Cay Sua - Dalbergia tonkinensis Prain is a valuable and rare forest timber which belongs to Fabaceae family. They naturally distribute themselves in humid tropical forests from the Highland to the Northwest of Vietnam, but mostly seen in Phong Nha-Ke Bang and were planted for shade trees in Ha Noi for long time ago. Recently, it has been regarded as a kind of timber which offers great value. Though nobody declares its uses (some of which were only rumoured in the public), its price in the market has reached a dizzily-high level (hundreds of million VN Dong per kilogram). However, mentioning the name of this tree without its scientific identity will possibly result in mistakes, as this name involves at least 5 different species: (1) Dalbergia tonkinensis Prain, (2) Dalbergia boniana Gagn., (3) Dalbergia balansae Prain, (4) Dalbergia assamica Benth. and (5) Pterocarpus echinatus Pers...