This is the site :
http://www.plantfactory-tech.com/download/
What do you think ?
I think you should search "the plant factory", here in the forum. ;)
Having a copies of both speed tree and plant factory they are similar when it comes to modeling.
But when you come to exporting speed tree is a mile ahead better mesh and UVs.
plant factory makes a total mess of it, but they are improving.
Do you have any examples exported out to Terragen? Haven't seen that many TPF images here.