From the text ... 'Although small litter particles produce more tightly packed and less flammable litter, smaller particles have greater surface-area-to-mass ratios and can promote fire in well aerated samples. But the burning characteristics of well-aerated samples do not simulate natural litter fuels, and litter-bed flammability studies find that the litter density effect outweights any countervailing influence of surface-area-to-mass. Leaf size, however, most likely plays the opposite role in canopy flammability. Narrow leaves with high surface area to mass burn with high ignitability and intensity. Plant species with small leaves have fine and highly branched canopies as well and these tightly spaced leaves and twigs, at densities well below those that cause oxygen limitation, allow efficient heat transfer. Therefore, plants with low flammability leaf litter may have highly flammable canopy structure (Scarff & Westoby, 2006)' © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.