Keruing is from the Apitong tree (Dipterocarpus) in Southeast Asia. Keruing is the most popular hardwood used in the trailer decking and transportation industry. You’ll find Keruing hardwoods in use on semi-trailer trucks, rail cars, flatbed trucks, and many others. Keruing’s popularity comes from its durability, light weight, and low cost. Keruing is almost twice as hard as oak on the Janka hardness test.