The best way for this is if your kid joins a club or organization that spends a lot of time in nature. My nephew has been a member of a mountain climbers club since he was five. The main rule of mountain climbers is to keep nature. Besides, he learnt how to really LOVE nature, not to pick up every flower he sees and to take care about the green areas in our town. He also learnt what things are recycled when you throw them in nature and what are not. Anyway, you should try to make the kid be A PART of nature.