Trees, the source of wood, have a trunk enveloped by a shielding layer of dead bark.
Under the dead outer bark is living bark. Next is the cambium, then the thick sapwood, which becomes heartwood as it ages. The pith is at the core of the trunk.
The tree's age can be determined by counting the concentric bands called growth rings in a tree's trunk.
Elongated, tubular cells aligned with the trunk's length define the wood's grain. Wood can take a greater load in the direction of grains than in the direction perpendicular to the grains.
Wood is procured from trees in the form of long cylindrical logs, which are transported to the mills for cutting.
The logs are usually cut into boards and slabs in the mills and seasoned before use.
Wood, particularly in the form of lumber and timber, is one of the most familiar construction materials.
Doors, windows, flooring, columns, beams, and stair railings are constructed using wood.
Additionally, wood is used to manufacture plywood, particleboard, and hardboard.
