Toxicondendron vernicifluum (formerly known as Rhus Verniciflua) grows in forests on hills and mountains between 800 and 2800 meter in East Asia. It grows up to 20 meter tall.
Since 3000 years the trees are cultivated and tapped for their toxic sap, which is used as a highly durable lacquer to make japanese lacquerware. The sap glazes and protects from wood worm and humidity and was used as an adhesive.
The sap of the lacquer tree is very toxic due to the urushiol and causes extreme rashes, even from vapours. Urushiol is the same substance found in poison ivy from Northamerica.
Once hardened, reactions are possible but uncommon. Finished products are water- and alcoholproof, acid- and solvent resistant, resilient and food safe. The sap also prevents from growing moulds, which is beneficial in humid environments. Only long-time consistent sunlight can harm urushi.
A caustic, toxic sap, called urushiol, is tapped in summer from the trunk by cutting 5 to 10 horizontal lines on the trunk of 10 year old trees, and then collecting the greyish yellow sap that exudes. The tree will die due to the cuts for extraction, but quickly develop new saplings.
