EPA Research Report recommend cessation of afforestation on some peat soils

The recently published “HYDROFOR: Assessment of the Impacts of Forest Operations on the Ecological Quality of Water” report has made a number of policy recommendations, including the cessation of afforestation on peat soils in acid-sensitive headwater catchments, and has raised serious concerns with respect to the reforestation of sites in such catchments.

Assessment of the Impacts of Forest Operations on the Ecological Quality of Water, also known as the HYDROFOR Project, was a 7-year (2008–2014 inclusive), inter-institutional co-operative project funded by the Environmental Protection Agency (EPA) and the Department of Agriculture, Food and the Marine (DAFM).

The policy recommendations of the report include:

·         Sediment release to water courses during felling and replanting may be reduced by careful onsite management of felling and windrowing operations, installation of silt traps and greater application and oversight of best practice guidelines.

·         A combination of several sediment traps may be more effective at trapping a range of sediment particle sizes than single isolated traps.

·         Retention of phosphorus requires attention, as it is more challenging on peat soils and will depend on the occurrence of mineral content in riparian soils or installation of mineral barriers.

·         Based on the suite of impacts from planting to harvesting, including elevated DOC, nutrient and sediment release, and aquatic biodiversity concerns, cessation of afforestation on peat soils in acid-sensitive headwater catchments is recommended by the project team. In relation to reforestation of sites in such catchments, there are serious concerns with respect to the aforementioned impacts. Where replanting is considered, the design should be hydrologically informed and demonstrate empirically on a site-specific basis that it can mitigate impacts on water quality and aquatic biodiversity through the forest management cycle, as highlighted in this report. A number of mitigation measures (riparian buffer zones and sediment traps) were investigated in this study, and the research evidence highlighted their ability to reduce some pollutant inputs. Their effectiveness is likely to be site specific and other measures, not investigated in this project, e.g. reduced catchment tree cover, minimising drainage and soil disturbance, may reduce impact, but these remain to be validated by further research.

A full copy of the report is available on the EPA website at: http://www.epa.ie/pubs/reports/research/water/researchreport169.html


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