The sign for tree looks like a tree waving above the ground. To make the tree sign, take your non-dominant hand and extend it flat across your body to make the ground. Then take your dominant hand and stand it up at right angles, with your fingers extended and pivoting back and forth at the wrist, like the swaying leaves and branches of a tree.
When you go out and look out onto the garden, make the tree sign when showing your baby a tree. Help make the experience more vivid by letting your baby feel the bark of the tree and play with some leaves.
You can use the tree sign when you go outside, such as when you take your walk around the neighborhood or park.