To ask the Secretary of State for the Environment what proportion of acid rain deposition, and contamination of groundwater by acidity is caused by monocultural foresty development in the United Kingdom.

The Department's acid waters review group in their second report, copies of which have been placed in the Library of the House, concluded that the primary cause of acidification in sensitive areas of the United Kingdom was acid deposition from the atmosphere. Afforestation might increase the deposition of pollutants by 30 per cent. in a mature stand. The effect of the contamination of groundwater is difficult to quantify. Research by the Forestry Commission and within the Department's air pollution research programme on quantifying the effect of afforestation, including mono-cultural forestry, on acid deposition is continuing.