Although this article is now 6 years old it is still a good summary of blackwood growing in New Zealand.
Ian Brown is coauthor of the New Zealand blackwood growers handbook. As a farmer his research has helped define the current success of blackwood in NZ.
His comment about blackwood growth rates in NZ compared vs Tasmania should not be taken too seriously.
Undoubtedly NZ has some very good sites for growing blackwood. But we have yet to really test the potential here in Tasmania.