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I won't derail the thread beyond this: http://www.scientificamerican.com/article.cfm?id=carbon-nanotube-danger

Careful cutting those arrow shafts. Carbon nanotubes are structurally similar to asbestos fibers and have similar effects on the lungs when they're airborne.

I have never used anything but twigs I find on the ground. I have many, many nights on them. It is important to make sure the twigs aren't rotten and are thumb thickness or thicker, but that's about...