This year our wonderful 4th grade teacher at my school found a "Moulding Christmas Tree" in Sunset magazine and asked if I'd help her students each make one. She and her husband did all the legwork, so it was piece of cake for me. All I had to do was help students paint the branches.
These are the measurements we used:
Branches are 5 pieces of moulding @ 8", 7", 6", 5", and 4"
Then the top is a small piece of moulding (as shown), or it can be a small triangle of wood.
The trunk is a 1"x1" piece of wood, 18" tall.
The base is 16" across.
Branches were glued on with hot glue and base was attached with screws.
The kids were so proud of their creations!!