I like the giant hemp trees!
Do you make them with a L-System?
Not really L-System, I pinched the algorithm from a Phd thesis on environmental simulation - lost the link now

I don't get it - but I did still quite enjoy watching it for ten minutes.
Is there cross-pollination between different tree types? I couldn't spot any, but maybe it's a subtle effect.
Yeah, they cross-pollenate with a random neighbour (or themselves!).
If you plant a new tree close to several existing ones you can soon see the effect.