What are four main components of timber?

The four main components of timber are cellulose, hemicellulose, lignin, and extractives. Cellulose provides structural strength and rigidity, while hemicellulose contributes to the overall stability and flexibility. Lignin acts as a binding agent, giving timber its hardness and resistance to decay. Extractives, which include various chemicals, can affect the color, durability, and resistance to pests and fungi.