4758

5(3): Timber trees; Lesser-known timbers

Acronychia J.R. Forster & J.G. Forster

Charact. gen. pl.: 27 (1775).

RUTACEAE

x = 18; A. pedunculata: 2n = 36

Acronychia comprises 47 species occurring from Sri Lanka and India to Indo-China, south-western China, Taiwan, Thailand, the whole of the Malesian archipelago, east to the Solomon Islands, New Caledonia and Lord Howe Island, and south to eastern and southern Australia. The majority of the species are endemic to New Guinea and Australia.

The wood of Acronychia is used for house building, utility furniture, flooring, lining, panelling, mouldings, turnery, carving and tool handles. It also produces a good quality charcoal and has been used as firewood.
In Indo-China an extract from the roots of A. pedunculata has been applied to the skin against rheumatism, and an extract from the bark against itch. Roots have also been used as a fish poison; the bark for caulking boats and toughening fishing nets. The leaves contain a volatile, aromatic oil used in stimulating baths. Young leaves are sometimes eaten as a condiment and applied to promote digestion.

As supplies and the size of the timber of Acronychia are generally small, utilization is on a local scale only.

Acronychia yields a medium-weight hardwood with a density of 490-830 kg/m³ at 15% moisture content. The following description is based on the Australian species A. laevis J.R. Forster & J.G. Forster. Wood whitish, darkening to pale brown or pale yellow on exposure; grain interlocked; texture fine and even. Growth rings indistinct; vessels very small to small, just visible with a hand lens, some solitary but mostly in radial multiples of up to 4, with yellowish deposits; parenchyma paratracheal vasicentric and apotracheal in irregularly spaced bands; rays very fine, only visible with a hand lens; ripple marks absent.
Shrinkage of the wood upon air drying is moderate. The wood of South-East Asian species is not very strong and is not durable. The sapwood is susceptible to Lyctus.
Leaves contain 0.06% of an aromatic oil. Several species contain alkaloids.
See also the table on microscopic wood anatomy.

Aromatic shrubs or small to medium-sized trees up to 27(-35) m tall, rarely climbers; bole sometimes straight but more often crooked, branchless for up to 23 m, up to 60 cm in diameter, without buttresses; bark surface smooth to finely cracked, greyish, inner bark pale brown to cream-coloured. Leaves opposite, 1-foliolate or 3-foliolate, leaflets entire, with pellucid dots; stipules absent. Inflorescence axillary, paniculate, subcorymbose or reduced to 1 or a few flowers. Flowers bisexual, 4-merous; sepals free or connate at base; petals valvate, deciduous or rarely persistent, white; stamens 8, filaments usually densely ciliate at base; disk intrastaminal; ovary superior, 4(-8)-carpellate, with or without septicidal fissures, with 2 axillary ovules in each cell, style twisted. Fruit a 4(-8)-locular drupe with (1-)2 seeds per cell.
Annual height increment can be 0.5-0.6 m. In Java A. pedunculata flowers and fruits throughout the year whereas A. trifoliolata has been observed flowering in September to November.
A. trifoliolata is very variable and has been subdivided into 3 varieties. Two of these, var. ampla T.G. Hartley and var. microcarpa T.G. Hartley, are confined to New Guinea. A. pedunculata is also highly variable, especially in the size of the fruit and the pubescence of the disk.

Within Malesia Acronychia species are often found scattered in evergreen, primary or sometimes secondary, upper or lower montane forest. Sometimes they are even present in alpine habitats (e.g. A. murina and A. pullei), although some are fairly common in lowland forest as well. A. pedunculata is found in primary and secondary rain forest and in coastal scrub, up to 2200 m altitude. A. trifoliolata is also found in monsoon forest and along the margins of Casuarina forest, up to 2400 m altitude.

Acronychia can be propagated by seed, which germinates easily.

There are no records of in situ conservation of Acronychia. Many narrow-endemic species from New Guinea and Australia may easily become endangered by destruction of their habitat.

The timber of Acronychia appears to be hardly used in South-East Asia. This situation is unlikely to change in the near future.

[70]Backer, C.A. & Bakhuizen van den Brink Jr., R.C., 1963-1968. Flora of Java. 3 volumes. Wolters-Noordhoff, Groningen.
[163]Burkill, I.H., 1966. A dictionary of the economic products of the Malay Peninsula. 2nd edition. Ministry of Agriculture and Co-operatives, Kuala Lumpur. Vol. 1 (A-H) pp. 1-1240. Vol. 2 (I-Z) pp. 1241-2444.
[221]Dan Nguyen Van & Nhu Nguyen Thi, 1995. Medicinal plants in Vietnam. Science and Technics Publishing House, Hanoi. 640 pp.
[413]Hartley, T.G., 1974. A revision of the genus Acronychia (Rutaceae). Journal of the Arnold Arboretum 55: 469-523, 525-567.
[436]Heyne, K., 1927. De nuttige planten van Nederlands-Indië [The useful plants of the Dutch East Indies]. 2nd edition, 3 volumes. Departement van Landbouw, Nijverheid en Handel in Nederlandsch-Indië. 1953 pp. (3rd edition, 1950. van Hoeve, 's-Gravenhage/Bandung. 1660 pp.).
[464]Ilic, J., 1990. The CSIRO macro key for hardwood identification. CSIRO, Highett. 125 pp.
[497]Johns, R.J. & Stevens, P.F., 1971. Mount Wilhelm Flora: a checklist of the species. Botany Bulletin No 6. Division of Botany, Department of Forests, Lae. 60 pp.
[568]Kingston, R.S.T. & Risdon, C.J.E., 1961. Shrinkage and density of Australian and other South-West Pacific woods. Technological Paper No 13. Division of Forest Products, CSIRO, Melbourne. 65 pp.
[595]Koorders, S.H. & Valeton, T., 1894-1915. Bijdrage tot de kennis der boomsoorten van Java [Contribution to the knowledge of the tree species of Java]. 13 parts. G. Kolff & Co., Batavia, 's-Gravenhage.
[672]Lecomte, H., 1907-1950. Flore générale de l'Indo-Chine [General flora of Indo-China]. 7 vols & Supplément. Masson & Cie, Paris.
[861]Oey Djoen Seng, 1951. De soortelijke gewichten van Indonesische houtsoorten en hun betekenis voor de praktijk [Specific gravity of Indonesian woods and its significance for practical use]. Rapport No 46. Bosbouwproefstation, Bogor. 183 pp.
[883]Pham Hoang Ho, 1991-1993. An illustrated flora of Vietnam. 2 Volumes. Mekong Publisher, Montreal.
[974]Salvosa, F.M., 1963. Lexicon of Philippine trees. Bulletin No 1. Forest Products Research Institute, College, Laguna. 136 pp.
[1038]Smitinand, T., 1980. Thai plant names. Royal Forest Department, Bangkok. 379 pp.
[1048]Soepadmo, E., Wong, K.M. & Saw, L.G. (Editors), 1995-. Tree flora of Sabah and Sarawak. Sabah Forestry Department, Forest Research Institute Malaysia and Sarawak Forestry Department, Kepong.
[1170]Vietnam Forest Inventory and Planning Institute, 1978. Forestry timber trees in Vietnam. 3 Volumes.
[1221]Whitmore, T.C. & Ng, F.S.P. (Editors), 1972-1989. Tree flora of Malaya. A manual for foresters. 4 volumes. Malayan Forest Records No 26. Longman Malaysia Sdn. Berhad, Kuala Lumpur & Petaling Jaya.

Ha Van Tue (general part), M.S.M. Sosef (selection of species)

Acronychia carrii
Acronychia ledermannii
Acronychia murina
Acronychia pedunculata
Acronychia pullei
Acronychia rugosa
Acronychia trifoliolata

Tue, H.V. & Sosef, M.S.M., 1998. Acronychia J.R. Forster & J.G. Forster. In: Sosef, M.S.M., Hong, L.T. and Prawirohatmodjo, S. (Editors): Plant Resources of South-East Asia No 5(3): Timber trees; Lesser-known timbers. PROSEA Foundation, Bogor, Indonesia. Database record: prota4u.org/prosea

The following species in this genus are important in this commodity group and are treated separatedly in this database:
Acronychia carrii
Acronychia ledermannii
Acronychia murina
Acronychia pedunculata
Acronychia pullei
Acronychia rugosa
Acronychia trifoliolata