The effect of Norway spruce stump harvesting on net nitrogen mineralization and nutrient leaching

•The effect of stump harvesting on annual net nitrogen mineralization (NNM) was variable and soil specific.•Stump harvesting affected the proportion of the nitrification and ammonification processes in NNM.•Annual net nitrogen mineralization at highly fertile spruce sites can be relatively high.•The stump harvesting increased nitrogen leaching in only one study area.•Stump harvesting does not induce serious environmental hazards in relation of N cycling.