What Is the Latest Hickory Nut? A Detailed Guide
The hickory nut, also known as Manchurian walnut, walnut catalpa, and small walnut, among other names, is a deciduous tree of the genus Carya in the family Juglandaceae. Because its fruit has extremely high nutritional value and a unique taste and flavor, it has gained consumer recognition and gradually become a widely popular premium nut. China is one of its places of origin, mainly produced in the Tianmu Mountain area at the border of Zhejiang and Anhui, the Changbei area and Henglu Township, and other places. It is suitable for growing in sparse forests at the foot of mountains or in valleys rich in humus.
The hickory tree reaches 10-20 m in height, with a diameter at breast height of 30-60 cm. The bark is smooth and grayish white. The branchlets are slender, and the new branches are densely covered with shield-shaped orange-yellow glands. The compound leaves are 16-30 cm long. The petiole is covered with hairs and glands when young, and the hairs gradually fall off later, while the leaf rachis is more densely covered with hairs that do not easily fall off. The edges of the leaflets have fine serrations. When young, only the midrib, lateral veins, and leaf margins have soft hairs on the upper surface, while the lower surface has hairs on the veins that may persist or fall off and is fully covered with orange-yellow glands. The lateral leaflets have short petiolules or are almost sessile, lanceolate or obovate-lanceolate, with a wedge-shaped or slightly rounded base. The terminal leaflet has a petiolule about 5-10 mm long and is the same shape, the same size, or slightly larger than the lateral leaflets at the upper end.
The male catkins of the hickory tree are in groups of 3, and the inflorescence axis is covered with soft hairs and glands. The male flowers have short stalks, narrow bracts, and are long elliptic-linear; the bracteoles are triangular-ovate; the 2-7 stamens are borne on a narrow and long receptacle, and the anthers have hairs. The female spike is upright, and the inflorescence axis is densely covered with glands. It has 1-3 female flowers, and the female flowers are ovate or broadly elliptic. The fruit is obovate and gradually narrows toward the base. The exocarp is leathery after drying. The nut is obovate or elliptic-ovate, and the endocarp is hard and pale grayish yellow-brown, with no cavities within the septum or the wall. It flowers in April-May, and the fruit ripens in September.
The hickory kernel is crisp and sweet, with an intense aroma. It can be pressed for oil, stir-fried for eating, and also used as an ingredient in making candies and pastries. The kernel contains 7.8-9.6% protein, more than 7 kinds of essential amino acids for the human body with a content as high as more than 25%, and also contains 22 trace elements required by the human body, among which calcium, magnesium, phosphorus, zinc, and iron are very rich. Every kilogram of walnut kernel equals the nutritional value of 9 kg of fresh milk, 5 kg of eggs, or 2 kg of beef, and its nutrients are easier for the human body to absorb than those of milk, eggs, and beef. It also has various effects such as moistening the lungs and tonifying qi, nourishing the blood and calming asthma, moistening dryness and resolving phlegm, and dispelling deficiency cold.
The hickory nutshell can be made into activated carbon. The nutshells, pericarps, branches, and leaves can produce natural plant fuel. The involucre can be used to extract tannin. The wood can be used to make furniture and for military use. The hickory trunk is straight, the crown is nearly broadly ovate, the root system is well developed, and it is tolerant of water and moisture. It can be planted alone or in groups beside lakes and on lawns, and is suitable as a shade tree and street tree. It is also suitable for greening and afforestation along river banks and in plain areas. It is a very good tree species for urban and rural greening and a tree species for both fruit and timber, and can be planted in large economic forests on both banks of the Yangtze River in Jiangsu Province.