The emphasis is mainly on soil water nutrient levels, acidification, heavy metals, organic pollutants, and leaching of nutrients from the site. Nevertheless, some studies have addressed these issues in different Nordic countries. For example, the effect of final felling of forest stands on runoff water chemistry and discharge has been widely studied, as has the effect of wooded strips along streams (buffer zones) on runoff water chemistry and aquatic organisms in northern Sweden. In Finland the role of forest land in artificial recharge of high quality groundwater resources to compensate for water extraction has also been studied.