HICKORY, a shortened form of the American Indian name pohickery. Hickory trees are natives of North America, and belong to the genus Carya. They are closely allied to the walnuts (Juglans), the chief or at least one very obvious difference being that, whilst in Carya the husk which covers the shell of the nut separates into four valves, in Juglans it consists of but one piece, which bursts irregularly. The timber is both strong and heavy, and remarkable for its extreme elasticity, but it decays rapidly when exposed to heat and moisture, and is peculiarly subject to the attacks of worms. It is very extensively employed in manufacturing musket stocks, axle-trees, screws, rake teeth, the bows of yokes, the wooden rings used on the rigging of vessels, chair-backs, axe-handles, whip-handles and other purposes requiring great strength and elasticity. Its principal use in America is for hoop-making; and it is the only American wood found perfectly fit for that purpose.

The wood of the hickory is of great value as fuel, on account of the brilliancy with which it burns and the ardent heat which it gives out, the charcoal being heavy, compact and long-lived. The species which furnish the best wood are Carya alba (shell-bark hickory), C. tomentosa (mockernut), C. olivaeformis (pecan or pacane nut), and C. porcina (pig-nut), that of the last named, on account of its extreme tenacity, being preferred for axle-trees and axle-handles. The wood of C. alba splits very easily and is very elastic, so that it is much used for making whip-handles and baskets. The wood of this species is also used in the neighbourhood of New York and Philadelphia for making the back bows of Windsor chairs. The timber of C. amara and C. aquatica is considered of inferior quality.

Most of the hickories form fine-looking noble trees of from 60 to 90 ft. in height, with straight, symmetrical trunks, well-balanced ample heads, and bold, handsome, pinnated foliage. When confined in the forest they shoot up 50 to 60 ft. without branches, but when standing alone they expand into a fine head, and produce a lofty round-headed pyramid of foliage. They have all the qualities necessary to constitute fine graceful park trees. The most ornamental of the species are C. olivaeformis, C. alba and C. porcina, the last two also producing delicious nuts, and being worthy of cultivation for their fruit alone.

The husk of the hickory nut, as already stated, breaks up into four equal valves or sepaiates into four equal portions in the upper part, while the nut itself is tolerably even on the surface, but has four or more blunt angles in its transverse outline. The hickory nuts of the American markets are the produce of C. alba, called the shell-bark hickory because of the roughness of its bark, which becomes loosened from the trunk in long scales bending outwards at the extremities and adhering only by the middle. The nuts are much esteemed in all parts of the States, and are exported in considerable quantities to Europe. The pecan-nuts, which come from the Western States, are from 1 in. to 1½ in. long, smooth, cylindrical, pointed at the ends and thin-shelled, with the kernels full, not like those of most of the hickories divided by partitions, and of delicate and agreeable flavour. The thick-shelled fruits of the pig-nut are generally left on the ground for swine, squirrels, &c., to devour. In C. amara the kernel is so bitter that even squirrels refuse to eat it.