https://nwestfelt.gumroad.com/l/SimpleTreeTools

Simple Tree Tools 2.7 - A complete set of fully procedural tree modeling tools for Houdini. Simple and intuitive to use, yet advanced enough for creating any kind of procedural tree or foliage.  All the features needed for realistic tree creation is here. Everything from simple bending to more advanced features like 4 types of Tropisms and Real Time Wind and Growth animation.  There are also tools included aimed for game developer workflows.