Gen info
- The name 'guijo' is a Philippine-Spanish word derived from the Tagalog "giho".
- In the Philippines, Guijo was found in abundance in 1921, when it was estimated to cover 5% of the forest volume. The number has been dramatically decimated by logging, kaingin or slash-and-burn. It was listed by the IUCN Red List as "vulnerable" in 2017, while the website Binhi, a greening program of Energy Development Corporation from the Philippines has listed it as "critically endangered." (12)

Botany
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.

Distribution
- Native to the Philippines.
- 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 one of the most useful timbers of the Philippines. (8)
-In 2017, the tree was classified as "Vulnerable" in the IUCN Red List of Threatened Species. (9)
- Also native to Borneo, Cambodia, Laos, Malaya, Sumatera, Thailand, Vietnam. (5)

Constituents
- 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. (10)

Uses
Folkloric
- No reported medicinal use in the Philippines.
Others
• Timber: Wood used for flooring, boat building, carpentry, furniture, cooperage, musical instruments, decorativer veneer, pallets, paneling, etc.(1) (11) Used as a decking product due to resistance to rot and insect, but not termites.
• 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)

Studies
• 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)

Availability
Wild-crafted.

Additional Sources and Suggested Readings
(1)
Balau (Shorea guiso) / Woodsourcing
(2)
An Antimicrobial Triterpene from Shorea guiso / Consolacion Y. Ragasa, Agnes B. Alimboyoguen, John A. Rideout / Kimika, Journal of the Kapisanang Kimika ng Pilipinas, VOL 23, NO 1 (2010)
(3)
Sorting Shorea names / /Maintained by: Michel H. Porcher / MULTILINGUAL MULTISCRIPT PLANT NAME DATABASE / Copyright © 1995 - 2020 / A Work in Progress. School of Agriculture and Food Systems. Faculty of Land & Food Resources. The University of Melbourne. Australia.
(4)
Sawdust pulp for paper manufacture. / Zerrudo, J. V.; Escolano, JO. et al / Philippine Lumberman 1970 Vol. 16 No. 11 pp. 10, 12, 14
(5)
Shorea guiso / KEW: Plants of the World Online
(6)
The Potential Non-Timber Forest Products for Trading in Cambodia / ITTO—International Tropical Timber Organization
(7)
Shorea guiso / Useful Tropical Plants
(8)
The Encyclopedia Americana (1920)/Tropical Forest Products / Wikisource
(9)
Shorea guiso / The IUCN Red List of Threatened Species
(10)
The utility of leaf flavonoids as taxonomic markers for some Malaysian species of the tribe Shoreae (Dipterocarpaceae)  / Noraaini Talip et al. / Bot J Linn Soc (2008) 157 (4): 755-762. / DOI: https://doi.org/10.1111/j.1095-8339.2008.00833.x
(11)
Balau / WoodworkersSource
(12)
Shorea guiso / Wikipedia

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