To sign wood, take your non-dominant hand and lay it flat in front of you. Then take your flat, open dominant hand and make the motion of sliding it on its pinkie side above and across the non-dominant hand, back and forth a couple of times. It is as if you are sawing wood.
Use the wood once your baby or toddler begins to show natural curiosity for different materials and textures. You can teach the sign by contrasting a wooden chair versus a plastic chair.
Teach your toddler the wood sign in context, especially when they begin to show curiosity for different materials and textures around the house or outdoors.