Dacryodes (PROSEA)
Introduction |
Dacryodes Vahl
- Protologue: Skr. Naturhist.-Selsk. 6: 116 (1810).
- Family: Burseraceae
- Chromosome number: x= unknown; 2n= unknown
Vernacular names
- Kedondong (trade name)
- Indonesia: kenari
- Malaysia: kerantai (Peninsular), seladah (Iban, Sarawak), upi (Sarawak)
- Philippines: kamingi (Tagalog).
Origin and geographic distribution
Dacryodes comprises about 40 species distributed in tropical America (2 species), tropical Africa (about 22 species) and tropical Asia (16 species). In the latter area it occurs in the Nicobar Islands, southern Vietnam, Peninsular Malaysia, Singapore, Sumatra, western Java, Borneo, the Philippines and North Sulawesi.
Uses
The wood of Dacryodes is used for general light or temporary construction under cover (e.g. for doors, window frames, planking, cladding, shuttering, light duty flooring) and for utility furniture, packing cases, pallets and agricultural implements like rice pounders. It is suitable for the production of veneer and plywood and has been applied for the manufacture of particle board.
The pulp of the fruit of D. macrocarpa , D. expansa (Ridley) Lam and D. rostrata is edible; in Brunei the latter has even been cultivated for its fruits whereas its resin is used to make torches. Leaves of D. kingii (Engl.) Kalkman are reputed to be used as thatch.
Production and international trade
Dacryodes timber is traded together with that of many other Burseraceae genera as "kedondong", but comprises only a small proportion of the total amount traded. In 1992 the export of kedondong from Sabah amounted to 2500 m3of sawn timber and 12 000 m3of logs with a total value of about US$ 1.3 million (US$ 170/m3for sawn timber, US$ 69/m3for logs).
Properties
Dacryodes yields a medium-weight to heavy hardwood with a density of 520-1040 kg/m3at 15% moisture content. Heartwood pale pink-brown, slightly darkening on exposure, not clearly differentiated from the 2-4 cm wide paler sapwood; grain interlocked, occasionally straight or wavy; texture fine to moderately coarse and even; wood with red-brown speckles due to the rays. Growth rings indistinct; vessels moderately small to medium-sized, solitary or rarely in radial multiples of 2-4, tyloses present; parenchyma sparse, paratracheal vasicentric but inconspicuous; rays extremely fine to moderately fine; ripple marks absent; radial canals containing a black, oily substance present in D. incurvata , D. rostrata and D. rubiginosa .
Shrinkage of the wood upon seasoning is low; the wood seasons well but is liable to warp and check if not carefully handled. The wood is hard, fairly strong and tough. It is difficult to saw as it contains silica but it planes well and takes a very high polish. Immediately after sawing the wood should be treated with anti-stain chemicals. The wood is non-durable when exposed to the weather or in contact with the ground. The heartwood is very resistant to impregnation, the sapwood is permeable. The heartwood is susceptible to dry-wood termites. The sapwood is susceptible to Lyctus .
See also the table on microscopic wood anatomy.
Botany
Evergreen, dioecious, small to fairly large trees up to 30(-45) m tall; bole usually cylindrical, straight, up to 100(-120) cm in diameter, sometimes with small thin buttresses up to 2(-3.5) m high, sometimes stilt-rooted; bark surface smooth to scaly, lenticellate, greenish-brown, inner bark orange, yellowish-white or pink, with little clear or rarely white exudate. Leaves arranged spirally, imparipinnate, exstipulate; leaflets 3-15(-31), entire; petiolules swollen at both ends. Flowers in an axillary or terminal panicle, unisexual, 3-merous, small; sepals free or connate, caducous in fruit; petals thickened and inflexed at apex; stamens 6, filaments free or connate with the disk; disk intrastaminal; ovary superior, (2-)3-locular with 2 ovules in each cell, stigma sessile. Fruit an oblong to ellipsoid, 1-seeded drupe; pericarp thick and fleshy, wrinkled when dry. Seedling with epigeal germination; cotyledons emergent, palmately lobed; hypocotyl elongated; first 2 leaves opposite, subsequent ones arranged spirally, at first simple, eventually imparipinnate.
In Borneo Dacryodes flowers in (February-)March-November and bears fruit from (March-)April-December. The flowering-to-fruiting period of D. kingii and D. rostrata is 3 months, that of D. costata 4 months. The fruits are eaten and dispersed by animals.
Dacryodes has been divided into 3 sections, one in each continent. The Asian representatives belong to the section Tenuipyrena Engl.
Ecology
Dacryodes is found in primary or sometimes secondary, evergreen or monsoon forest, often on hills and ridges, occasionally in freshwater or peat-swamp forest, up to 1500 m altitude.
Silviculture Dacryodes can be propagated by seed. In a germination trial in Peninsular Malaysia sown fruits of several species showed 15-45% germination in 18-76 days.
Genetic resources and breeding
As Dacryodes is not rare and species have a fairly wide geographical distribution, there is no risk of genetic erosion.
Prospects
Dacryodes will probably continue to be traded as a minor component of the kedondong trade group.
Literature
15, 46, 70, 151, 162, 163, 198, 238, 267, 341, 436, 512, 526, 543, 553, 651, 740, 749, 780, 800, 829, 830, 831, 861, 934, 974, 1048, 1221, 1242.