GUIYANG - The southwestern province of Guizhou, which has the most tea plantations in the country, exported almost 600 tons of tea in 2015, more than double the export volume in 2014.

In 2015, Guizhou exported 598.7 tons of tea, with a total value of $36.47 million, according to the Guizhou Entry-Exit Inspection and Quarantine Bureau.

This is 307.8 tons more than the volume in 2014. About 58 percent of the exported tea was black tea and Wulong tea, or Oolong tea. Guizhou tea is exported to 11 countries and regions including the United States, Canada, Germany, Saudi Arabia and Vietnam.

The export growth has been partly attributed to investment by foreign companies such as British John Swire & Sons Ltd and Starbucks, industry sources said.

Guizhou is mountainous and one of the least developed provinces in China. Its tea is known for having less pesticides.

Tea plantations occupy over 459,000 hectares in Guizhou. Total production value was 224,000 tons in 2015, up 23.7 percent year on year.