There is an article here on which wood is best to burn to heat up a house most efficiently. The main points the article makes is that factors such as stove type and the dryness of the wood have an effect but one of the main ways to make a difference is by burning dense wood rather then light.

Slower growing, denser woods such as oak, beech, and hickory are known as “hardwoods.” .. Evergreen trees are generally called softwoods. Softwoods burn easily but with less heat, and are good for kindling or when less heat is needed. Fruit woods apparently make lovely, hot firewood but take quite a long time to dry sufficiently.

Grist via Reallynatural