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Record Number

6480

PROSEA Handbook Number

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

Taxon

Xanthostemon F. v. Mueller

Protologue

Hook. Journ. Bot. Kew Gard. Misc. 9: 17 (1857).

Family

MYRTACEAE

Chromosome Numbers

x = unknown; 2n = unknown

Vernacular Names

Philippine ironwood (En, trade name). Indonesia: lara. Papua New Guinea: kasi kasi (trade name).

Origin and Geographic Distribution

Xanthostemon comprises about 50 species. New Caledonia is the richest in species (approximately 35), Australia has about 8 species, and 11 species occur in Malesia (4 in the Philippines, 4 in New Guinea, 2 in Sulawesi and 1 in the Moluccas).

Uses

In the Philippines the wood of X. verdugonianus is considered a luxury timber. It is especially used for posts because of its durability, for salt-water piling, tool handles, rollers, pulleys, bearings, bowling balls and other novelties. The timber of other species (e.g. X. brassii and X. verus) is also rated as very durable and used for house and bridge building, wharves, salt-water piling, rollers, pulleys, fenders, mallets, caulking hammers, and for rudders and anchors of boats. It makes excellent firewood.
The charcoal and sawdust are used medicinally to cure ulcers. The bark is used against diarrhoea.

Production and International Trade

Supplies of Xanthostemon timber are limited, but it is locally in great demand and fetches high prices (e.g. in the Philippines). In 1996 Papua New Guinea exported 455 m3 of "kasi kasi"" logs at an average free-on-board (FOB) price of US$ 90/m3, which is low in comparison with the Philippines.

Properties

Xanthostemon yields a heavy hardwood with a density of (805-)1015-1410 kg/m3 at 15% moisture content. Heartwood red-brown to dark brown turning very dark brown with age, not sharply demarcated from the pale brown or pale yellow sapwood; grain wavy, alternating or interlocked; texture fine to very fine and even; wood lustrous. Growth rings not distinct; vessels very small to moderately small, almost exclusively solitary, somewhat unevenly distributed, often plugged with tyloses or filled with a dark gum and yellowish-white or pink deposits; parenchyma sparse, paratracheal vasicentric and apotracheal diffuse, fairly inconspicuous; rays fine, only visible with a hand lens, paler than surrounding tissue.
Shrinkage is high and the wood requires careful seasoning to prevent warping and twisting. The logs are subject to severe end-checking and need protection. The wood is siliceous and very hard, extremely strong and extremely tough. It is very difficult to work, mortise and saw due its hardness, abrasiveness and the interlocked or spiral grain; a low cutting angle improves the finish. The "glassy"" surface after planing is a special feature. The wood has very good wearing and weathering properties. It is extremely durable, even under the most severe conditions, X. verdugonianus is considered the most durable wood in the Philippines. The heartwood is extremely resistant to preservative treatment and the sapwood is resistant. The wood is almost immune to termite and marine borer attack. The sapwood is non-susceptible to Lyctus.
See also the table on microscopic wood anatomy.

Botany

Shrubs to medium-sized trees up to 30(-40) m tall; bole usually straight, branchless for up to 12 m, up to 50(-150) cm in diameter; bark surface smooth, greyish; branches often low on the bole. Leaves alternate or opposite, simple, entire, exstipulate. Inflorescence an axillary, simple or compound pleiochasium or reduced to a few or a single flower. Flowers with a shallow to deep hypanthium, (3-)4(-5)-merous; sepals and petals free, dotted; stamens numerous, free, not grouped, long and with a gland at the apex; ovary superior or half-inferior, 3-5-locular with many ovules, placentas axile and horizontal or inserted obliquely in basal angles of locules, style 1, long. Fruit a woody, many-seeded capsule opening by valves. Seeds in a ring or arc in each locule, more or less semi-circular, laterally flattened, few fertile.
The trees may be briefly deciduous. X. verus was reported to flower in the Bogor Botanical Gardens (Java) almost throughout the year. X. verdugonianus flowers in the Philippines from July to October. The fruits ripen in 2-3 months. Trees may produce ripe seeds when 2 m tall.
The name Xanthostemon is conserved against Nani (which was published by Adanson in 1763). Nani was formerly considered to be a synonym of the large genus Metrosideros (it was often treated as a section of that genus), but recently proved to be identical with Xanthostemon.

Image

Xanthostemon verdugonianus Naves ex Fernandez-Villar – 1, flowering twig; 2, infructescence.

Ecology

Xanthostemon occurs in lowland rain forest, but often also in savanna forest. X. verdugonianus occurs on sandy and rocky soils, often on steep slopes along the coast, and is usually associated with Shorea, Tristania and other Xanthostemon species.

Silviculture and Management

Xanthostemon can be propagated by seeds or by wildlings. A seed count from South Sulawesi estimated that there are about 960 000 dry seeds/kg. Germination of X. verdugonianus is 30-50% in 7-40 days, the highest germination rate being obtained on a humus medium, but germination on sand is only about 13%. Seedlings attain an average height of 7 cm after 6 months. Wildlings of X. verdugonianus collected in October-November showed only 5% mortality 1 week after transfer to the nursery. Height increment, however, is also very small. In Java a plantation trial of a Xanthostemon sp. from South Sulawesi was not very successful: seedling mortality was high and 10.5 years after planting the average height of the surviving trees was 6 m and the diameter was 7 cm. Regeneration is sparse or absent in closed forest, but can be abundant in open sites (e.g. on landslides or along trails). Growth of Xanthostemon may also be vigorous in open areas on steep sandy slopes and its natural occurrence on rocks prove that it is tolerates low fertility.

Genetic Resources and Breeding

In the Philippines X. verdugonianus is considered to be endangered because it has been subjected to excessive logging due to the high price of its timber. Moreover, it shows poor regeneration and has a limited distribution. The same probably applies to other species such as X. brassii and X. verus. Protective measures are needed to ensure their survival.

Prospects

The future of Xanthostemon timber is uncertain. Because of the heavily depleted stands and/or the rarity of some species the availability may even diminish further unless protective measures are implemented.

Literature

[39]Alberto, E.B. & Doydora, U.B., 1986. Germination media for mangkono. Canopy International 12(5): 12.
[231]Dawson, J.W., 1972. Pacific capsular Myrtaceae 4. The Metrosideros complex: Xanthostemon, Nani, Pleurocalyptus, Purpureostemon. Blumea 20: 315-322.
[300]Eddowes, P.J., 1977. Commercial timbers of Papua New Guinea, their properties and uses. Forest Products Research Centre, Department of Primary Industry, Port Moresby. xiv + 195 pp.
[304]Eddowes, P.J., 1995-1997. The forests and timbers of Papua New Guinea. (unpublished data).
[348]Forest Products Research Centre, 1967. Properties and uses of Papua and New Guinea timbers. Forest Products Research Centre, Port Moresby. 30 pp.
[405]Hardjowasono, M.S., 1942. Gewicht en volume van verschillende vrucht- en zaadsoorten [Weight and volume of various fruits and seeds]. Korte Mededelingen No 20. Bosbouwproefstation, Buitenzorg. 172 pp.
[427]Hellinga, G., 1950. Resultaten van de proeftuinen voor boomgewassen sedert 1937. Loofhoutsoorten II [Results from trial plots for trees since 1937. Deciduous trees II]. Rapport No 27. Bosbouwproefstation, Buitenzorg. 29 pp.
[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.).
[536]Keating, W.G. & Bolza, E., 1982. Characteristics, properties and uses of timbers. Vol. 1. South-East Asia, northern Australia and the Pacific. Inkata Press Proprietary Ltd., Melbourne, Sydney & London. 362 pp.
[632]Kraemer, J.H., 1951. Trees of the western Pacific region. Tri-State Offset Company, Cincinnatti. 436 pp.
[786]Merrill, E.D., 1952. Notes on Xanthostemon F. Mueller and Kjellbergiodendron Burret. Journal of the Arnold Arboretum 33: 150-165.
[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.
[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.
[1080]Swart, J.J., 1942. A monograph of the genus Protium and some allied genera (Burseraceae). Recueil des Travaux Botaniques Néerlandais 39: 211-446.
[1114]Valeton, T., 1901. Icones Bogorienses. Vol. 1. E.J. Brill, Leiden. Tab. 98.
[1228]Wilson, P.G., 1990. A revision of the genus Xanthostemon (Myrtaceae) in Australia. Telopea 3(4): 451-476.
[1229]Wilson, P.G. & Dawson, J.W., 1981. Proposal for the conservation of the generic name Xanthostemon F. Mueller (1857) against Nani Adanson (1763). Taxon 30: 325-327.
[1232]Wisse, J.H., 1965. Volumegewichten van een aantal houtmonsters uit West Nieuw Guinea [Specific gravity of some wood samples from West New Guinea]. Afdeling Bosexploitatie en Boshuishoudkunde, Landbouwhogeschool, Wageningen. 23 pp.
[1257]Yao, C.E. & Ulep, E.V., 1981. Mangkono in Babatngon. The Philippine iron wood. Canopy International 7(12): 5.
[1258]Yao, C.E. & Ulep, E.V., 1983. More on mangkono. Canopy International 9(4): 6-7.

Author(s)

W.G. Keating (general part), E. Boer (general part), M.S.M. Sosef (general part, selection of species)

Xanthostemon bracteatus
Xanthostemon brassii
Xanthostemon philippinensis
Xanthostemon verdugonianus
Xanthostemon verus

Correct Citation of this Article

Keating, W.G., Boer, E. & Sosef, M.S.M., 1998. Xanthostemon F. v. Mueller. 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

Selection of Species

The following species in this genus are important in this commodity group and are treated separatedly in this database:
Xanthostemon bracteatus
Xanthostemon brassii
Xanthostemon philippinensis
Xanthostemon verdugonianus
Xanthostemon verus

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