Tree Conservation Information Service
| Eusideroxylon zwageri
Lauraceae Ironwood, Belian, Borneo Ironwood, bois de fer (Fr). Brunei: belian. Malaysia: belian (Sarawak, Sabah), tambulian (Sabah), im muk (Cantonese, Sabah), Ulin. Indonesia: belian (general), onglen, tulian, tebelian (Kalimantan). Philippines: tambulian, sakian, biliran (Sulu). Distribution Sumatra, Bangka, Belitung, Borneo, Sulu Archipelago, Kalimantan, Sabah, Sarawak, Philippines (Palawan). Habitat E. zwageri is widespread in Borneo and Sumatra as a scattered component of the Dipterocarp forest and in some localities forms a single dominant variant. It is generally found in lowland areas of primary forest 5-400 m, in flat or sloping terrain, and also occurs in old secondary forest (Suselo, 1987). Population status and trends Belian is one of the most renowned timbers of Borneo. It has been favoured both for local use and the export trade. Over-exploitation together with forest clearance have led to the decline of this slow-growing timber species. The increased availability of forest roads opened by concessionaires is leading to greater problems of uncontrollable exploitation in Kalimantan (Partomihardjo, 1987). On the flat lowlands of southern Sumatra, great stands of ironwood, (E. zwageri) once stood, these have now been almost entirely destroyed (WWF and IUCN, 1994-1995). E. zwageri is considered to be Vulnerable in Indonesia by Tantra (1983) and was in a shortlist of Endangered species of the country (Anon., 1978). It is included in a list of vanishing timber species of the Philippines (de Guzman, 1975). The species is considered to be almost extinct in Sabah (Meijer, pers. comm. 1997). Over 30 years ago, the scarcity of E. zwageri in Sarawak was noted by Browne (1955), who pointed out that, "Our surviving supplies of Belian are by no means very large and are undoubtably dwindling." The main causes given for this are shifting cultivation and wasteful use. Role of species in the ecosystem Threats Over-exploitation and shifting cultivation (Soerianegara & Lemmens, 1993). The introduction of chain saws and extensive road systems by the timber industry (Peluso, 1992). Utilisation Belian is used locally in house construction and for water butts. Its commercial uses are for heavy construction, marine work, boat building, printing blocks, industrial flooring, roofing and furniture. Belian has been esteemed by the Chinese as a coffin wood. Production and trade Primarily used locally with limited exports recorded by Sabah. In southern Kalimantan this timber is felled by the owners of concession rights and also by local people coordinated by Ulin traders (Partomihardjo, 1987). Kartawinata et al. (1981) note that transmigrant settlers in East Kalimantan cut this species for sale to supplement their income from cultivation. In 1987 Sabah exported 3 836 070 m3 of Belian (source: Forestry Department), in 1992 the export was 7350 m3 (Soerianegara & Lemmens, 1993). IUCN Conservation category VU A1c,d &2c,d (Asia Regional Workshop, 1997). Conservation measures There are attempts to conserve supplies of this species in Sarawak (Asia Regional Workshop, 1997). Legislation Indonesia - Thought to be totally protected by law (Anon., 1978). Indonesian law forbids its export (out of country) and restricts cutting to trees over 60 cm diameter at breast height (Peluso, 1992). The need for control of exploitation and better cutting criteria are pointed out by Partomihardjo (1987). Sarawak - Under the Forest Rules of Sarawak, export of E. zwageri in log, sawn or hewn form is not allowed without special permission. Export controls have been in force since 1950. Presence in protected areas Indonesia Kutai National Park, East Kalimantan - has pure stands of Eusideroxylon zwageri, Tanjung Putting National Park, Kalimantan, Gunung Penrisen/Gunung Nyiut Game Reserve, Kalimantan, Lempakai Botanical Park, East Kalimantan Sabah Tabin Wildlife Reserve Forest management and silviculture Browne (1955) noted that the patchy distribution, limited extent and inaccessibility of many Belian forests in Sarawak made assessment of remaining stands and sustained yield management very difficult. Poor seedling regeneration in logged forests has been noted (Kartawinata, 1978). Some plantation was carried out in secondary forest in Sumatra (Browne, 1955) and plantation continues on a trial basis both in Sumatra and West Kalimantan. Inadequacies of seed and seedling supply limit more extensive plantation and the need for tissue culture has been suggested by Suselo (1987). In natural forests ulin is usually cut selectively with a diameter limit of 50 cm. Harvesting is usually done manually. Regeneration in logged-over forests is often not sufficient, although ulin may coppice freely and be persistent (Soerianegara & Lemmens, 1993). References Anon. 1978. Endangered species of trees. Conservation Indonesia 2(4). Asia Regional Workshop, 1997. Conservation and Sustainable Management of Trees project workshop held in Hanoi, VietNam, August 1997 Browne, F.G. 1955. Forest trees of Sarawak and Brunei and their products. Government Printing Office, Kuching. de Guzman, E.D. 1975. Conservation of vanishing timber species in the Philippines. In: Williams, J., Lamourak, C.H. and Wulijarni-Soetjipto, N. (Eds), South-East Asian plant genetic resources. Symposium Proceedings Bogor, Indonesia, March 1975. IBPGR, Bogor. Kartawinata, K. 1978. Biological changes after logging in lowland dipterocarp forest. In: Suparto, R.S. et al. (Eds), Proceedings of a Symposium on the long-term effects of logging in Southeast Asia. BIOTROP Special Publication No. 3, pp. 43-56. Kartawinata, K., Adisoemarto, S., Riswan, S. and Vayda, A.P. 1981. The impact of man on a tropical forest in Indonesia. Ambio 10(2-3): 115-119 Meijer, W. 1997. Personal communication to Amy MacKinven Partomihardjo, T. (1987). The ulin wood which is threatened to extinction. Duta Rimba 87-88(13): 10-15. Soerianegara, I. & Lemmens, R.H.M.J. (Eds.) 1993 Plant Resources of South-East Asia (PROSEA) 5(1) Timber trees: major commercial timbers. Pudoc Scientific Publishers, Wageningen. Peluso, N.L. 1992. The Ironwood Problem: (Mis)Management and Development of an Extractive Rainforest Product. Conservation Biology Vol. 6, No. 2: 210-219 Suselo, T.B. (1987). Autecology of E. zwageri T. & B. (Lauraceae) as applied to forest regeneration. In: Proc. Symp. Forest Regeneration in South East Asia. Biotrop Special Publication No. 25 BIOTROP, Bogor. Tantra, G.M. (1983). Erosi plasma nutfah nabati. J. Penelitian & Penembangan Pertanian 2(1): 1-5. WWF and IUCN. 1994-1995. Centres of plant diversity. A guide and strategy for their conservation. Vol 2. IUCN publications Unit, Cambridge, UK. |
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