Bark (corteza). Exterior layer that protects the trunk.
Cambium (cambium). Thin transparent layer. Not used for wood work.
Heartwood (duramen). The strongest and hardest part of the trunk. Used for wood boards.
Sapwood (albura). Recent growth wood, Softer and lighter than heartwood. Used for wood boards.
Pith (médula). Centre of the trunk. Weak and not used.