I like POVTree,,  (although the meshs can become very 'heavy' if you go for the full realism).  Open-source program, outputs to PovRay, which can be converted to .obj using Pose_Ray.  Let's see if my example image is still on my hard-drive.... [rummage, rummage....]   Mesh size depends on whether you want leaves, twigs, or root systems on it.  Comes with a wide variety of realistic presets, from conifers to [my favorite] a twisty, gnarly olive.

 

RosemaryR
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"This...this is magnificent!"
"Oh, yeah. Ooooo. Aaaaah. That's how it starts.
Then, later, there's ...running. And....screaming."