This is one of my tiny air-layered She-oak/Casuarina. It comes in at 8cm tall with a 4.5cm base. The She-oak air-layered easily. In early spring, it takes only about 4 weeks to get new roots. This bonsai was first trained on the branch of a big tree. When it was about 80 -90 % complete, I air-layered it. In about 6 months they can be put into the bonsai pot. This is one very fast way to obtain a decent small bonsai in less than 2 years.
CJ