see OpensimWorlds
also an experiment from VirtualWhite? is referred to in TheRealWorld
PlanT is implemented, e.g. as EnginE:OpensimTree ..fun to use for load testing:
14:00 < timaanv> do a uptime sim load test 14:01 < timaanv> let the trees grow till region dies or is completely full 14:01 < timaanv> see how it behaves 14:01 < timaanv> night all for now 14:01 < timaanv> thankyou this is a GREAT project
has happy users :)