I've milled White Ash and it's not as bad as White Oak or Hickory.
My Dad bought a brand new 72 Chevy 12' stake body. Side and Floor boards were some kind of pine, lasted almost 10 years. I replaced it all with White Oak, only lasted 3-4 years. Really surprised me. We often let hot steaming chips set on it over night or over the weekend if it was raining when we got home. Couldn't get down to the chip field when it was too wet. That might have had something to do with breaking down the Oak. But, the Pine held up well. Don't know how the Ash will hold up as floor boards.