Characteristics:
Large tree, 25(30) m tall, with a diameter of 50 – 80(100) cm. The trunk is straight, often with buttress roots. Branches are numerous, and the bark is black. The leaves are even-pinnate compound, 30 – 50 cm long, sometimes longer, with (7)10 – 16(20) pairs of leaflets. Leaflets are ovate-lanceolate, with entire margins, sized 7 – 12 x 3 – 5 cm, with an acuminate apex, and an asymmetrical cuneate base. They are glabrous except at the vein axils on the underside. Young leaves are red. Inflorescences are panicles, located in the leaf axils and at the branch tips. Flowers are bisexual, cream-colored. There are 4 – 5 petals. The filaments are fused into a tube, with 8 – 10 anthers. The ovary is pubescent; the style is short and cylindrical, with hairs at the base. Fruits are sub-globose, with 3 – 5 locules, sized 3.5 – 4.5 x 2.5 – 3.5 cm, each locule containing many seeds. Seeds have a wing at the apex.
Biology and Ecology:
Flowering season is April – May(July), with fruits appearing from October – December. Reproduction is by seeds and shoots. It grows in humid tropical evergreen forests, including limestone mountain valleys, alongside species such as Trai (Garcinia fagraeoides), Nghiến (Burretiodendron tonkinense), and Gội (Amoora gigantea), at altitudes of 800 m and below.
Distribution:
In Vietnam: Lai Châu (Mường Nhé), Sơn La, Hà Giang, Tuyên Quang, Lạng Sơn, Phú Thọ, Vĩnh Phúc, Hòa Bình, Ninh Bình, Thanh Hóa, Nghệ An, Hà Tĩnh, and the Central Highlands provinces.
Globally: India, China, Laos, Cambodia, Malaysia.
Value:
A valuable timber tree with beautiful growth rings (especially in the base and roots), a bright red color, medium hardness, little shrinkage, and resistance to termites. Highly prized in architecture and the manufacture of furniture, such as beds, cabinets, tables, chairs, and export handicrafts.
Conservation Status:
The species is heavily and extensively exploited (including root extraction). Forest area is shrinking. A decline of at least 20% is observed currently, and another decline is expected within the next 5-10 years. It is an endangered species.
Ranking:
Vu A1a,c,d+2d.
Conservation Measures:
The species is listed in the Vietnam Red Data Book (1996) with the assessment “not accurately known” (Category K). It is recommended to cultivate the species in botanical gardens and along roadsides and to expand forest plantations to protect the gene pool and for timber usage.