it has two modes, they are switched with shift+left click.
https://github.com/obneq/treegen/archive/master.zip
use /giveme treegen:edit to get one. it does not wear off.
l-system editor
this mode allows you to edit tree definitions (right click) and spawn the resulting tree (left click).


axiom generator
this mode allows you to generate axioms using a simple forth like language, and spawn the resulting structure.
this is somewhat similar to turtle graphics and forth.


