okay, and now about the models and polygon count.
First of all -it´s detailed models, thought that you can use them closeup. So yes, its not lightweight models ;-)
Many applications already are able - or will be in near future - to make use of instancing.
Especially in this case, where the main target group is Terragen, higher poly counts don´t really matter. And of course I always try to find a good balance between best possible details and lowest possible poly count with this level of detail.
Also because there are dozens or even hundreds of lower poly models available, I usually tend to go the high detail route. But if people would like to see some lowpoly stuff also - just raise your voice ;-)

And now about a false legend - Xfrog objects are highpoly objects. Thats simply not true.
You can create lowpoly plants with Xfrog, trees with less then 1000 quads -depending on species even less then 300 quads.
You must know that Greenworks also does custom plants and actually we have created many thousands of lowpoly plants - they are simply not available to the public. And no, you don´t need Xfrog tune to do lowpoly plants.

And now about another legend - highpoly objects slow down rendering. The worst case scenario for most render engines is, if rays have to pass many alpha planes. The less polygons you want to use, the more you have to make use of alpha planes - and this often slows down rendering a lot more, then using many polygons.
So in fact in my visualizations I often add details to plant objects to be able to remove as much alpha as possible.
The only drawback is of course memory. But with 64bit being available for half a decade, its a good idea to make use of this power. Almost all PC´s offer 64 nowadays - people just have to drop their fears about 64bit OS ;-)

So a short summary - low detail objects (in my eyes) are mainly good for realtime nowadays, for the rest I prefer to go with high detail. If you feel different, let companies like Greenworks know this. Tell modellers like forester or me what you need.

best,
Walli