Ancient Ginkgo biloba Resources Characters and Age Detection in Changxing County

Field investigations were carried out on distribution and structural characteristics of Ginkgo biloba with age of more than 100 years in Changxing county, Zhejiang province during June and August of 2017. In March of 2018, detection was implemented on 20 G. biloba individuals random selected from above-mentioned trees. The results showed that 4047 ancient G. biloba in Changxing county concentrate distributed, with age ranged from 100 to 1 200 years, among them, 3819 ones with age of 100-300 years, accounting for 94.37% of the total. Their height varied from 6 m to 35 m, 2 945 trees were in 10-20 m, about 72.77% of the total. The perimeter at breast height of 3 234 ancient trees was concentrated in 1.0-2.0 m, accounting for 79.91 % of the total. The average crown diameter of 2 528 trees was less than 10 m in a range from 5 to 28m, about 62.4 % of the total. Determination of age of 20 ancient trees demonstrated that there was a great difference with estimated one, reached 500.82 year. It found that there was a linear relationship between age of ancient trees (Y) and perimeter at breast height (S), Y=0.071 8 S (R2=0.970 2).