Hello there ProfGremlin, glad you found the tut to be of some use. Hm, you know I haven't actually tried using other brushes besides a hard round brush to stamp on the stragglers. However I set the size of the brush fairly small, .5px I believe, and the jitter fairly high. Then I used somewhat jittery, circular motions to stamp on the trees. While I could detect a slight repeating pattern, both the size and the jitter of the brush helped to minimize it. However if you find in experimenting that other brushes work better for you, fantastic.

I'll mention a few suggestions. First, instead of using the stamp tool on the outside border of the forests, which, with the jitter turned up will cast trees everywhere, try painting inside the forests themselves. That way, while most of the trees end up underneath the forest (and hence out of view), the jitter effect will ensure that enough trees make it to the outside border. That way, you don't end up with such a clear cut off point between the dense forests, and their sparser edges. Second, I'm not sure but it looks like you've added a drop shadow to the main forest patterns, but haven't done so for the individual trees layer. Adding a drop shadow to the individual trees helps them to blend in more naturally with the forest patterns. Third, I noticed that your main forest patterns have a fairly stark white north-eastern edge. This looks somewhat unnatural and makes it difficult to smoothly integrate individual trees along those edges into the main forest patterns. Now I'm not sure what is causing those edges to be so light, but one way you might try to fix it is to set one of your mid-toned green "Tree Color" layers to Multiply, and then add additional lighter colored yellow and green layers to compensate for the darkness that results.

I hope that helped, but if you try these tips out and still aren't satisfied, let me know and I'll run through the tun on my own again and see if I can offer you any other suggestions.

Cheers,
-Arsheesh