Aquilaria, as the main agarwood-producing genus, is likely to be particularly affected by unsustainable resin collection. Aquilaria rostrata, the only agarwood-producing species thought to be endemic to Malaysia, was listed as “Data Deficient (DD)”. This assessment was made by the World Conservation Monitoring Centre (WCMC) using the IUCN criteria (ver. 2.3) and on data collection forms for endemic trees of Peninsular Malaysia completed by Chua et al. (1997). The assessors decided that there was insufficient information to make an assessment, noting that: “The species’ taxonomic status is doubtful. It is similar to A. malaccensis but the specimen material is too poor to verify the floral characters” (Oldfield et al. 1998).
In 2007, the Malaysian population of Aquilaria malaccensis was evaluated to be Vulnerable (VU A4c) (Chua 2008). Furthermore, a recent study has found that illegal agarwood collection is widespread in Malaysia (Lim and Awang Anak 2009). Therefore it is necessary to re-evaluate the status of Aquilaria rostrata and determine whether new information is available that would justify assigning a threatened status to the species. The present version of the IUCN Red List Criteria (ver. 3.1) note that “it is important to recognize that taxa that are poorly known can often be assigned a threat category on the basis of background information concerning the deterioration of their habitat and/or other causal factors; … If the range of a taxon is suspected to be relatively circumscribed, and a considerable period of time has elapsed since the last record of the taxon, threatened status may well be justified” (IUCN 2001).
This poorly known tree is confined to a single location in the State of Pahang, Peninsular Malaysia. Although it is only known from type material collected in 1911, given the known threats to other Aquilaria species, it seems highly probable that this species is very threatened. It is therefore listed as Critically Endangered based on its extent of occurrence being almost certainly well less than 100 km², it is a single location and there is projected continuing decline in the number of mature individuals given the demand for agarwood. Attempts are required to relocate this species in the wild and to assess its status properly; it may well already be extinct.