White seraya  (Parashorea malaanonan)

Classified as Critically Endangered (CR) on the IUCN Red List (1).

Dipterocarpaceae trees dominate tropical lowland rainforests in Southeast Asia and consist of many economically and ecologically important species (3), with white seraya being considered the most important commercial timber of northern Borneo (1). This enormous tree has a tall, straight, cylindrical trunk, characterized by pronounced buttressing at its base (2). Large flowers with yellow anthers exist amongst the tree’s crown of leaves, found in or above the canopy (4).

Found on Borneo, in Brunei Darussalam and Malaysia (Sabah and Sarawak), as well as in the Philippines (1).

Lowland primary forest (1).

Parashorea species are thought to be primarily pollinated by bees (4) and all trees of the Dipterocarpaceae family produce fruits with a single-seeded nut (5). The fruit of Parashorea species are five-winged (5), having evolved, like many Dipterocarpaceae species, to utilise wind dispersal (6).

White seraya is an extremely important commercial timber (1) and, as such, has become critically endangered through over-harvesting, and probably extensive illegal logging. In the Philippines, large areas of forest had already been cleared by the end of the nineteenth century for agricultural expansion, which continued throughout the twentieth century (7). However, the most extensive and rapid deforestation in the latter half of the century has been caused by commercial logging, with has particularly impacted the valuable primary lowland dipterocarp forests, which shrunk from an estimated 10 million hectares in the 1950s to only one million by the late 1980s (7). Forest clearance and habitat degradation throughout Borneo and the Philippines may also be having a detrimental effect on the tree’s natural pollinators, reducing the rate at which the species can reproduce and recover its populations (4).

This threatened species is located in a proposed reserve site (1), which, if awarded official reserve status in the future, would confer some degree of protection to the species. The Philippines’ Department of Environment and Natural Resources (DENR) has also established a genebank of economically useful, endemic and endangered forest tree species, including white seraya (8). This project has involved collecting and propagating the species to be maintained in an arboretum, and gathering data on growth and survival of the species planted (8). A large scale project has also been initiated in Sabah, Malaysia, to rehabilitate 25,000 hectares of logged forests using indigenous tree species such as dipterocarps, in order to counteract atmospheric carbon dioxide (9). Parashorea malaanonan has been one of the main dipterocarp species planted to date (9). Indeed, although such conservation efforts are not directed specifically at white seraya, the tree is likely to benefit indirectly from a variety of such efforts to conserve lowland forests generally. Whether for environmental concerns or to protect the host of endangered species that inhabit lowland forests across Borneo and the Philippines, conservation of such forests will undoubtedly help preserve this enormous tree, which needs to be recognised for its crucial ecological importance as much as for its economic value.

For more information on this species see:

• Center for International Forestry Research (CIFOR):
  http://www.cifor.cgiar.org/publications/pdf_files/Books/Dipterocarps.pdf