6266

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

Securinega Comm. ex A.L. Juss.

Gen. pl.: 388 (1789).

EUPHORBIACEAE

x = 13; S. virosa (Roxb. ex Willd.) Baillon: 2n = 26

Philippines: anislag (Filipino), katamangan (Manobo), malagau (Butuan).

Securinega comprises some 20-25 species occurring in tropical and subtropical regions of the world. Four species are found within Malesia but only one, S. flexuosa (Müll. Arg.) Müll. Arg. (synonyms: S. acuminatissima (C.B. Rob.) C.B. Rob., S. keyensis Warb., S. samoana Croizat), is used as a timber. It occurs in the Philippines, the Sula Islands, the Kai Islands, New Guinea (Irian Jaya), the Solomon Islands, New Caledonia, Fiji, Samoa and Vanuatu.

In the Philippines the wood of S. flexuosa is locally highly valued for house and fence posts, and additionally used for joists, rafters and tool handles. It also yields a good fuelwood.
In the Solomon Islands, where it is important for house posts, it is regarded as a potential multipurpose and community forest tree and may be important in future reforestation programmes. Pollen and nectar (honey) can be obtained from the flowers. The leaves are used for staining. The bark is applied medicinally in a fever-reducing drink.

Supplies are very limited and the wood of S. flexuosa is used on a local scale only.

S. flexuosa yields a heavy hardwood with a density of 810-935 kg/m³ at 15% moisture content. Heartwood pale yellowish-brown, hardly distinguishable from the up to 3 cm wide pale sapwood; grain straight; texture moderately fine; wood fairly lustrous; wood with a bitter taste. Growth rings indistinct, occasionally colour differences indicate growth ring boundaries; vessels very small to medium-sized, mostly in radial multiples of 2-4(-6), in radial arrangement, most vessels blocked by tyloses; parenchyma absent; rays moderately broad, tending to 2 distinct widths; ripple marks absent.
The wood is hard and strong but somewhat brittle. It finishes well, is durable and not susceptible to fungal or dry-wood termite attack. The sapwood is non-susceptible to Lyctus.
See also the table on microscopic wood anatomy.

A deciduous, dioecious shrub or small or rarely medium-sized tree up to 10(-30) m tall; bole often irregular, branchless for up to 6 m, up to 30(-50) cm in diameter, sometimes with indistinct buttresses; bark surface smooth, becoming fissured and scaly with age, peeling in small, thin strips, lenticellate, pale grey to pale brown. Leaves arranged spirally but distichous on twigs, simple, entire, with short petioles; stipules small. Flowers in an axillary fascicle, unisexual, small, whitish or greenish-yellow; sepals 5; petals absent. Male flowers with 3-5 stamens; disk composed of 5 glands; pistillode present. Female flowers with an annular, crenate disk; ovary superior, 3-locular with 2 ovules in each cell, styles short, connate at base, stigmas deeply 2-lobed or double 2-lobed. Fruit drupaceous, many in clusters, fleshy, red turning black when ripe. Seed angled.
Growth is reputed to be fast. In the Philippines flowering has been observed in January and in May-June, fruiting in January and May. In the Pacific it flowers and fruits several times a year and has been recorded to bloom in January, April, July and September. The fruits are taken and dispersed by birds.
There is some dispute about whether the genus Securinega should include Flueggea. When two distinct genera are recognized, the Malesian species refer to the latter genus.

S. flexuosa has been found in primary forest at low altitudes and in dense shrub savanna. It is often a pioneer growing in river floodplains, fallowed fields and abandoned coconut plantations. It grows well on nutrient-poor soils.

S. flexuosa is a light-demanding tree.

In the Philippines the highly esteemed wood of S. flexuosa has been sought after and, therefore, the risk of genetic erosion is high.

The timber of S. flexuosa will probably not gain commercial interest, but local importance for house construction and firewood may increase. Moreover, its rapid growth, outstanding form and heavy wood combined with non-wood uses make it a promising tree for farmers to plant, especially on infertile soils.

[32]Airy Shaw, H.K., 1980. The Euphorbiaceae of New Guinea. Kew Bulletin Additional Series VIII. Her Majesty's Stationery Office, London. 243 pp.
[33]Airy Shaw, H.K., 1981. An alphabetical enumeration of the Euphorbiaceae of the Philippine islands. Royal Botanic Gardens, Kew. 56 pp.
[36]Airy Shaw, H.K., 1983. The Euphorbiaceae of Central Malesia (Celebes, Moluccas, Lesser Sunda Is.). Kew Bulletin 37: 1-40.
[184]Chaplin, G.E., 1993. Silvicultural manual of the Solomon Islands. Solomon Islands Forest Record 6 (Overseas Development Administration Forestry Series 1). National Resources Institute, Chatham Maritime. 305 pp.
[185]Chaplin, G.E. & Ngoro, M.L., 1988. The status of Securinega flexuosa in Solomon Islands - an appropriate species for small scale forestry. Forest Research Note, Forestry Division, Solomon Islands No 46-18/88. v + 14 pp.
[235]de Guzman, E.D., Umali, R.M. & Sotalbo, E.D., 1986. Guide to the Philippine flora and fauna. Vol. 3: Dipterocarps, non-dipterocarps. Natural Resources Management Centre, Ministry of Natural Resources, Quezon City & University of the Philippines, Los Baños. xx + 414 pp.
[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.
[974]Salvosa, F.M., 1963. Lexicon of Philippine trees. Bulletin No 1. Forest Products Research Institute, College, Laguna. 136 pp.
[1195]Webster, G.L., 1994. Synopsis of the genera and suprageneric taxa of Euphorbiaceae. Annals of the Missouri Botanical Garden 81: 33-144.
[1202]Wheatley, J.I., 1992. A guide to the common trees of Vanuatu. Department of Forestry, Port Vila. 308 pp.

P.C. van Welzen

Van Welzen, P.C., 1998. Securinega Comm. ex A.L. Juss.. 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