I think this Stacked Paper Christmas Tree by Pintalalluna would be really cute, but also a great little project for the little ones.
The basic instructions are in Spanish, translated roughly as such:
With scraps of paper from our crafts,
we cut squares of different sizes
and we are putting them from highest to lowest on a stick,
to form our little tree!
and we are putting them from highest to lowest on a stick,
to form our little tree!