The name for the sawed wood we use to build our homes comes from a Germanic tribe called the Lombards (long beards), who invaded Italy in the 6th century and from whom Lombardy took its name.
These Lombardi (Ital.) merchants were pawnbrokers - they accumulated stores of discarded household items left as pledges on loans. A lot of it was furniture. Their pawnshops were called lombards, pronounced "lumber" in English.
But the primary meaning of lumber in the United States and Canada is timber that's been sawed and split into planks, beams, joists, and boards. How did that happen?
In American pioneer days, when the land was cleared for farming, there were many felled trees lying around. These, being discarded material, followed European tradition, and were called lumber.
This expression, meaning outside the rules of society or civilized behavior, has no connection to white or colorless. Pale, in this case, comes from Latin palus: a stake in the ground to mark a territory.
During Roman times, palings, or picket fences, were driven into the ground all over Europe to designate areas that were under a ruler's control. Beyond the pale meant simply to be outside the limits of a kingdom, and by extension, became a place for social outcasts.
At various times in history, France and Ireland were held by the English, and pales were erected to show limits of the British territories. Fourteen-century Ireland had a fenced enclave, or restricted area, in and around Dublin known as the British Pale.