Ginkgolide. It is a tall deciduous tree of Ginkgo in Ginkgo family, and its fruit is commonly known as ginkgo, also known as ginkgo tree. Ginkgo trees grow slowly and have a long life. It takes more than 20 years to bear fruit under natural conditions, and it takes 40 years for a large number of results. Therefore, it is called "Gongsun Tree", which means "the public species is edible" and has ornamental, economic and medicinal values. Ginkgo biloba first appeared in the Carboniferous period 345 million years ago. Ginkgo biloba was widely distributed in the northern hemisphere in Mesozoic and Jurassic and began to decline in the late Cretaceous. Ginkgo biloba distribution mostly belongs to artificial cultivation areas, mainly cultivated in China, French and South Carolina, USA, and foreign ginkgo biloba is mostly imported from China. Ginkgo biloba is a rare tree species left over from Mesozoic era, which is a specialty of China and cultivated in gardens all over the world. Ginkgo trees are lush in summer and golden in autumn, giving people a sense of precipitousness, grandeur and elegance, and are known as "living art sculptures". The trunk is straight, the leaves are fan-shaped, the leaf shape is simple, the life span is long, there are no pests and diseases, the adaptability is strong, it is smoke-resistant, fire-resistant, poisonous gas-resistant, the posture is beautiful, it is green in spring and summer, and golden in late autumn. Ginkgo biloba is an ideal typical demonstration of landscaping and street tree species. In recent years, a large number of ginkgo trees have been planted in urban landscaping in Tianshui and its surrounding areas, forming a unique landscape. Perfect characteristics make ginkgo one of the four long-lived ornamental trees (pine, cypress, locust tree and ginkgo) in China.

Botanical characteristics, growth habits and resource distribution of 1

Ginkgo biloba is a deciduous tree with a DBH of 4m. The bark of young trees is smooth, light gray, and the bark of big trees is grayish brown, irregularly longitudinally cracked and rough. The crown is conical, the branches are nearly whorled and extend obliquely; 1 year-old growth branches are light brown, turn gray after 2 years, and have fine longitudinal cracks; Short branches densely covered with leaf scars, dark gray; Leaves alternate, scattered radially on long branches, with 3-5 leaves clustered on short branches, slender petiole in fan shape, light green on both sides, hairless, with many branched parallel veinlets, notched or 2-cleft on the broad top edge, 5-8 cm wide, and many branched veinlets that turn yellow before falling leaves in autumn. Cones are dioecious, unisexual and clustered in the axils of scaly leaves at the top of short branches. Male cones are inflorescence-shaped, drooping, with loose stamens and short peduncle, usually with 2 anthers, long oval, longitudinally dehiscent anthers, and no drug-separated hairs; Female cones have long stems, which are often divided into two branches, 3-5 or none. There is a disc-shaped ovule at the top of each fork, and the ovule is attached to it. Usually, the ovule with only one bifurcation develops into a seed and pollinates internally. It blooms in April and matures in June, 5438+ 10. The seeds are long-stalked, pendulous, often oval, obovate, ovoid or nearly spherical, 2.5 ~ 3.5 cm long, and the aril is bony and white, often with 2 (sparse 3) longitudinal edges. Endosperm membranous. It is cultivated all over China and distributed in Xiaolongshan mountain area.

2. Overview of the environment in Xiaolongshan mountain area

Xiaolongshan Forestry Experimental Bureau is located in Tianshui, Longnan, Qin Zhou, McKee, Qingshui, Wushan, Huixian, Liangdang, Lixian and Zhang Xian in Dingxi. Geographical coordinates are 104 22' ~ 106 43' east longitude, 33 30' ~ 34 49' north latitude, 700~3330m above sea level, annual average temperature 7 ~ 12℃, annual average precipitation 460~800mm and frost-free period 6500. The forest region has a mild climate, abundant rainfall and superior natural conditions, belonging to the warm temperate semi-humid continental monsoon climate, with plenty of sunshine and rainfall in the growing season, which is suitable for seedling growth.

3 sowing and cultivation methods

Ginkgo biloba can be cut, grafted and propagated by sowing.

Cutting propagation can be divided into old branch cutting and tender branch cutting. Old branch cutting is suitable for the propagation of large-scale green seedlings, and tender branch cutting is suitable for the propagation of a small number of seedlings in families or garden units. Generally, cuttings of old branches are carried out in March-April in spring. Select high-quality branches of 1-2 years old, cut them into cuttings of 15-20 cm long, wash them with clear water, soak them in 100 mg/ml of Bt rooting powder 1h, and insert them into loose seedbeds. After transplanting, water is poured enough to keep the soil moist, and it can take root in about 40 days. After survival, it can be transplanted in the next spring. Grafting propagation can be carried out from late May to early August, avoiding high temperature, drought and rainy days. Collect well-developed perennial branches from the mother plant of Ginkgo biloba, cut off 1 leaf on the scion, leaving only the petiole, and cut off 1 segment every 2 ~ 3 buds, then immerse the lower end of the scion in water or wrap it with wet cloth, and it is best to use it for grafting. Grafting rootstock can choose 2 ~ 3-year-old sowing seedlings and cutting seedlings. Generally, the scion is cut inward, inserted into the incision of the rootstock to make it match, the cambium is aligned, the joint is wrapped with plastic film tape, and the fruit begins to bear fruit 5 ~ 8 years after grafting. Sowing and propagation are mostly used for large-scale greening seedlings or making bonsai. After harvesting the seeds in autumn, remove the seed coat and dry the seeds with the peel for sowing in winter or the next spring. If you sow in spring, you must first carry out mixed sand stratification to accelerate germination. When sowing, put the seed germ into the sowing ditch horizontally, cover the soil with a thickness of 3 ~ 4 cm and compact it, and the seedlings can grow to a height of 15 ~ 25 cm in the same year. After the leaves fall in autumn, they can be transplanted. However, it should be noted that the seedbed should be selected in a well-drained place to prevent the accumulated water from rotting the seedlings near the ground.

4 potential customers

Because of its perfect characteristics, Ginkgo biloba is called a tree in many cities (Chengdu, Dandong, etc.). ). Its lush greenery and autumn comfort give people the feeling of precipitousness, elegance, perfect tree structure and strong resistance, and it is an excellent tree species for environmental protection and greening. Ginkgo biloba is a treasure, not only a representative of culture, but also a good wood and medicinal tree species. In the Ming Dynasty, Li Shizhen once said: "Entering the lung meridian can benefit the temper, relieve asthma and cough, and reduce defecation." In the Ming Dynasty, Chinese patent medicines made of Ginkgo biloba appeared in Jiangsu, Sichuan and other places for clinical use. Ginkgo trees are tall and straight, and wood is a high-grade material for making musical instruments and furniture. Ginkgo wood is of high quality and low price, and is known as "silver fragrant wood" or "silver wood". Ginkgo wood has luster, straight texture, fine structure, easy processing, no cracking, strong corrosion resistance, easy painting, low nail digging power, special medicinal flavor and strong insect resistance.