*sighs*

Wood is made from trees, and trees are still common (there is a moderate amount still left). So, wood isn't so scarce at the time but if we continue to cut down these trees to create paper, wood and other such, we'll be short of trees. By the way, how old are you? You should be able to tell that we aren't that scarce of trees at the moment because trees are almost everyone, except for those that have environments which isn't suitable for plant growth or places were trees and stumps are being cut down/removed like crazy.