Castanopsis (PROSEA Timbers)

Plant Resources of South-East Asia Introduction

List of species

Castanopsis (D. Don) Spach

Protologue: Hist. nat. vég. 11: 142, 185 (1841).

Family: Fagaceae

Chromosome number: x= 12; for several non-Malesian species:n= 12, 2n= 24.

Trade groups

Berangan: medium-weight to heavy hardwood, e.g. Castanopsis acuminatissima (Blume) A.DC., C. argentea (Blume) A.DC., C. javanica (Blume) A.DC., C. tungurrut (Blume) A.DC.

It has been reported that locally Lithocarpus spp. and Quercus spp. are traded as berangan timber as well. This may, however, be due to misidentification of the logs.

Vernacular names

• Berangan: saninten (En, Fr)
• Indonesia: saninten
• Malaysia: Malayan chestnut (general), jertek tangga (Peninsular), kata (Sabah)
• Papua New Guinea: New Guinea oak, Papua New Guinea oak, white oak
• Philippines: Philippine chestnut (general). Burma (Myanmar): katia
• Laos: ko¹
• Thailand: ko, ko-nam
• Vietnam: cà ôi.

Origin and geographic distribution

Castanopsis consists of about 120 species and is distributed from north-eastern India towards western China, Korea and Japan, through Indo-China and Thailand, and throughout Malesia except for eastern Java and the Lesser SundaIslands. A single species occurs in south-western North America. Fossil records are available from Europe, North America, Australia and eastern Russia, some of which should, however, be considered with caution, as the genera of Fagaceae are not always easily distinguishable from fossil remains. As the most primitive species are found in South-East Asia, the origin of the genus is thought to be located here.

Most species have only a small distribution area; for example, none of the 15 or so commercial species of Vietnam occur within Malesia.

Uses

Berangan is suitable for medium to heavy construction under cover, house posts, lining, bridges, furniture, cabinet making, interior fittings, panelling, flooring, plywood, sliced veneer, packing cases, pallets, fence posts, mine props, shingles, shakes and boat building. The wood is also used as firewood.

The nuts of several species are eaten raw, cooked, roasted or are used in chocolates and pastries. The bark or the heartwood sometimes yields tannin and rarely also a dye. The twigs are used for mushroom cultivation.

Production and international trade

In Sabah, the log export of berangan in 1987 was 11 500 m³with a value of US$ 700 000 (US$ 61/m³); in 1992 the export amounted to 6200 m³(33% as sawn timber and 67% as logs) with a total value of US$ 700 000 (US$ 197/m³for sawn timber and US$ 72/m³for logs). In Papua New Guinea, the export of logs has been banned and only processed wood, which fetches comparatively high prices, is permitted to be exported.

Properties

Berangan is a medium-weight to heavy and moderately hard wood with a rather uniform appearance. The heartwood is generally pale red or pinkish when freshly cut but it turns to yellowish-brown, brown or dark red-brown upon exposure; it is indistinctly demarcated from the sapwood, which is straw-coloured to pale brown, often with a greenish tinge. The density is (550-)610-850(-975) kg/m³at 15% moisture content. The grain is usually fairly straight but sometimes interlocked, the texture is rather coarse and uneven. The wood is lustrous when freshly cut but it becomes dull with age; it feels somewhat rough, and freshly sawn wood smells of leather.

At 15% moisture content, the modulus of rupture is 75-96 N/mm², modulus of elasticity 11 000-13 400 N/mm², compression parallel to grain 38.5-53.5 N/mm², compression perpendicular to grain c. 5 N/mm², shear 7-8.5 N/mm², cleavage c. 64 N/mm radial and 79.5 N/mm tangential, Janka side hardness 4650 N and Janka end hardness 5500 N.

The rates of shrinkage of berangan are moderate to fairly high: from green to 15% moisture content 1.2-2.3% radial and 2.3-4.5% tangential, and from green to oven dry 3.7-5.1% radial and 6.6-9.6% tangential. The seasoning properties of berangan vary considerably: sometimes the timber seasons fairly rapidly without serious defects, but often it air dries rather slowly and it is liable to splitting, cupping and twisting, especially in wood with interlocked grain. Special care is required with timber of larger dimensions and high initial moisture content. It takes about 2 months to air dry 2 cm thick boards of C. argentea to 17% moisture content. In general, thin stickers should be used in seasoning and stacks must be protected. Honeycombing may develop during kiln drying if fast kiln-drying schedules are used. A recommended kiln schedule is a temperature of 37-62C and corresponding relative humidity of 86% to 38%.

The wood is non-siliceous and easy to fairly difficult to saw. It is very easy to split. Planing is easy to moderately easy and, with some care, the finish is good. When brought to a good finish, the figure is almost invisible, but when polish is applied a fine and beautiful silver-grain figure often becomes visible. Boring, turning, mortising and sanding are rated as easy to moderate. Pre-boring before nailing and screwing is recommended because of the tendency to split. Planed surfaces take paint, varnish and lacquer well; heartwood can be glued satisfactorily. Wood of C. argentea can be peeled into 1.5 mm thick veneer at a peeling angle of 92after boiling for 48 hours, but the veneer is brittle and cannot be rolled. The veneer can be glued with urea-formaldehyde, producing plywood complying with the German standard.

In general, berangan heartwood is rated as moderately durable, but there is a considerable variation between species. In Papua New Guinea the wood is classified as non-durable. Graveyard tests in Malaysia showed severe fungal attack after 2.5 years indicating that this wood is not durable under exposed conditions or in contact with the ground in wet tropical areas. In Indonesia, the fungus Paecilomyces variotis has recently been identified attacking C. javanica wood in graveyard tests. Termite attacks are also recorded, and pinhole borers may attack standing trees. The wood is not resistant to marine borers. The heartwood is reported to vary in resistance to preservative treatment: from extremely resistant to unevenly permeable. The sapwood is easy to treat by the pressure treatment; generally the penetration is complete.

Wood of C. argentea contains 55% cellulose, 26% lignin, 19.5% pentosan and 0.5% ash. The solubility is 5.2% in alcohol-benzene, 3.1% in cold water, 5.2% in hot water and 19.4% in a 1% NaOH solution. The energy value is 19 240 kJ/kg.

Description

Evergreen monoecious small to large trees up to 45 m tall; bole sometimes hoop-marked, branchless for up to 25 m, up to 150 cm in diameter, sometimes buttressed; slash often with bluish discolouring wood; bark surface smooth with shallow fissures and prominentlenticels often in lines, usually grey, inner bark not penetrating the wood. Rooting is superficial and most trees have several suckers growing from their base. Leaves arranged spirally, simple, margin entire or rarely serrulate (but frequently serrulate outside Malesia), glabrous above, sometimes hairy or scaly below; stipules deltoid to linear-acute, small, caducous or rarely persistent. Inflorescence an erect spike, male, female, androgynous or mixed, densely stellate-pubescent, with flowers solitary or in clusters of 3-7 along a rachis; rachis axillary, usually simple, solitary or in dense paniculate clusters on the lateral or subterminal young shoots. Flowers with campanulate perianth, (5-)6(-7)-lobed; male flowers with (10-)12(-15) stamens, with globose anthers and a woolly pubescent rudimentary pistillode; female flowers with 10-12 staminodes and 3-5 styles, conical to terete, with a terminal and punctiform stigma. Cupule completely enclosing the 1-7 fruits, splitting irregularly or into a regular number of segments, variously spiny or warty or with a few undulating ridges, the processes more or less in rings. Fruit an indehiscent nut, more or less rounded with the adjoining sides flat, with a part (the scar) adnate to and a part free from the cupule; wall bony to woody, glabrous to densely yellowish-brown to fulvous tomentulose. Seedling with hypogeal germination; cotyledons non-emergent, hypocotyl not elongated; leaves conduplicate, often reduced to scales at the first few nodes.

Wood anatomy

• Macroscopic characters:

Heartwood yellowish-brown to brown, not distinctly demarcated from the pale yellowish or pale brownish sapwood. Grain straight or shallowly interlocked. Texture moderately coarse to coarse. Growth rings indistinct to fairly distinct. Vasicentric tracheids and paratracheal parenchyma visible with a hand lens as thin white sheaths around the vessels. Apotracheal parenchyma visible with a hand lens on moistened surfaces.

• Microscopic characters:

Growth rings, if present, usually marked by flattened fibres. Vessels in a radial pattern, 2-8/mm²to 6-18/mm², depending on the sample, exclusively solitary, oval, 120-270μm or 90-170μm in tangential diameter; perforations simple; vessel-tracheid pits more or less diffuse, 6-8μm in diameter; vessel-ray and vessel-parenchyma pits gash-like or palisade-like, with strongly reduced borders; tyloses present. Fibres 930-1800μm long, thin-walled to thick-walled (walls 2-6μm thick in C. acuminatissima , 2-3μm thick in C. javanica ), pits scarce and indistinct, minutely bordered, in the radial walls. Vasicentric tracheids, associated with scarce paratracheal parenchyma, with numerous distinctly bordered pits. Paratracheal parenchyma scarce; apotracheal parenchyma reticulate, bands sometimes interrupted, partly 2-3 cells wide; in strands of 4-8 cells. Rays (7-)9-12(-15)/mm, usually uniseriate, but occasionally 2-seriate, 120-440μm high, homocellular (Kribs type homogeneous uniseriate), exclusively composed of procumbent cells. Prismatic crystals present in chambered axial parenchyma cells, usually in chains of 4-8, and in ray cells, where they usually appear single. Silica bodies absent.

Species studied: C. acuminatissima , C. javanica .

Growth and development

Berangan grows slowly. In natural forest, seedlings are about 25 cm tall after 1 year, 2-3 m after 3 years, and 3-4 m after 5 years.

In Sarawak, trees of C. foxworthyi and C. motleyana start flowering at the end of the wet season or early in the dry season, which is around May-June. Anthesis follows in 4-6 weeks, and fruits are mature by October. Generally a large portion of the female flowers does not mature into fruits. In Java the four most common Castanopsis species ( C. acuminatissima , C. argentea , C. javanica and C. tungurrut ) flower from (July-)September-October(-November) and ripe fruits can be found in January-April.

Castanopsis species are entomophilous, and during anthesis the flowers produce fetid odours that attract small insects.

Other botanical information

In the past many specimens were misidentified, mainly due to confusion between Castanopsis , Lithocarpus and Quercus . The latter genus differs from the first two genera in having the umbo of the acorn ringed, and having a lamellate cupule and pendulous male inflorescences. Lithocarpus differs from Castanopsis in having an indehiscent cupule which does not completely enclose the fruit. The broad bark rays penetrating the wood are characteristic of Lithocarpus and Quercus but are absent in Castanopsis .

Often the various species of Castanopsis can only be correctly identified from ripe chestnuts.

Ecology

Berangan occurs in primary or old secondary forest from the lowland to the mid-montane zone. It is usually most common between 1000 m and 1500 m altitude, but may ascend up to 2500 m. The individual species occur on a variety of soils, but not on limestone and rarely tolerate a seasonal climate. The trees are usually found scattered in the lowland and more gregarious or even in pure stands at medium and higher altitudes. In New Guinea, C. acuminatissima sometimes forms almost pure stands or occurs as a co-dominant together with Lithocarpus or Nothofagus species between 1000 and 1500 m, elsewhere also with Anisoptera or Intsia species.

Propagation and planting

The number of seeds varies from 280-1850/kg. The viability ofthe seeds varies among species and ranges from 20-75%. Germination is "delayed"; 50% of the viable seeds do not germinate until after 31-52 weeks. Germination starts after 4 weeks in C. megacarpa , after 14 weeks in C. javanica and after 32 weeks in C. foxworthyi . Covering the seeds with damp cloth or horse manure for 5-6 days enhances the rate and speed of germination. Seeds should be sown in polybags under shade. When the seedlings attain 25 cm they can be planted out in the field at 4 m × 3 m. When planted in containers in the nursery the survival of wildlings after four months will be nearly 100%.

Silviculture and management

Natural regeneration of berangan is very poor; seeds are readily attacked by insect larvae or by fungi and may be eaten by animals. Although seedfall is profuse in mountainous areas of Java, the maximum number of seedlings 15 months after seedfall is no more than 16 per 100 m². Natural regeneration cannot develop in artificial gaps of 1000-3000 m², but in gaps smaller than 1000 m²seedlings may develop and the young trees attain 10 m in height 12 years after cutting. The coppicing ability of C. acuminatissima is good and provides potential for regeneration. C. acuminatissima , C. argentea , C. javanica and C. tungurrut have been planted in mountainous areas of West and Central Java.

C. argentea and C. javanica trees with a bole diameter of 80 cm are still very vigorous. The length of the branchless part of the bole varies considerably depending on the growing conditions.

In lowland Peninsular Malaysia, some Castanopsis species are considered to be weed species, because they suppress regeneration of meranti. Weed species are very fast growing, have large and dense crowns and are persistent, but do not develop into acceptable timber trees.

The litter of Castanopsis decomposes very slowly. In Thailand, in evergreen hill forest consisting mainly of Fagaceae , including C. acuminatissima , only about 60% of the litter decomposed during one year.

Diseases and pests

The roots of young plants are vulnerable to fungal attack. The fungus Paecilomyces variotis causes soft-rot disease and has been identified recently attacking the wood of C. javanica . Dendrophtoe magna Danser is a mistletoe parasitic on C. acuminatissima . Castanopsis fruits are eaten by various animals.

Harvesting

As most berangan species grow on hills or mountain slopes, exploitation should be carried out carefully because of the danger of erosion. Small-scale exploitation followed by immediate planting is advisable.

Yield

In a mixed forest stand in East Kalimantan the timber volume of C. javanica was only 1.3-2.5 m³/ha, while in an almost pure C. acuminatissima stand in montane forest in Papua New Guinea it was 38 m³/ha.

The timber volume was estimated at 8.9 m³for large C. argentea trees (31.5 m tall and 110 cm in diameter), and 4.8 m³for C. tungurrut (29.5 m tall and 80 cm in diameter).

Genetic resources

Several Castanopsis species have very limited areas of distribution and are vulnerable to genetic erosion. Although berangan is generally not cut for timber on a very large scale, deforestation may easily endanger these species, especially in mountainous areas where natural regeneration is very limited.

Prospects

Berangan does not seem to have good prospects for timber production as the wood is not in great demand and is generally not easy to handle. Moreover, the trees are often slow growing.

Literature

• Bolza, E. & Kloot, N.H., 1966. The mechanical properties of 81 New Guinea timbers. Division of Forest Products Technological Paper No 41. Commonwealth Scientific and Industrial Research Organization, Melbourne. pp. 12-15.
• Cockburn, P.F., 1983. Fagaceae. In: Whitmore, T.C. (Editor): Tree flora of Malaya. A manual for foresters. 2nd Edition. Vol. 1. Forest Research Institute Malaysia. Longman Malaysia SDN. Berhad, Kuala Lumpur. pp. 196-208.
• Corner, E.J.H., 1988. Wayside trees of Malaya. 3rd Edition. Vol. 1. Malayan Nature Society, Kuala Lumpur. pp. 327-331.
• Dahms, K.-G., 1982. Asiatische, ozeanische und australische Exporthölzer [Asiatic, Pacific and Australian export timbers]. DRW-Verlag, Stuttgart. pp. 72-74.
• Kaul, R.B., 1986. Evolution and reproductive biology of inflorescences in Lithocarpus, Castanopsis, Castanea, and Quercus (Fagaceae). Annals of the Missouri Botanical Garden 73: 284-296.
• Kramer, F., 1933. De natuurlijke verjonging in Goenoeng Gedeh complex [Natural regeneration in the Gunung Gedeh complex]. Tectona 26: 155-185.
• Malaysian Timber Industry Board, 1986. 100 Malaysian timbers. Kuala Lumpur. pp. 120-121.
• Martawijaya, A., Kartasujana, I., Mandang, Y.I., Prawira, S.A. & Kadir, K., 1992. Indonesian wood atlas. Vol. 2. Forest Products Research and Development Centre, Bogor. pp. 118-122.
• Ng, F.S.P., 1991. Manual of forest fruits, seeds and seedlings. Malayan Forest Record No 34. Vol. 1. Forest Research Institute Malaysia, Kepong. pp. 85-86.
• Soepadmo, E., 1972. Fagaceae. In: van Steenis, C.G.G.J. (Editor): Flora Malesiana. Ser. 1, Vol. 7. Noordhoff International Publishing, Leiden. pp. 265-403.