Impact of clearfelling on dissolved nitrogen content in soil-, ground-, and surface waters: initial results from a study in Latvia
¹ Latvian State Forest Research Institute ‘Silava’, Rigas str. 111, LV-2169 Salaspils, Latvia
² MNKC, Dzerbenes Str. 27, LV-1006 Riga, Latvia
Conventional forest management has traditionally been targeted to enhance provisioning ecosystem services. Recently, however, awareness about the effect of forest management on other groups of ecosystem goods and services has been raised at the European and global levels. A number of initiatives addressing the evaluation and mitigation of the impact of forest management operations on biodiversity, soil quality, nutrient cycling, and water quality have been reported. In 2011, the development of a monitoring system to assess the impact of forest management on biodiversity and environment in the state forests of Latvia was initiated in the Latvian State Forest Research Institute ‘Silava’. A number of studies to obtain experimental data and to test potential monitoring methods were implemented during this project. Among other activities, three research objects related to the quantification of changes in nutrient cycling after clearcut with whole-tree harvesting and stem-only harvesting were established. Data on changes in nutrient concentrations in soil solution, ground water, and surface waters, and on nutrient input through precipitation, are presently available for one year before and two years after clearfelling. Significant increase of dissolved nitrogen concentration in soil solution, as well as differences between stem-only and whole-tree harvested plots emerged only in the second year after harvesting. No significant increase of the dissolved N in the streams was observed, compared to the reference period. Ground vegetation recovery, amount of slash, soil properties and processes in the buffer zone are among those factors influencing the N leaching most, and these will be investigated further.