(If this post belongs in another section, just kick its butt where it does, I don't know my way around just yet )

I've decided to start a new world map using brushes I made myself instead of the premade/downloaded ones I have accumulated. I've been looking for a few tips, pointers, or (hopefully) tutorials for two things:

1. Trees.
2. Mountains.

Trees always float in the atmosphere, how do I get them grounded?
I've searched everywhere for beginner tutorials for drawing mountains, specifically for maps but I'm guessing my search keywords/parameters might be off because I haven't found anything on either DA or here at the guild. I was thinking of something similar to the Rivers sticky that's here? Any help would be MUCH MUCH appreciated and would save me from pulling out my hair.

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