You can get wood from chopping down trees, and you can get wool from killing sheep. The process for each is different, but both result in the player obtaining a renewable resource.
Wood can be obtained by using an axe on a tree. This will cause the tree to fall and provide the player with wood. The amount of wood obtained will depend on the size of the tree. Smaller trees will provide less wood than larger trees.
Wool can be obtained by using a knife on a sheep. This will cause the sheep to bleed out and provide the player with wool. The amount of wool obtained will depend on the size of the sheep. Smaller sheep will provide less wool than larger sheep.