4115

5(2): Timber trees; Minor commercial timbers

Dacrycarpus (Endl.) de Laubenf.

Journ. Arn. Arb. 50: 315 (1969).

PODOCARPACEAE

x = 10, 20; Dacrycarpus imbricatus: 2n = 20

Trade groups Podocarp: lightweight to medium-weight softwood, e.g. Dacrycarpus cinctus (Pilger) de Laubenf., Dacrycarpus cumingii (Parl.) de Laubenf., Dacrycarpus imbricatus (Blume) de Laubenf.
The timber is traded as podocarp together with that of the genera Nageia, Podocarpus and Prumnopitys. In Indonesia, all Podocarpaceae timber is traded as "melur"".

Podocarp (En, Fr), kajoerapat (En, Am, Fr). Indonesia: jamuju. Malaysia: rempayan (Sabah), landin (Sarawak). Papua New Guinea: high mountain podocarp. Philippines: igem. Burma (Myanmar): thitmin. Thailand: paya, makhampom. Vietnam: thong nang.

Dacrycarpus consists of 7 species and occurs from northern Burma (Myanmar), Indo-China and southernmost China throughout Thailand and Malesia towards Fiji and New Zealand. The greatest diversity is found in New Guinea where 5 species occur. Fossil records from the Eocene are known in New Zealand, Victoria (Australia) and Tasmania.

The wood of Dacrycarpus is used for furniture, panelling, cabinet work, carving, masts, beams, tea chests, face material for blockboard, veneer, utensils and light construction work; it has good qualities for paper manufacture. It is also used for the manufacture of fine engineering instruments (e.g. rulers, T-squares, drawing boards, pencil slats) because of the light and fine grained wood. It is highly valued locally for construction wood.
Copal has been collected by tapping the trees. Dacrycarpus is planted as ornamental; its beautiful needles make it an attractive tree in parks and gardens.

Podocarp timber is generally consumed by the local industry. Export of sawn timber of Dacrycarpus imbricatus from North Sumatra to Singapore in 1978/1979 was only 162 m³ with a value of US$ 16 000. Export of sawn timber of Dacrycarpus imbricatus, mixed with Dacrydium and some other softwoods from Indonesia was 661 m³ in 1981 with a value of US$ 147 000. In Papua New Guinea, podocarp timber commands high prices and the export of logs is banned to encourage domestic processing.

Podocarp is a lightweight to medium-weight softwood. The heartwood is pale yellow with a greenish tinge or pale golden brown and not clearly demarcated from the sapwood. The density is 380—770 kg/m³ at 15% moisture content. The grain is straight, texture fine and even; wood without figure, lustrous.
A test on the mechanical properties of Dacrycarpus imbricatus var. patulus from Fiji at 12% moisture content showed the following results: the modulus of rupture 77.5 N/mm², modulus of elasticity 9175 N/mm², compression parallel to grain 47 N/mm², shear 10.5—12.0 N/mm², cleavage 38 N/mm radial and 54 N/mm tangential, Janka side hardness 3295—3825 N and Janka end hardness 5585 N.
The rates of shrinkage are moderate: from green to oven dry 3.4% radial and 7.1% tangential for Dacrycarpus imbricatus wood. The wood seasons well with little degrade, but is susceptible to brown-stain caused by the leaching out of a soluble manganese compound.
Podocarp wood is easy to work with machines and hand tools and is easy to saw, but softer boards show a tendency to crumble on end grain. The wood can be planed, shaped, turned, mortised and sanded with good results and to a smooth finish, but the results of boring are sometimes rated as moderate. Generally, the wood holds nails well, but large nails may cause some splitting. The gluing, staining, varnishing and painting properties are satisfactory. The peeling and slicing properties are rated as good with a negligible degrade upon drying; pretreatment is not needed. The wood is suitable for the production of sulphate pulp for paper making.
Podocarp wood is classified as non-durable when used in contact with the ground or exposed to the weather in the lowland tropics. At higher elevations or in a temperate climate, however, it is considered fairly durable. It is susceptible to termite, pinhole borer, longhorn beetle and marine borer attack, but not to Lyctus beetle attack. The sapwood is permeable for preservatives, but the heartwood is moderately resistant to impregnation. Hot soaking of the wood for 1, 2 and 3 hours results in retentions of BFCA active substances of 8.9 kg/m³, 9.4 kg/m³ and 9.5 kg/m³, respectively. Retention of copper-chrome-arsenic preservative is 12.7 kg/m³.
Wood of Dacrycarpus imbricatus contains 52.5% cellulose, 29% lignin, 10% pentosan, 1% ash and 0.3% silica. The solubility is 4.3% in alcohol-benzene, 1.9% in cold water, 2.7% in hot water and 12.3% in a 1% NaOH solution. The energy value of Dacrycarpus imbricatus wood is 20 400 kJ/kg. The wood is resistant to burning.

Dioecious shrubs or small to large trees up to 50 m tall; bole cylindrical; bark on older trees breaking off into small, thick plates or sometimes short strips, bark surface rough with occasional lenticels, dark brown or blackish but becoming grey, inner bark pink to reddish-brown. Leaves arranged spirally, lanceolate or sometimes triangular, flattened, broadly decurrent, apiculate, with stomata on both surfaces; juvenile leaves spreading at about 60° and giving the shoot a feather-like appearance, falcate but with the apex curved and pointing parallel to the shoot, flattened and usually keeled on both surfaces; adult leaves not distichous, shorter and more robust than the juvenile leaves. Fertile structure terminal on short, mostly lateral shoots, the seed-bearing structure usually on a considerably longer shoot than the pollen cone. Pollen cone elongated, mostly 6—10 mm 2—3 mm; apex of microsporophyll triangular, acute to apiculate. Seed-bearing structure solitary, with an involucre of sharply elongated leaves at the base, composed of a small warty receptacle which enlarges when mature, fleshy, orange at first becoming red or purple and later brown, bearing 1 or 2 protruding sterile leaf-like bracts and 1 or 2 fertile bracts; inverted ovules fused as a rib along 1 side with the fertile bract. Mature seed spherical to ovate, remaining covered by the leathery epimatium and scale, forming an erect or somewhat oblique dark structure of about 5—6 mm 4.5—5.5 mm. Seedling with epigeal germination.

— Macroscopic characters:
Heartwood straw-coloured, yellow-brown to pale brown, rarely with darker streaks (usually near the pith and resulting from compression wood), often not clearly demarcated from the paler sapwood. Grain straight. Texture fine and even; wood without figure except in samples with tendency to growth rings, lustrous. Growth rings indistinct; diffuse parenchyma rarely evident to the naked eye; rays very fine, not visible to the naked eye.
— Microscopic characters:
Growth rings not clearly marked, tracheid wall thickness in latewood barely different from that in earlywood. Tracheids square, rounded, polygonal to irregular in cross-section, radially aligned, tangential diameter approximately 45—55 µm, 2—6 mm long; intertracheid pits in 1 row, sometimes opposite and paired near the tips, moderately large (14—18 µm in diameter), rounded, rarely flattened due to compression on radial section; smaller pits on tangential walls in latewood tracheids sometimes present, c. 14 µm in diameter. Parenchyma diffuse, moderately abundant to abundant, end walls thin and smooth. Rays 4—8/mm, predominantly uniseriate, biseriate rays rare, (1—)2—35(—40) cells high, end walls smooth; ray-tracheid pits half-bordered, mainly cupressoid to piceoid, medium-sized, 8—10 µm in diameter, 1—2 per crossfield. Ray tracheids absent, resin ducts absent. Reddish-brown extraneous material abundant in parenchyma cells, less in ray cells.
Species studied: Dacrycarpus cinctus, Dacrycarpus imbricatus.
Wood of Agathis, Falcatifolium, Nageia, Phyllocladus, Podocarpus and Prumnopitys may resemble Dacrycarpus. Agathis differs from the other genera by having alternate intertracheid pits. In Phyllocladus and Prumnopitys parenchyma is absent. Falcatifolium, Nageia and Podocarpus are very similar to Dacrycarpus, though the wood of Dacrycarpus tends to have a pinkish tinge.

The annual diameter increment of Dacrycarpus imbricatus in natural forest in the Philippines is 0.7 mm and 2.1 mm for diameter class 0—10 cm and 50—60 cm, respectively. The mean annual height increment of Dacrycarpus imbricatus in a 28-year-old plantation in Java dominated by Schima wallichii (DC.) Korth. ssp. noronhae (Reinw. ex Blume) Bloembergen var. noronhae and a second layer of Altingia excelsa Noroña is 0.3—0.7 m. The mean annual increment in a 7.5-year-old open plantation was 0.9—1.0 m in height and 1.0 cm in diameter.
Dacrycarpus is pollinated by wind. In Thailand Dacrycarpus imbricatus flowers from January to May and the seeds ripen from March to September. Root nodules have been observed, but it is unknown whether nitrogen fixation occurs.

The genus Dacrycarpus was formerly treated as a section within Podocarpus (section Dacrycarpus Endl.). Sterile specimens closely resemble Dacrydium but they can be distinguished by the distinctive dimorphic foliage. Dacrycarpus is thought to be most closely related to Acmophyle (New Caledonia and Fiji) and Falcatifolium (Peninsular Malaysia to New Caledonia) on the basis of resemblance of female reproductive structures and morphology of the leaves.
Chromosomal evolution within the Podocarpaceae seems to have involved fusion and splitting of chromosomes, leading to a wide range of chromosome numbers with a basic number of 10 or 20.

Dacrycarpus generally occurs scattered but sometimes it is common and even dominant, or rarely occurs in pure stands in primary rain forest. It often grows in very humid locations such as poorly drained or boggy sites, sometimes on river banks or well-drained mountain slopes. Most species occur in submontane or montane habitats at 800—2500 m altitude but may descend almost to sea-level or ascend to 3600 m although at the higher altitudes the trees do not reach exploitable timber sizes.

Dacrycarpus can be propagated by seed or cuttings. Dacrycarpus imbricatus has about 16 000 dry seeds/kg. In this species, 59% of the seeds germinated in 16—63 days in Peninsular Malaysia; a germination rate of 88—98% has been reported for the Philippines. Exposure to the sun for 6—18 hours prior to sowing enhanced germination significantly.
The moisture retention capacity of the medium used in the nursery should be very high. Early development of Dacrycarpus is slow. Although natural regeneration is generally scarce, seedlings can be used to make stumps. The rooting success of short stem cuttings of Dacrycarpus imbricatus with one node, a leaf and an axillary bud from juvenile material was found to be 50%. Wildlings planted at 3 m 2 m in North Sumatra showed a survival of 90%.

In 1890, Dacrycarpus imbricatus was already reported to be in cultivation. Natural regeneration is very difficult, but Dacrycarpus imbricatus is planted in the same way as Altingia excelsa and underplanted in Acacia mearnsii De Wild. in protection forest in Java.
Canopy closure of Dacrycarpus imbricatus in pure plantations takes a long time. Dacrycarpus is one of the most fire-resistant trees in the natural forest of Java.

The mistletoe Korthalsella dacrydii (Ridley) Dans. has been observed on Dacrycarpus, but its importance is probably insignificant.

Felling with strips of 20 m wide left untouched to diminish erosion and to favour establishment of natural regeneration is recommended for Dacrycarpus imbricatus forest in Java on erodible sandy soils; the conventional selective cutting system has been abandoned. Forest containing Dacrycarpus imbricatus is difficult to exploit as the rugged topography poses problems when conventional machinery is used. Wire skidding is used for log extraction.

The exploitable timber volume of a montane forest in West Java dominated by Dacrycarpus imbricatus is estimated at 300 m³/ha. Individual trees with a diameter of 41 cm at breast height and a clear bole height of 12 m have an estimated timber volume of 1.2 m³, and trees with a diameter of 102 cm and a clear bole height of 18 m have 9.9 m³.

As the timber is non-durable, it should be converted as soon as possible after felling.

Large-scale exploitation of Dacrycarpus is not possible because it occurs in not easily accessible forest. Species are locally common, but may have a restricted area of distribution. Therefore, it is expected that genetic resources are generally satisfactorily conserved. In-situ and ex-situ conservation of Dacrycarpus imbricatus in the South-East Asian region is found in national parks and in botanical gardens.

The quality of the wood is valued locally, and mature trees can no longer be found close to human settlements. Research into small-scale silvicultural management of forest containing Dacrycarpus may increase its utilization beyond the local level.

Bakhoven, A.C., 1930. Vul-, drijf- en dekkingshout in wildhoutbergculturen, dan wel, de in bergwildhoutculturen in te brengen houtsoorten voor blijvend onderbestand en ondergroei [Auxiliary, nursing and soil-covering tree species in the non-teak plantations in the mountains and tree species to mix in the non-teak plantations in the mountains to form a permanent understorey tree layer and undergrowth]. Tectona 23: 558-569.
de Laubenfels, D.J., 1969. A revision of the Malesian and Pacific rainforest conifers, I. Podocarpaceae, in part. Journal of the Arnold Arboretum 50: 315-337.
de Laubenfels, D.J., 1988. Coniferales. In: van Steenis, C.G.G.J. & de Wilde, W.J.J.O. (Editors): Flora Malesiana. Ser. 1, Vol. 10. Kluwer Academic Publishers, Dordrecht, Boston, London. pp. 374-384.
Gaussen, H., 1974. Les Gymnospermes actuelles et fossiles. Chapitre 20: Les Coniférales 12. Les Podocarpacées autres que Podocarpus s.s. [Contemporary and fossil gymnosperms. Chapter 20: The Coniferales 12. The Podocarpaceae excluding Podocarpus s.s.]. Travaux du Laboratoire Forestier de Toulouse. Tom. 2, Etudes dendrologiques. Vol. 1, part. II-3. pp. 133-166.
Hair, J.B. & Beuzenberg, E.J., 1958. Chromosomal evolution in the Podocarpaceae. Nature 181: 1584-1586.
Keng, H., 1983. Coniferae. In: Whitmore, T.C. (Editor): Tree flora of Malaya. A manual for foresters. 2nd edition. Vol. 1. Malayan Forest Records No 26. Forest Research Institute Malaysia. Longman Malaysia SDN. Berhad, Kuala Lumpur. pp. 39-53.
Page, C.N., 1990. Podocarpaceae. In: Kramer, K.U. & Green, P.S. (Editors): The families and genera of vascular plants I. Pteridophytes and Gymnosperms. Springer Verlag, Berlin, Heidelberg. pp. 332-346.
Soerianegara, I., 1972. Survey orientasi hutan djamudju (Podocarpus imbricatus) di lereng Gn. Tjeremai, Djawa Barat [Preliminary survey of jamuju (Podocarpus imbricatus) forest on the slopes of Mount Ceremai, West Java]. Laporan No 109. Lembaga Penelitian Hutan, Bogor. 8 pp.
Soewarsono, P.H., 1965. Identifikasi kaju-kaju konifer Indonesia jang penting-penting [Identification of important Indonesian conifer woods]. Rimba Indonesia 10: 175-193.
Wasscher, J., 1941. The genus Podocarpus in the Netherlands Indies. Blumea 4: 359-542.
Selection of species

B. Sunarno (general part), E. Boer (properties), J. Ilic (wood anatomy), M.S.M. Sosef (selection of species)

Dacrycarpus cinctus
Dacrycarpus cumingii
Dacrycarpus expansus
Dacrycarpus imbricatus
Dacrycarpus steupii

Sunarno, B., Boer, E., Ilic, J. & Sosef, M.S.M., 1995. Dacrycarpus (Endl.) de Laubenf.. In: Lemmens, R.H.M.J., Soerianegara, I. and Wong, W.C. (Editors): Plant Resources of South-East Asia No 5(2): Timber trees; Minor commercial timbers. PROSEA Foundation, Bogor, Indonesia. Database record: prota4u.org/prosea

The following species in this genus are important in this commodity group and are treated separatedly in this database:
Dacrycarpus cinctus
Dacrycarpus cumingii
Dacrycarpus expansus
Dacrycarpus imbricatus
Dacrycarpus steupii