The objectives of this study were to estimate the population density and distribution of <I>Aquilaria </I>spp., and to evaluate the impact of trade in gaharu on populations of the species in natural forests. Investigations were made of factors influencing regeneration, reproductive ecology and stand structure of <I>Aquilaria,</I> and the status of the species was evaluated in relation to IUCN categories of threat and CITES criteria. Six species of <I>Aquilaria</I> are recorded in Indonesia; <I>A. beccariana, A. cumingiana, A. hirta, A. filaria, A. malaccensis</I> and <I>A. microcarpa. </I>Based on the national forest inventory (NFI), the density of <I>Aquilaria</I> spp. in Sumatra appears to be lower than in Kalimantan (0.4 ha<SUP>-1</SUP> and 0.36 ha<SUP>-1</SUP> and 0.83 ha<SUP>-1</SUP> and 1.17 ha<SUP>-1</SUP> in lowland and upland Sumatra and Kalimantan respectively). <I>A. malaccensis</I> has the highest germination probability and <I>A. filaria</I> the lowest. A positive relationship between light availability and seedling growth was recorded in the field for <I>A. malaccensis</I> and <I>A. microcarpa. </I>Mortality of these species in natural populations was found to vary with size class; highest mortalities were recorded for seedlings. These data were used to parameterize a matrix model to predict population dynamics under different harvesting regimes. Based on trade data and field analysis of harvesting, it was estimated that 59,000 trees of <I>Aquilaria</I> species were felled in East Sumatra in 1992 and 70,000 trees were felled in East Kalimantan in 1996. Matrix models predicted that harvesting of the species will be sustainable provided that the annual cutting level is set at a maximum of 30% of harvestable individuals with a minimum dbh > 10 cm. According to IUCN criteria, the species should be considered as vulnerable to extinction. The species also qualifies for listing under Appendix II of CITES.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:662236 |
| Date | January 1999 |
| Creators | Soehartono, Tonny Rakhmat |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/14439 |
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