Line baking sheet with waxed paper.
Pour popcorn into large bowl.
Combine sugar and corn syrup in medium saucepan.
Bring to a boil over medium heat, stirring constantly; boil 1 minute.
Remove from heat.
Add peanut butter and green food color; stir until peanut butter is completely melted.
Pour over popcorn; stir to coat well.
Lightly butter hands and shape popcorn mixture into trees.
While trees are still warm, press red cinnamon candies into trees.
Place on prepared baking sheet; let stand until firm, about 30 minutes.