Zanthoxylum heitzi - Rutaceaei

8/8/2019 Zanthoxylum heitzi - Rutaceaei

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Zanthoxylum heitzii (Aubrv. & Pellegr.)P.G.Waterman

ProtologueTaxon 24: 363 (1975).

FamilyRutaceae

SynonymsFagara heitziiAubrv. & Pellegr. (1950), Fagara brieyiVermoesen ex

G.C.C.Gilbert (1958).

Vernacular namesOlon tendre (Fr).

Origin and geographic distributionZanthoxylum heitziioccurs from southern Cameroon and the Central African

Republic to Gabon and Bas-Congo province of DR Congo.

UsesThe wood, often traded as olon or light olon, is suitable for light construction,

light flooring, joinery, interior trim, moulding, shipbuilding, furniture, cabinet work,


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toys, novelties, boxes, crates, turnery, veneer, plywood, hardboard and particle

board. It is used locally for canoes, drums and beehives. It is sometimes also

used as firewood.

Zanthoxylum heitziiis used in traditional medicine. In Cameroon scrapings from

the stem bark are applied externally to treat malaria, and in Congo to soothe

toothache. In Gabon the bark is applied externally in lotions to treat rheumatism

and stiffness, and a maceration of young twigs in lemon juice to treat heart

complaints. In Cameroon the bark is used to treat gonorrhoea, abscesses and

painful joints and male sexual impotence. In Congo the bark is used as an

analgesic. It serves as a fish poison. The tree is sometimes retained by farmers

after clearing the forest for agricultural land, to serve as a shade tree for

cultivation of crops such as coffee and cocoa.

Production and international tradeThe annual production ofZanthoxylum heitziitimber in Gabon in 19941995 has

been estimated at 5700 m. The timber ofZanthoxylum heitziihas little

importance on the international market and is mostly traded for local use. Few

trade statistics are available because the wood ofZanthoxylum gilletii(De Wild.)

P.G.Waterman is sometimes sold as olon too. Annual olon log exports duringthe 1960s were 50006000 m from Equatorial Guinea and 13003000 m/year

from Gabon, whereas only very small volumes were exported from Cameroon

and Congo. In 19971998 Equatorial Guinea exported about 1900 m/year.

According to ATIBT statistics, Gabon exported 310 m in 2001, 499 m in 2002,

1071 m in 2003 and 886 m in 2004. Sawnwood exports are insignificant.

The bark is sold on local markets for medicinal purposes, e.g. in Yaound

(Cameroon), where in 2002 the price was 58 XAF (CFA Central Franc) per g.

PropertiesThe heartwood is pale yellow to greenish yellow and indistinctly demarcated from

the pale yellow, 12 cm wide sapwood. The grain is usually interlocked,


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sometimes straight, texture fine to moderately coarse. Quartercut surfaces show

a slight ribbon-like figure. Freshly cut wood has a slight, pleasant scent. The

wood is lustrous.

The wood is medium-weight, with a density of 450560 kg/m at 12% moisture

content. It air dries rapidly with slight risk of distortion and checking. The rates of

shrinkage are moderate, from green to oven dry 3.73.9% radial and 5.76.1%

tangential. Once dry, it is moderately stable in service.

At 12% moisture content, the modulus of rupture is 72122 N/mm, modulus of

elasticity 10,00012,400 N/mm, compression parallel to grain 3551 N/mm,

shear 6 N/mm, cleavage 712 N/mm and Chalais-Meudon side hardness 1.5

2.9.

The wood saws and works well with ordinary machine and hand tools. Planing

may cause some difficulties due to interlocked grain. The moulding, polishing,

gluing, painting and varnishing properties are all satisfactory. The screwing and

nailing properties are good and the wood holds screws well, but nails are easy to

draw. It produces good veneer by slicing and rotary cutting. The wood is not

durable and susceptible to fungal, termite, Lyctusand marine borer attacks. The

heartwood is resistant to impregnation with preservatives, the sapwood

moderately resistant. The sawdust may be irritant; allergic contact dermatitis hasbeen recorded in workers.

The wood contains: cellulose 4147%, pentosans 1014%, lignin 3031% and

ash 0.10.2%. Solubilities are 1.82.4% in hot water, 3.25.8% in alcohol-

benzene and 11.112.7% in 1% NaOH. The wood fibres are 1.17 mm long and

30 m wide, with a lumen diameter of 21 m and a cell wall thickness of 8 m.

Good pulps can be obtained from the wood using the kraft process and other

chemical pulping processes.The secondary alkaloid flindersine has been extracted from the heartwood; the

bark yielded several lignans, the triterpenes lupeol and lupeone, and the

alkaloids skimmianine and 6-methylnitidine.


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Adulterations and substitutesThe wood ofZanthoxylum gilletiiis often sold as olon, although it has a higher

density and it is harder.

DescriptionMedium-sized to fairly large tree up to 35 m tall; bole branchless for up to 20 m,

usually straight and cylindrical, up to 150 cm in diameter, with many woody,

prickle-bearing protuberances up to 9 cm long but old trees often lacking these,

usually without buttresses but often slightly thickened at base; outer bark grey to

greenish grey, smooth to slightly fissured and scaly in old trees, inner bark

granular to fibrous, yellowish brown, often mottled with orange; crown large, with

ascending, strongly branched branches; branches glabrous, armed with conical

prickles. Leaves alternate, clustered at ends of branches, imparipinnately

compound with 2551 leaflets, up to 100 cm long; stipules absent; rachis

glabrous, sometimes with small prickles; leaflets nearly opposite, sessile, oblong

to oblong-lanceolate, 415(20) cm 25 cm, rounded to slightly cordate and

asymmetrical at base, shortly acuminate at apex, margin slightly toothed with

rounded teeth, leathery, glabrous, with scattered minute glandular dots, pinnately

veined with 1020 pairs of lateral veins. Inflorescence a terminal or axillarypanicle up to 40 cm long, many-flowered with flowers in clusters. Flowers

unisexual, regular, 5-merous, small, sessile; sepals united for most of their

length, 0.51 mm long; petals oblanceolate, c. 2 mm long, white, turning brown;

male flowers with 5 stamens, disk conical, thick, ovary rudimentary; female

flowers with superior, globose ovary 11.5 mm long, stamens rudimentary. Fruit

a globose follicle c. 4 mm in diameter, glandular pitted, dehiscent, 1-seeded.

Seed globose, c. 2.5 mm in diameter, black and shiny.

Other botanical informationZanthoxylumis pantropical and comprises about 200 species, with tropical

America being richest in species. Mainland Africa harbours about 35 species,


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whereas about 5 species are endemic to Madagascar. Zanthoxylum heitziiis

often confused with Zanthoxylum gilletii, which produces a heavier and harder

timber and also differs in less numerous and larger leaflets with often entire

margins.

AnatomyWood-anatomical description (IAWA hardwood codes):

Growth rings: 2: growth ring boundaries indistinct or absent. Vessels: 5: wood

diffuse-porous; 13: simple perforation plates; 22: intervessel pits alternate; (23:

shape of alternate pits polygonal); 25: intervessel pits small (47 m); 30: vessel-

ray pits with distinct borders; similar to intervessel pits in size and shape

throughout the ray cell; 42: mean tangential diameter of vessel lumina 100200

m; 47: 520 vessels per square millimetre; (48: 2040 vessels per square

millimetre); 58: gums and other deposits in heartwood vessels. Tracheids and

fibres: 61: fibres with simple to minutely bordered pits; 66: non-septate fibres

present; 69: fibres thin- to thick-walled. Axial parenchyma: 78: axial parenchyma

scanty paratracheal; (79: axial parenchyma vasicentric); (89: axial parenchyma in

marginal or in seemingly marginal bands); (91: two cells per parenchyma strand);

92: four (34) cells per parenchyma strand. Rays: (97: ray width 13 cells); (98:larger rays commonly 4- to 10-seriate); 104: all ray cells procumbent; (106: body

ray cells procumbent with one row of upright and/or square marginal cells); 115:

412 rays per mm. Secretory elements and cambial variants: (131: intercellular

canals of traumatic origin). Mineral inclusions: 136: prismatic crystals present;

142: prismatic crystals in chambered axial parenchyma cells.

(N.P. Mollel, P. Dtienne & E.A. Wheeler)

Growth and developmentZanthoxylum heitziigrows rapidly. The seeds are probably dispersed by birds.

Ecology


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Zanthoxylum heitziioccurs in evergreen and semi-deciduous forest, up to 1200

m altitude. It is a pioneer species that is most common in secondary forest. It

prefers well-drained soils.

Propagation and plantingSeedlings are light-demanding and natural regeneration may be abundant in

larger gaps in the forest. Seeds may germinate 2530 days after sowing. Seeds

that have been soaked in water for longer periods do not germinate.

ManagementMature Zanthoxylum heitziitrees usually occur scattered in the forest. For

southern Cameroon average exploitable timber volumes of less than 0.1 m/ha to

0.8 m/ha have been recorded, and for Gabon an average timber volume of 0.3

m/ha.

Diseases and pestsThe wood-boring beetleApate monachusand the hemipterous Lerida punctata

have been recorded as pests ofZanthoxylum heitziiin natural forest in

Cameroon.

HarvestingThe minimum bole diameter for harvesting is 60 cm in Cameroon and 50 cm in

Central African Republic.

Handling after harvestThe wood is susceptible to blue stain and logs should be removed from the forestimmediately after felling or be treated with an anti-sapstain chemical. Logs float

in water and can be transported by river.

Genetic resources


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Zanthoxylum heitziiis valued for its multipurpose timber and there is high

demand locally for its bark, which is used in traditional medicine. Although this

species is not considered of conservation concern at present, the logging and

debarking may make it liable to genetic erosion in the near future. The pressure

on the trees because of bark collection can be locally high, as was recorded

around the Dja reserve in southern Cameroon.

ProspectsZanthoxylum heitziimay have good prospects as a plantation timber tree, but

more research is needed on propagation techniques. It seems to be a suitable

candidate for sustainable timber exploitation in natural forest because it is able to

regenerate in logged-over forest.

The medicinal properties deserve more attention, particularly the analgesic

activity. Several of the claimed activities in traditional medicine are comparable to

those ofZanthoxylum gilletii, which has been subject to much more

pharmacological research, with promising results.

Major references Bolza, E. & Keating, W.G., 1972. African timbers: the properties, uses andcharacteristics of 700 species. Division of Building Research, CSIRO, Melbourne,

Australia. 710 pp.

CIRAD Forestry Department, 2003. Olon. [Internet] Tropix 5.0.

http://tropix.cirad.fr/ afr/olon.pdf. Accessed September 2007.

CTFT (Centre Technique Forestier Tropical), 1980. Olon. Bois et Forts des

Tropiques 191: 4757.

de Saint-Aubin, G., 1963. La fort du Gabon. Publication No 21 du CentreTechnique Forestier Tropical, Nogent-sur-Marne, France. 208 pp.

Petroff, G., Doat, J. & Tissot, M., 1967. Caractristiques papetires de quelques

essences tropicales de reboisement. Centre Technique Forestier Tropical,

Nogent-sur-Marne, France. 166 pp.


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Sallenave, P., 1955. Proprits physiques et mcaniques des bois tropicaux de

lUnion franaise. Centre Technique Forestier Tropical, Nogent sur Marne,

France. 129 pp.

Sallenave, P., 1964. Proprits physiques et mcaniques des bois tropicaux.

Premier supplment. Centre Technique Forestier Tropical, Nogent-sur-Marne,

France. 79 pp.

Takahashi, A., 1978. Compilation of data on the mechanical properties of

foreign woods (part 3) Africa. Shimane University, Matsue, Japan, 248 pp.

Other references Adjanohoun, E.J., Ahyi, A.M.R., Ak Assi, L., Baniakina, J., Chibon, P., Cusset,

G., Doulou, V., Enzanza, A., Eym, J., Goudot, E., Keita, A., Mbemba, C.,

Mollet, J., Moutsambot, J.-M., Mpati, J. & Sita, P. (Editors), 1988. Mdecine

traditionnelle et pharmacope - Contribution aux tudes ethnobotaniques et

floristiques en Rpublique Populaire du Congo. Agence de Coopration

Culturelle et Technique, Paris, France. 606 pp.

ATIBT (Association Technique Internationale des Bois Tropicaux), 1986.

Tropical timber atlas: Part 1 Africa. ATIBT, Paris, France. 208 pp.

ATIBT (Association Technique Internationale des Bois Tropicaux), 2005.Statistics. ATIBT Newsletter 22: 2647.

Betti, J.L., 2001. Vulnrabilit des plantes utilises comme antipaludiques dans

l'arrondissement de Mintom au sud de la rserve de biosphre du Dja

(Cameroun). Systematics and Geography of Plants 71: 661-678.

Betti, J.L., 2002. Medicinal plants sold in Yaound markets, Cameroon. African

Study Monographs 23(2): 4764.

Betti, J.L., 2003. Plantes utilises pour soigner le paludisme dans la rserve duDja, Cameroun. Revue de Mdecines et Pharmacopes Africaines 17: 121130.

Bongui, J.-B., Blanckaert, A., Elomri, A. & Seguin, E., 2005. Constituents of

Zanthoxylum heitzii (Rutaceae). Biochemical Systematics and Ecology 33(8):

845847.


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Cond-Salazar, D., Guimaraens, D., Romero, V. & Gonzalez, M.A., 1987.

Allergic contact dermatitis to Olon wood. Contact Dermatitis 16(4): 231232.

Foahom, B., 2002. Insect pest incidence on timber tree species in natural forest

in South Cameroon. Tropenbos-Cameroon Document 12. Tropenbos Cameroon

Programme, Kribi, Cameroon. 54 pp.

Gassita, J.N., Nze Ekekang, L., De Vecchy, H., Louis, A.M., Koudogbo, B. &

Ekomi, R. (Editors), 1982. Les plantes mdicinales du Gabon. CENAREST,

IPHAMETRA, mission ethnobotanique de lACCT au Gabon, 1031 juillet 1982.

26 pp.

Gilbert, G., 1958. Rutaceae. In: Robyns, W., Staner, P., Demaret, F., Germain,

R., Gilbert, G., Hauman, L., Homs, M., Jurion, F., Lebrun, J., Vanden Abeele,

M. & Boutique, R. (Editors). Flore du Congo belge et du Ruanda-Urundi.

Spermatophytes. Volume 7. Institut National pour ltude Agronomique du Congo

belge, Brussels, Belgium. pp. 69108.

InsideWood, undated. [Internet] http://insidewood.lib.ncsu.edu/search/ .

Accessed May 2007.

Letouzey, R., 1963. Rutaces. Flore du Cameroun. Volume 1. Musum

National dHistoire Naturelle, Paris, France. pp. 32153.

Letouzey, R., 1963. Rutaces. Flore du Gabon. Volume 6. Musum NationaldHistoire Naturelle, Paris, France. pp. 3109.

Ngavoura, P., 1990. Fiabilit de la mdecine traditionnelle dans le monde

moderne - Contribution du forestier. Mmoire de fin de cycle, Ecole nationale

des eaux et forts (ENEF), Cap-Estrias, Gabon. 115 pp.

Ngouela, S., Tsamo, E. & Connolly, J.D., 1994. Lignans and other constituents

of Zanthoxylum heitzii. Phytochemistry 37(3): 867869.

Nkeoua, G. & Boundzanga, G.C., 1999. Donnes sur les produits forestiresnon ligneux en Rpublique du Congo. FAO, Brazzaville, Congo. 125 pp.

Raponda-Walker, A. & Sillans, R., 1961. Les plantes utiles du Gabon. Paul

Lechevalier, Paris, France. 614 pp.

Tailfer, Y., 1989. La fort dense dAfrique centrale. Identification pratique des


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principaux arbres. Tome 2. CTA, Wageningen, Pays Bas. pp. 4651271.

Vivien, J. & Faure, J.J., 1985. Arbres des forts denses dAfrique Centrale.

Agence de Coopration Culturelle et Technique, Paris, France. 565 pp.

Wilks, C. & Issemb, Y., 2000. Les arbres de la Guine Equatoriale: Guide

pratique didentification: rgion continentale. Projet CUREF, Bata, Guine

Equatoriale. 546 pp.

Sources of illustration Letouzey, R., 1963. Rutaces. Flore du Gabon. Volume 6. Musum National

dHistoire Naturelle, Paris, France. pp. 3109.

Wilks, C. & Issemb, Y., 2000. Les arbres de la Guine Equatoriale: Guide

pratique didentification: rgion continentale. Projet CUREF, Bata, Guine

Equatoriale. 546 pp.

Author(s) R.B. Jiofack Tafokou

Ecologic Museum of Cameroon, P.O. Box 8038, Yaound, Cameroon

Editors D. Louppe

CIRAD, Dpartement Environnements et Socits, Cirad es-dir, Campus

international de Baillarguet, TA C-DIR / B (Bt. C, Bur. 113), 34398 Montpellier

Cedex 5, France

A.A. Oteng-Amoako

Forestry Research Institute of Ghana (FORIG), University P.O. Box 63,

KNUST, Kumasi, Ghana

M. Brink


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PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700

AH Wageningen, Netherlands

General editors R.H.M.J. Lemmens



L.P.A. Oyen



J.R. Cobbinah

Forestry Research Institute of Ghana (FORIG), University P.O. Box 63,

KNUST, Kumasi, Ghana

Photo editor G.H. Schmelzer



wild


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1, base of bole; 2, leaf; 3, leaflet; 4, male inflorescence; 5, female inflorescence;

6, fruit.

Redrawn and adapted by Achmad Satiri Nurhaman

base of bole


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bark

slash


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wood in transverse section

wood in tangential section

wood in radial section


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Zanthoxylum heitzi - Rutaceaei