See-oh-too is an influential guy.  Trees Are Made of Gas teaches young readers all about carbon dioxide, an invisible, odorless gas that is essential for plant growth--but is also responsible for global climate change. Kids learn both the science and impact of the massive release of carbon dioxide into the atmosphere, making a clear argument for conservation and clean up.   Providing simple explanations along with ways to reduce your own carbon footprint, this engaging book is sure to engage young environmentalists.