We care very much about this...we haven't done as much homework as we'd like on this issue but if anyone has more information and would like to help us find responsible suppliers, I'd love to speak to them.
Maton has been developing the use of these timbers for the last 50 years and it would be safe to say that nobody knows Australian tonewoods better than Maton. We are fortunate enough to have the support of many of Australia's most knowledgeable and skilled timber gatherers and continue to try new species on guitars and to learn more about the way these timbers are capable of producing beautiful music. ..."
That's how Maton tackle the problem, http://www.maton.com.au/main/timbers.html I don't know if this is possible in the US mainland.