Chionanthus (PROSEA)
Introduction |
Chionanthus L.
- Protologue: Sp. pl. 1: 8 (1753); Gen. pl., ed. 5: 9 (1754).
- Family: Oleaceae
- Chromosome number: x= 23; 2n= 46 for several non-Malesian species
Vernacular names
- Malaysia: kayu buda (Kayan, Sarawak), mok, sapah (Iban, Sarawak)
- Philippines: karaksan (Filipino)
- Vietnam: săng.
Origin and geographic distribution
Chionanthus comprises about 120 species mostly confined to the tropics and subtropics with a few representatives in temperate regions. Some 55 species occur within the Malesian region, which serves as a major centre of diversification.
Uses
Chionanthus wood is used locally for general construction (planks, posts) and boat building and is suitable for small articles requiring a hard, heavy and fine-textured wood like chisel handles, bowling pins, boot and shoe lasts, bobbins, shuttles, spindles and piano parts. The heartwood of C. laxiflorus is used for carving tobacco pipes. C. curvicarpus provides an excellent firewood.
Production and international trade
The use of Chionanthus wood is limited and on a local scale only.
Properties
Chionanthus yields a medium-weight hardwood with a density of 480-865 kg/m3at 15% moisture content. Heartwood pale brown to red-brown, sometimes with darker streaks, generally sharply demarcated from the up to 3 cm wide, straw-coloured sapwood which occasionally has a pink tinge; grain straight to slightly interlocked; texture fine to moderately fine and even; wood with slight watered-silk figure on longitudinal surface. Growth rings indistinct to distinct, boundaries indicated by marginal bands of parenchyma; vessels moderately small to medium-sized, some solitary but mostly in radial multiples of 2-4(-12), sometimes in clusters, white or yellow deposits sometimes present; parenchyma moderately abundant, scanty paratracheal, vasicentric to aliform and apotracheal in marginal or seemingly marginal bands; rays very fine or moderately fine, visible with a hand lens; ripple marks absent.
The wood is moderately hard to hard and moderately strong. It is non-durable. The wood is susceptible to blue stain. The sapwood is probably susceptible to Lyctus .
The mean fibre length is 1.26-1.51 mm.
See also the table on microscopic wood anatomy.
Botany
Evergreen, small to medium-sized or rarely large trees up to 30(-50) m tall, rarely shrubs or climbers; bole straight, up to 65 cm in diameter, occasionally slightly fluted or with small buttresses up to 1 m high; bark surface usually smooth, sometimes flaky or scaly, sometimes lenticellate, white to dark grey or brown, inner bark light to orange-brown or red, without exudate. Leaves opposite, simple, entire, exstipulate. Inflorescence axillary, paniculate or cymose, sometimes condensed and fasciculate. Flowers small, bisexual or rarely unisexual, white or yellow, rarely red; calyx 4-lobed; petals 4, usually basally fused in pairs or rarely with a short tube ( C. ramiflorus ); stamens 2 or rarely 4; ovary superior, 2-locular with 2 ovules in each cell, stigma almost sessile, capitate or obscurely 2-lobed. Fruit a 1(-3)-seeded drupe. Seed with thin testa. Seedling with hypogeal ( C. evenius ), semi-epigeal ( C. virginicus L.) or epigeal (American and African species) germination. In C. evenius the cotyledons are not emergent, the hypocotyl not elongated and the epicotyl bears about 2 pairs of subopposite scales followed by opposite or subopposite leaves.
Some species (e.g. C. laxiflorus ) produce flushes of new shoots throughout the year, with the flowers sometimes developing before the new leaves. Others (e.g. C. ramiflorus ) flower and fruit throughout the year, whereas still others (e.g. C. callophyllus , C. cuspidatus Blume) flower in February-March and fruit in May to December. The fruits are probably dispersed by birds.
The genus Linociera has been incorporated into Chionanthus .
Ecology
Chionanthus is generally encountered as an understorey tree in evergreen, primary, lowland or hill forest, but is never common. A few species are confined to peat-swamp forest (e.g. C. evenius ) or montane forest, up to 2500 m altitude. The widespread C. ramiflorus also occurs in secondary and coastal forest.
Silviculture Chionanthus can be propagated by seed. In C. ramiflorus there are about 1300 dry stones/kg. Sown stones of C. evenius have a germination rate of about 95% in 24-81 days. Chionanthus is usually not fire-resistant.
Genetic resources and breeding
Apart from some individual trees in botanic gardens there are no records of ex situ conservation of Chionanthus . As Chionanthus is used only locally, it does not seem liable to genetic erosion.
Prospects
Chionanthus is hardly used locally, indicating poor potential. Other species within the Oleaceae such as Fraxinus griffithii C.B. Clarke (which is used for carving in the Philippines) or Olea paniculata R. Br. (which has potential as a timber in monsoon regions) may have better prospects.
Literature
67, 70, 163, 209, 235, 238, 267, 348, 405, 436, 553, 559, 560, 561, 562, 779, 780, 783, 829, 831, 1038, 1052, 1054, 1221, 1222.