§ Mr. Maclennanasked the Secretary of State for Scotland on what grounds the Forestry Commission bases its advice that conifers should be planted at least 15 to 20 m back from main watercourses; what account is taken of local geography in reaching this assessment; and in what ways the Forestry Commission establishes whether this advice has been observed by planters.
§ Mr. John MacKayThe Forestry Commission's advice on this matter is published in its leaflet "The Management of Forest Streams", a copy of which has been placed in the Library of the House. This leaflet recommends that, depending on the land form, the area to be kept free of conifers at each side of the watercourse should be about 10 times the width of the watercourse up to a maximum of 30 m. This is to avoid dense shading which would block out the sunlight that is essential if water plants and fish food organisms are to flourish. Such areas also provide ground through which water from drainage channels can be filtered to remove silt, space in which broadleaved trees can be planted for landscaping and to improve stream habitats, and easy access for anglers and walkers. The commission monitors whether such advice is being observed in the course of inspections of planting for which grants have been claimed.