Researches On The Ancient Ginkgo Tree Resources In Hubei Province

Ancient Ginkgo trees are invaluable resources of Hubei Province. In order to get a clear inventory of the resources of the ancient Ginkgo trees in Hubei Province, an overall investigation was made in this paper, and deep-going researches were made on the ancient Ginkgo trees in the main regions on the following aspects: distribution, site condition, appearance characteristics, sex structure, age structure, growing state and protection state. The results are as following:(1) There are 4988 ancient Ginkgo trees in Hubei Province, in which 517 trees are of grade one, 941 trees are of grade two and 3530 trees are of grade three.(2) In the 17 administrative areas under the jurisdiction of the provincial government, there are only two areas (Xiantao city and Tianmen City) without ancient Ginkgo trees. Areas that have more than 500 ancient Ginkgo trees are Suizhou City (1492 trees), Huanggang City (908 trees), Xiaogan City (866 trees) and Enshi Autonomous Prefecture (614 trees). The number of the ancient Ginkgo trees of these 4 areas together accounts for 77.79% of the total number of the province, and that of Suizhou City nearly accounts for 30% of the total number of the province.(3) There are 5 counties (or districts, cities) that each has more than 250 ancient Ginkgo trees (i.e. accounts for more than 5% of the total number of the province). In which, Zengdu District of Suizhou City has 1443 ancient Ginkgo trees, which is 28.93% of the total number of the province. The other 4 counties (or districts, cities) are Anlu city (718 trees), Luotian county (409 trees), Macheng city (389 trees) and Badong county (274 trees). These 5 main counties (or districts, cities) have 3233 ancient Ginkgo trees together, which accounts for 64.82% of the total number of the province.(4) There are 407 towns that have ancient Ginkgo trees, in which 11 towns each has more than 50 ancient Ginkgo trees (i.e. accounts for more than 1% of the total number of the province). These 11 towns together have 2838 ancient Ginkgo trees, which accounts for 56.9% of the total number of the province). Luoyang Town of Zengdu District, Suizhou City is in the first place with 1390 ancient Ginkgo trees, which is 27.87% of the total number of the province. Wangyizhen town with 609 ancient Ginkgo trees is in the second. From the third to the eleventh are Yeshanguan town of Badong County, Muzidian town of Macheng City, Xiaowu Town of Xiaochang County, BofanTown of Anlu City, Jiuzihe town of Luotian County, Sanhe Town of Macheng City, Qingtaiping town of Badong County, Hepu Town and Shengli Town of Luotian County.(5) The ancient Ginkgo trees are mainly distributed in three natural regions, i.e. the Dahong Mountain region in the middle of Hubei Province, the South-west Hubeimountainous region and the Dabie Mountain region in the North-east of Hubei. There are 2280 ancient Ginkgo trees in the Dahong Mountain region, which accounts for 45.75% of the total number of the province. 2100 ancient Ginkgo trees, which is the majority of those in this region and accounts for 42.1% of the total number of the province, are located in three neighbor towns situated in the east part of this region, i.e. Luoyang, Wangyizhen and Bofan. Therefore, the east part of the Dahong Mountain Region is the largest distribution area of the ancient Ginkgo trees in Hubei province. In this region, the ancient Ginkgo trees distributed concentratedly and densely. There are about 1000 ancient Ginkgo trees in the other two main regions respectively. Two of the 11 main towns of the province, i.e. Yeshanguan Town and Qingtaiping Town in Badong County, are in the South-west Hubei mountainous region; other 6 main towns are in the Dabie Mountain region. Compared with those in Dahong Mountain region, the ancient Ginkgo trees in these two regions scattered sparsely in relatively expansive areas and only formed few small colonies. Most of the counties (or districts, cities) without ancient Ginkgo trees are in Hubei Province are in the Jianghan Plain.(6) The majority of the ancient Ginkgo trees grow in the countryside, and almost all around houses or not far from houses. They usually grow on the gentle slope or flat ground, but seldom on the top of mountain. Their site conditions are good. In the Dahong Mountain region, ancient Ginkgo trees usually grow in those places below 500m above sea level, while in the South-west Hubei mountainous region usually below 1200m and in the Dabie Mountain region usually below 600m.(7) The age structure of the ancient Ginkgo trees in Hubei Province is a pyramid-like type. The ratio among the numbers of trees of grade one, grade two and grade three is 1 '. 1.82 .' 6.82. In those areas with relatively more ancient Ginkgo trees, the general tendency is: the older the age is, the less the number of trees is. For the 3233 ancient Ginkgo trees in the 5 main counties (districts or cities), the ratio of grade one, grade two and grade three is 1 : 2.14 '. 11.43. That of the 2838 ancient Ginkgo trees in the 11 main towns is 1 '. 2.30 : 17.96. And that of the 2282 ancient Ginkgo trees in Dahong Mountain Region is 1 '. 1.90 '. 12.83. In all the main distribution areas, trees under 400 years old are the majority. In addition, there are lots of ancient Ginkgo trees with rather high age in the Dahong Mountain Region and the South-west Hubei Mountainous Region, while there is less in the Dabie Mountain Region.(8) The female individuals are much more than the males, which revealed that the ancient Ginkgo trees endured high artificial selections.(9) The ancient Ginkgo trees vary greatly in appearance. The height of the trees is from several meters to forty or even fifty meters, girth at breast height is from above 1meter to more than 10 meters, while the biggest crown width reaches 30 meters. Most of the trees are single-stemmed, while some have more than one stem. They are also different in crown shape. Lots of trees are of high ornamental value and are special landscapes or landmarks in the areas where they grow.(10) The growing state of the ancient Ginkgo trees is generally good. But the growing state of the ancient Ginkgo trees in Dabie Mountain Region is somewhat worse than those in Dahong Mountain Region and South-west Hubei Mountainous Region. The level of management and maintenance of the ancient Ginkgo trees are still very low, even in the main areas, and are urgent to be improved.The ancient Ginkgo tree is a kind of natural landscape and natural resources that is difficult to regenerate, and is a kind of humane resources that cannot regenerate. Therefore, it is necessary to carefully protect, fully exploit and thoroughly research these precious resources. Following are some suggestions: 1) strengthen the protection of the ancient Ginkgo trees and enhance the researches of protection technology; 2) strengthen the researches and exploitation of the genetic resources of these ancient trees; 3) make full use of their value of "living fossil" and "living cultural relic"; 4) strengthen the exploitation of their touring value; 5) reinforce the researches and exploitation on their economic value.