Discovery Communications has bought out the popular green-lifestyle and news site Treehugger. Terms were not disclosed, but our sources say that piece is around $15 million, and that includes performance based earnout as well.

The new site will become part of Discovery’s PlanetGreen network, which includes the eco-lifestyle TV network launching next year. Last year, Discovery-owned Animal Planet bought two online pet sites: Petfinder.com and PetsIncredible.

Treehugger, based in Brooklyn, NY, was formed in 2004, and offers a mix of text and video news, blogs and advice and also has a user-generated site, Hugg.com. The company says it has about 1.4 million unique monthly visitors. More in release.

From Treehugger’s own blog: We suspected that at a certain point in TreeHugger’s life that we would need to attract significant investment or partner up with a large media organization if we were to really take our message to the masses and fulfill our mission. Over the last year, we were approached by over 15 large companies interested in playing this role.

• Animal Planet Buys Two Pet Websites