This idea I grabbed from Pinterest totally works!
And it's sew-free (and mine is even glue-free).
1. Buy green felt. I bought 3/4 yard and it made two good-sized trees.
2. Buy colored felt. I just bought small squares of pre-cut from Hobby Lobby.
3. Cut out the tree.
4. Cut out the ornaments.
The lady I got this idea from made her ornaments a little more detailed.
But I have a 3-month-old. So basic it is.
5. Stick the tree on the wall with re-usable wall hanging stuff.
Command, Scotch, etc. I used Scotch brand found in the office section at Walmart.
By the way, I'm not being endorsed to mention these products.
6. Grab your kids and let them decorate...over and over and over.
Felt sticks to felt, so no glue required!
Update: The Scotch stickies don't like felt. Guess thumbtacks it will be...