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Eastern Black Walnut is a species of flowering tree. The black walnut is a large deciduous tree attaining heights of 30–40 m (98–130 ft). 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, with 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 are terminal, in clusters of two to five, ripening during the autumn into a fruit (nut) with a brownish-green, semifleshy 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. Fruiting may begin when the tree is 4–6 years old, however large crops take 20 years. Total lifespan of J. nigra is about 130 years.
It 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. This one was photographed near a bottomland forest in Edgefield County, SC.
It is cultivated there and in North America as a forest tree for its high-quality wood. More nuts are produced by open-grown trees. 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. 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. The roots, nut husks, and leaves secrete a substance into the soil called juglone that is a respiratory inhibitor to some plants. 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. The plant can cause contact dermatitis in humans.