In this work, 10 different biomasses were selected which included directly grown energy crops, industrial waste material and different wood types. Each biomass was sieved into six different size fractions and pyrolysed in a fixed bed furnace preheated to 1000 degrees C to produce a char residue. Intrinsic reactivity during burnout was measured using a non-isothermal thermogravimetric method. Scanning electron microscopy and oil immersion microscopy were used to characterise the morphology of the products. Char morphology was summarised in terms of degree of deformation, internal particle structure and wall thickness. Intrinsic reactivity corresponded directly with these morphology groupings showing a significant correlation between char morphotypes, char reactivity and the initial biomass material. (C) 2011 Elsevier Ltd. All rights reserved.