problems representing foliage (jungle) on map

[cursor]

I'm trying to come up with a quality vector graphic representation of foliage on a map (bitmap satellite data). I'm hoping that some of you might chip in some ideas.

I've attached a partial map that illustrates one of my several attempts. The process involves overlayed shapes fabricated using two brushes, Convert Line to Shape, transparency, and Apply Clipview. The client's comment (that'd be my 89 year old father, a retired anthropologist) on the nine options that I've submitted so far was:

Note these observations: The strip of jungle/wilderness, narrow or not, cannot be as crisply defined as all these versions make it. Can the boundaries be a little more vague? In the highlands of Chiapas spread the swath out some so that it is not uniformly “narrow” (in a strict sense). In other words make it more of a feature of nature, with appropriate variability in its boundaries, somewhat wider here and there. Any move in that direction would be welcome. But I can’t expect perfection because I don’t know what perfection is! Please try one more time.

An constructive/creative advice that you folks might offer me would be greatly appreciated. Thanks.