Maranthes (PROSEA)
Introduction |
Maranthes Blume
- Protologue: Bijdr. fl. Ned. Ind. 2: 89 (1825).
- Family: Chrysobalanaceae
- Chromosome number: x= unknown; 2n= unknown
Vernacular names
- Merbatu (trade name). Liusin (En, Fr), sea beam (En)
- Indonesia: kayu batu (general), kalek kureseng (Sumatra), kolaka (Sulawesi)
- Malaysia: bangkawang (Dusun, Malay, Sabah), merbatu laut (Peninsular), nyalin laut (Sarawak)
- Papua New Guinea: busu plum (En)
- Philippines: liusin (general), alamag (Tagalog), bingas (Iloko)
- Thailand: chi khat phen, chi ot phen (peninsular).
Origin and geographic distribution
Maranthes comprises 12 species, 10 of which occur in tropical Africa, one in Central America and one in peninsular Thailand, throughout the Malesian region, northern Australia, the Solomon Islands and the Caroline Islands. The latter species is M. corymbosa Blume (synonyms: Parinarium corymbosum (Blume) Miq., Parinarium griffithianum Benth., Parinarium palauense Kanehira).
Uses
The wood of Maranthes is used for medium to heavy construction under cover, generally in the round, such as beams, columns and posts. It is also suitable for parquet flooring, cart poles and wheels, package for heavy articles, dunnage and plywood. When treated it can be used for salt-water piling and other marine constructions and ship building. The wood yields a good fuel and excellent charcoal.
The fruit is edible and the seed kernel contains 70-75% oil, which has been applied in the manufacture of paint. In Peninsular Malaysia the tree is planted as an ornamental along roads and avenues.
Production and international trade
Wood of Maranthes is probably traded in mixed consignments of medium-weight timber, or together with that of the genera Atuna and Parinari as "merbatu". Production is generally limited, but a fairly large volume of merbatu is exported to Japan from Papua New Guinea and the Solomon Islands. In 1996 Papua New Guinea exported a fair volume of about 17 500 m3of "busu plum" logs at an average free-on-board (FOB) price of US$ 94/m3.
Properties
M. corymbosa yields a medium-weight to heavy hardwood with a density of 680-1090 kg/m3at 15% moisture content. Heartwood red-brown to dark brown with occasional purplish tinge, not clearly demarcated from the pale brown to straw-coloured sapwood; grain straight to slightly interlocked, occasionally spiral; texture rather coarse but even; watered-silk figure may occur on tangential surface; wood with a sweet odour. Growth rings indistinct; vessels medium-sized to very large, exclusively solitary, with a tendency to oblique arrangement; parenchyma moderately abundant to abundant, apotracheal in narrow bands, distinct to the naked eye, and diffuse-in-aggregates; rays very fine and not distinct to the naked eye; ripple marks absent.
Shrinkage upon seasoning is high; the wood seasons fairly rapidly, but is liable to check and warp. It is very hard and strong. Because of its siliceous nature it is very difficult to saw and work with tools, especially when seasoned; it splits well. It is moderately durable in protected situations. The sapwood is permeable and the heartwood is moderately permeable to impregnation, with a retention of about 350 kg/m3under the pressure treating method. The wood is resistant to dry-wood termites and fairly resistant to marine borers after being pressure-treated, but an outer coat of creosote is recommended for salt-water piling. The sapwood is non-susceptible to Lyctus , but liable to pinhole borer attack.
See also the tables on microscopic wood anatomy and wood properties.
Botany
A medium-sized to fairly large tree up to 40 m tall; bole straight, cylindrical, slightly tapering, branchless for up to 25 m, up to 100(-160) cm in diameter, without buttresses, sometimes spur-rooted; bark surface smooth to shallowly grooved, lenticellate, pale grey-brown, peeling off in large and thick pieces below the crown, inner bark fibrous, pink to red-brown, occasionally with a watery exudate. Leaves arranged spirally, simple, entire, glabrous when mature, with paired glands at the junction of blade and petiole; stipules caducous. Flowers in a many-flowered corymbose panicle, slightly zygomorphic, with an obconical receptacle; sepals 5, unequal; petals 5; stamens 25-35, inserted on one side of the throat of the receptacle and staminodes on the opposite side; ovary inserted laterally at the mouth of the receptacle, 2-locular with 1 ovule in each cell, style basal. Fruit a large, fleshy, smooth drupe, ripening dark purple and with hairs between seed-coat and endocarp. Seedling with epigeal germination; cotyledons emergent; hypocotyl elongated; scale leaves absent; first 2 leaves opposite, subsequent ones alternate.
In a perhumid climate trees measured on average 10.9 m in height and 9.6 cm in diameter after 6 years. For a seasonal climate these figures were 17.8 m and 18.5 cm respectively, after 10.5 years. In West Java flowering is from July to October and ripe fruits have been observed from September to December. In Peninsular Malaysia the trees may flower twice a year. Fruits are eaten and dispersed by birds, e.g. hornbills and fruit pigeons, and are also scatter-hoarded by squirrels.
The family Chrysobalanaceae has sometimes been treated as a subfamily of the Rosaceae .
Ecology
M. corymbosa is generally found in sandy or rocky coastal areas, sometimes more inland in primary and secondary forest up to 600(-1500) m altitude. In Australia it has also been observed in gallery forest.
Silviculture M. corymbosa can be propagated by seed. There are about 335 dry seeds/kg. Germination tests in Peninsular Malaysia showed 22% germination of cleaned stones in 3-12 months and 14% germination of whole fruits in 5-12 months. Seeds are sown under shade and seedlings can be planted out 5 months later when they have attained 15 cm. Seedlings do not tolerate stumping before planting. In Indonesia the seedlings are planted at 1 m × 3 m with Leucaena leucocephala (Lamk) de Wit as a cover crop between the lines. The canopy closes at 2 years and the first thinning is done after 4 years. The mean annual increment excluding yield from thinnings for the first ten years is 8 m3/ha. Under natural conditions, seedlings establish themselves and grow up in dense forest; therefore planting on open sites is not recommended.
Genetic resources and breeding
As M. corymbosa occurs throughout and beyond Malesia, the risk of genetic erosion posed by logging is very low.
Prospects
M. corymbosa is too hard and too difficult to work to become a valuable sawn timber. The use of round logs for marine construction and posts and poles, especially when pressure-treated, will probably remain important in the near future.
Literature
40, 151, 161, 162, 163, 198, 209, 267, 300, 301, 304, 341, 346, 348, 405, 426, 427, 464, 536, 615, 741, 757, 829, 831, 861, 905, 933, 934, 1039, 1048, 1221, 1239, 1242, 1248.
G.T. Prance