I only have two guitars. I'm not much of a collector. The realization that I can only play one at a time and the lack of a proper budget was a big influence. But both guitars are very nice. One (my "daily driver") has a cedar top and Indian rosewood back and sides, the other (my favorite) has a spruce top and Brazilian rosewood back and sides. The second one was built for me by Japanese luthier Masaru Kohno in 1971 and is the only concert quality guitar I've ever owned.
When I was very young I was taught that rosewood was the best material for the back and sides and the many guitars I've played over the years has born that out. I've played some nice guitars with mahogany back and sides, and others with maple but none sounded as nice as the rosewood to my ears. Rosewood is such a beautiful wood that it seemed fitting that it sounded the best too.
A couple of unpleasant thoughts have been creeping into my brain though. About 40 years ago I read how a 19th century spanish luthier, Antonio Torres, had argued that the guitars tone really developed from the top. To prove his point he built a guitar with the back and sides made from paper mache. The guitar exists today in a museum and the few people who've been allowed to play it speak very highly (and somewhat surprised) of its tone.
Around 30 years ago the Taylor guitar company built a guitar entirely of wood salvaged from shipping pallets. They spent time and care to build it to their exacting specifications and turned out a wonderful guitar.
Rosewood is so beautiful that furniture companies built their best furniture from it. I once saw a grand piano built around 1900 with a solid, not laminate, rosewood body and lid. These companies used far more rosewood than any guitar companies ever did.
Globally rosewood forests are nearly all gone now. Most countries that have rosewood have either banned or put severe restrictions on harvesting and exporting.
So what should an environmentally conscious guitarist or luthier do? Well we can start by accepting that the back and sides are going to need to be built with other woods. I've heard some wonderful sounding guitars made with some beautiful figured maple recently. If I were in the market for a new instrument I would surely begin my search there.
We can also acknowledge that the hands of the craftsman may be far more important than the actual materials used. Perhaps the craftsmen of yore put more effort into the rosewood guitars and that's why they sounded better than the others?
I'm not sure I'm smart enough to know the right questions let alone pretend that I have any answers. But it seems to me that, although others are starting to notice the problem, much more needs to be done.