Giam

Overview

Giam usually occurs scattered in the forest, and although regeneration may be plentiful, it takes a very long time for trees to reach a commercially interesting size. Giam has a specific geographic distribution range, this plant is naturally found in Borneo, Malaya, Sumatera, and Thailand.

Vernacular Names

Khiam khaao (Thailand), Resak tempurong (Malaysia), Resak Hitam (Brunei)

Agroecology

A plant of the moist to wet, lowland tropics, where it is found at elevations up to 300 m. It grows best in areas where annual daytime temperatures are within the range 22-34 °C, but can tolerate 12-38 °C. It prefers a mean annual rainfall in the range 2,100-2,700 mm, but tolerates 1,800-3,000 mm. Grows best in a sunny position. Prefers dry, often sandy or loamy soils and moist podzols in the wild. Prefers a pH in the range 4-4.5, tolerating 3.7-5.

Morphology

• Bole - frequently twisted with low buttresses. It can be unbranched for up to 30 m and up to160 cm in diameter.
• Leaves - simple, alternate, ovate-lanceolate, 5-10 cm × 2-6 cm,the margin slightly revolute, lower surface glabrescent, the intramarginal vein at about2 mm from the margin.
• Flowers - 13 mm in diameter, white, placed in small panicles
• Fruits - 10 mm long, yellow-green to reddish, nut with 2 wings up to 60 mm long, wind-dispersed.

Cultivation

Generative propagation is done by seeds. When seeds are kept for more than 3 weeks, the germination rate decreases to 30-40% or less. They are ready for planting into the field when they are 1.5-2 years old. It can be cultivated using stem cutting.

Chemical Constituents

Triterpenoids, flavonoids, tannins, β-sitosterol, stilbene dimer (ampelopsin, isoampelopsin F, epsilon-vinife), aliphatic compounds.

Traditional Medicinal Uses

• Local people in Thailand have suggest C. melanoxylon used as anti-diabetic, anti laxative and blood coagulant.
• The antibacterial activity of the bark is induced by endophytic fungi that live in the region of the bark.
• The bark has been used by local communities in North Sumatra as antidiarrheal drugs, also as antidiabetics.
• The leaves are also used to treat wounds by the local people, it is also used as antimalaria.