"Carya" redirects here. For the archaic nut-tree goddess, see Caryatis. For the walnut tree nymph in Greek mythology, see Hamadryad. For the other mythical figure of that name, see Carya (daughter of Dion). For the town of ancient Arcadia, Greece, see Carya (Arcadia).
Hickory is a common name for trees composing the genusCarya, which includes around 18 species.[3] Five or six species are native to China, Indochina, and India (Assam), as many as twelve are native to the United States, four are found in Mexico, and two to four are native to Canada.[4][5] A number of hickory species are used for their edible nuts, lumber or other wood and woodcraft products .
Hickories are temperate forest trees with pinnatelycompound leaves and large nuts. Hickory flowers are small, yellow-green catkins produced in spring. They are wind-pollinated and self-incompatible. The fruit is a globose or oval nut, 2–5 cm (0.8–2.0 in) long and 1.5–3 cm (0.6–1.2 in) diameter, enclosed in a four-valvedhusk, which splits open at maturity. The nut shell is thick and bony in most species, and thin in a few, notably the pecan (C. illinoinensis); it is divided into two halves, which split apart when the seed germinates.
Etymology
The name "hickory" derives from a Native American word in an Algonquian language (perhaps Powhatan). It is a shortening of pockerchicory, pocohicora, or a similar word, which may be the name for the hickory tree's nut, or may be a milky drink made from such nuts.[6] The genus name Carya is Ancient Greek: κάρυον, káryon, meaning "nut".
Species and classification
The genus Carya (not to be confused with Careya in the Lecythidaceae) is in the walnut family, Juglandaceae. In the APG system, this family is included in the order Fagales. Several species are known to hybridize, with around nine accepted, named hybrids.[3][7]Beaked hickory (Annamocarya sinensis) is a species formerly classified as Carya sinensis, but now considered its own genus, Annamocarya.
Asian hickories
Carya sect. Sinocarya
Carya dabieshanensis M.C. Liu – Dabie Shan hickory (may be synonymous with C. cathayensis)
The hickory leaf stem gall phylloxera (Phylloxera caryaecaulis) also uses the hickory tree as a food source. Phylloxeridae are related to aphids and have a similarly complex life cycle. Eggs hatch in early spring and the galls quickly form around the developing insects. Phylloxera galls may damage weakened or stressed hickories, but are generally harmless. Deformed leaves and twigs can rain down from the tree in the spring as squirrels break off infected tissue and eat the galls, possibly for the protein content or because the galls are fleshy and tasty to the squirrels. The pecan gall curculio (Conotrachelus elegans) is a true weevil species also found feeding on galls of the hickory leaf stem gall phylloxera.
The oldest fossils attributed to Carya are Cretaceous pollen grains from Mexico and New Mexico. Fossil and molecular data suggest the genus Carya may have diversified during the Miocene.[9] Modern Carya first appear in Oligocene strata 34 million years ago. Recent discoveries of Carya fruit fossils further support the hypothesis that the genus has long been a member of Eastern North American landscapes, however its range has contracted and Carya is no longer extant west of the Rocky Mountains.[10][11]
Fossils of early hickory nuts show simpler, thinner shells than modern species with the exception of pecans, suggesting that the trees gradually developed defenses to rodent seed predation.[citation needed] During this time, the genus had a distribution across the Northern Hemisphere, but the Pleistocene Ice Age beginning 2 million years ago obliterated it from Europe.[12] In Anatolia, the genus appears to have disappeared only in the early Holocene, probably related to human disturbance.[13] The distribution of Carya in North America also contracted and it completely disappeared from the continent west of the Rocky Mountains. Since fossil records show North America as having the largest number of Juglandaceae species, it is likely that the genus originated there and later spread to Europe and Asia.[citation needed]
Some fruits are borderline and difficult to categorize. Hickory nuts (Carya) and walnuts (Juglans) in the Juglandaceae family grow within an outer husk; these fruits are sometimes considered to be drupes or drupaceous nuts, rather than true botanical nuts. "Tryma" is a specialized term for such nut-like drupes.[16][17]
Hickory wood is hard, stiff, dense and shock resistant. There are woods stronger than hickory and woods that are harder, but the combination of strength, toughness, hardness, and stiffness found in hickory wood is not found in any other commercial wood.[18] Hickory is therefore used in a number of items requiring these properties, such as tool handles, bows, wheel spokes, walking sticks, and wood flooring. Baseball bats were formerly made of hickory, but are now more commonly made of ash; however, it is replacing ash as the wood of choice for Scottish shinty sticks. Hickory was also extensively used for the construction of early aircraft.
Due to its grain structure, hickory is more susceptible to moisture absorption than other species of wood, and is therefore more prone to shrinkage, warping or swelling with changes in humidity.[19]
Hickory is also highly prized for wood-burning stoves and chimineas, as its density and high energy content make it an efficient fuel.[20] Hickory wood is also a preferred type for smokingcured meats. In the Southern United States, hickory is popular for cooking barbecue, as hickory grows abundantly in the region and adds flavor to the meat.
An extract from shagbark hickory bark is also used in an edible syrup similar to maple syrup, with a slightly bitter, smoky taste. The Cherokee people would produce a green dye from hickory bark, which they used to dye cloth.[21][22] When this bark was mixed with maple bark, it produced a yellow dye pigment. The ashes of burnt hickory wood were traditionally used to produce a strong lye (potash) fit for soapmaking.[23]
The nuts of some species are palatable and were used by Cherokee Indians in making Kanuchi soup, while others are bitter and only suitable for animal feed. Shagbark and shellbark hickory, along with pecan, are regarded by some as the finest nut trees. Pecans are the most important nut tree native to North America.[4]
When cultivated for their nuts, clonal (grafted) trees of the same cultivar cannot pollinate each other because of their self-incompatibility. Two or more cultivars must be planted together for successful pollination. Seedlings (grown from hickory nuts) will usually have sufficient genetic variation.
^Huang, Y.J.; Yusheng Liu; M.S. Zavada (2014). "New fossil fruits of Carya (Juglandaceae) from the latest Miocene to earliest Pliocene in Tennessee, eastern United States". Journal of Systematics and Evolution. 52 (4): 508–520. doi:10.1111/jse.12085. S2CID83492234.
^National Academies of Sciences, Engineering, and Medicine; Health and Medicine Division; Food and Nutrition Board; Committee to Review the Dietary Reference Intakes for Sodium and Potassium (2019). Oria, Maria; Harrison, Meghan; Stallings, Virginia A. (eds.). Dietary Reference Intakes for Sodium and Potassium. The National Academies Collection: Reports funded by National Institutes of Health. Washington, DC: National Academies Press (US). ISBN978-0-309-48834-1. PMID30844154. Archived from the original on 2024-05-09. Retrieved 2024-06-21.
^Knight, Oliver (1956–57), "History of the Cherokees, 1830–1846", Chronicles of Oklahoma, Oklahoma City: Oklahoma Historical Society, p. 164, OCLC647927893