“In some cultures, the pineapple has become associated with the notion of welcome^[14], an association bespoken by the use of pineapple motifs as carved decorations in woodworking.  (wikipedia.org)

The pineapple was adopted by the Spanish as a symbol of hospitality, who incorporated the pineapple design into their woodworks. Pineapple designs were prominent on all types of furniture. This motif eventually migrated back to the colonies of North America, where it became quite popular in the South. (homecooking.about.com)”

Thanks MJ for taking the mystery out of this.