3033

11: Auxiliary plants

Peltophorum dasyrhachis (Miquel) Kurz

Journ. As. Soc. Beng. 45(2): 128 (1876), 293 (1877).

LEGUMINOSAE - CAESALPINIOIDEAE

2n = unknown

Caesalpinia dasyrhachis Miquel (1861), Peltophorum grande Prain (1897), Peltophorum tonkinense (Pierre) Gagnep. (1913).

Peltophorum (En). Indonesia: soga (Palembang), petaian (Lampung). Malaysia: batai, jemerelang. Cambodia: trâse:k. Laos: s'a:z kha:m, sa: f'ang, sa: ph'ang. Thailand: nonsi (central), arang (north-eastern). Vietnam: lim x[ej]t, lim v[af]ng.

Peltophorum dasyrhachis is found in Thailand, Indo-China, Peninsular Malaysia, Sumatra and Borneo. It is also cultivated in many other tropical regions, e.g. in Java.

In the first half of the 20th Century, Peltophorum dasyrhachis was used as a shade tree mainly in coffee in Java. In central Thailand it is maintained after bush fallow as a shade tree for fruit trees and for its role in soil improvement. Its use in the reclamation of Imperata cylindrica (L.) Raeuschel grasslands is being tested; in Indonesia and Malaysia, young trees planted in tall Imperata grassland and left untended after planting remained alive, but grew slowly. The red-yellow wood is locally used for planks in house-building, but is of little market value. It is suitable as firewood. Medicinally, the bark is used in an infusion for coughs.

Due to a fairly high content of polyphenolic substances, leaf litter decomposition is slow, allowing a humus layer to build up in the soil. The yellowish-red heartwood is heavy, but brittle and is attacked by termites and boring insects. The weight of 1000 seeds is about 37 g.

A usually deciduous tree, up to 30 m tall, with a straight trunk and rather diffuse crown; root system with well-developed taproot and few superficial lateral roots; trunk up to 70 cm in diameter; bark up to 10 mm thick, reddish-brown inside; young branches reddish-tomentose, glabrescent. Leaves bipinnate, with 5—9 pairs of pinnae and 6—16 pairs of leaflets per pinna; stipules large, bipartite, branches pinnatifid or bipinnatifid; petiole up to 7 cm long, rachis up to 40 cm long, both reddish-pubescent; leaflets oblong-elliptical, 10—25 mm x 4—10 mm, sessile, base acute, obtuse or rounded, apex rounded-emarginate, finely pubescent, glabrescent, rather glaucous below, shiny above. Inflorescence an axillary, unbranched raceme, 15—30 cm long; bracts linear, 10—12 mm long, persisting until flowers open; pedicel 1.7—4 cm long; calyx deeply 5-lobed, lobes ovate, 10—15 mm x 5—6 mm, densely velvety outside, glabrous inside; petals 5, obovate, 15—25 mm x 10—12 mm, spreading, yellow, hairy towards the base inside; stamens 10, free, filaments 10—15 mm long, woolly at base, anthers dorsifixed; ovary sessile, 5 mm long, hairy, 4—8-ovuled, style filiform, 12 mm long. Pod elliptical, sharp-pointed, 10—15 cm x 2—4 cm, flat, with a wing-like extension 4—5 mm broad on each suture, dull-brown when ripe, later blackish, 4—8-seeded, indehiscent, often hanging in bunches below the leaves. Seed flattened oblongoid, 10—12 mm x 5 mm, transversely positioned. Seedling with epigeal germination; hypocotyl 4—6 cm long; cotyledons stalked, 3-nerved, glabrous.
In Malaysia, trees may grow up to 7 m tall with a stem diameter of 5 cm in 2 years. Upon pruning, trees resprout abundantly and form a dense hedge. In Lampung (Indonesia), it does not shed its leaves, flowering takes place during the dry season (September—October) and fruits ripen 1 year later. In Indo-China, flowering is from February to April, while new leaves are formed and fruits ripen from May to November. Seed germinates in abundance after a bush fire.
Peltophorum dasyrhachis (often erroneously spelled 'dasyrrhachis') is related to Peltophorum pterocarpum (DC.) Backer ex K. Heyne, an important source of 'soga' dye. Peltophorum dasyrhachis can be distinguished by its crown that is uneven and not umbrella-shaped, its branched stipules, and its thick, reddish tomentum. The two species have occasionally been confounded in the literature. In northern Vietnam, a form of Peltophorum dasyrhachis occurs with unbranched stipules and early falling bracts, named var. tonkinense (Pierre) K. & S.S. Larsen.

Peltophorum dasyrhachis is found in secondary, deciduous or evergreen forest below 800 m altitude with an annual rainfall of 1500—2500 mm. It is mainly found on ultisols. Due to its relatively deep rooting system, it is drought tolerant. Its hairiness and fairly thick bark have been associated with its tolerance of fire.

Peltophorum dasyrhachis is propagated by seed or cuttings. It has been tested as a tree in alley-cropping systems. When unpruned, it provides a rather dense shade to control weeds during fallow periods, and can be managed in hedges without too much shading of inter-row crops. Because its growth rate is slower than that of Leucaena leucocephala (Lamk) de Wit and Gliricidia sepium (Jacq.) Kunth ex Walp., it requires less frequent pruning. When hedges were pruned 2—4 times per year, an annual yield of prunings of 8 t/ha was found in Lampung (Indonesia), containing 200 kg nitrogen. The slow rate of decomposition of the leaves reduces erosion and contributes to the suppression of weeds. Seeds of Imperata cylindrica hardly germinate in soil covered by the leaves.
Few insects have been recorded as damaging the leaves, whereas large stem-boring insects attack older trees.

No germplasm collections or breeding programmes are known to exist for Peltophorum dasyrhachis.

Preliminary research has indicated the potential of Peltophorum dasyrhachis as an initial tree-cover in Imperata grasslands and as a first step in the reclamation of degraded land. This needs confirmation by further experimentation. Its possible suitability as a tree for alley cropping also requires further investigation.

Ding Hou, 1996. Caesalpiniaceae. Peltophorum. In: Flora Malesiana. Series 1, Vol. 12. Foundation Flora Malesiana, Rijksherbarium, Leiden University, Leiden, the Netherlands. pp. 650-654.
Hairiah, K., van Noordwijk, M., Santoso, B. & Syekhfani, M.S., 1992. Biomass production and root distribution of eight trees and their potential for hedgerow intercropping on an ultisol in Lampung. Agrivita 15: 54-68.
Handayanto, E., Cadisch, G. & Giller, K.E., 1994. Nitrogen release from prunings of legume hedgerow trees in relation to quality of the prunings and incubation method. Plant and Soil 160: 237-248.
Handayanto, E., Nuraini, Y., Purnomosidi, P., Hanegraaf, M., Agterberg, G., Hassink, J. & van Noordwijk, M., 1992. Decomposition rates of legume residues and N-mineralization in an ultisol in Lampung. Agrivita 15: 75-86.
Larsen, K., Larsen, S.S., 1980. Leguminosae (Fabaceae), Caesalpinioideae. Peltophorum. In: Vidal, J.E. & Vidal, Y. (Editors): Flore du Cambodge du Laos et du Vietnam. Vol. 18. Muséum National d'Histoire Naturelle, Laboratoire de Phanérogamie, Paris, France. pp. 59-63.
Sitompul, S.M., Syekhfani, M.S., van der Heide, J. & van Noordwijk, M., 1992. Yield of maize and soybean in a hedgerow intercropping system on an ultisol in Lampung. Agrivita 15: 69-75.
van Noordwijk, M., Hairiah, K., Sitompul, S.M. & Syekhfani, M., 1992. Rotational hedgerow in intercropping + Peltophorum pterocarpum = new hope for weed-infested soils. Agroforestry Today 4(4): 4-6.
Whitmore, T.C. (Editor), 1972. Tree flora of Malaya. A manual for foresters. 2nd edition, Vol. 1. Malayan Forest Records No 26. Longman Malaysia Sendirian Berhad, Kuala Lumpur, Malaysia. pp. 267-268.

M. van Noordwijk & Rudjiman

van Noordwijk, M. & Rudjiman, 1997. Peltophorum dasyrhachis (Miquel) Kurz. In: Faridah Hanum, I & van der Maesen, L.J.G. (Editors): Plant Resources of South-East Asia No 11: Auxiliary plants. PROSEA Foundation, Bogor, Indonesia. Database record: prota4u.org/prosea