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Gleditsia triacanthos L.

Caesalpiniaceae
Honeylocust

Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.

  1. Uses
  2. Folk Medicine
  3. Chemistry
  4. Description
  5. Germplasm
  6. Distribution
  7. Ecology
  8. Cultivation
  9. Harvesting
  10. Yields and Economics
  11. Energy
  12. Biotic Factors
  13. References

Uses

Widely introduced as a fast-growing tree for fuel and fodder and fence posts, for ornament, shade and soil reclamation. The wood is said to be coarse-grained, durable, hard, and resistant to soil decay. Hence it is used for fence posts, railroad ties and tubs for wheels. South Africans sometimes plant orchards of the tree for fodder. The gum from the seeds has been suggested as an emulsifying substitute for acacia and tragacanth. Flowers very attractive to bees. The pulp has always attracted the sweet tooth of animal and man alike, when better sweets were not available. A potable or energy alcohol can be made by fermenting the pulp. Seeds have been roasted and used as a coffee substitute. Wood is hard, coarse grained, reddish-brown and takes a high polish; the wood resists decay and makes good fence posts. Lumber is used for various purposes, but the chief use is as an ornamental. The pods are readily eaten by cattle, goats, deer, squirrel, rabbits, quail, and starlings (Brown and Brown, 1972).

Folk Medicine

Sokoloff et al. (1964) note that recently, Soviet investigators have been studying the biological factors present in the fruit and leaves of Gleditsia triacanthos. The alcoholic extract of the fruits of the Kirgis honey locust, after elimination of tannin, considerably retarded the growth, up to 63% of Ehrlich mouse carcinoma. However, the cytotoxicity of the extract was quite high and the animals, besides losing weight, showed dystrophic changes in their liver and spleen. The alcoholic extract of the fruit exerted moderate oncostatic activity against sarcoma 180 and Ehrlich carcinoma at the total dose 350 mg/kg/body weight/mouse. Weight loss was considerable. Epicatechol-3-D-glucoside dihydride, isolated from the flowers, exhibited no oncostatic or cytotoxic activity. The Pigment tentatively identified as dihydroxy-4-methoxyisoflavone, isolated from the fruit, exerted considerable oncostatic activity (and cytotoxicity). Triacanthine from the leaves was highly toxic (LD50 ca 35 mg/kg) and of questionable oncostatic activity (Sokoloff et al., 1964). In Lesotho, fruit pulp is used for catarrh of of the lung. Powdered seed used as a snuff for head cold. Some people, probably having seen the erroneous report of cocaine in the leaves, state that "ingestion of a suitable preparation of the leaf increases the capacity for muscular work and delays the onset of fatigue." Reported to be anodyne, mydriatic, narcotic, and experimentally oxytocic (Duke and Wain, 1981), honeylocust pods are a folk remedy for dyspepsia and measles among the Cherokee. The bark tea is used for whooping cough. Delaware Indians used the bark for blood disorders and coughs, the Fox for colds, fevers, measles, and smallpox. Chinese probed tumors and abscesses with the thorns of Gleditsia sinensis, considering them counterirritant.

Chemistry

Per 100 g, the fruit is reported to contain (ZMB): 23.1 g protein, 4.6 g fat, 66.9 g total carbohydrate, 12.7 fiber, 5.4 g ash. The seed is said to contain 10.6 g protein, 0.8 g fat, 84.7 g total carbohydrate, 21.1 g fiber, 3.9 g ash, 280 mg Ca and 320 mg P. Scanlon (1980), interested in the potential of honeylocust for alcohol production, presents the following analytical data. Differences in sugar content are possible in trees of the same clone grown in different locations. 'Millwood' pods from trees grown in Beltsville, Maryland, contained 21.07% total sugars, while 'Millwood' at Auburn, Alabama, contained 36.8%. Small differences in sugars were found in pods from the same clonal trees collected in different years.

Constituents of 'Millwood'Whole podsPods without seedsSeeds only
Ash 3.75 3.82 10.23
Crude fat (ether extract) 0.81 0.52 3.06
Crude protein (%N x 6.25) 10.15 8.21 28.74
Crude fiber 14.19 13.81 11.02
Nitrogen-free extract 71.10 73.64 46.95
Reducing sugars (glucose) 2.86 3.32
Nonreducing sugars (sucrose) 29.12 32.22
Total sugars 31.98 35.54
Air-dried leaf yields 0.5% of an alkaloid triacanthine C8H10N4 which in intravenous doses of 0.1 mg/kg, depresses the action of the cat heart, the intensity apparently depending on the intensity of effect on the vasomotor centre (145). Heart-wood contains 4–4.8% tannin and also fustin and fisetin (Watt and Breyer-Brandwijk, 1962). The alkaloid gleditschine is said to produce stupor and loss of reflex activity in a frog. Stenocarpine has been used for local anesthesia (Grieve 1931). "It also contains cocaine" (Grieve 1931). To the best of my knowledge it does not contain cocaine!

Description

Tree 20–30 m tall with trunk 3–6 dm in diameter, occasionally reaching a maximum of 50 m tall, diameter to 1.5 m; bark with many large plates, loose at edges, grayish-brown. Twigs brown, glabrous; buds small, glabrous, superposed, the upper one producing a thorn or an inflorescence. Thorns axillary, lustrous, reddish-brown, ca 5–8 cm long, with 2 short branches near base, those on trunk often longer and more branched, with new ones produced for many years. Leaves 1.6–2 dm long; if bipinnate, composed of 4–7 pairs of pinnae, each pinna 18–28 leaflets, or the ultimate sections of the leaf pinnate. Leaflets oval to ovate-oblong, 1.5–3 cm long, 1.25 cm wide, dark green and glossy above, yellowish-green and essentially glabrous beneath; margins nearly entire, obtuse at both ends. Racemes 5–12 cm long, flowers about 5 mm broad, greenish. Pod dark brown 2–4 dm long, 2.5–3.5 cm wide, about 1 cm thick, smooth and shining. Space between the seeds filled with sweet edible pulp.

Germplasm

Reported from the North American Center of Diversity, honeylocust or cvs thereof is reported to tolerate drought, frost, pests, poor soil and slope. Germplasm is covered rather thoroughly in the SERI symposium on Tree Crops for Energy Co-production on Farms, especially the papers by McDaniel (1980) and Scanlon (1980). 'Moraine' and 'sunburst' locusts are nursery selections of the unarmed types.

Distribution

Native to the central United States, now naturalized east of the Appalachian Mountains from South Carolina to New England. Also introduced, established and possibly spreading, sometimes as a weed tree in India, New Zealand and South Africa.

Ecology

Ranging from Warm Temperate Dry to Moist through Cool Temperate Dry to Moist Forest Life Zones, honeylocust is speculated to tolerate annual precipitation of 6 to 15 dm, annual temperature of 10 to 21°C, and pH of 6 to 8.

Cultivation

Pretreated seeds (hot water or sulfuric acid) are drilled in rows 15–25 cm apart and covered with 1–2 cm soil with 30–40 seed per linear meter. Seedlings reach suitable size for outplanting in one year. Clonal reproduction of select germplasm is often recommended. (2n = 28)

Harvesting

There is a trend toward biennial production in the cultivars, a hectare of Millwood yielding ca 8000 kg/ha in 1946, but only 550 kg/ha in 1947. Harvesting of pods is rather difficult, especially in thorny cvs.

Yields and Economics

'Calhoun' 3 yrs old yielded ca 0.5 kg/tree, 4-yr-olds ca 2 kg/tree, and 5-yr-olds ca 12 kg. 'Millwood 3-yr-olds yielded ca 0.6 kg/tree, 4-yr-olds ca 2 kg/tree, and 5-yr-olds ca 27 kg/ha. With such low yields (Scanlon, 1980) it is difficult to see how we could get 50 barrels of ethanol per ha. Older 'Millwoods' averaged 33 kg which would give only 3,300 kg/ha if spaced at 100 trees/ha. In Alabama, nearly 6.5 MT Lespedeza sericea hay was produced annually in the shade of honeylocust spaced at ca 85 trees/ha.

Energy

Freedman (1980) cited figures suggesting yields of only 3 MT/ha which would yield only ca 5 barrels ethanol. The wood has been described as good fuel wood (C.S.I.R., 1948–1976). Williams (1980) ranks this as a highly feasible (high yield, low maintenance) woody perennial for ethanol production in Applachia, along with blackberry, blueberry, cranberry, elderberry, hawthorn, mulberry, persimmon, raspberry and serviceberry. He estimated yields at ca 10–58 barrels alcohol per ha, much higher than is consonant with fruit dry weights of 3.3 MT/ha/yr, which is closer to the lower barrel figure (Scanlon, 1980; Williams, 1980). Avgerinos and Wang (1980) were more pessimistic about honeylocust than mesquite pods for alcohol production.

Biotic Factors

Allen and Allen (1981) report the invasion of honeylocust root hairs by rhizobia from Erythrina, Glycine, Leucaena, Lupinus, Pisum, and Vigna species. The infection threads did not penetrate beyond the epidermal wall. Disk assay tests using aqueous root extracts showed the presence of antirhizobial substances that were suggestive of flavones in other tests. Nodulation was not inhibited or diminished on diverse species of other leguminous genera grown in association with honeylocust. It was concluded that the nodule-inhibitory principle was root-contained, or nonfunctional, if exuded into the rhizosphere (Allen and Allen 1981). In the middle Atlantic states, the mimosa webworm is beginning to cause problems. Grazing animals may damage young plants, while other animals and birds may eat the pods. Agriculture Handbook 165 lists quite a few diseases: Aglaospora anomia, Agrobacterium rhizogenes, B. ribis, Cercospora condensata, C. olivacea, Curcurbitaria elongata, C. recuperata, Cytospora gleditschiae, Daelalea ambigua, D. elegans, Dothiorella gleditschiae, Eutypella fraxinicola, Fomes spp., F. applanatus, F. connatus, F. igiarius var. laevigatus, F. marmoratus, F. meliae, Ganoderma curtisii, G. lucidum, Glomerella cingulata, Haplosporella gleditschiae, H. gleditschiicola, Hendersonia sp., Libertella gleditschiae, Linospora gleditsiae, Macrophoma mamillaris, Melasmia hypophila, Microsphaera alni, M. ravenelii, Mycosphaerella sp., Nectria cinnabarina, Parodiella perisporioides, Phoradendron flavescens Phymatotrichum omnivorum Physalospora obtusa, P. rhodina Phytophthora citrophthora, Polyporus spp., P. adustus, P. Albus, P. arcularius, P. hydnoides, P. pargamenus, P. pulchellus, P. sulphureus, P. supinus, P. tulipiferus, P. versicolor, Poria ambigua, Ravenelia opaca, Schizophyllum commune, Septobasidium curtisii, Sphaeropsis gleditschiae, S. gleditschiicola, Sphaeropsis mamillaris, S. triacanthi, Thyronectria austro-americana, Xylaria mali and Chlorogenus robiniae. Nematodes of the genus Meloidogyne may be present.

References

Complete list of references for Duke, Handbook of Energy Crops
Last update Wednesday, January 7, 1998 by aw