6139

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

Premna L.

Mant. pl. 2: 154, 252 (1771).

VERBENACEAE

x = 19; P. latifolia Roxb.: n = 19

Premna (En).

Premna comprises about 200 species occurring in the tropical and subtropical regions of the Old World. Most species are found in Asia, from Sri Lanka and India to Indo-China, China, Japan, Thailand, throughout the Malesian region, northern Australia and Polynesia. Some species are cultivated in Europe, North and South America, New Zealand and southern Australia.

The wood of Premna is used for general construction, house building (mainly as posts), household implements, agricultural implements and paddles; it might be suitable for furniture. In India it is generally used for turning, carving, weaving shuttles and bobbins. The nicely figured root wood has also been used for knife handles.
Several species are well-known for their medicinal properties. The roots of P. cordifolia are applied medicinally against shortness of breath, its roots and leaves against fever, and the young sprouts are edible. P. serratifolia is occasionally grown as hedge. Its bark is used for binding whereas the boiled leaves are eaten with fish and by women to stimulate milk production. A decoction of the leaves of P. cumingiana has been used as a remedy for dropsy and also as a diuretic. The sap obtained from the bark of P. tomentosa is used against diarrhoea; a decoction of its roots is applied against stomach-ache; the pounded leaves may be used to treat wounds in animals. In the Philippines a decoction of the roots, leaves, flowers and fruits of P. odorata is used as a sudorific and is said to be carminative.

Mainly due to the small size of Premna trees, use is on a local scale only.

Premna yields a medium-weight to heavy hardwood with a density of 535-860(-960) kg/m³ at 15% moisture content. Heartwood pale yellow to pale brown, not clearly differentiated from the sapwood; grain straight or interlocked; texture fine and even; wood with slight silver grain. Growth rings distinct, boundaries indicated by marginal parenchyma, sometimes latewood clearly denser than earlywood; vessels moderately small to medium-sized, solitary and in radial multiples of 2-4, open or with tyloses; parenchyma abundant, apotracheal in marginal bands conspicuous to the naked eye, paratracheal vasicentric, with the slightest tendency to aliform; rays very fine to moderately broad, the latter producing the silver grain; ripple marks absent.
The wood is hard and fairly strong to strong. It is moderately durable but susceptible to sap-stain. The heartwood of P. odorata is resistant to dry-wood termites. The sapwood is non-susceptible to Lyctus.
The gross energy value of the wood of P. nauseosa Blanco is 19 740-20 735 kJ/kg.
See also the table on microscopic wood anatomy.

Shrubs (sometimes lianescent) or small to occasionally medium-sized trees up to 20(-30) m tall; bole up to 30(-60) cm in diameter, often fluted, without buttresses; bark surface slightly fissured and flaky, greyish or pinkish, inner bark without exudate. Leaves decussate, simple, with reticulate venation, rather foetid odour when crushed, margin entire to dentate; stipules absent. Flowers in a terminal, cymose, often much-branched inflorescence, small, zygomorphic, bisexual; calyx tubular or somewhat campanulate, often slightly 2-lipped with 2-5 teeth; corolla 2-lipped, with a short tube and 4-5 lobes; stamens 4, of 2 lengths, exerted, inserted on the corolla tube; ovary superior, 4-locular with 1 ovule in each cell, style filiform with 2 small stigmatic lobes. Fruit a small globose to obovoid drupe with a hard 4-celled kernel, seated on the persistent calyx. Seed without endosperm. Seedling with epigeal germination; cotyledons emergent, leafy; hypocotyl elongated; leaves opposite, conduplicate.
In the Philippines a mean annual diameter increment of 0.9 cm has been recorded for P. cumingiana and 2.1 cm for P. odorata. A mean annual increment of 0.6-1.3 cm was determined from wood samples of P. tomentosa originating from India. P. serratifolia is deciduous; on Henderson Island (South Pacific) it remained leafless for about 2 months. In Java P. tomentosa has been observed with flowers almost all year round. Pollination is by insects.
The taxonomy of many of the Malesian Premna species is still poorly understood, and the genus is in need of a thorough revision. P. nauseosa is probably identical to P. dallachyana, but as the type specimen of the former has been destroyed, this remains uncertain. Premna is closely related to Gmelina but can be readily distinguished by its short and cylindrical corolla tube.

Timber-yielding Premna species are usually found in open secondary forest or thickets, up to 800 m altitude. They occur in a wide variety of habitats including sandy seashores and peat-swamp forest.

Premna can be propagated by seed. Sown fruits of P. serratifolia showed about 60% germination in 12 days to 5 months. The short and often deeply fluted bole strongly diminishes the value of Premna as a timber.

There are no records of Premna in seed or germplasm banks. As the timber-yielding species usually have a wide ecological range it is unlikely that genetic erosion is a major risk.

The use of Premna for timber is unlikely to increase in the near future.

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[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.).
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[648]Lam, H.J., 1919. The Verbenaceae of the Malayan Archipelago, together with those from the Malayan Peninsula, the Philippines, the Bismarck Archipelago and the Palau-, Marianne- and Caroline-Islands. M. de Waal, Groningen. 370 pp. + 3 plates.
[653]Lam, H.J. & Bakhuizen van den Brink, R.C., 1921. Revision of the Verbenaceae of the Dutch East Indies and surrounding countries. Bulletin du Jardin Botanique, Buitenzorg, Série III, vol. 3: 1-116.
[813]Munir, A.A., 1984. A taxonomic revision of the genus Premna L. (Verbenaceae) in Australia. Journal of the Adelaide Botanic Gardens 7: 1-44.
[829]Ng, F.S.P., 1991-1992. Manual of forest fruits, seeds and seedlings. 2 volumes. Malayan Forest Record No 34. Forest Research Institute Malaysia, Kepong. 997 pp.
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[934]Reyes, L.J., 1938. Philippine woods. Technical Bulletin No 7. Commonwealth of the Philippines, Department of Agriculture and Commerce. Bureau of Printing, Manila. 536 pp. + 88 plates.
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[1038]Smitinand, T., 1980. Thai plant names. Royal Forest Department, Bangkok. 379 pp.
[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.

Rusea Go

Premna adenosticta
Premna cordifolia
Premna cumingiana
Premna dallachyana
Premna odorata
Premna serratifolia
Premna tomentosa

Go, R., 1998. Premna L.. 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:
Premna adenosticta
Premna cordifolia
Premna cumingiana
Premna dallachyana
Premna odorata
Premna serratifolia
Premna tomentosa