Seeking Treehouse Textures

I'm a rookie builder trying to make a Treehouse to live in, once I finally buckle down and get a block of land. The problem is, I'm having an awfully hard time finding the textures I need for it, particularly the leaves I want to put at the ends of the branches. Can anyone direct me to a good place to obtain leaf textures?

I'm also looking for some good railing textures, so I can add some comfortable and attractive retaining walls without using huge amounts of prims.

Thanks for your help!