Wood doesn't conduct heat so how does it catches fire ??
The wood absorbs kinetic energy until the activation energy is reached and the molecules of wood react with Oxygen.
The wood is a non conductor. So the kinetic energy of the flame around the wood is absorbed by the molecules and the kinetic accumulates until the kinetic energy causes the bonds between the molecules and atoms start to break. This is called the kindling temperature or reaction activation energy.
When the activation energy is reached the Carbon and Hydrogen atoms of the wood can undergo a chemical reaction with the Oxygen in the air to form Carbon Dioxide and Water. These chemical reactions are highly exothermic providing enough kinetic energy to cause further wood molecules to achieve activation levels and continue the reactions.
The smaller the volume and density of the wood the lower the activation energy. Small pieces of wood are called kindling because they reach the kindling point at a lower temperature.