The project 'The influence of stump harvest on the creation of hot-spots for mercury methylation and releases' started in 2012 and ended in 2015.
Earlier studies have shown that forestry can increase the runoff of mercury and the production of methyl mercury. Knowledge about the influence of stump harvest is based on only few studies. There is also large variation in how different sites responded to stump harvest and other types of forestry activities. Earlier STEM projects have improved knowledge of stump harvesting's aquatic influence in a catchment perspective.
The study seeked knowledge of the processes that influence the production of methyl mercury. The hypothesis was that stump harvest creates more "hot-spots" for methylation than traditional site preparation will be tested by mapping the signature that methylation hotspots leave on the soil in the ratio of MeHg to THg. The soil conditions and bacterial communities of these hot-spots in relation to forest treatment were be compared and supported by more detailed study on a subset of identified hot-spots. This will build a better basis for balancing the environmental risks associated with stump harvest and refining existing guidelines for protection of forest water quality.
The project was financed by The Swedish Energy Agency (Energimyndigheten) and had a total budget of 2.5 MSEK.
Participating from the Department were Kevin Bishop and Karin Eklöf.
External partner was Uppsala University.