What are the energy transformations that occur when a piece of wood is burned?

The bonds in the wood between the atoms in its structure contain potential energy. Lighting the wood on fire introduces a combustion reaction which ignites this energy. Potential energy is transformed into chemical energy as the wood burns to create heat, smoke (released into the air), and soot (by product of burning the wood). 

Hope this helps!

The geographic feature in the westernmost corner of kenya is answer: the great rift vally