How far does wood expand

*Under constant humidity wood won't expand much from 20c to 30c. Moisture is the leading cause of expansion in wood products.

* Knowing that wood will naturally attempt to equalize with the humidity in it's environment, a woodworker must know how the wood will expand. Movement in a piece of stock will occur across the grain, as opposed to along the grain. That is to say, a 1x6 that is four feet long will almost always stay four feet long. However, depending on the moisture content of the stock and the air (and the variety of wood used), the width and thickness (to a lesser extent) may vary considerably.