Wood doesn't burn or rot in the lifeless vacuum of space, but it will incinerate into a fine ash upon reentry into Earth's atmosphere — making it a surprisingly useful, biodegradable material for future satellites.
No, actually. Metal doesn't burn up, it melts to slag and disintegrates, but the metal particles don't become gas the way carbon does. Then you just have a bunch of a space debris and reactive, aerosolized metal particles knocking around the upper atmostphere. Aluminum Oxide ash can float to the ground, or it can cause ozone decomposition. We're not entirely sure which is worse based on the amount coming back from satellites, but the number of satellites we're sending up is increasing rapidly. So it wouldn't hurt if they were a little less toxic.