Here is the first result of rendering SpeedTree through Unity Graphic.DrawMesh functionality. The result is not same as provided by SpeedTree code, because for now I used some simple shader.

Trees are static so there is no wind yet. I have implemented leaf mesh geometry only so leaves as billboards are not rendered correctly. It will be done in next few days. Also materials are rendered from back side only, leaf cards do not have set culling for front and back side, for example palm leaves are rendered only from one side.