Managing forests in acid sensitive water catchments

Atmospheric pollution in the form of acid deposition has been dramatically reduced since international controls on emissions were introduced in the 1980s. However, acidification still affects acid-sensitive regions of the UK, damaging fisheries and causing adverse ecological changes in freshwaters. Forestry is known to influence the degree of acidification, principally due to the ability of forest canopies to capture more acid sulphur and nitrogen pollutants from the atmosphere than other types of vegetation. As a result, there is a need to manage forestry within vulnerable areas to ensure that it does not lead to increased acidification or delay the recovery of waters to Good Ecological Status. This Practice Guide describes the measures that can be taken to minimise adverse impacts and provides a methodology for determining whether new planting, restocking or felling proposals could pose a risk to freshwaters. It includes maps showing the locations of vulnerable areas and decision trees to guide those involved with woodland creation or the felling and restocking of existing forests in affected areas through the steps of catchment-based critical load and site impact assessments.