Various water quality parameters covering a pre and post-planting regime (Halladale study 1995-2010)

Our study was driven by concerns that afforesting the headwaters of the Upper Halladale River in North Scotland would affect water quality and the local salmon fishery. The main issue was the threat of increased surface water acidification due to pollutant scavenging by the growing conifer forest but there were also worries about the impact of the soil disturbance and hydrological changes accompanying ploughing and drainage operations and nutrient losses following planned fertiliser applications. The headwaters support important spawning and nursery areas for salmon and were therefore considered to be especially vulnerable to afforestation. Following an initial one-year study to evaluate the potential impacts, the scheme was agreed and planting proceeded in 1996. This presented an ideal opportunity to continue the monitoring to look at the short, medium and long-term effects of afforestation and forest growth on the chemistry and biology of a sensitive freshwater system. Water samples are regularly taken from six sites and analysed for a wide range of water quality parameters. The results of our study will also assess the efficacy of forest management practices in protecting the freshwater environment. See papers below for more details: Forestry Commission (1994). Final report on research at Halladale, February 1993 to April 1994. Forest Research, Farnham, Surrey, UK. Forestry Commission (1997). The sustainability of afforestation development within Highland catchments supporting important salmonids fisheries – the Upper Halladale Rive. Research report for the period January to December 1997. Forestry Commission (1999). The Sustainability of Afforestation Development within Highland Catchments Supporting Important Salmonid Fisheries - the Upper Halladale River. Research Report for the Period January - December 1999. T.R. Nisbet, J. Pitman & S. Broadmeadow (2007) ANC Response Function for Salmonids: An Assessment of the Critical Limit for Protecting Surface Waters from Acidification in Scotland. Forest Research, Farnham, Surrey, UK. Shah, N.W. and Nisbet, T.R. (2016) The short and long-term effects of peatland conifer afforestation on water quality in a sensitive freshwater system. Manuscript in preparation.