The species is confirmed on Sumatra however the species range may be restricted to one national park, giving an estimated extent of occurrence (EOO) of just over 1,600 km2 or could extend further north giving a much larger extent of occurrence however this estimate is based on a specimen made in 1934 so it is suspected to no longer be present here. The population is currently suspected to be in decline due to fragmentation and forest loss across the region and there is the threat of further expansion of oil palm plantations.
This is a particular concern in the region of Krui where the species is cultivated for Dammar. In this region the species is cultivated but is managed to allow the natural regeneration of sites and therefore still provides a genetic reservoir for the species. This area is targeted for the development of the oil palm industry. The species can also be used for timber but the extent to which this is a threat to the species is not known. Overall, it is likely that the species has a restricted geographic range, small population and is subject to decline and is potentially only found in up to three locations. The species is globally assessed as Endangered.
Population
The population of this species is reported to be small and restricted. It is found in fragmented forests and is rare. Population experienced great decline prior to the 1990’s but since this time the pressure from logging has ceased and current decline is minimal. There was extensive deforestation within Sumatra that was 2.5 times more than the global average. The species is considered to have low genetic diversity, with homzygote loci contributing to much of the genome although microsatellite diversity is higher than predicted. So far the species has avoided inbreeding depression. Within Bukit Barisan Selatan National Park the species is common. The species is thought to have become isolated since the last glacial epoch.
Habitat and Ecology
Shorea javanica is a large tree species, growing to over 15 m and up to 40 or 50 m in height. The species shows habitat specificity making it restricted to lowland areas on volcanic soils only. It grows within primary and secondary forests on land that is periodically inundated. It forms important ectomycorrhizae relationships which encourages growth. Seedling are shade tolerant, however, the best growth occurs within gaps in the canopy. It most commonly flowers in January and is pollinated by insects.
Seed is dispersed in the wind and generally exhibits good germination. The species is also found in danmar gardens whose structure often bear good resemblance to natural forests with an age structure canopy and good biodiversity. Within these gardens the species is allowed to regenerate naturally. The species is found within patchy forests which are at risk from decline due to logging and expansion of plantations in southern Sumatra.
Use and Trade
This species is used for timber but is more popular for its {{Gum Damar Suppliers}} which is harvested locally by villages. For timber it is traded under the name white meranti but the harvest of this species for this is very uncommon. The species is used and prized for its dammar, which is of higher quality than from other Shorea. This is used in the production of varnishes, to caulk boats and to produce torches. The species is found within agro-forests and danmar gardens for this purpose where it is often cultivated alongside coffee trees.
Individuals are grown up from seed and the forests are managed naturally allowing trees to fall in their own time and encouraging Shorea javanica seedlings to grow in their place. In 1994 and 1995, 14,750 and 9,900 tonnes of danmar was traded, respectively, out of Indonesia. Trees can produce between 2 and 15 kg of danmar per year depending on size and age, however tapping for this does damage the tree and reduce its lifespan. Cultivation of the tree began in the mid 19th century however due to the natural management of these sites the species has maintained good genetic diversity for a cultivated tree. There is some collection from natural stands of the tree.
Threats
This species is threatened by habitat loss and fragmentation which is already thought to have caused a massive reduction in range for the species. The sites of the danmar gardens in Krui are also under threat as they are in a prime area for the development of oil palm plantations. The price of danmar is in decline and there are more artificial substitutes which may be pushing garden conversion to oil palm, although this is illegal. This puts a remaining reservoir of genetic diversity at risk.
As the remaining population of the species is small and relict there are concerns that there will be genetic erosion and inbreeding depression in the near future. The tapping of any remaining natural trees will reduce their life span and this is a potential risk to the species. It needs confirmation if tapping of wild populations is still occurring or not. Timber harvest is not a threat to the species.
Conservation Actions This species is present in ex situ collections in Bogor Botanic Gardens, Java and in wild individuals are found Bukit Barisan Selatan National Park, Sumatra showing that the species is subject to some in situ conservation. In the National Park, the population size should be calculated and there species presence north of this location should be confirmed. Although the populations within Danmar gardens in Kuri are not wild it should be ensured that they are not taken over by palm oil plantations as they provide an important genetic reserve for this species.