White lauan  (Shorea contorta)

Classified as Critically Endangered (CR) on the IUCN Red List 2007 (1).

The white lauan belongs to the dipterocarp family, a group of important timber trees that dominate the lowland rainforests of Asia (3). The white lauan has brown to nearly black bark, although it can look grey when exposed to bright sunlight. The upper part of the trunk may have distinct longitudinal ridges. The leaves of the white lauan have a thin, leathery texture and can measure up to 29 centimetres long and 11 centimetres wide (2). Dipterocarp plants have fairly large and showy flowers, to attract insects, and the fruit is a single-seeded nut enclosed within a winged case (3).

Endemic to the Philippines, where it occurs on the islands of Babuyanes, Luzon, Polillo, Marinduque, Masbate, Samar, Leyte, Negros, Sibuyan, Mindanao, Polaui and Basilan (2).

The white lauan grows in lowland, seasonal, semi-evergreen dipterocarp forest (4), from sea level up to about 700 metres (2).

Little information is available about the biology of the white lauan. This tree flowers between March and May and fruiting takes place from April until September (2). Like other dipterocarps, the white lauan is probably pollinated by insects (3).

Numbers of white lauan have become depleted due to logging and slash-and-burn agriculture (2) (4). The valuable timber of the white lauan is used for general construction and for furniture making (2).

The white lauan most likely occurs in a number of protected areas throughout the Philippines, such as the Sierra Madre. However, despite this so-called protection, illegal logging activities can continue to pose a threat (5).