Place popcorn in a large bowl; set aside. In a heavy saucepan over medium heat, bring sugar and corn syrup to a boil, stirring occasionally. Boil and stir for 1 minute. Remove from the heat; stir in peanut butter and food coloring until blended. Pour over popcorn and stir to coat.
With wet hands, shape mixture by 3/4 cupfuls into evergreen tree shapes. While warm, press a few M&M's into each tree. Place on a greased baking sheet; let stand until firm, about 30 minutes. Yield: 8 servings.