A biomass can also be classified on the basis of its relative proportion of cel­lulose, hemicellulose, and lignin. For example, we can predict the behavior of a biomass during pyrolysis from knowledge of these components (Jones et al., 2006). Figure 2.11 plots the ratio of hemicellulose to lignin against the ratio of cellulose to lignin. In spite of some scatter, a certain proportionality can be detected between the two. Biomass falling within these clusters behaves simi­larly irrespective of its type. For a typical biomass, the cellulose-lignin ratio increases from ~0.5 to ~2.7, while the hemicellulose-lignin ratio increases from 0.5 to 2.0.