I feel like rambling....
Cottonwood was historically used in mines for support beams. The reason being that when cottonwood is stressed it makes rather loud popping noises before it breaks. That would give the miners at least some warning when timbers were about to give way.
Another interesting cottonwood story involves the second Battle of Adobe Walls (June, 1874) where some 700 Comanche and Kiowas led by Quanah Parker and others lead an early morning attack on about 28 or so Buffalo hunters in the Texas Panhandle. What saved the buffalo hunters was a cottonwood support beam cracking and waking up everyone - that and the hunters were armed with Sharps 50 cals - it's a long story and one worth reading about.
Hollow cottonwood logs were used by American Indians to make drums, masks, Kachinas and other carved items - it carves well and is still being used today.
So, that's what I have to say about cottonwood.