When you say pineapple, everyone thinks of that succulent tropical multiple fruit. But like all monocots, the long narrow leaves of pineapple have parallel vascular bundle fibers that run their length, and unlike the better known coarse structural fibers of Manila hemp from Musa textilis sisal and henequen from species of Agave, pineapple fiber is quite fine for a structural fiber and can be made into very lustrous, light-weight fabric. And of course once you've grown your pineapple fruits, the old leafy stalk gets removed so make way for new shoots, and mostly these get burned. Sounds like a win-win situation, but then again it sounded that way when someone proposed making paper and other fiber products out of corn stalks left after harvesting. Nothing much seems to have happened with regard to that either. The very nice pineapple image (couldn't find mine) was borrowed from here.