Robinia pseudoacacia

 

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Family: Leguminosae

 

 

 

 

 

 

 

 

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Black Locust

 

 

 

Robinia is a genus of about 10 species native to eastern North America and Mexico. The genus Robinia is named for Jean Robin (1550-1629) and his son Vespasian Robin (1579-1662), herbalists to kings of France and first to cultivate locust in Europe.

Robinia kelseyi-Kelsey Locust

Robinia neomexicana-Locust, Mexican Locust, New Mexican Locust, New Mexican Robinia, New Mexico Locust, Southwestern Locust, Thorny Locust, Western Locust

Robinia pseudoacacia*- Acacia, Bastard Locust, Black Laurel, Black Locust, Common Locust, Common

Robinia, False Acacia, False Black Locust, Green Locust, Honey Locust, Locust, Peaflower Locust, Post Locust, Red Locust, Robinia, Shipmast Locust, White Locust, White Honey-flower, Yellow Locust

Robinia viscosa-Black Locust, Clammy-bark Locust, Clammy Locust, False Acacia, Honey Locust, Red Locust, Red-flowering Locust, Rose Acacia, Rose-flowering Locust

* commercial species

 

Distribution

Black Locust is native to the Appalachian Mountains from Pennsylvania to northern Georgia and Alabama and to the Ozark Mountains of southern Missouri, Arkansas and eastern Oklahoma. Also in southern Illinois and Indiana. It has been extensively naturalized in the United States and Canada.

 

The Tree

Black Locust reaches heights of 100 feet, with a diameter of 3 feet.

 

The Wood

General

The sapwood of Black Locust is a creamy white, while the heartwood varies from a greenish yellow to dark brown. It turns a reddish brown when exposed to the air. The wood is often confused with Osage Orange (Maclura pomifera). It has a high density and decay resistance. It shows slight shrinkage and stays in place well. It is very strong in bending and is one of the hardest woods in America. It’s shock resistance is almost that of Hickory (Carya spp.).

 

 

 

 

 

 

Mechanical Properties (2-inch standard)

 

 

 

 

Compression

 

 

 

 

Specific

gravity

MOE

x106 lbf/in2

MOR

lbf/in2

Parallel

lbf/in2

Perpendicular

lbf/in2

WMLa

in-lbf/in3

Hardness

lbf

Shear

lbf/in2

Green

0.66

1.85

13,800

6,800

1,160

15.4

1,570

1,760

Dry

0.69

2.05

19,400

10,200

1,830

18.4

1,700

2,480

aWML = Work to maximum load.

Reference (98).

 

Drying and Shrinkage

Type of shrinkage

Percentage of shrinkage
(green to final moisture content)

0% MC

6% MC

20% MC

Tangential

7.2

5.8

2.4

Radial

4.6

3.7

1.5

Volumetric

10.2

8.2

3.4

References: 0% MC (98),
6% and 20% MC (90).

Kiln Drying Schedulesa

 

Stock

Condition

4/4, 5/4, 6/4

8/4

10/4

12/4

16/4

Standard

T6-A3

T3-A1

β€”

β€”

β€”

aReferences (6, 86).

Working Properties: It is difficult to work with hand tools, but turns well on a lathe and nails well. It has no distinctive odor or taste.

Durability: It is extremely durable.

Preservation: No information available at this time.

Uses: Fencing, insulator pins, furniture, mine timbers, treenails for ships. The trees are used in strip mine reclamation, due to their ability to survive the acid conditions and for their nitrogen fixing roots.

Toxicity: The bark is poisonous, and there are reports of dermatitis from the wood. (40, 64, & 105)

Additional Reading and References Cited (in parentheses)

6. Boone, R.S., C.J. Kozlik, P.J. Bois & E.M. Wengert. 1988. Dry kiln schedules for ?commercial woods - temperate and tropical. USDA Forest Service, FPL ?General Technical Report FPL-GTR-57.

20. Cuno, J.B. 1930. Utilization of black locust. USDA Circular No. 131.

3. Elias, T.S. 1980. The complete trees of North America, field guide and natural history. ?Van Nostrand Reinhold Co., New York, 948 pp.

40. Hausen, B. M. 1981. Wood Injurious to Human Health: A Manual. Walter deGruyter ?& Co., Berlin, Germany; New York, NY.

41. Hopp, H. 1942. Mystery among the locusts. American Forests. Jan.:27-30.

55. Little, Jr., E.L. 1979. Checklist of United States trees (native and naturalized). USDA ?Forest Service, Ag. Handbook No. 541, USGPO, Washington, DC.

59. Markwardt, L.J. and T.R.C. Wilson. 1935. Strength and related properties of woods ?grown in the United States. USDA Forest Service, Tech. Bull. No. 479. USGPO, ?Washington, DC.

60. McAlister, R.H. 1971. Black locust. USDA Forest Service, American Woods - FS-244.

64. Mitchell, J.; Rook, A. 1979. Botanical Dermatology: Plants and Plant Products ?Injurious to the Skin. Greenglass Ltd., 691 W. 28th Ave., Vancouver, British ?Columbia, Canada V5H 2H4.

68. Panshin, A.J. and C. de Zeeuw. 1980. Textbook of Wood Technology, 4th Ed., ?McGraw-Hill Book Co., New York, 722 pp.

74. Record, S.J. and R.W. Hess. 1943. Timbers of the new world. Yale University Press, ?New Haven, 640 pp.

82. Scheffer, T.C. 1949. Decay resistance of black locust heartwood. USDA Technical ?Bulletin No. 984.

86. Simpson, W.T. 1991. Dry kiln operator's manual. USDA Forest Service, FPL Ag. ?Handbook 188.

90. Summitt, R. and A. Sliker. 1980. CRC handbook of materials science. Volume 4, ?wood. CRC Press, Inc., Boca Raton, FL. 459 pp.

98. USDA Forest Service, FPL. 1974. Wood handbook: wood as an engineering material. ?Ag. Handbook 72.

104. Wollerman, E.H. 1962. The locust borer. USDA Forest Service, Forest Pest Leaflet ?71.

105. Woods, B.; Calnan, C. D. 1976. Toxic Woods. British Journal of Dermatology; ?95(13):1-97 Published by Blackwell Scientific Publications, Oxford, England OX2 ?OEL.