Growth and biomass of wildtype (WT) and transgenic P. × canescens genotypes.

CCR, COMT and CAD refer to transgenic poplar lines with suppressed activities of cinnamoyl coenzyme A reductase, caffeic acid O-methyl transferase, and cinnamyl alcohol dehydrogenase, respectively. The plantation was established in June 2008 and measurements were taken in October 2009 and October 2010. Data are means (± SE, n = 9). Cum Height: cumulated height of all stems of one plant was calculated as the sum of the length of the main stem and the side shoots. Biomass = dry mass of the main stem, RCD: root collar diameter. Significant differences are indicated by different letters (ANOVA, followed by TukeyHSD p≤0.05). * = calculated with estimated stem volumes and wood density.