A piece of wood does not burn.  Combustion happens when wood is heated to a point at which it starts volatilizing or producing a flammable gaseous mixture.  This is called pyrolysis.  The ignition of this vapor in turn heats the wood to produce more gas and more fire.

A single person cannot alone change the world.  Progress is made when the support and resources from others empower the individual.  This is called boldness.  This energy is then spread to others and increases the impact on our world.