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A growing demand for bioenergy from conventional forestry in Sweden will increase the need of nutrient compensation, that preferably should be made relatively shortly after harvesting and have no undesired side-effects. This study compared the effects of granulated wood ash (Ash), N-free, dolomite-based fertiliser (Vitality) and the green fraction of harvest residues (Residues) on the podsolic soil and soil solution of a young Norway spruce (Picea abies (L.) Karst) stand in SW Sweden. The treatments were applied three years after clear-felling and whole-tree harvesting. The soil solution was repeatedly sampled in the rooting zone 2-5 years after treatment. The soil study was performed 4 years after the Ash treatment and 3 years after Residues treatment and the last Vitality treatment (the Vitality treatment was applied on two occasions over 2 years). The Vitality treatment increased base saturation and effective CEC in the humus layer in relation to the other treatments, and also increased Ca and K concentrations in the soil solution. The Ash treatment resulted in higher exchangeable K concentration than Vitality in the litter layer, and Residues increased K concentrations in the soil water. No treatment influenced the KCl-exchangeable nitrate concentrations in the soil or the nitrate levels in the soil water. The results indicate that granulated wood ash could be used for long-term nutrient compensation without undesired short-term side-effects.

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Treatments added to young conifer stands aiming to compensate for the loss of nutrients and alkalinity associated with whole-tree harvesting for bioenergy purposes have the potential to affect the growth of competitors to the conifers. Three different nutrient compensation treatments were applied to a young Picea abies (L.) Karst. stand in south-west Sweden, 2 or 3 years following final felling. The treatments were; fine fraction of harvest residues (15 Mg dw ha −1 ); granulated wood ash (4.1 Mg dw ha −1 ); nitrogen-free vitality fertiliser (twice 1.5 Mg ha −1 ); untreated control. Root biomass and total biomass of graminoids (mainly Deschampsia flexuosa (L.) Trin) were significantly greater in the wood ash and vitality fertiliser treatments than in the residues and control treatments. The aboveground and coarse root biomass of naturally regenerated birch (Betula spp.) and the aboveground biomass of dwarf shrubs (mainly Calluna vulgaris (L.) Hull.) and bottom layer were not affected by the treatments. Calcium and magnesium concentrations in the aboveground biomass of graminoids and phosphorus concentration in the biomass of bottom layer were significantly the highest in the vitality fertiliser treatment. Thus, nutrient compensation with vitality fertiliser or granulated wood ash may increase competition from graminoids in the establishment phase.