DR NEIL BURROWS, Senior Research Scientist: It’s live and dead vegetation that accumulates after the fire that is the fuel for the next bushfire. And that includes material such as this, that lies on the forest floor, leaves and twigs that are shed from the trees, vegetation that accumulates in the shrubs, it’s very flammable because it’s suspended above the forest floor, and tall shrubs such as the understorey here that becomes very flammable and burns very ferociously during a bushfire. Another form of fuel is the stringy bark that accumulates on the stems of trees. This bark is very flammable, and during a bushfire it catches alight and can go up with a convection column, and land downwind of the fire, creating more fires known as spot fires. This is a suppression nightmare for firefighters.