Wow cheers guys,
Am certainly now fully charged after a month of relaxing and no work, with regards to the knowledge of vue I owe it all to one of my work mates who left me with a shed load of tutorials he purchased. It is a great piece of kit and as I now have a much better idea of exactly how to use it I am able to get stuff done without any crashing and reasonable render times. Also have found vue x stream to be a lot more stable now and is working really well with mental ray.
on the tree trunk side they are currently running off a simple bitmap and I will try to sort out a decent texture before rendering out any final animation.

Thanks again guys,

Leon