I think you are right about those forests: it has always been the river's dominion, not really men's. Harvested or not, preserved or not, National Park or not, they will keep evolving at their own path no matter what we do. Drought and fire will model them, as it has always been.
Now, if that "now protected from the chainsaw forever" Australian red mahogany timber ends up as dead dry or rotting stubs, or as charcoal in some years, with the owls, bats and parrots moving elsewhere for a living... if those attempting sustainable forestry management of the mahogany for many years are also gone... and if 4 generations of knowledge on this precious and unique timber are lost forever... will those same persons taking and hailing the decision today make another media campaign to say "sorry, we screwed it badly 40 years ago"?
That after 40 x 72 = 2888 million AU$ not generated over the period (cost of opportunity), plus 96 million AU$ to shut down a sustainable industry, plus whatever million AU$ to "manage the forests for preservation purposes". Grim scenario. Expensive scenario. That's why I always say conservation is necessary, even cute, but it costs money to the taxpayer. Sometimes, a lot. And sadly, sometimes, for nothing. I am not saying this is the case, just mentioning it could be.
As long as that does not also mean that during the same period some other sort of "red mahogany" from non sustainably managed forests elsewhere ends up in the Sydney offices of those same lobbyists shaped as desks and chairs...
In my opinion, there is room for all of it: conservation and mahogany timber. Decisions taken half a state away from everyone affected, without considering everyone affected, may look good as media releases, but they rarely solve any environmental problem.
A last funny comment: the fact that a good chunk of the "world class, cross-border National Park that permanently protects more than 70,000 hectares of Red Gum" exists because of a dam on the river exists is, at least, ironic. It means it will last as long as the dam does?
Sorry Phil, I am too far away to be accurate. But I see similar trends at this side, and in many other places. And I can tell you that in some cases, it is plain human stupidity taking advantage of fashionable concepts.