This is a relatively new material that luthiers have discovered can be quite eye-catching when used for a guitar top. Spalted maple comes from a particular maple species, Acer saccharum, which is closely related to hard rock maple and sugar maple. These trees often tower to heights of up to 120 feet, with trunks up to 36 inches across. The spalt effect is created as decaying logs are attacked by certain types of fungi. The lumber must be selected and used in the manufacturing process after decay has started, but before the wood deteriorates to the point of becoming soft and spongy. The final effect can be subtle or dramatic and often produces an effect similar to a fine art pen and ink drawing. Bookmatching spalted maple can produce a quite stunning top.