Carbon dioxide comes in, oxygen goes out.
Forests, through photosynthesis, draw carbon dioxide out of the air, creating wood cells with the carbon and releasing oxygen back into the atmosphere. Clearing a forest releases some carbon back into the atmosphere as the wood is processed and the logging debris is burned or decays. That carbon joins carbon dioxide from power plants, automobiles and even natural-gas furnaces to trap heat and warm the atmosphere. World leaders are now gathered in the Netherlands to discuss the role of forests in the 1997 Kyoto agreement to reduce greenhouse gases during the next decade and beyond. In theory, a Midwest utility could offset the amount of carbon dioxide it emits by paying a Pacific Northwest landowner to grow more trees.