[ihartley]

Depending on when the land was flooded, some areas may me good candidates for underwater logging now or in the future. Apparently in some places this is a great source of wood for high quality musical instruments because there aren't many old hardwood trees available anymore.

https://en.wikipedia.org/wiki/Underwater_logging

[Elv13]

The Hydro Quebec plants are near the arctic. Some of them are near the tundra line (where trees suddenly stop growing and lichen takes over).

Don't expect much rotting that far north. It will take centuries to even start to rot. Also don't expect underwater logging either. This is the Boreal forest, not the rockies one. It's even past the northern limit for Boreal Cedar, the only mildly valuable tree you might find. After that, you get young evergreen and pine. They burn before they get old and grow slowly due to the climate.