Baccaurea (PROSEA Timbers)

Plant Resources of South-East Asia Introduction

List of species

Baccaurea Lour.

Protologue: Fl. cochinch.: 641, 661 (1790).

Family: Euphorbiaceae

Chromosome number: x= 13;B. ramiflora:n= 13, 13 + 1B

Vernacular names

• Tampoi (trade name)
• Indonesia: kepundung, menteng, tampui (general)
• Malaysia: tampoi (general), kunau kunau (Sabah), rambai hutan (Peninsular, Sabah)
• Philippines: dilak. Burma (Myanmar): kanaso, mai-mak-hpa
• Laos: fai
• Thailand: mafai, rambai, somfai
• Vietnam: dâu da.

Origin and geographic distribution

Baccaurea comprises about 55 species occurring from India to Indo-China, southern China, the Andaman Islands, Thailand, throughout the Malesian region (except for the Lesser Sunda Islands) towards the Pacific Islands (east to Fiji, Tahiti and Samoa). Some 40 species are found within Malesia and are distributed as follows: Peninsular Malaysia 20 species, Sumatra 22, Java 5, Borneo 2, the Philippines c. 3, Sulawesi c. 5, the Moluccas c. 4 and New Guinea c. 4.

Uses

The wood of Baccaurea is used mainly for poles in native house construction, boat building, wharf piling, furniture (general-utility purposes) and boxes. Additionally, it is suitable for general light construction under cover such as posts, beams, joists and rafters, carving, and for general-utility plywood.

Four Baccaurea species are frequently cultivated for their generally sour-tasting fruits: B. dulcis , B. motleyana , B. racemosa and B. ramiflora . Most other species have edible, but less tasty fruits. Baccaurea species are also considered good support trees for rattan cultivation. The cultivated species are used as shade and avenue trees. The bark of a few species is used, along with other ingredients, to colour silk yellow, red or mauve. The bark is also applied medicinally to treat skin diseases and inflammation of the eyes.

Production and international trade

As the supply of Baccaurea timber is very limited, the wood is utilized on a local scale only.

Properties

Baccaurea yields a medium-weight to heavy hardwood with a density of 630-950 kg/m³at 15% moisture content. Heartwood yellowish-brown, darkening to brown with an orange-yellow or purple-red tinge, not clearly differentiated from the sapwood; grain straight or interlocked; texture moderately fine and uneven due to wide rays; wood with slight silver grain on quarter-sawn surface. Growth rings indistinct, sometimes suggested by darker coloured tissue; vessels moderately small to medium-sized, angular, solitary and in radial multiples of 2-4(-more), tyloses sparse; parenchyma abundant, apotracheal diffuse-in-aggregates; rays of 2 kinds, very fine or medium-sized to moderately broad; ripple marks absent.

Shrinkage is moderate and the wood seasons moderately slowly without serious degrade. The wood is moderately hard and moderately strong. It is reputed to be durable and can be treated with preservatives.

The leaves of B. angulata Merr. and possibly other species accumulate aluminium, rendering them pale when dried.

See also the tables on microscopic wood anatomy and wood properties.

Botany

Evergreen, dioecious, small to medium-sized trees up to 30(-40) m tall; bole straight to rather poorly shaped and/or forked, branchless for up to 20 m, up to 70 cm in diameter, often with small buttresses or prominently fluted; bark very thin, surface shallowly finely dippled or with minute papery scales, red to orange-brown, inner bark softly fibrous, often deep red-brown; crown rather dense. Indumentum of simple to stellate hairs. Leaves arranged spirally, often crowded towards the end of twigs, simple, entire; petiole often long and kneed at the top; stipules early caducous. Inflorescence axillary to cauliflorous; male inflorescence narrowly thyrsoid; female inflorescence narrowly racemose. Flowers unisexual, small; sepals 4-5; petals absent. Male flowers with 4-8 stamens; disk-glands absent or free or connate; pistillode evident. Female flowers somewhat larger; disk absent; ovary superior, 2-5-locular with 2 ovules in each cell, styles bifid. Fruit variably fleshy and indehiscent or sometimes dry and dehiscent, (2-)3(-5)-locular capsule, 1-6-seeded. Seed often enclosed in a juicy, brightly coloured outer layer. Seedling with epigeal germination; cotyledons emergent, leafy, often bilobed; hypocotyl elongated; first pair of leaves opposite or alternate, subsequent ones arranged spirally.

Some species show rhythmic growth, with the branches produced in pseudo-whorls as in Terminalia . Flowering is synchronized, particularly in male trees and takes 2-3 weeks. In Malaysia flowering occurs in January-March and in Papua New Guinea B. papuana flowers in July-August. Flowering and fruiting is annually or biannually. The flowers are pollinated by bees and flies; those of some species are reported as fragrant or with a musky odour. Birds, deer, monkeys and rats eat and disperse the fruits.

The actual morphological origin of the outer seed layer, sometimes erroneously called an aril, is still unknown.

Ecology

Baccaurea species are generally uncommon, but may locally occur as an important element of the lower storey of primary lowland rain forest. They are found in well-drained as well as swampy locations, up to 1000(-1800) m altitude, on a wide range of soils in primary and secondary evergreen rain forest, kerangas and peat-swamp forest.

Silviculture

Baccaurea can be propagated by seed, but some fruit-producing species are also vegetatively propagated by air layering of female trees. Seeds of several species usually germinate in 2-6 weeks after sowing, with a germination rate of over 65%. The germination rate of fruits or seed sown with adhering pulp is less predictable: 3-100% germination in approximately the same time.

Genetic resources and breeding

There are no records of Baccaurea in seed and germplasm banks. In several fruit-producing species there appears to be serious genetic erosion. Harvesting for timber, however, is unlikely to have a great impact on the genetic resource base.

Prospects

Since Baccaurea species are fairly widespread and locally common as lower storey trees in primary forest, there is some scope for increased utilization of the wood for timber and wood-based panels.

Literature

26, 28, 32, 33, 34, 36, 70, 82, 151, 162, 163, 189, 209, 267, 436, 464, 543, 553, 644, 740, 741, 825, 829, 831, 861, 974, 977, 1038, 1043, 1164, 1169, 1195, 1221, 1242, 1259.

Selection of species