Bengorm's black eye

At this mid-point in summer, even the worst scars of Connacht's overgrazed hills have taken on a cosmetic haze of green, like make-up on a black eye. But nothing could disguise the flaying of the slopes beneath Bengorm mountain, at the Newport corner of Clew Bay. Even at a distance, across the lake, the bruises speak of wet days in winter when the skinned peat is blackened and gleaming, when the rock gleams, too - fresh knuckles of schist and quartz washed bare in the steeper scarp above.

In one wet fortnight last winter, this hillside was losing peat at the rate of 250 tonnes per square kilometre. The dark silt flowed straight into Lough Feeagh and down through the traps and sluices of the Salmon Research Centre at Furnace, where everything that passes gets measured. In the complex computer maps of the centre's Geographic Information System, even the new erosion of Bengorm can be summoned up, patches of bare rock freckling the screen like a skin disease.

The centre's geneticist, Dr Philip McGinnity, made no bones about it: the overgrazing has been "a catastrophe". He made sure we took a good look before we moved on up the valley.

It was a field visit by the Society of Irish Foresters, at which I was tagging along. How innocent that sounds - an educational ramble in the pinewoods on a summer afternoon. Yet 10 years ago, semistate foresters and fishery people just weren't speaking to each other, such was the depth of aggro and defensiveness over forestry's damage to catchments and breeding streams. Now, within Coillte's commercial brief, there has been a great coming-to-terms with "the environment": marketing demands it; the extra costs must be absorbed. Even on this amiable outing, the earnestness of corporate revisionism, of personal, hand-on-heart commitment, could not be missed. The Burrishoole catchment (named for the short estuary river below the lakes) was perfect ground on which to celebrate such a fresh meeting of minds.

The Salmon Research Centre has swung away from studying the fish to focus on its habitat: get that right and the salmon can look after itself. In the elaborate overlays of the GIS digital maps, conditions along every metre of river and feeder stream are quantified and monitored: a neural network of life branching out through the great glaciated valleys between the Nephin Beg mountains.

These are filled, almost brim to brim, with conifers planted half a century ago, in the days of Minister Joe Blowick and civil-service forestry. Among them were some of the thousands of hectares of the Lulu Island lodgepole pine that grew so poorly on Connacht's peatlands - one of the great silvicultural mistakes, now being erased in Coillte's clear-felling.

We looked down at the valley floor, where the Srahmore River gathers in some of its tributaries above Lough Feeagh. The old, failed trees have been cleared and the hope is never to replace them, at least with Sitka spruce that would normally need three applications of fertiliser in their lifetime, all sprayed by helicopter. Coillte's forests are managed for "sustainability", complying with Forestry Acts which compel the replanting of all clear-fell areas but, in such fragile catchments, there will have to be exceptions.

Much of the tension between fisheries, farming and forestry rests on a fundamental difference highlighted by Dr McGinnity. Farmers and foresters want to rush the rainfall off the land as rapidly as possible. But a productive salmon fishery depends on the land storing water and releasing it gently, with neither winter flash-floods to rip the gravel redds apart, nor summers when streams and waterfalls dry up for want of a natural flow from the land. The bog was the perfect natural sponge until the foresters carved their drains through it.

Clear-felling hillside conifers can choke the breeding streams in silt and brash, smothering the redds and blocking the salmon's progress upstream. This happened at Nephin Beg four years ago, when a contractor was allowed to harvest too late on a steep hillside, in an autumn of unrelenting rain. Coillte's team-leader confessed the consequences, standing below the bare hillside in true contrition. It was rather moving: like a scene from a village meeting in Mao's China.

The incident was a turning point in relations between the local forest managers and the salmon scientists. Now, contract harvesters work only in summer, with a "Plan B" to make use of their machinery on particularly rainy days. A question on the costs of halting machines to spare the ground brought an uncompromising answer from a Coillte man: philosophy and practice have changed, and these environmental costs must be spread across the industry.

WE were led to the green banks of an important breeding stream, newly liberated from the trees and left sparkling and immaculate amid the clear-fell brash: a lesson in how things should be done. When the slopes are replanted, a clear margin will be left along the banks. This sunlit riparian zone, left to grow its own natural vegetation, will help buffer the stream against phosphate pollution from the forest's fertiliser and enrich its insect life.

The Geographic Information System in the salmon centre's computer is a perfect tool for cooperative planning. Its limitless elaboration of data, assembled, monitored and overlaid as maps, begins to mimic the complexity of the natural ecosystem it describes. Applied to the Burrishoole catchment, it should help to maximise productivity of fish, trees and farming, while sustaining the environment and balancing the claims of all the stakeholders.

This, at least, is the theory. And listening to it, in a mountain valley, scented with spruce resin and lush with rhododendron blossom, one can get quite carried away, in the knowledge that GIS, in whatever software package, is humming away in one land-use agency after another, right across the land.

At last, a welcome for nature's complexity, for biodiversity, for holistic planning! Let the computers get on with it, I say.