Cleistanthus (PROSEA)
Introduction |
Cleistanthus Hook. f. ex Planch.
- Protologue: Hooker's Icon. pl. 8: t. 779 (1848).
- Family: Euphorbiaceae
- Chromosome number: x= 11;C. collinus(Roxb.) Benth.:n= 11
Vernacular names
- Indonesia: asam-asam (Sumatra), asam gunung (Indonesian, Kalimantan), bajar buhu (Kutai, Kalimantan)
- Vietnam: cọc rào, vừng tàu.
Origin and geographic distribution
Cleistanthus comprises over 100 species, 30 of which occur in Africa and Madagascar. The rest are found in tropical Asia from India to the Malesian region, Melanesia and northern Australia. The distribution of species within Malesia is as follows: Peninsular Malaysia 34 species, Sumatra 11, Java 3, Borneo 37, the Philippines 22, Sulawesi 4, the Lesser Sunda Islands 7, the Moluccas 5 and New Guinea 9.
Uses
The wood of Cleistanthus is used for temporary construction, native houses, tool handles and household utensils; possibly also for poles and fuel.
The toxic Indian species C. collinus (Roxb.) Benth. is planted for fuel, and its pulp, when mixed with that of other species, is suitable for the production of packaging paper.
Production and international trade
As supplies are generally scarce and trees seldom reach commercial size, Cleistanthus timber is used on a local scale only.
Properties
Cleistanthus yields a medium-weight hardwood with a density of 550-820 kg/m3at 15% moisture content. Heartwood pink-brown with a purple-grey tinge or reddish-grey, not clearly differentiated from the sapwood; grain wavy; texture moderately fine and even. Growth rings absent; vessels moderately small, mostly in radial multiples of 2-4; parenchyma sparse, apotracheal diffuse to diffuse-in-aggregates, difficult to see even with a hand lens; rays moderately fine, barely visible to the naked eye; ripple marks absent.
The wood is moderately hard and fairly strong. It is probably only slightly durable when exposed to the weather or in contact with the ground.
See also the table on microscopic wood anatomy.
Botany
Monoecious shrubs and usually small or rarely medium-sized trees up to 20(-40) m tall; bole straight to crooked, up to 50 (very rarely to 150) cm in diameter, rarely with small buttresses. Leaves alternate, simple, entire, usually with lax and more or less reticulate tertiary venation, often glaucous below; stipules small. Inflorescence axillary, fasciculate-glomerate, male, female or bisexual. Flowers very small, 5-merous; sepals valvate; petals smaller than sepals; disk annular or cupular. Male flower with stamens united below into a column; pistillode very small, borne at the apex of the column. Female flower with a superior, (2-)3(-4)-locular ovary with 2 ovules in each cell, styles 3, simple, bifid or twice bifid. Fruit a lobed, mainly 3-locular capsule with 2 seeds per locule.
Ecology
Most Cleistanthus species occur in the lower strata of primary evergreen rain forest or less often monsoon forest, up to 700(-1100) m altitude. They may be locally common but scattered in dipterocarp forest, kerangas, less frequently in swamp forest, and occur on a wide variety of soils including limestone soils.
Silviculture Most Cleistanthus species appear to be fire-resistant.
Genetic resources and breeding
Deforestation may endanger those Cleistanthus species with a limited area of geographic distribution.
Prospects
Since supplies are limited no increase in the use of Cleistanthus wood is foreseen.
Literature
26, 28, 31, 32, 33, 34, 36, 70, 162, 163, 174, 267, 391, 436, 481, 543, 795, 834, 835, 861, 883, 974, 1038, 1195, 1221, 1232.