Gluta usitata aka Black Varnishtree

Gluta usitata is a large tree in the cashew family. Common names include Burmese varnish tree and Pegu black varnish tree. Older works may call it Melanorrhoea usitata. Kew places its native range from Assam to Thailand. Useful Tropical Plants also lists Laos and Vietnam. It grows in open forests, but seldom in dry forests. Kew links the species with a wet tropical climate.

This deciduous tree sheds its leaves rather than staying evergreen. Plants For A Future gives a height of 82 feet [25 metres]. It gives a spread of 66 feet [20 metres]. The trunk grows straight, with a clear, round bole. Dark leaves form a broad crown above it. Plants For A Future describes its growth rate as moderate. The supplied accounts give no flower season or fruit details.

Plants For A Future lists a site with full sun. It says the tree cannot grow in shade. It needs moist ground that drains well. Suitable soils include sand, loam, and clay. It accepts mildly acid, neutral, and mildly alkaline soil. The same source lists USDA zones 10–12. Seed is the stated means of raising new plants. Useful Tropical Plants records wild use, but gives no cultivation details. These accounts provide little detail on care in gardens.

The trunk yields lacquer, which gives the tree its main use. People use this material locally and export it. They tap the inner bark through cuts in the trunk. Bamboo tubes catch the sap as it drains out. Workers renew the cuts when the flow slows. Young trees appear to yield more than fully grown trees. The liquid coats wood and helps protect it. Mixed with fillers, it also serves as cement or moulding material. Craftspeople can add colour and apply it to turned objects. The wood has value for furniture and inlay work.

Skin contact is a major concern with this tree. Even brief contact can cause an allergic reaction or irritation. The sap can cause dermatitis. Resin from the wood can cause severe skin irritation. Burning the wood makes smoke that can severely irritate eyes. Plants For A Future says timber needs years of drying and exposure. Neither that source nor Useful Tropical Plants records edible uses. Both also report no known medicinal uses. The supplied accounts name no specific pests or diseases.