Vernicia montana aka Chinese Wood Oil Tree

Vernicia montana, the abrasin oil tree, belongs to the spurge family. Its native range spans southern China, Taiwan, and Indochina. It grows in disturbed ground and along evergreen forest edges. In Laos, it also grows beside roads in dry, sandy soil. Growers raise it across tropical and subtropical regions for seed oil. People also plant it for shade and as an ornamental tree.

Garden references give a height of 39 feet [12 metres]. They list a spread of 33 feet [10 metres]. Other accounts report heights of 49–66 feet [15–20 metres]. Its straight trunk can reach 0.8 feet [0.25 metres] across. Growth is moderate. The tree keeps its leaves where the climate suits it. Cold or dry seasons can make the leaves fall. The large leaves have three lobes. White flowers grow in clusters, which attract bees and butterflies. The tree is not self-fertile. Its round fruit is a drupe with a wrinkled surface. Fruits range from green to yellow and hold three oil-rich seeds.

This tree needs full sun and soil that drains well. Sandy and loamy soils suit it. It prefers slightly acid ground but tolerates pH 5.5–8. It can grow in dry or moist soil. Good soil fertility supports seed production. Both slopes and flat sites suit it when drainage is good. It grows best without frost, with mean annual temperatures of 15–27°C. The cited rainfall range is 850–2,000 millimetres per year. Plants For A Future lists USDA zones 10–12. Fresh seed sprouts quickly, while stored seed develops a hard coat.

The seeds yield a fast-drying oil used in varnish and paint. Other uses include black ink, waterproof cloth, and waterproof paper. The oil also serves in ship coatings and wire insulation. Farmers sometimes grow food crops between the trees. Long-term intercropping can damage the shallow roots. Traditional medicine uses the oil for skin disease and parasites. It also appears in Chinese medicinal plasters. These uses do not make the oil safe to swallow.

All parts of the tree are poisonous, so it is not a food plant. Even one seed can cause severe poisoning in people. Signs include stomach cramps, vomiting, diarrhoea, and marked weakness. These may start three to five hours after eating a seed. Leaves and seed cake can also poison animals. Severe cases can be fatal. Its toxic fruit needs careful consideration in gardens and shade plantings.