Arbaro

Superb, though if you have a slow computer it can take a while to get any decent results. I recently went from a very old 500MHz Mac to a more modern quad core Mac, and now this program is a lot easier to use. To get the best from this software you need to be prepared to spend some time experimenting, but it is worth the effort if you need good quality models of trees. It could do with an update but even without it it's a useful plant and tree generator.