When Martin wants to climb an extra tall maple tree, Daddy introduces him to the first rule of the 'treeclimber's code:' a climber must be able to climb entirely on their own with no help.  When he decides instead to climb a spruce tree and gets up higher than ever, Daddy introduces him to the second rule: only climb as high as you can comfortably get down.   When Martin is finally down and covered in sticky sap, Daddy introduces him to the third rule:  climbers clean off their own pine sap!