Krita - Krita is a professional FREE and open source painting program. It is made by artists that want to seaffordable art tools for everyone. Concept art. texture and matte painters, illustrations and comics.
SpeedTree - SpeedTree is a powerful toolkit used to create 3D vegetation for video games, films, and animations.
Clip Studio Paint - The artist's software for drawing and painting.
The Grove 3D - Model or grow adaptive 3D Tree models for use in CG renderings.
MyPaint - MyPaint is a fast, distraction-free, and easy painting tool for digital artists.
Arbaro - Arbaro is an implementation of the tree generating algorithm described in Jason Weber & Joseph...