A TINY creature is about to cost the Irish forestry industry millions in lost revenue. The pearl mussel, which lives 120 years and is extremely sensitive to pollution, is set to change forever the way trees are grown and felled in parts of Ireland.

The difficulties for Coillte, the state forestry agency, began after phosphorous and nitrate silt leaked into the Owenriff river in Galway in May 2004, and caused an algae bloom that asphyxiated most of the mussels living downstream.

The bivalve is a protected species under European law, and Ireland has the largest remaining population.

Mary Coughlan, the minister for agriculture, imposed a moratorium on forestry activities in all pearl mussel areas last May, some 18 months after officials in the National Parks and Wildlife Service (NPWS) recognised the problem. Coillte can now neither continue fertilising the trees in these areas nor cut them down in an economically viable way. Gerry Egan, Coillte’s company secretary, said yesterday less than a quarter of the company’s forests, were affected. But internal documents and environmentalists suggest otherwise.

Aine O’Connor, an environmental officer at the NPWS, began an internal debate on the issue in an e-mail to her colleagues in October 2004, five months after the bloom emerged.

“I am very concerned that populations in other river catchments are at risk,” she wrote.

“Current evidence suggests that clear felling of conifer plantations in blanket bog and heath catchments lead to massive losses . . . I believe that all forestry activities in mussel catchments should be suspended.”

One of her colleagues, Noel Kirby, replied: “Having looked at the Owenriff situation it is my impression that we are sitting on fertiliser time bombs that are coming to the fore after 50-plus years of fertiliser usage for forestry.”

A spokesman for the Department of Agriculture said last week that clear felling had been prohibited in 25 river catchment areas and there was now a ban on new planting as well. Studies are being carried out to decide what kind of forestry might be more suitable in these areas.

The mussel is known to live in 25 rivers nationwide, including the Shannon, Suir, Barrow, Nore, Slaney, Bandon, both Blackwaters and Lough Corrib. The Department of Agriculture confirmed that if the mussel is discovered elsewhere, the ban will be extended to those rivers too. In the past the species has lived in most Irish waterways.

In another internal e-mail released to Friends of the Irish Environment under a European access to information law Pat Warner, a Forest Service inspector, warned the problem could be bigger than expected.

“Please be aware,” he wrote, “that unless [pearl mussels] are a lot more rare than I think, you are contemplating closing down a significant amount of the state’s afforestation programme, both private and public, if you ban fertilisers in whole catchments. You can’t grow commercial timber in uplands without fertiliser.”

Coillte’s forestry model, which involves regular clear felling of swathes of forest, is now known to acidify soil and dump huge amounts of phosphorous and nitrates into the ground and rivers.

Jim Ryan, an official at the NPWS, told his colleagues he was “stunned” at the amount of fertiliser used by Coillte and the Forest Service and referred to one study in the Cloosh forest in Galway where phosphorous levels in the water from fertilisation and clear felling were 40 times the accepted limit.

Coillte, established in 1989 with the principal remit of making a profit, has almost exclusively grown non-native coniferous trees in poor-quality peat uplands, the same areas susceptible to the chemical leaching that pollutes rivers and kills the pearl mussel.

Last year the European Environment Agency found that 83% of all forestry planted between 1990 and 2000, most of which is still waiting to be harvested and sold, was on peat. While Coillte and the government say the study is wrong, another analysis by University College Cork (UCC) found that at least 50% of forested land is planted on peat bogs.

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