Wood Species: Walnut, American Black

Scientific Name: Juglans nigra

Trade Name: Black Walnut

Family Name: Hickory

Common Names: Walnut, American Black walnut, Eastern black walnut

Regions of Distribution: Eastern USA and Hawaii.

Countries of Distribution: USA

Appearance

Color: Heartwood ranges from a deep, rich dark brown to a purplish black. Sapwood is nearly white to
tan. Difference between heartwood and sapwood color is great; some flooring manufacturers steam lumber to bleed the darker heartwood color into the sapwood, resulting in a more uniform color.

GRAIN: Mostly straight and open, some also have curly/ burly grain. Pore pattern is that of a hickory but the size of pores are smaller

Variations within species and grade: lower grades have many more color variations, especially when not steamed prior to kiln-dying. Higher grades keep color uniform.

Properties

Hardness/Janka: 1010 (22% softer than Northern red oak)

Dimensional stability: Average (7.8; 9% more stable than Northern red oak).

Origin: North America.

Availability: Moderately Available

Average and maximum lifespan: 150 years to max 250 years.

Workability

Sawing/Machining: Excellent machining qualities

Sanding: Satisfactory with proper technique and sequence.

Nailing: No known problems

Finishing: No known finishing problems.

Common Uses:
Dye to highlight material in inlays and borders and designs. Juglone (5-hydroxy-1,4-naphthoquinone), plumbagin (yellow quinone pigments), and tannin. Food, linoleic acid (27.80—33.34g/100g dry kernel, oleic acid (14.52—24.40), palmitic acid (1.61—2.15), stearic acid (1.07—1.69), abrasive cleaning, cosmetics, and oil well drilling and water filtration, furniture, flooring, and rifle stocks, ink, wood stains. Also used for Landscaping in lawns and parks.

Detailed Description

Plant habit and life style:
American Black walnut tree grows to 50-120' tall and 50-75' wide, with a rounded shape. A quite large deciduous tree with an oval, open crown. Moderate Growth rate.

Stems: Long thick stems carrying many heavy leaves. Twigs with distal edge of leaf scar (where the leaf falls off the branch) notched. Plith, light brown.

Buds: Downy, terminal buds, approximately 0.33" long.

Leaves: Leaves are chartreuse, yellow-green, have a notch at the base of leaflets and usually are prone to fall off prematurely due to disease. Leaves are fragrant and made up of 2-5" leaflets. Combining to make one to two foot leaves. Scales scattered over veins and blade.

Flowers: Black walnuts are monoecious. Bloom in April, May.  The male flowers are catkins (cylindrical flower cluster with little or no pedals) and the female flowers are small clusters. Female flowers are up to 8-flowered spikes. Not ornamentally important. Both appear at different times during the spring. Wind pollinate tree needs more than one to pollinate correctly.

Fruits: A hard yellow fruit that hardens and turns into a walnut. They ripen in September and October. Fruit turns green and splits showing the Nut. Nuts cause plants below not to grow due to the toxicity.
Habitat: J. nigra prefers warm, fertile, lowlands with a high water table. High drain soil. No weeds or other plants around.

Special Diagnostic Characters: Secretes poison into the soil which can kill other plants upon absorption. Trees reproduce after 12-15 years. Pests that may affect black walnut are black walnut caterpillar, tent caterpillars, webworms, scale, mites, bud borers, curculios, ambrosia beetle, a certain type of maggot, and casebearers. Diseases include walnut anthracnose, blight, root rot, cankers, and leaf spot. Soil should have a Minimum pH: 6.1  and a Maximum pH: 6.5. Full sun is highly recommended. Prune the tree at 3 years of age. Plant during a weaning moon.  Doesn't do well sharing nutrients with weeds or other plant life. Juglone is the toxin secreted by he trees roots into the soil that kills other plant life. Typically found at an altitude of 0 to 1,113 meters (0 to 3,652 feet). Cold Hardiness: 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b.