Modular Tree is described as 'this is an addon for blender3d which works pretty nice and isvery easy to use if you are familiar with nodes'. There are five alternatives to Modular Tree for Windows, Linux, Mac and Etabs. The best alternative is Treeit, which is free. Other great apps like Modular Tree are SpeedTree (Paid), Tree Studio (Paid), The Grove 3D (Paid) and TreeGen - 3D Tree Generator (Free, Open Source).
Tree It is an easy to use real time 3d tree generator for the simple creation of your very own 3d tree models for your dark basic pro and dark GDK apps and games. Features Very easy to create high quality 3D trees.
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.