asked the Secretary of State for Scotland whether he has any evidence that acid rain falling upon Forestry Commission woodlands and subsequently concentrated by being trapped upon the needles of the conifer trees, may cause the acidification of some Scottish streams and lakes resulting in the deaths of fish; and if he will make a statement.
It is known that salmonid fish are very vulnerable to high concentrations of acidity and aluminium, particularly at the hatching and fry stages. Waters which frequently, or continually, have high acid levels are unlikely to support self-generating fish populations.Scotland, like most countries in the northern hemisphere, is now subjected to acid precipitation resulting primarily from industrial emissions. The longterm solution to this phenomenon, however, can only be provided by world-wide action.Whilst coniferous afforestation can itself give rise to some acidity in surface waters, my Department is—in consultation with the Forestry Commission—examining the extent to which major coniferous afforestation may adversely affect freshwater fisheries with particular reference to the question of augmentation of the effect of acid rain. Further work is in hand, but based on the results already available the Forestry Commission has adopted revised forest management practices and has issued guidelines to the private sector.