Wood has different strength properties when loaded in different manners. In fact, there are six main design values that are published for lumber and timbers in order for engineers to appropriately design a structure.
Bending: Two values are published for bending properties. The fiber stress in bending, Fb, is related to the breaking strength of a piece when loaded in bending. The Modulus of Elasticity, MOE, or E, is related to the stiffness of a piece loaded in bending. The stiffness is considered a “serviceability” factor and determines how much a piece bends as well as the magnitude of vibrations, say when someone walks across a floor. The following figure shows an example of a beam loaded with a bending load: