Longbow

The Longbow is a larger Bow variant.Most Longbows are self-bows, made out of only one material (preferred are Yew, Hazel, Ash and Elm, Bamboo in southern and eastern Middle-Earth.But there are also larger Composite bow variants.The Númenoreans used a special type of longbow made of hollow Steel.

see:
 * Steel Bow

Outer information
Longbows are usually as tall as the persons who use them, but there are even larger variants such as the japanese yumi can be exceptionally tall, since they are asymetrical they are among the few long bows that can be used by cavalry.The Bows in Tolkien´s writings usually are thought to be based on the welsh and english Longbow of the medieval period, although orcish bows are decribed as smaller and made of horn which implies a Composite design.