Lignum Vitae, Latin for "Tree of Life," is the national tree of the Bahamas. It's also the world's densest wood, and has such unusual properties that the USS Nautilus, the world's first nuclear-powered submarine, has its aft main shaft strut bearings made out of the stuff. In addition to being strong, hard, heavy, dense, water- and salt-water-resistant, Lignum Vitae contains natural oils that make the bearings self-lubricating.
The USS Nautilus isn't an anomaly; Lignum Vitae has been used as propellor shaft bearings in conventional ships, and hydroelectric plants dating back to the 1920s have used bearings for their turbines made out of the stuff.
Virginia-based Lignum Vitae Bearings calls their product "the world's only renewable (and greenest) bearing on the market." Company President Bob Shortridge has acquired land in the Bahamas, one of the tree's native origin islands, and plants at least one Lignum Vitae tree for every block of the stuff that passes through his facility. "Although Lignum Vitae has been harvested for over 500 years before I was born," Shortridge writes, "I feel an obligation to replace it... I wish for this incredibly useful wood to be available for generations to come."
Here's Shortridge himself explaining Lignum Vitae's properties and applications:
This factoid came to us by way of Rob Wilkey, Core77's newest guest writer, who will shortly be breaking down the properties of different species of wood. Stay tuned for his contributions to our Material Matters: Wood series.