Trace the child's hand with fingers spread wide and up his arm as far as the paper will allow. This will be the trunk and branches of the trees. Write each child's name on their tree trunk and cut it out of brown construction paper or a brown paper bag.
Cut out a few leaves and lots of apples. Put the tree trunks on the bulletin board. Add a few leaves around the branches.
When the child does something good, add an apple to his or her tree.
For example, everyone who comes to Sunday school gets to add an apple. If the child cleans up her or his place, add an apple. Sharing, saying thank you, helping someone, etc. can also earn apples. Two apples for bringing a friend!
Consider giving a small prize such as a package of stickers for those who earn a set number of apples for the month depending on the age group.
The caption of the bulletin board would say, Branching Out For Jesus. (Matthew 25 :40 And the King shall answer and say unto them, Verily I say unto you, Inasmuch as ye have done it unto one of the least of these my brethren, ye have done it unto me.)