Carbon and nutrients of Scots pine stands on sandy soils in Lithuania in relation to bioenergy sustainability

•Mean nutrient concentrations of Scots pine often differed between compartments and stand age.•Crown C and nutrient stocks did not change with age, while stemwood stocks increased with stand age.•Removals of C and N in a 100-year rotation were 129 Mg ha−1 and 445 kg ha−1, respectively.•The examined sites might be able to sustain forest fuel harvesting for some rotations.

Sustainable forestry is based on the principle that harvesting practices should avoid negative influence on soil fertility, wood production and long-term soil carbon (C) stocks. We examined C and nutrient concentrations and stocks of Scots pine (Pinus sylvestris L.) stands on Arenosols in south-western Lithuania. The stands were 10, 20, 40, 50 and 65 years of age. C concentrations were relatively constant, while the concentrations of N, P, K, Ca, Mg and S often varied between compartments and stand ages.The total aboveground stocks of nitrogen (N) were estimated to be in the range of 185–260 kg ha−1, and 78–189 kg ha−1 for calcium (Ca), 75–104 kg ha−1 for potassium (K), 22–33 kg ha−1 for phosphorus (P), 21–41 kg ha−1 for magnesium (Mg) and 16–28 kg ha−1 for sulphur (S). Corresponding stocks of the crown alone were 139–207 kg ha−1 of N, 54–88 kg ha−1 of Ca, 44–79 kg ha−1 of K, 15–26 kg ha−1 of P, 15–23 kg ha−1 of Mg, and 11–15 kg ha−1 of S. Biomass, C and nutrient stocks in the crown did not change with age, whereas the stemwood stocks increased with stand age. The total removals of C and N over a whole 100-year rotation were simulated to be 129 Mg ha−1 and 449 kg ha−1, respectively. An example scenario was created to compare the magnitude of potential nutrient removals with the atmospheric influx, soil stocks, and the internal litterfall flux. We suggest that intensified utilisation of these stands for bioenergy may be sustainable.