That would be any "pressure treated" lumber products. Yes, completely different animals. The only similarities between the two are they are both a cellulose.I have to admit for some reason when i here people on here say Marine plywood My mind has a image of Treated Ground contact ply .Something i use occasionally for exterior projects . Not Actual Marine grade Finish plywood Something this is Generally not available in this area. I know they are Completely Different animals .
I do as well feel this is a much better place to discuss a topic then others.