Guijo is a large, medium-sized tree, reaching a height of 50 to 60 meters, with a trunk diameter of about 175 centimeters, with dark colored branchlets. Tree has a strongly buttressed hole at the lower portion of the trunk. Leaves are alternate, simple, entire, and ovate-oblong, 8 to 10 centimeters long, 3 to 5 centimeters wide, with a rounded base and tapering tip. Flowers are short-stalked, developing into 3 long- and 2 short-winged fruits which are expanded at the base. Petals are 9 times as long as the sepals. Stamens are in clusters of 20 to 40 in three groups, with filaments dilated at the base.
- Found in primary forests throughout the Philippines.
- Critically endangered.
- Also found in Brunei, Indonesia, Malaysia, Thailand, Vietnam.
- In the Encyclopedia Americana (1920)/Tropical Forest Products, guijo was considered on of the most useful timbers of the Philippines. (8) Today, the tree is classified as 'Critically endangered' in the IUCN Red List of Threatened Species (2010). (9)
- Species provide a hard resin, which coagulate on the trunk and main branch, then drop down. (6)
- Plant yielded flavanol aglycones, condensed and hydrolysable tannins.
- No reported medicinal use in the Philippines.
• Timber: Wood used for flooring, boat building, carpentry, furniture, cooperage, musical instruments. (1)
• Papermaking: Study showed Shorea guiso can be used in a mixture of sawdust pulp as filler in the production of printing and writing papers. (4)
• Resin: A dammar resin, known as "huille de bios" is obtained from the tree. Commercially, it is an ingredient of inks, lacquers, oil paints, varnishes, etc, and used as glazing agent in foods. (7) Value of hard resin similar to liquid resin, the good quality is 2000-2500 riel/kg. (6)
• Shoreic Acid / Antimicrobial: Study of dichlormethane extract of air-dried leaves of Shorea guiso yielded shoreic acid which exhibited antibacterial activity against E. coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis. It also showed antifungal activity against Candida albicans, Trichophyton mentagrophytes. (2)