RunTime DNA has an awesome set of trees called "RDNA Old Wood" by Modualz, I believe it is. They have several packages available, and Vol. 2, Gnarled Trees, has seperate roots that conform or can be used on their own. And, as an additional bonus, they are on sale for 50% off! I used the tree models in my one and only gallery pic I have, if you would like to see how they render without any postwork. As a matter of fact, the only postwork done was the hair on Stasia.

Now for your picture, Towal, it is so beautiful!! Seriously, I really like it a lot. You did a great job. =)

<3