level and peat began to grow around their trunks. (A magnificent salvaged specimen stands at the heart of the Céide Fields Visitor Centre, in north Mayo; iti.ms/1NqhnDN.) Between that and clearance for farming, building and firewood, the native trees had disappeared by about 1600.

Or had they? Arguments about this have persisted for many years. In his Trees of Ireland (1993) the botanical historian Charles Nelson found enough to persuade him that descendants of the aboriginal trees could have survived, here and there, to overlap with the later planting of pines from Scottish seed.

The latest study, published in the Royal Irish Academy journal Biology and Environment, is chiefly concerned with how well the introduced Scots pines, now covering about 7,360 hectares – 1.2 per cent of Ireland's forest cover – match up floristically with the lost native pines of our bogs and the native pine forests of Europe. So these are important habitats for the island's biodiversity.

The research team, led by Dr Jenni Roche, biodiversity officer of Dublin City Council, compared the mosses and liverworts of Irish plots of planted Scots pine, along with similar species in fossil pollens around the roots of our buried pines, with the corresponding plants of native pine forests in Scotland and western Norway. There were enough similarities to conclude that, despite its history of reintroduction, the Scots pine deserves to be kept and managed as a native woodland species.

The ecosystem it creates is not a perfect match for that of our ancient pinewoods. We have, for example, lost the capercaillie, a turkey-sized bird that once strutted through their shade, and the pine-dependent beetles that tunnelled the fallen trees.

The new study supports the inclusion of Scots pine in the scheme for restoring native woodlands. But it also urges “clarification” of its future as self-sown species spreading from adjacent pine plantations across cut-over peatland.

The Irish Peatland Conservation Council wants to treat the tree as a threatening invasive species, citing its presence on 29 raised bogs of the midlands, as unwelcome as the sprawl of rhododendron (iti.ms/1IEfUEs).

I close by including a book, published earlier in the year, among the options for Christmas. Kilmacurragh: Sourced in the Wild (Systems Publishing , €30) is a splendidly produced exploration of a largely unknown arboretum just 30 minutes south of Bray, Co Wicklow.

While thousands of Scots pine were, indeed, planted here by an early owner, William Acton (1789-1854), it is the often spectacular trees of exotic species that led the National Botanic Gardens to take over the crumbling estate in 1996. Megan O’Beirne, the book’s dedicated author and photographer, traces the Acton family history with roots in Cromwellian settlement and the steady arboreal enrichment of the estate from the finds of the great travelling plant-hunters of the 19th century.

Readers intrigued by my recent column on Ireland's fossils might also enjoy 648 Billion Sunrises: A Geological Miscellany of Ireland, published by the Department of Communications, Energy and Natural Resources (€16.99). The geologist Patrick Roycroft offers an enthusiastic, endlessly informative, breezily enjoyable kaleidoscope of the island's rock and fossil history.

I recently gave a wrong email for the purchase of Dordán Dúlra, about the landscape and natural history of Cill Chomáin in the northwestern corner of Mayo. The right address is dunchaochain1@eircom.net.

Michael Viney's Reflections on Another Life, a selection of columns from the past four decades, is available from irishtimes.com/irishtimesbooks