Forest impacts on freshwater acidification: an investigation of policy and practice in Galloway, S.W. Scotland

Abstract

This thesis takes an interdisciplinary approach to investigate factors that influence the extent to which environmental policy and practice are founded on the best available knowledge of the environment. The study focuses on the "forest effect", a long-contested environmental impact whereby afforestation is seen to exacerbate freshwater acidification. A social constructivist approach is taken to focus on the factors that impact the inclusion and exclusion of different forms of knowledge (scientific and lay, local and outside knowledges) held by different environmental actors within the environmental decision making process. The methodology follows a stakeholder-based approach. It works alongside a group including policy makers, land managers, environmental regulators and NGO "interested parties" to develop an understanding of the contested nature of the "forest effect". Many methods from the social sciences such as participant observation, semi-structured interviews and discussion of participatory maps are utilised. Key differences in the ways that stakeholders conceptualise the "forest effect" are identified. These differences in conceptualisation are identified as being the primary factors contributing to the prevention of information from local knowledge being included within the decision making process. Two significantly different conceptions of the "forest effect" were identified. The first, the "mechanism-down" effect, draws on scientific understandings of the sulphate-scavenging role of forestry and is reflected in policy by a risk- based approach using catchment-based Critical Loads analysis. The second view of a wider "forest effect" was drawn from local knowledge of unusually high acidity and damage to fish populations in afforested areas. To explore these two "forest effects" in a statistical manner, regional datasets were collated in a catchment-based database that included contemporary and long-term regional field surveys of water quality data, forest maps generated from satellite imagery. Statistical analysis supports a wider "forest effect" than that represented by the "mechanism-down" effect represented in the Forestry Commission's Forest and Water Guidelines. A statistically significant "forest effect" of decreasing pH, charge balance ANC and increasing sulphate, chloride, sodium, CI:Na ratio and DOC with increasing catchment forest in areas outside of those identified as at risk by the Forest and Water Guidelines. Furthermore, further supporting evidence for a "forest effect" as a factor reducing the potential for long-term recovery from acidification is identified. Three factors are identified as having influenced the extent to which knowledge of this wider "forest effect" is recognised by environmental policy and practice. Firstly, it was shown that privilege was given by policy makers to one interpretation of science surrounding the "forest effect". The faith put in the science-derived risk-based approaches as sufficient to control for the "forest effect" lead to the exclusion of local knowledge that contradicted this. Furthermore, this lead to real but pragmatic factors (such as the impracticalities of wide-scale water chemistry survey or the cost of felling large proportions of the forest estate) often being either couched in terms of Science, or not being directly discussed, rather than raised frankly as legitimate issues. Secondly, there was little recognition of the complexity and uncertainty surrounding either the nature of the "forest effect" itself, the scientific process used to study it and the ramifications for the varied actors depending on both the forest and water resources. Finally, it was shown that relationships between organisations played a key role in encouraging/deterring the transmission of knowledge; decisions were shown to be based on Better Available Knowledge when the parties involved integrate knowledge from other actors. Hierarchical and institutional ties, on the other hand, were shown to have the potential to restrict the openness to knowledge transfer. This thesis suggests a social learning approach is taken. This approach encourages the recognition of environmental problems as resource uncertainties to which there is no one determinable answer that suits all and around which decisions can best be legitimised through consensus between impacted parties, informed by the best available scientific data and with recognition of the wider social, political and economic consequences of any action taken.