The comparisons between timbers are all practical considerations:

1. Cost: The cost of Australian timbers, particularly for structural purposes, is a hands-down win for Australian economy. That makes a big difference, when you’re talking about any sort of large structure, like a house. If you can get superior timber that’s suitable, why wouldn’t you?
2. Market forces: Foreign timbers, sadly, are also subject to a market-based supply; lack of variety. Foreign suppliers tend to deal with large amounts of basic timbers, like kwila, to also meet demand overseas. The other timbers, like teak, are in short supply over there, while Australian teak is relatively challenging to get, there are other foreign species that tend to be offered that may not be as good.
3. Variety: Australia has a dazzling range of top quality timbers of all kinds. Even our softwoods, are unique, and incredibly beautiful. If you’re looking for a fabulous selection of timbers, start in Australia.
4. Building quality standards: The basic benchmarks of building quality, our Australian Standards, not too surprisingly, are a much better fit for Australian timbers. This really is a no-brainer; if you want good timber beams, boards and supports, you get the Australian Standard quality products. That means almost entirely Australian timbers.
5. Foreign timber isn’t what it was: The days of craftsman-quality timbers overseas are gone. With all due respect to some few surviving good American and European timbers, it’s no contest. The modern foreign timbers are mass market products, nowhere near the fantastic quality control of the past. Compare a good piece of Ironbark or Redgum and frankly, why would you want some dull old foreign bit of anonymous-looking board?
6. Foreign timbers vs Australian climate: If ever there was a total mismatch between timbers and environments, our climate and cold climate timbers must be it. The Australian climate can be incredibly dry, (high humidity, for example) causing splitting on green timbers . The heat, too, creates distortion of timbers on a scale most foreign timbers can’t endure.