Ancient Hawaiians used pulu, the golden, silky fibers found at the base of hapuʻu (tree fern) fiddleheads, to dress wounds and embalm the dead. In the 1860s entrepreneurs collected tons of pulu to stuff pillows and mattresses. A factory employing 50 to 75 people was established to harvest, process and export the fibers. It closed in 1880, and not much remains but the rock walls of three structures occasionally liberated from the jungle by park rangers. It's 6 miles down the Napau Crater Trail.