Artificial Wood Chips/Smoke for smoking meat
I'm confused. 
You don't want fake smoke but you don't want to use wood? Are you asking for a synthetic substance you can burn that will not be worse for the environment than burning wood?

First of all- burning wood is not bad for the environment- that carbon has not been sequestered and so it would be released into the atmosphere anyway when the wood decayed.

Secondly- mesquite is a cancerous weed here in Texas and I encourage everyone to smoke with it to restore the damaged ecosystem.

Thirdly- You can't fake the taste of smoking with wood. That's the point. Even liquid smoke is actually made by distilling real smoke.

(I originally posted a comment and decided to modify it into an answer.)