In situ and Ex situ Conservation of Commercial Tropical Trees - ITTO

395services and biodiversity, may not be fully realized in plantations.The success of eucalypts, pines and teak in the sub-tropics and drytropics is used as evidence for their viability in the wetter regions of SoutheastAsia. However, the history of plantations in the region does not appear easyand straightforward. There are numerous difficulties whether they are indigenousor exotics, and whether they are monocultures or mixed species. In Table 6,the plantation areas in the region are shown. It is obvious that hardly any of thecountries have even reached 1% in area compared to the natural forest areasfound in their countries. Indonesia is the only one that has so far goneaggressively into developing their plantations.Table 6. Forest resources of Southeast Asian countries (000 ha) (ca. 1985)Countries Land area ClosedforestsContinental:Kampuchea17,550Lao PDR23,080Myanmar65,770Thailand 51,180 32,540VietnamInsular:BruneiIndonesiaMalaysiaPhilippines590181,16032,85029,8507,5488,41031,9419,2358,770393113,89520,9969,510TimberPlantations611151292040.51,918120300The majority of plantations are monocultures with exotic speciesoriginating from subtropical parts of the world. In the 1970s, fast growinghardwood species such as Acacia, Eucalyptus, Paraserianthes, Gmelina,and Leucaena, and softwood species such as Pinus and Araucaria wereplanted (Appanah & Weinland 1993). All of these have short rotations, simplestand structure, and uniform timber and can be harvested at one felling.Monocultures are not without problems either.At present, more species are being tested, particularly the indigenousspecies and those with longer rotations. With appropriate silviculture and hygiene,the plantations are beginning to look more promising than the initial experiencesindicated. With more research, particularly in production of planting materialand tree selection and improvement, the plantations would meet their initialexpectations and may produce more of the industrial timber by the end of thenext two decades.