If you're in Libreville for business and only have a few hours to get away, The Raponda Walker Arboretum is only a 20 minute drive from the city center. The park has rangers who will give you a tour, point out the native species, important fauna for their history and culture, and if you're lucky, you can see a African grey parrot, native to Gabon. There are a few different trails to choose from depending on the amount of time you have to spend in the forest. The guides are friendly and knowledgeable. There are French speaking and English speaking guides.