I understand DougeTX.  You are absolutely correct that standing submerged trees are not found in Minnesota (at least, not in abundance).  The trees found at the bottoms of lakes and rivers here are already cut and sunk during log drives.  But I can tell you that the trees are considered ancient.  Although that term may often be used loosely.  The timber used to build our own home was said to have grown before Columbus discovered the new world.  That would make it hundreds of years old, but certainly not thousands.  My grandfather had a mill and farm in Alexandria, and the first European to discover the headwaters of the Mississippi was a relative of mine.