Here are some sites with ideas you might find helpful.

The DIY Craft Club describes bio-degradable glitter. (who knew??).

Beauty HQ describes seven creative centerpieces made from nature and recycled materials.

Mindful of the Home gives hints for a variety of natural Christmas decoations.

And, when it is all over, here are answers to the question about what to do with the tree.

Also in early December, many Chicago-centric sites (eg blockclubchicago.org, choosechicago.com, etc) will offer local gift shopping ideas.