Comparison of enzymatic saccharification yields of the three genotypes present in the pot trial and the Rothamsted Research (RRes) and Orkney field sites. Yields are presented as grams of glucose release per gram of biomass and so encompass variation in both glucan content and glucan accessibility. Low reaction wood inducing (RWI) conditions = control trees (pot) and RRes site (field). High RWI conditions = RW induced trees (pot) and Orkney site (field). Error bars represent standard error (n = 3 trees). * Significant difference (t-test, p < 0.05).