They are a very small organization, but they think big and really make a difference on a very limited budget. They are also very efficient - the directors and founders cover all of the adminstrative costs with their donations. So your donations go straight to the eveironmental causes. In this event, over 200 trees were planted and volunteers were allowed to participate regardless of whether they had donated to the organization. Everything was well organized. You can check out their website at www.thinknaturally.org. It lists lots of things you can do to help the environment.
Great local charity with impact you can see through their support of local parks and recreation areas. The board covers all of their overhead expenses so all donations go to direct impact and programming including tree planting, trail cleanup, advocacy, purchases of land for public use, and trail construction.