With the development of Taxus industry,bark is becoming more important as the raw medicinal material due to the highest content of taxol in Taxus yunnanensis. With reference to classification of tree diameter class standard,the stem and branch diameter of Taxus yunnanensis in plantation could be divided into 5 classes. A study was carried out on 270 stem and branch samples from Kunming site and 67 samples from Yibin site. The result shows that the content of fresh bark weight varied from 12. 88 % to28. 98 %...