One of the things I really miss about the UK is the really old buildings. Adelaide was only settled in about 1830 so it's one of the newest states really.
I didn't know it took 40 years for oaks to produce acorns. We recently went to a home nearer the city centre which had a oak dropping acorns on the street in front of it. I realised it must have been pretty old, but this helps to give an idea of how early on they must have planted it.