When humidity is high, wood absorbs moisture and swells. When humidity drops, wood shrinks. This “movement” is gradual, so you probably won’t notice weekly changes. But seasonal changes cause problems you can’t miss, like sticking doors, ugly gaps in woodwork or cracks in a tabletop.This movement occurs whether wood is fresh from the mill or centuries old, whether it was kiln dried or air dried. And it exerts tremendous force that’s almost unstoppable. But with a little knowledge, you can minimize the consequences. This article will explain the basics of wood movement and show you real-world solutions.