I remember reading of companies who mined submerged logs from swamps years ago. The quality of the wood was still good after all these years.
http://www.dennistwpmuseum.org/pdfdoc/cedarmining.pdf
Lake Superior is over 1000 ft. deep in places.
I doubt at the bottom it’s more than a couple of ticks above freezing.
I once knew a guy from the U.P of Michigan whose drunken uncle stumbled off a town pier and was presumed drowned in Lake Superior. His perfectly preserved body washed up on a beach 36 miles away.....seven years later!
I recall seeing a documentary some years back about the Lk Superior operations...there are hundreds of thousands of such logs up there because of the logging ops that went on for so many decades. I’ve seen underwater pix (which I am looking for to post so far unsuccessfully) where these logs are piled up like 8 sets of pickup-stix toys.
Scroll down about 1/4 page at this link to see a bass guitar that was made out of a 32,000 year-old cedar log pulled out of a sand quarry in Georgia.
http://www.spectorworld.com/wspector.htm