Heartwood

In the very center of the piece of wood shown above, is the Heartwood. The name is very fitting, because it is located in the middle of the wood, like it is the literal 'heart'. The heartwood is composed of dead cells and is more resistant to decay than the rest of the wood. Being that it is generally harder than the surrounding wood, it is crucial for the structure of the plant/tree. In addition, the heartwood is usually darker than the rest of the wood, when viewed directly.