Robinia pseudoacacia L.
Black locust, False acacia
Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.
- Folk Medicine
- Yields and Economics
- Biotic Factors
- Chemical Analysis of Biomass Fuels
According to Grieve (1931), this is "one of the most valuable timber trees of
the American forest, where it grows to a very large size." It was one of the
first trees introduced into England from America, and is cultivated as an
ornamental tree in the milder parts of Britain. It is great for posts, but one
of the hardest of American wood and very difficult to work (640800 kg/m, 15%
moisture). Amerindians and Asian Indians report that the seeds are edible.
Watt and Breyer-Brandwijk (1962) suggest that the seeds left in fruits hanging
on the trees may still be edible, after processing. Frankly I am reluctant to
experiment with this as a food source. Robinia, dangerous as it is, can serve
as a vegetable rennet. The essential oil from the flowers has been used as a
spice, in sherberts and toilet waters. Wood is suitable for agricultural
implements, tool handles, shoe lasts, sports goods, dowels and pins for
insulators on telephone and telegraph wires, tree nails, boat ribs, brackets,
sleepers, and sills. It is used also for light construction, gates, wagon
hubs, cart wheels, shipbuilding, furniture and turnery work. Some burrs of the
trees provide attractive wood for tabletops, and music cabinets. Robinetin is
a strong dyestuff yielding with different mordants different shades similar to
those obtained with fisetin, quercetin, and myricetin; with aluminum mordant,
it dyes cotton to a brown-orange shade (C.S.I.R., 19481976).
Reported to be astringent, cholagogue, diuretic, emetic, emollient, laxative,
POISON, protisticidal, purgative, sedative, tonic, and vircidal, black locust
is a folk remedy for dyspepsia and spasms (Duke and Wain, 1981). Cherokee used
the plant as an emetic and for toothache.
Per 100 g, the seed is reported to contain 17.025.5 g protein, 3.03.3 g fat,
35.046.5 g NFE, 17.239.0 g fiber, 6.17.5 g ash, 12901500 mg Ca, 0.260.32
mg P. The predominant flavonoids in the heartwood are dihydrorobinetin
(17.6%), robinetin (3,3',4',5',7-pentahydroxyflavone, 8%),
7,3',4',5'-tetrahydroxyflavan-3,4-diol (6.2%), and robtin (1.5%). Other
flavonoids present in the heartwood are liquiritigenin, robtein, fustin, butin,
butein, fisetin, 7,3',4'-trihydroxyflavan-3,4-diol, and 2',4',4-trihydroxy
chalkone. Bark, leaves, and roots are reported to be toxic due to the presence
of a toxal-bumin, robin (1.6% in the bark). Toxic symptoms are suggestive of
those associated with belladonna poisoning. Bark also contains a glucoside
robinitin (3%), syringin, tannin (up to ca 7.0%), some coloring matter and an
unidentified, unstable alkaloid. Inner bark is reported to contain amygdalin,
and urease. Leaves, considered antispasmodic and laxative, prescribed in
digestive disorders, are poisonous to chicken. Leaves contain a coloring
matter acacetin (apigenin-4'-methyl ether). Apigenin-7-bioside,
apigenin-7-trioside, and indican, have also been reported. Leaves contain a
volatile oil (0.01%) and carotene (209 mg/100 g). Hexene-3-ol (1) and
trans-2-hexenal have been identified in the oil, the latter toxic to ciliates,
such as Paramoecium. Flowers are powerfully diuretic due to the glycoside,
robinin (kaempferol-7-1-rhamnosido-3'-robinobioside, 4.4%). Flowers also
contain 1-asparagine a volatile oil and wax. The oil contains methyl
anthranilate, linalool, a-terpineol, benzaldehyde, benzylalcohol, farnesol,
heliotropin, indole, an aldehyde or ketone having a peach-like odor, and traces
of pyridine-like bases. Seeds contain: moisture, 10.311.5; crude protein,
38.839.5; fat, 10.211.0; N-free extract, 20.423.0; crude fiber, 12.913.6;
ash, 4.04.7; calcium (CaO), 0.19; and phosphorus (P2O5), 1.65%. Seeds contain
the sugars sucrose, raffinose (traces) and stachyose, and the amino acids
arginine and glutamic acid, and canavanine. Roots are rich in asparagine and
are also reported to contain robin (C.S.I.R., 19461978).
Occasional cases of poisoning are on record in which boys have chewed the bark
and swallowed the juice: the principal symptoms being dryness of the throat,
burning pain in the abdomen, dilation of the pupils, vertigo, and muscular
twitches; excessive quantities causing also weak and irregular heart action
(Grieve, 1931). Resistance to rot may be due to the wood containing 4%
taxifolin, an isomer of dihydroquercetin, or dihydrorobinetin, a
growth-inhibitor of wood-destroying fungi. The flower is said to contain the
antitumor compound benzoaldehyde. Some have classified the honey as toxic,
others as the best of honeys (Shah, 1972).
Tree to 30 m tall, 1 m or more in diameter; bark thick, deeply furrowed, the
outer bark gray, the inner yellow. Twigs brown and glabrous, usually with
nodal thorns representing modified stipules; buds minute. Leaves 23.5 dm
long, with 919 stalked, oval or ovate leaflets 2.55 cm long, 1.252 cm wide;
glabrous, margins entire; bases rounded; tips truncate to rounded and
mucronate; petioles 13.5 cm long, glabrous. Racemes 0.72 dm long, bearing
many fragrant, creamy white flowers. Flowers 1.52.3 cm long. Pods brown,
flat 510 cm long, 1012 mm wide, glabrous, 47-seeded, finally splitting into
2 wind-carried valves with seeds attached (Brown and Brown, 1972). Seed ca
Reported from North American Center of Diversity, black locust, or cvs thereof,
is reported to tolerate drought, frost, high pH, limestone, low pH, poor soil,
slope, stripmine spoil. The wood of var. rectissima, so called 'Long
Island' or shipmast locust has greater resistance to decay and wood borers,
outlasting other locust posts and stakes by 50100%. (2n = 22)
From Pennsylvania to northern Alabama, north to southern Illinois. Ozark
Mountains in Missouri, Arkansas, Oklahoma. Now naturalized widely east of
Rocky Mountains (Ag. Handbook 450). Widely introduced in the temperate and
sub-temperate zones of the world, perhaps with weed potential. In
southeastern Ohio, root suckers encroached on farmland at rates of ca 13 m/yr.
Ranging from Cool Temperate Moist to Wet through Subtropical Dry to Moist
Forest Life Zones, black locust is reported to tolerate annual precipitation of
6.1 to 19.1 dm (mean of 6 cases = 11.2), annual temperature of 7.6 to 20.3°C
(mean of 6 cases = 13.0), and pH of (4.6) 6.0 to 7.0 (8.2) (mean of 6 cases =
6.6). (Duke, 1978, 1979)
Scarified seed may be drilled in rows 1520 cm apart at 65100 seeds per meter,
or broadcast in fertile soil (MarMay; US) and covered with ca I cm or less
soil, sand, or sand and sawdust. If beds have been fumigated, inoculation may
be advisable. Well-drained deep soils with adequate moisture are recommended.
In dry areas, in India, sowings are in sunken beds, but in wet areas, raised
beds are used. The one-year old seedlings, which may attain I m, are
transplanted in nurseries at 225 x 225 cm for outplanting at ca 2.4 by 2.4 m
apart in wet climates. Rainy periods are avoided for plantings because they
tend to encourage damping off.
Posts and fuels may be harvested as needed, once the proper size is attained.
In India, 5 year old trees, on good sites, were nearly 10 m tall, 17 cm in
diameter, on bad sites, nearly 3 m tall, 7 cm in diameter. On good sites, 10
year old trees were 32 cm DBH, nearly 12 m tall; on poor sites, 8 cm DBH, ca 4
cm tall. Ag Handbook 271 suggests 1520 years to produce post-size trees.
Growth is rapid in early years, but slows down after ca 30 years. In India, a
25 year old plantation in the Simla Hills (Jutogh) gave 140 m3
stacked. Well grown 44 year old trees in the Kashmir gave 48 m3 of
which 0.7 m3 was timber. According to Ag. Handbook 271, "The
average yields for 22 plantations 27 years of age in the Central States was
1,800 cubic feet of wood per acre. This was equivalent to 1,100 posts or 4,100
board feet per acre. In 1960, only ca 7,000 m3 timber were used in
the US, 70% in lumber and wood productivity, the rest in household furniture.
Individual bee colonies have produced an attractive surplus of 34.5 kg honey in
Kashmir, besides providing a nucleus colony. Robinia honey only
contains 20.2% moisture, unprocessed (Shah, 1972). In the Danube basin,
"acacia" honey commands a higher price than other honey types.
The wood is used as fuel, but I personally have been trying to burn back a
stump for more than 5 years. Nonetheless, Shah (1972) characterizes it as "a
very good source of firewood." Ag Handbook 271 suggests that litter
decomposition releases soluble nitrates at the rate of ca 67 kg/ha under solid
stands, more than twice the amount of N turnover in other forest types. N
increases totaling 670 kg/ha occurred in the top 50 cm soil under 1620 year
old stands, although there was no increase under stands 510 years old.
An important honey tree, the nectar secretion peaking around 2627°C.
Nonpromiscuity of Robinia spp. to nodulation by heterologous strains,
and, similarly noninfectiveness of locust rhizobia for other species have been
repeatedly demonstrated. One rhizobial strain, for Caragana produced nodules
on black locust, but the response was not reciprocal (Allen and Allen, 1981).
Browne (1968) lists: Fungi. Armillaria mellea, Camarosporium robiniae,
Cerrena unicolor, Cucurbitaria elongata, Diaporthe oncostoma, Diplodia profusa,
Erysiphe polygoni, Fomes fraxineus, Fomes robiniae, Fomes, robustus, Ganoderma
lucidum, Gibberella baccata, Laetiporus sulphureus., Nectria cinnabarina,
Oxyporus populinus, Phaseospora robiniae, Phytophthora cactorum, Phytophthora
parasitica, Polyporus obtusus, Schizophyllum commune, Stereum purpureum,
Thanatephorus cucumeris, Trametes trogii, Verticillum alboatrum.
Angiospermae. Elytranthe colensoiiscum, Viscum album. Acarina.
Tetranychus telarius. Coleoptera. Cerambyx cerdo, Dereodus
pollinosus, Leperisinus varius, Megacyllene robiniae, Mesosa nebulosa, Odontota
dorsal. Hemiptera. Parthenolecanium corni, Quadraspidiotus
perniciosus. Hymenoptera. Nematus tibialis. Lepidoptera.
Alsophila pometaria, Cacoecimorpha pronubana, Datana integerrima,
Epargyrecus clarus, Halysidota caryae, Halysidota maculata, Prionoxystus
robiniae. Mammalia. Bos taurus, Erethizon dorsatum, Lepus europaeus,
Microtis agrestis, Sciurus carolinensis. Agriculture Handbook No.
165 lists the following diseases: Aglaospora anomia (twig blight),
Alternaria sp. (seedling leaf blight), Armillaria mellea (root
rot), Botryosphaeria ribis, Cladosporium epiphyllum (leaf spot),
Coryneum timerum, Cryptosporium robiniae, Cucurbitaria elongata, Cuscuta
arvensis (dodder), Cylindrosporium solitarium (leaf spot),
Cytospora coccinea, Cytospora leucosperma, Daedalea unicolor (wood rot),
Diaporthe oncostoma (canker, dieback), Dothiorella glandulosa (on
branches), Erysiphe polygoni (powdery mildew), Fomes applanatus
(white-mottled heart rot), Fomes igniarius (white spongy heart rot),
Fomes rimosus (yellow spongy heart rot), Fusarium avenaceum (on
twigs), Fusarium sarcochroum (twig canker), Fusicladium robiniae
(seedling leaf blight), Gibberella baccata (on twigs), Gloeosporium
revolutum (leaf spot), Herpotrichia lanuginosa (on decaying wood),
Heterosporium robiniae (on leaves), Macrophoma numerosa (on
branches), Melanconium viscosum (on dead branches), Microsphaera
diffusa (powdery mildew), Nectaria cinnabarina (on branches),
Nectaria coccinea, Phleospora robiniae (leaf spot), Phoradendron
flavescens (mistletoe), Phoradendron flavescens var.
macrophyllum, Phyllactinia corylea (powdery mildew), Pyllosticta
robiniae (leaf spot), Phymatotrichum omnivorum (root rot),
Physalospora obtuse (on branches), Phytophthora cinnamomi
(seedling root rot), Phytophthora parasitica (seedling top wilt),
Polyporus biformis, Polyporus gilvus, Polyporus obtusus, Polyporus units,
Polyporus robiniophilus (white spongy heart rot), Polyporus
sulphureus (brown cubical heart rot), Poria ambigua, Poria
ferruginosa,Poria incrassata (on postswidespread), Poria robustus,
Poria umbrina, Pratylenchus sp. (root nematode), Pythium myriotylum
(seedling root rot), Rhabdospora breviuscula (on branches),
Rhizoctonia bataticola (seedling stem rot), Rhizoctonia solani
(damping-off, seedling leaf blight), Sclerotium bataticola (seedling
stem rot), Septoria curvata, Sphaeropsis robiniae, Thielavia basicola
(on dead roots), Tryblidiella rufula (on twigs), Verticillium
alto-atrum (wilt), Xylaria longeana (wood rot), and Xylaria
polymorpha (wood rot). Golden (p.c. 1984) lists Longidorus maximus,
Meloidogyne sp., and Pratylenchus penetrans among the nematodes.
Analysing 62 kinds of biomass for heating value, Jenkins and Ebeling (1985)
reported a spread of 19.71 to 18.55 MJ/kg, compared to 13.76 for
weathered rice straw to 23.28 MJ/kg for prune pits. On a % DM basis, the
forest residue contained 80.94 % volatiles, 0.80% ash, 18.26% fixed carbon,
50.73% C, 5.71% H, 41.93% O, 0.57% N, 0.01% S, 0.08% Cl, and undetermined
Complete list of references for Duke, Handbook of Energy Crops
- Agriculture Handbook 271. 1965. Silvics of forest trees of the United States.
Forest Service, USDA. USGPO. Washington.
- Agriculture Handbook 450. 1974. Seeds of woody plants in the United States.
Forest Service, USDA. USGPO. Washington.
- Allen, O.N. and Allen, E.K. 1981. The Leguminosae. The University of Wisconsin
Press. 812 p.
- Brown, R.C. and Brown, M.L. 1972. Woody plants of Maryland. Port City Press,
- C.S.I.R. (Council of Scientific and Industrial Research). 19481976. The wealth
of India. 11 vols. New Delhi.
- Duke, J.A. 1978. The quest for tolerant germplasm. p. 161. In: ASA Special
Symposium 32, Crop tolerance to suboptimal land conditions. Am. Soc. Agron.
- Duke, J.A. 1979. Ecosystematic data on economic plants. Quart. J. Crude Drug
- Duke, J.A. and Wain, K.K. 1981. Medicinal plants of the world. Computer index
with more than 85,000 entries. 3 vols.
- Grieve, M. 1931. A modern herbal. Reprint 1974. Hafner Press, New York.
- Jenkins, B.M. and Ebeling, J.M. 1985. Thermochemical properties of biomass
fuels. Calif. Agric. 39(5/6):1416.
- Shah, F.A. 1972. False acaciaa promising bee plant of Kashmir. Indian Bee J.
- Watt, J.M. and Breyer-Brandwijk, M.G. 1962. The medicinal and poisonous plants
of southern and eastern Africa. 2nd ed. E.&S. Livingstone, Ltd., Edinburgh
Last update Friday, January 9, 1998 by aw