Sorry, I hoped the model credit was made clear in the first post.
The model was made by Ogre and thanks for his generosity.
This render took about 24 hours. Detail 9, AA 8 , GI 3,4. It does not do its final wrap up promptly.
As some others have reported, this render goes into a "not responding" state for
about 15 minutes after the last bucket is completely posted to the screen. ( in this case it's a bucket of water

)
I don't know what is going on, but
I did watch the memory usage of the Terragen process go from 2.8 gig to nearly 4 gig in that 15 minutes and
then in the final seconds memory use goes back to about 1.6 gig.
Though it may not be apparent there are a
lot of plants populated. The start up populating takes nearly an hour as I have a lot of ground cover.