My all time favorite "natural" ornaments were the walnut shell ornaments I made as a child AND as an adult with my children.  You get walnuts and crack them so that you have the 2 halves and pick out the nut meat (use for whatever your cooking heart desires).  Then take a portion of twine or ribbon and glue it into the shell  and glue the edges of the shell and put together.  We either held the two shell pieces for a time till the glue set enough to let go or we wrapped a rubber band around the shell.  Then you can remove the rubber band when dry and hang 'as is' on the tree -- or for a 'bird friendly' ornament outside cover with peanut butter and bird seed and hang.  Or for the inside tree you can paint or glue and glitter ... have fun!!

A word of caution, if you are trying the popcorn strings, make sure you use stale popcorn! (i know, it sounds weird). Fresh popcorn breaks too easily when you try to string it. After you make the popcorn, let it sit for 1-2 days to go stale and it won't break. 

I will try out the walnut ornaments, although if I put mine outdoors the only birds i will get are pigeons ;-) Thanks for the suggestion!

These sound like it would make a very classic looking tree.

Question - how do you keep kids and animals (and hungry hubbies) from eating the decorations?

I love the idea of gingerbread cookie ornaments, and when the kids are old enough to not eat the tree, i will totally do some of those. We used to take clemantines and push cloves into them and hang them, the nicest smell in the world!

Sarah