A nice large tree. I didn't use any reference so it is not any particular kind of tree. The textures are from 3dtextures.com with some photoshop changes. 3d textures is a great cheap source for textures. i am pretty sure these were in the free downloads I have a membership so I cannot tell the difference as the restriction tags do not appear.
the textures are just mental ray standard. there is no opacity mapped to the leaves so that I could get quick test renders. The leaves are just two poly squares. If you would like a defined shape simply put the opacity map of your choice into the cutout channel.
You might also wish to swap out the arch materials for something translucent.
lastly if you have vray you can use a displacement on the bark. Mental ray's displacement is difficult to work with.