A wild gleditsia velutina tree. Photo: screenshot of video posted by Pear Video

Two trees of a critically endangered species have been discovered in Central China's Hunan Province, bringing their known total number to just six.

Researchers found two gleditsia velutina trees near a river in Hengshan Mountain in Hunan Province. One is growing in a crack of a rock by the river and has a trunk of just two centimeters in diameter, according to a report posted by Pear Video.

"Seeds of this tree are very difficult to sprout," Kuang Jianjun, one of the researchers who found the trees told Pear Video. "The tree's wax on its seeds hinder sprouting," said Kuang, explaining one of the reasons that the trees are so rare now.

All six of the near-extinct trees are now growing in Central China.

Kuang said the extinction of one of species of the tree could impact 10 to 30 other species, so the discovery of the two trees means a lot to the ecosphere.

"The endangered species should be well protected. It is so precious," a Sina Weibo user commented.