Pterocarpus santalinus aka Red Sandalwood

Pterocarpus santalinus is a deciduous tree in the pea family, Fabaceae. Its common names include red sandalwood and red saunderswood. It comes from a small range in southeastern India. There, it grows in dry forests on rocky hills. Its sites include low ridges, slopes, and steep hillsides. These lie from 492 to 3,281 feet [150–1,000 metres] above sea level.

The tree grows slowly and forms a dense, rounded crown. Reported heights range from 33 to 66 feet [10–20 metres]. The source also lists a height of 49 feet [15 metres]. Its trunk tends to grow straight. Trunk widths reach about 1–1.6 feet [0.3–0.5 metres]. It sheds its leaves rather than keeping them year-round. Bees pollinate the tree, and it is self-fertile. Natural fruit set depends on visits from pollinators.

This tropical tree suits places with a clear dry season. It grows best in full sun and warm conditions. Its preferred mean yearly temperature is 26–32°C. Reported tolerance extends from 7°C to 46°C. Temperatures below freezing kill it. It prefers annual rainfall of about 1,000–1,900 millimetres. Light to medium soils suit it best. It can grow where soil fertility is low. It prefers acid soil, with a pH of 5–5.5. The reported tolerance spans pH 4.5–6.5.

People grow this tree for timber and red dye. They also plant it as a windbreak around citrus crops. Its wood serves in traditional Chinese furniture making. The dark red to black heartwood yields the dye santalin. This colours cloth, foods, and some drug products. Ground heartwood adds orange-red colour to sauces and spice mixes. It also adds a sweet, spicy taste. Wood and stem extracts have uses in skin and hair products. The wood also serves as a base for incense.

Wood and bark have several uses in traditional medicine. These include treatments for diarrhoea, dysentery, and diabetes. Such uses do not establish that these remedies work. The source lists no known hazards, but gives no detailed safety assessment. Wild trees face illegal logging and loss of habitat quality. Grazing adds pressure to their native sites. The source cites a 2018 IUCN assessment of Near Threatened. National and international rules protect trade in the species.