for a Barbie Christmas tree

It's easy to find a small artificial tree that's 1/6 (AKA Barbie) scale.  But the ornaments are another matter.  Here are some suggestions for what to look for in 2013.
When you are shopping, either at garage sales or at discount sales, look for shiny, dangly earrings, even those without mates.
Save your Mardi Gras beads.  You can cut the necklaces and drape the strings of beads around the tree.
And, of course, at the after-Christmas sales, look for itty-bitty ornament sets.