My understanding was Burl Ives suffered from serious dry mouth problems and he chewed gum constantly while singing to keep his mouth moist. Possibly caused by his heavy smoking of cigars. I saw a performance at the Chatauqua resort about 25 years ago. He mentioned the gum at some point and made a bit of a joke about it. I don't recall if this was during the performance or afterward. He died of cancer of the mouth in 1995, a possible connection.

Don