Yunnan Yew Seedling Encyclopedia: A Comprehensive Guide in One Article

Family Chinese name: Taxaceae

Family Latin name: Taxaceae

Genus Chinese name: Taxus

Species Chinese name: Yunnan yew

Species Latin name: Taxus yunnanensis Cheng et L. K. Fu

Other common names: purple yew, sacred wood

National Class I key protected wild plant (approved by the State Council on August 4, 1999)

Yunnan yew is one of the 4 species of yew in China. It is a tall evergreen tree with luxuriant branches and leaves and strong vitality. A single tree can live for more than a thousand years and is honored as the "sacred wood" by local ethnic minorities. In Luobu Township, Weixin County, Yunnan, there is a yew tree 72 m tall with a diameter at breast height of 202 cm, and it is already 800 years old. It generally can reach 30 m in height. It is dioecious, with a fruiting period from October to November. The fruit is bean-like, with an aril, and red.

Yunnan yew is an endemic species whose distribution center is Yunnan, mainly distributed in Baoshan City and Tengchong County in western Yunnan, and the areas of Zhongdian, Lijiang and Weixi in northwestern Yunnan. It often grows in subtropical mountain areas at an altitude of 2000-3500 m. Its habitat includes shady slopes and semi-shady slopes in mid-mountain and subalpine gentle slopes, gullies, dark coniferous forests on both banks of streams, mid-mountain mixed coniferous and broad-leaved forests, and evergreen broad-leaved forests, where it grows scattered or in patches and often becomes an understory tree.

Yunnan yew is a provincial-level precious tree species in Yunnan and also a first-class key protected tree species in Yunnan Province. The bark contains taxol, harringtonine and other components. In recent years, scientists have found that the relevant components of yew are effective drugs for treating many kinds of cancer; yew is also a traditional Chinese medicinal material. Its seeds are used as medicine, the seeds contain starch and sugar, and the aril is edible.

Yunnan yew is the main tree species in China for producing taxol drugs. Based on many years of measured data on the content of taxol and the semi-synthetic raw materials baccatins (including 10-deacetylbaccatin III and baccatin III) in Yunnan yew forest tree samples, and compared with other Taxus species, it shows that Yunnan yew is a tree species with high content of the above 3 effective components. In natural Yunnan yew forests, the taxol content in bark is about 0.02%, with a maximum of 0.0304%. The average taxol content in small branches and leaves is 0.0102%, with a maximum of 0.0217%. The total baccatin content can reach 0.0808% (bark) and 0.0845% (branches and leaves), both of which have excellent industrial utilization value. In planted Yunnan yew forests, the content of medicinal components does not decrease significantly. In the root systems of planted trees, samples with high taxol content of 0.0421%-0.0460% and baccatin content of 0.103% have appeared, all reaching the high content levels of taxol and baccatins in the world-famous taxol raw material tree species Taxus media (hybrid) and European yew. Among samples, the differences in the 3 effective components are very large, reaching several times to 17 times. The reasons may be in 3 aspects: (1) genetic differences among trees; (2) influence of the ecological environment; (3) differences in sample preparation, storage and analytical determination. Research and improvement from these 3 aspects are expected to increase the content of medicinal effective components in Yunnan yew.

Yunnan yew has excellent timber, which can be used for construction, furniture, utensils, etc., and its extract taxol has anticancer effects. It is a precious tree species integrating timber use, medicinal use and landscaping. In particular, its taxol content is far higher than that of other yew species. Yew has strong adaptability to the environment and is an excellent economic tree species for improving the ecological environment and building beautiful mountains and rivers in the new century. At the same time, it also has very broad development prospects in landscaping and indoor bonsai, and its boards can be exported. Experts predict that this tree will sell well for a long time and have extremely high benefits. It is suitable for cultivation in places with suitable conditions throughout China, and its development prospects are very broad.