ryanb is correct when he said there is a lot of other woods out there to chose from.
I don't need to say this but stay away from pine.
good Mahogany is getter hard to find for sure and when you do find it it has a high cost to it. I would say try another wood for your first building project and save the mahogany for another time.
cherry or alder, poplur is nice to work with.
the table thing would be cool if the wood is solid and not covered plywood.
a table from norway might be worth more then building a guitar from it but hey what ever works for you.
I live in the usa and work in a office furniture shop.
I honestly know your feeling in my heart.
I use to feel the same way you feel now about building with wood that is endangered.
I would be at working and have to cut up mahogany wood that was 12 feet long and 30 inches wide nice and clean on both sides [ looking awesome]
this made me sick to chop up a board that long and wide.
my point is the wood that is avaible to you what ever it might be has already been cut and there is nothing you or I can do to prevent this and life goes on.
there has been some nice wood cut up I would have wanted to have for my projects.
bottom line is if you don't build with it some one will and they might use more then is needed.
if it makes you feel better you might try and plant some trees to replace what you used to build with. I don't know what kind of stuff grows in norway but any tree would be cool.
Unrealize I hope that helps you feel better about your building and the wood you choses. good luck to you.