Pipe cookies. Thin green, light brown, blue, ivory and half of orange icing to count of 18. Prepare five decorating bags, separately, with thinned green, light brown, blue, ivory and orange icing. Reserve remaining orange icing for later step.
Cut ¼ in. off tip of each bag.
Outline and fill in cookies as desired.
Let dry overnight, 8 to 10 hours.