black walnut

1. An eastern North American tree (Juglans nigra) having dark brown wood and a deeply furrowed nut enclosed in a globose aromatic husk.
2. The wood of this tree, used especially for veneer, cabinets, furniture, and gunstocks.
3. The nut of this tree, having an edible kernel used especially in confections.

This native American nut has an extraordinarily hard shell, which makes it extremely difficult to crack and therefore not as popular as the more widely known english walnut. Its strong, slightly bitter flavor is highly valued by black-walnut devotees, but its high fat content makes it turn rancid quickly. See also nuts; walnut.

Description

Black walnut (Juglans nigra), is a short-trunked forest tree with a spreading crown that can grow to 100 ft (30 m). It is native to Eastern North America, where it is found from New Brunswick south to Georgia and as far west as Kansas and Minnesota. Although chiefly valued for its decorative fine-grained wood, the tree's bark, root, leaves, and nuts all have medicinal properties. These qualities are similar to those of the closely related Juglans regia (better known as English walnut), the tree most commonly used by commercial walnut growers.

General Use

The main active ingredients of black walnut are tannins such as galloyglucose and ellagitannins, and juglone (5-hydroxy-alphanapthaquinone). Walnut shells are very rich in vitamin C, and betacarotene, B₁,B₂, and B₆ are found in the leaves.

Herbalists use external applications of the plant for a variety of skin complaints including ringworm, jock itch, athlete's foot, psoriasis, blisters, eczema, scabbing pruritus, varicose ulcers, and even syphilis sores. The oil is a traditional hair tonic. Black walnut preparations have also been used for eye infections and irritations of the eyelid.

Internally, black walnut extracts are taken for ailments such as gout, rheumatism, glandular disturbances, worms, and parasites. It is also used to stimulate the appetite and as a laxative. Some authors consider it a blood purifier. There is evidence dating back to the 1960s showing that chemical components in the nut may help reduce blood pressure.

An April 2000 report in the Annals of Internal Medicine raised hope that walnuts might help reduce harmful LDL cholesterol. In a study conducted by a researcher at the Hospital Clinic Provincial in Barcelona, it was reported that substituting 8-11 walnuts a day for olive oil and other fatty foods in the cholesterol-lowering Mediterranean diet significantly improved the diet's effectiveness. In fact, the average reduction of LDL cholesterol in walnut dieters was twice that of participants using the traditional Mediterranean diet. However, the walnuts were added to a diet already known to be healthy, so the findings do not necessarily imply that addition of the nuts to a less nutritious diet would have a similar effect.

The ancient Doctrine of Signatures stated that hints to the healing properties of plants could be found in their physical appearance. In accordance with this belief, walnuts, with their convoluted surface, have long been thought useful in treating brain disorders. Discorides, the ancient Greek author of De materia medica which has been the foremost textbook of pharmacology for 16 centuries, considered walnuts to have an excitatory effect on the head. This effect has been attributed to the plant's high levels of serotonin.

In East Asia, dried black walnut is used to treat cough, asthma, and bronchitis. In chronic bronchitis and asthma in older patients, it is given two or three times a day for as long as two months. This is said to improve appetite and sleep patterns. East Asian practitioners also employ the plant in kidney stone remedies to ease pain.

The plant has dental applications. Homeopaths use a tincture of black walnut leaves to treat cutting wisdom teeth. In Pakistan, walnut bark is used in toothpaste.

Preparations

Black walnut extract can be bought at health food stores as a liquid or in capsules. Amateur herbalists can also prepare their own black walnut teas or salves. One traditional herbalist quoted in the 1989 book HerbalMedicine Past and Present said, "I take a double handful of hulls in boiling water to make a tea. Then I add hog lard and boil again to reduce it to a salve."

The following formula for English walnut leaves is from the 1994 book Herbal Drugs and Phytopharmaceuticals: "Making the tea: 1.5 g [1.67 tsp] of the finely chopped [leaves are] put into cold water, heated to boiling, and after three to five minutes passed through a tea strainer, Internally as an adjuvant.. for skin conditions, a cupful of the tea is drunk one to three times a day. For dressings and lotions, a decoction of 5 g [5.6 tsp] drug in 200 ml [3.8 oz (US)] water is used."

Another source recommends an extract produced by boiling black walnut bark in water for 10 or 15 minutes.

According to folklore, drinking a mixture of walnut kernel ash and red wine prevents loss of hair, but also tints it blonde. Another traditional preparation was to gargle with juice from unripened green walnut husks mixed with honey.

Black walnut leaves should be collected, free of leafstalk, early in the summer. The nuts are considered mature four-and-a-half to five months after flowering, and are harvested in the fall. Commercial growers use trunk and limb shakers to remove walnuts when the green, fleshy shucks begin to split and the inner nut is a light tan color. They then use forced-air dryers to reduce the moisture content to 8%.

Precautions

Directions and dosages should be carefully followed, as black walnut contains juglone, a powerful and toxic substance that prevents many plants from growing within the tree's root zone, extending as much as 80 ft (24 m) from a mature black walnut trunk. Juglone is especially strong in the roots, but is also found in the leaves, bark, and wood. Use of black walnut sawdust or wood chips as bedding material for horses has caused laminitis. In high doses, juglone is a kidney and liver toxin. Pollen from black walnut trees (usually shed in May) is a common cause of allergies in hypersensitive persons.

In their 1996 book Botanical Medicine: A European Professional Perspective, Dan Kenner and Yves Requena warn that black walnut should not be used against a cough involving fever.

Juglone can stain the skin yellow, brown, or black. This effect is so pronounced that black walnut oil is used to stain furniture and in artist's pigments.

Side Effects

Acknowledging the previous precautions, black walnut generally has no adverse side effects when properly administered in appropriate doses. However, users are advised to consult a health professional before using it.

Interactions

Although interactions are unlikely, it is advisable to see a health professional before using black walnut extracts or capsules.

Resources

Books

D'Amelio, Frank Sr. Botanicals: A Phytocosmetic Desk Reference. CRC Press, 1999.

Gruenewald, Joerg, Thomas Brendler, and Christof Jaenicke, eds. Physicians' Desk Reference for Herbal Medicines. Medical Economics Company, Inc., 1998.

Kenner, Dan and Yves Requena. Botanical Medicine: A European Professional Perspective. Paradigm Publications, 1996.

Periodicals

Zambon, Daniel, et al. "Substituting Walnuts for Monounsaturated Fat Improves the Serum Lipid Profile of Hypercholesterolemic Men and Women." Annals of Internal Medicine (April 2000) 132: 533-537.

[Article by: David Helwig]

"Black Walnut" redirects here. For other uses, see Black Walnut (disambiguation).

Eastern Black Walnut
Leaves and fruit
Scientific classification
Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Magnoliopsida
Order:	Fagales
Family:	Juglandaceae
Genus:	Juglans
Species:	J. nigra
Binomial name
Juglans nigra L.

The Eastern Black walnut (Juglans nigra) is a species of flowering tree in the hickory family, Juglandaceae, that is native to eastern North America. It grows mostly in riparian zones, from southern Ontario, west to southeast South Dakota, south to Georgia, northern Florida and southwest to central Texas. Isolated wild trees in the Upper Ottawa Valley may be an isolated native population or may have derived from planted trees.

The black walnut is a large deciduous tree attaining heights of 30–40 feet (9.1–12 m). Under forest competition it develops a tall, clear bole; the open-grown form has a short bole and broad crown. The bark is grey-black and deeply furrowed. The pith of the twigs contains air spaces. The leaves are alternate, 30-60 cm long, odd-pinnate with 15-23 leaflets, the largest leaflets located in the center, 7-10 cm long and 2-3 cm broad. The male flowers are in drooping catkins 8-10 cm long, the female flowers terminal, in clusters of two to five, ripening during the autumn into a fruit (nut) with a brownish-green, semi-fleshy husk and a brown corrugated nut. The whole fruit, including the husk, falls in October; the seed is relatively small and very hard. The tree tends to crop more heavily in alternate years.

While its primary native region is the midwest and east central United States, the black walnut was introduced into Europe in 1629. It is cultivated there and in North America as a forest tree for its high quality wood. Nuts are produced more by open-grown trees. Black walnut is more resistant to frost than the Persian walnut (also known as the English walnut), but thrives best in the warmer regions of fertile, lowland soils with a high water table. It is a light-demanding species. The wood is used to make furniture, flooring, and rifle stocks, and oil is pressed from the seeds. Nuts are harvested by hand from wild trees. About 65% of the annual wild harvest comes from the U.S. state of Missouri and the largest processing plant is in Stockton, Missouri.^{[citation needed]} The black walnut nutmeats are used as an ingredient in food while the hard black walnut shell is used commercially in abrasive cleaning, cosmetics, and oil well drilling and water filtration.

Where the range of J. nigra overlaps that of the Texas black walnut J. microcarpa, the two species sometimes interbreed, producing populations with characteristics intermediate between the two species^[1]

Contents 1 Use as food 2 Processing by hand 3 Wood 4 Dyes and other uses 5 Walnut Husk Fly 6 Toxicity 7 Big tree 8 Gallery 9 Notes 10 References 11 External links

Use as food

Black walnut nuts are shelled commercially in the United States. The nutmeats provide a robust, distinctive, natural flavor and crunch as a food ingredient. Popular uses include ice cream, baking and confection. Consumers include black walnuts in traditional treats such as cakes, cookies, fudge, and pies during the fall holiday season. The nut’s strong nutritional profile leads to uses in other foods such as salads, fish, pork, chicken, vegetables and pasta dishes. Nutritionally similar to the milder-tasting English walnut, the black walnut is high in unsaturated fat and protein and has no cholesterol.

An analysis of nut oil from five named J. nigra cultivars (Ogden, Sparrow, Baugh, Carter and Thomas) showed that the most prevalent fatty acid in J. nigra oil is linoleic acid (27.80—33.34g/100g dry kernel), followed (in the same units) by oleic acid (14.52—24.40), linolenic acid (1.61—3.23), palmitic acid (1.61—2.15), and stearic acid (1.07—1.69).^[2] The oil from the cultivar Carter had the highest mol percent of linoleate (61.6), linolenate (5.97%), and palmitate (3.98%); the oil from the cultivar Baugh had the highest mol percent of oleate (42.7%); the oil from the cultivar Ogden has the highest mol percent of stearate (2.98%).

Tapped in spring, the tree yields a sweet sap that can be drunk or concentrated into syrup or sugar.[1]

Processing by hand

A woman's hands after removing the husks from 500 black walnuts.

The extraction of the kernel from the fruit of the black walnut is difficult. The shell is covered by a thick husk that exudes a dark, staining, strong-smelling juice. The juice will often be a yellow-brown at first, and then rapidly assumes a deep black-green color upon exposure to the air. The shell often protrudes into the meat so that whole kernels often cannot be obtained.

The husk is best removed when green as the nuts taste better if it is removed then. Rolling the nut underfoot on a hard surface such as a driveway is a common method; commercial huskers use a car tire rotating against a metal mesh. Some take a thick plywood board and drill a nut sized hole in it (from one to two inches in diameter) and smash the nut through using a hammer. The nut goes through and the husk remains behind. To keep the husk juices from splattering, a board or canvas scrap may be used to cover the nut before hammering. The black walnut’s husks are known to leave durable, hard to remove stains on hands and clothing.

Before eating or storage, the nuts should be cured in a dry place for at least two weeks. Before cracking, the unshelled nuts may be soaked in hot water for 24 hours in order to soften the shells, but with a proper cracker this is not necessary. While the flavor is prized, the difficulty in preparing the black walnut may account for the wider popularity and availability of the Persian walnut.

Wood

Black walnut is highly prized for its dark-colored true heartwood. It is heavy and strong, yet easily split and worked. Walnut wood has historically been used for gunstocks, furniture, flooring, paddles, coffins, and a variety of other woodworking products. Due to its value, forestry officials often are called on to track down walnut poachers; in 2004, DNA testing was used to solve one such poaching case, involving a 55 foot (16m) tree worth US $2500. Black walnut has a density per cubic meter of 660kg (41.2 lb/cubic foot)^[3], which makes it lighter than oak.

Dyes and other uses

Black walnut drupes contain juglone (5-hydroxy-1,4-naphthoquinone), plumbagin (yellow quinone pigments), and tannin.^[4] The brownish-black dye was used by early settlers to dye hair.^[5] Extracts of the outer soft part of the drupe are still used as a natural dye for handicrafts.^[6] The tannins present in walnuts act as a mordant aiding in the dyeing process;^{[7] [8]}usable as a dark ink or wood stain.^[9]

Walnut Husk Fly

Maggots in the husk are common, though more a nuisance than a serious problem for amateurs, who may simply remove the affected husk as soon as infestation is noticed. Maggots can, however, be serious for commercial walnut growers, who tend to use chemical treatments in order to avoid damage to the crop. Some organic controls exist also.^[10][11][12]

Wilting tomato plant poisoned by juglone

Toxicity

The roots, nut husks, and leaves secrete a substance into the soil called juglone that is a respiratory inhibitor to some plants, such as this tomato that was grown too close to a black walnut tree. A number of other plants (most notably white birch) are also poisoned by juglone, and should not be planted in close proximity to a black walnut. Horses are susceptible to laminitis from exposure to black walnut wood in bedding.^[13]

Big tree

The largest known living black walnut tree on Sauvie Island, Oregon.

The national champion black walnut is on a residential property in Sauvie Island, Oregon. It is 8 feet 7 inches (2.62 m) diameter at breast height and 112 feet (34 m) tall, with a crown spread of 144 feet (44 m).^[14]

Gallery

Leaf detail. Note the notch at the base of the leaflet.

Fruit.

Detail of bark.

Cross-section of a black walnut board. This particular board is over 140 years old, demonstrating the durability.

Notes

1. ^ http://www.fs.fed.us/database/feis/plants/tree/jugmic/all.html
2. ^ Senter, S. D., Horvat, R. J., and Forbus, W. R.: "GLC-MS Analysis of Fatty Acids From Five Black Walnut Cultivars." Journal of Food Science 47(5) pp 1753, 1755 (1982)
3. ^ Niche Timbers Black Walnut
4. ^ Black Walnuts Drug Information
5. ^ Nuts with High Fat Content:Black Walnuts
6. ^ Black Walnut Basket Dye
7. ^ Fixing natural dyes from walnuts, goldenrod, sassafras and poke weed in cotton
8. ^ Dyeing with Tannic Acid and Iron: Walnut Husks (2005)
9. ^ Making Walnut Ink. Madame Elizabeth de Nevell.
10. ^ Walnut Husk Maggot, Rhagoletis Suavis (Loew) and Walnut Husk Fly, Rhagoletis Completa Cresson
11. ^ Walnut Husk Maggot. Ontario Ministry of Agriculture, Food and Rural Affairs.
12. ^ Walnut Husk Fly.
13. ^ "Laminitis Casued by Black Walnut Wood Residues". Purdue University. January 2005. http://www.ces.purdue.edu/extmedia/FNR/FNR-254.pdf. Retrieved 03-09-2009. 
14. ^ Oregon Big Tree Registry.

References

Wikimedia Commons has media related to: Juglans nigra

Wikibooks Cookbook has a recipe/module on Walnut

Wikispecies has information related to: Juglans nigra

• Hoadley, B. (1990). Identifying Wood: Accurate Results with Simple Tools. Taunton Press. p. 240 pages. ISBN 0-942391-04-7. 
• Dirr, M. A. (1998). Manual of Woody Landscape Plants. Stipes Publishing. ISBN 0-87563-795-7
• Petrides, G. A. and Wehr, J. (1998). Eastern Trees. Houghton Mifflin Company. ISBN 0-395-90455-2

External links

• Guide to “Growing Black Walnuts for Nut Production” University of Missouri Center for Agroforestry
• Walnut council
• Black Walnut Cultivars
• Extensive information about black walnuts
• Flora of North America: J. nigra RangeMap:
• Juglans nigra images at bioimages.vanderbilt.edu
• Set of Black Walnut ID photos and range map
• Harvesting Black Walnuts
• Home Production of Black Walnut Nutmeats
• Growing Black Walnut
• Black Walnut crackers
• Black Walnut Diagnostic photos: tree, leaves, bark and fruit
• The Hiker's Notebook
• Black Walnut Toxicity study

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