Fig. 2From: Biomass productivity of selected poplar (Populus spp.) cultivars in short rotations in northern Poland§ Dry matter (DM) yield comparison per unit area (t ha−1 year−1) of 5- and 6-year-old cultivars. The data were analysed using a contrast analysis. NS non-significant difference (p > 0.05); *significant difference (p < 0.05); **p < 0.01; ***p < 0.001Back to article page