Mature field-grown trees of eight genotypes grown at the Rothamsted Research (RRes) and Orkney sites. A Glucan composition expressed as a percentage of dry matter (DM). B Lignin composition expressed as a percentage of DM. C Glucose yields from enzymatic saccharification presented as grams of glucose release per gram of glucan present in the biomass. Error bars represent standard error (n = 3 trees). Full mass closed compositional tables are available in supplementary information. * Significant difference (t-test, p < 0.05).