Stump removal impacts nutrient status and young stand development in mesotrophic Latvian hemiboreal forests

Tree stumps are a potentially significant source of renewable energy, but their extraction may result in significant adverse impacts on ecosystems. To assess mid-term effects (up to 8 years after harvesting) of stump removal on nutrient status and young stand development in mesotrophic Latvian hemiboreal forests, we evaluated soil and soil solution chemistry, subsequent young stand growth, and foliar micro- and macroelement status in five sites where above-ground whole-tree harvesting (WTH) was compared to above-ground WTH with additional stump biomass removal (WTH + SB). Post-harvest soil organic carbon stocks and C/N ratio declined more after the WTH + SB than after WTH while soil nitrogen stocks increased. No additional acidification of the soil solution caused by stump removal was observed, and the inconsistent pattern of nutrient concentration change in soil solution (partial increase of phosphates, calcium and magnesium in WTH + SB relative to WTH, no clear response of nitrates) reflected site-specific conditions. N concentration in planted Norway spruce needles did not differ consistently between the treatments, and foliar nutrient concentrations of the regenerated stands were mostly within the typical range of similar forest site types in Latvia. Mean tree height was significantly greater after WTH compared to WTH + SB in sites with monodominant regeneration.