When you cut a tree, it is full of the water of life, and seasoning is the process of allowing this water to evaporate. As it loses water, the wood shrinks across the grain and becomes harder, stronger, and lighter. Careful seasoning involves even evaporation of the water so that the wood does not fracture under the stress or decay because of the action of fungi. Wood shrinks more with the annual growth rings than it does across them. If you cut a shape from green or wet wood, this uneven shrinkage will cause it to distort as it dries.