I recently acquired a copy of Corel Essentials 6 from the Bob Ross Humble Bundle as well as what was billed as the "Corel Painter Essentials Mystic Mountain Essentials Brush Pack". Much to my chagrin, when I started following their Mystic Mountain tutorial, I found it's apparently actually built for their Corel Painter product and another Mystic Mountain brush set. I've been able to adapt a fair amount of what they've suggested, but I'm slightly stymied where they're calling out for a "Foliage" brush.
As best I can tell, as seen at 22:15 of the tutorial, this creates alternating diagonal strokes in the direction of painting in slightly varying shades of the color chosen. It provides a stroke that fades in from a narrow line to a wider one based on pressure, with slightly furry edges. It does certainly seem to do the job of drawing a lot of trees very quickly.
Is there a way to emulate this in Corel Essentials, or perhaps in GIMP?
As it is, I've adapted a few other techniques to draw some of the far-off trees, and I'm attempting to learn how to simply hand draw the trees with a few strokes, but my drawing tablet is in the mail, and it's tricky to quickly swipe the trees in with mouse movements. They look like much less than happy accidents...