Tree3D is a Godot Extension (implemented via GDExtension) for Godot Engine 4.1 or higher that is used to create procedural trees. If you do not wish to build the extension from source, there are precompiled Windows binaries available here.
The project is open source, implemented in C++ and released under the MIT license.
Key Links
You can learn more about using Tree3D in Godot and see it in action in the video below.