SpeedTree is a group of vegetation programming and modeling software products developed and sold by Interactive Data Visualization, Inc. (IDV) that generates virtual foliage for animations, architecture and in real time for video games and demanding real time simulations.
Tree Studio is a product born from TwistedBrush Pro Studio but with a focus on 2D tree creation with a simpler, streamlined interface. Tree Studio has pairs of brushes for each tree type - one for the frame and one for the leaves.
TreeGen consists in a platform indipendent Python script which should work as a plugin for Blender . Thanks to the graphical interface, it aims to create random trees and forests in a simple and alternative way to L-System.