I'm having a bit of an issue with TreeThing, and it usually occurs only if I use a brush set with more than one tree brush (I'm unsure if this has anything to do with my using of a Mac). Sometimes it will work with the "Mixed Forest", but that seems to only be if it is in a smaller area. What gets me is that you had stated a few posts ago that it will work with your 8000 x 3000 pixel map, and my entire map is only 3000 x 2000 pixels. If I select a brush set with multiple brushes and I load my template, TreeThing will show that it has loaded the template, but the original square-shaped copse of trees remains on the screen. I figured that maybe it just needed a little while to render everything, but everything remained the same.

When I've been able to get TreeThing to load my templates and render all of the trees, something similar to what I mentioned before occurs at this time as well. Nothing will happen if I change some of the different parameters and hit the "Generate" button. What I have had to do is just hit "Clear Template" and re-load the template back into the program and it will show all of the changes. I've been using some work-arounds, so you really have no need to rush to find me an answer to the question. I just wanted to post this issue to give you some sort of feedback if you wanted to fix some various bugs and whatnot.

Other than this whole spiel, you have a great program on your hands! +Rep!