OK so yes I didn't have trees in geoconverted areas (Hawaii), so how the heck did one get trees? That has been figured out apparently.
My guess is that the current tree "populator" looks at the green on the ground image and depending on green patches implements a density of populating, but placement is kind of arbitrary, so that's how we end up with trees where they don't really belong.
There is a patch of vegetation in Socal in LA where there is no trees *where I fly RC), it's mostly bushes. In FS2 it's covered with trees.
Virtual roundup (no advertising intended) is what we need, that we can apply locally on the vegetation. Better a 2 step tool::
Trees to bushes
Bushes to nothing
Also for areas where there are a lot of buildings (like a city) there may also be a lot of trees. And when the only thing populated are trees and zero 3d building, then yes it looks completely weird.