Well, the South American Mahogany is getting to be in pretty short supply, and it is getting REALLY expensive to buy, but there is probably a few years before it goes on the
CITIES list. Honduran Mahogany (specifically) is already on the list, if I remember correctly, but the other South American species of mahogany are so similar it really doesn't matter. Sapele, which is usually called African Mahogany, is NOT actually a true mahogany (i.e., it is of genus Entandrophragma, not of genus Swietenia), but from the guitar builders point of view, it sounds the same, works the same, and I think it LOOKS even better (I like the striped appearance). There are true mahoganies in Africa and parts of the world other than South American, but they have not yet become popular commercially (which is probably a good thing, as they are, by their very nature, always going to be in short supply).
Sitka spruce is still in fine supply, and will be for the foreseeable future. Engelmann is also still in fine supply. Adirondack is in short supply (particularly for guitar quality wood), but even there it is not that the wood isn't there, only that it is not available. The large stands of wood from which the old 1930's Martin guitar tops were harvested still exist, but they are within a US National Park and are, as such, no longer available to harvest (fine with me, I don't really care much for Adirondack tops).
As for Rosewoods, well, Indian Rosewood is being well managed by the Indian Government, and is unlikely to ever become an issue. Other than that, they are a serious issue. Brazilian has been on the Category I CITES list for decades, which means that not only can you not transport raw wood, but you may not transport FINISHED GOODS. This means that, even if the wood was harvested before the CITES treaty was signed, you can not transport (for instance) a Brazilian Rosewood guitar across international boarders without getting a special permit from both countries FOR EACH BOARDER CROSSING. It is a very serious hassle to transport Category I materials. Personally, while I applaud the goals of the CITES treaty, I think the way it is enacted has some pretty serious problems.
Unfortunately, other than Indian, most of the "alternatives" to Brazilian, while not on the CITES treaty, are already in danger. The popular one these days is Cocobolo, which is already in short supply (unfortunately, because it makes GREAT guitars), and I've even heard some talk about putting it on the CITES list.
Another big one is Ebony, where we already are using substitute species, though it doesn't really matter as they are basically exactly like what was traditionally used; but the material which is available is clearly not as good as it used to be (smaller trees, and you will almost never find a quarter-sawn piece of ebony anymore), and even the substitute species are getting less and less available (which has lead to many companies using synthetic alternatives, including Martin on all guitars below the Style 28 line).
And of course, Koa was always in short supply, being as it is only grown on Hawaii. They are doing their best to manage the supply in a sensible way (in fact, you may not cut down wild Koa at all - any wood MUST come from dead trees), and they are doing plantation planting of it, but it will probably be at least 100 years or more before the plantations are ready to harvest, and it is questionable if the quality of to wood will be any good.
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"Cowards can never be moral."
M.K. Gandhi