Yew
(Scientific name: Taxus wallichiana var. chinensis (Pilg.) Florin): is a tree of the yew order, yew family, yew genus, up to 30 m tall, chest diameter of 60–100 cm; bark gray-brown, reddish brown or dark brown; winter buds yellow-brown, light brown or reddish brown, shiny, buds triangular ovate, spineless or longitudinal ridges on the back. The leaves are arranged in two columns, striped, slightly curved or straight, dark green above, shiny, and below pale yellowish green, with two stomata bands. The stoic flowers are pale yellow, with 8-14 stamens and 4-8 anthers. The seeds grow in cup-shaped red fleshy pseudoseeds, often ovate, narrowed in the upper part, sparsely ovate, slightly flattened or rounded, often with two blunt ridges in the upper part, with a short blunt tip protruding at the apex, and a nearly round or broad oval umbilicus.
The heartwood is orange-red, the sapwood is light yellowish-brown, the texture is straight, the structure is fine, it is firm and durable, and it has less cracking after drying. It can be used for construction, vehicles, furniture, appliances, agricultural tools and stationery.
It is endemic to China and is native to southern Gansu, southern Shaanxi, Chongqing, northeastern and southeastern Yunnan, western and southeastern Guizhou, western hubei, northeastern Hunan, northern Guangxi and southern Anhui (Huangshan), often growing in the upper parts of high mountains above 1000-1200 meters above sea level. It is cultivated in Lushan, Jiangxi.
Yew is also known as yew, also known as red cedar pine. A rare and protected tree species of the national level in China. Yew is a shallow-rooted plant with inconspicuous taproots and well-developed lateral roots. It is recognized as an endangered natural rare anti-cancer plant in the world, and is an ancient tree species left over from quaternary glaciers that has been on earth for 2.5 million years. Due to the slow growth rate and poor regeneration capacity of yew under natural conditions, for a long time, there has been no large-scale yew raw material forest base in the world. In 1994, yew was designated as a first-class rare and endangered protected plant by China, and at the same time, it was called a "national treasure" by 42 countries with yew trees in the world, and the United Nations also banned logging, which is a veritable "plant giant panda".
First, the morphological characteristics of yew trees
Yew is a tree up to 30 m tall and has a thorax diameter of 60–100 cm; bark is gray-brown, reddish-brown or dark brown, split into strips and falls off; large branches are unfolded, with annual branches green or pale yellowish-green, turning greenish yellowish or reddish-brown in autumn, yellowish brown, reddish brown or grey-brown on two- and triennial branches; yellowish brown, light brown or reddish-brown winter buds, glossy, triangular ovate buds, spineless or longitudinal ridges on the back, shedding or rarely dwelling at the base of the twigs.
The leaves are arranged in two columns, striped, slightly curved or straight, 1-3 cm long (mostly 1.5-2.2) cm, 2-4 (mostly 3) mm wide, slightly narrower in the upper part, often slightly sharp at the apex, rare sharp tip or tapering tip, dark green above, shiny, pale yellowish green below, with two stomata bands, and the midribal belt has a dense and uniform and tiny round horny papillary beginning, often the same color as the stomata, and the thin color is lighter.
The male bulbs are pale yellow, with 8-14 stamens and 4-8 anthers (mostly 5-6). Seeds grow in cup-shaped red fleshy pseudoseeds, occasionally on near-membranous disc-shaped seed trays (i.e., beads that have not developed into fleshy pseudocospers), often ovate, tapering and narrowing in the upper part, sparsely ovate, 5–7 mm long, 3.5–5 mm in diameter, slightly flattened or round, often with two blunt ridges in the upper part, three blunt ridges in the upper part, three blunt ridges in the sparse upper triangle, a short blunt pointed head protruding at the apex, a nearly round or broad oval shape of the seed umbilicus, and a sparse triangular circle.
Second, the growth habit of yew
Wild yew growing conditions are almost harsh, the growth area is narrow, and the climatic conditions are strict, why can there be such a lush growth community in the Milk source mountains? According to Mo Yibin, a local expert who has studied and protected the tree species for many years, the unique geographical environment, humid and humid climate, good ecological environment, and vigorous protection by the local people are indispensable. Daqiao Town belongs to the alpine limestone mountainous area, with an average altitude of more than 800 meters, a temperature difference of 7 °C between day and night, an average temperature of only 17 °C throughout the year, and a humid climate in spring and summer, which is very suitable for the growth of yew trees.
Yew has the characteristics of liking shade and moisture, afraid of sun, afraid of flooding, drought tolerance and cold resistance, and requires the soil PH value to be 5.5 to 7.0, and can be selected to be planted and promoted on a small scale in the ecological area similar to the climate and soil conditions of its origin.
Third, the variety of yew and the ornamental value of greening
1. Northeast yew is not only a rare medicinal plant but also a good product for gardening, courtyard greening and beautification, and is currently the most precious and rare high-grade greening tree species. With a unique ornamental value of bonsai is another major feature of northeast yew, the application of dwarfing technology treatment of northeast yew bonsai shape is simple and elegant, smooth red stems represent frankness and nobility, evergreen needles express perseverance and eternity, and red beans that resemble "acacia beans" show love and thoughts. The whole plant is implicit and not revealing, otherworldly, with a strong atmosphere of life and cultural heritage. Northeast Yew is listed as a first-class rare tree species in China for protection due to its scarce resources.
2. Yunnan yew (T.YUENNAN ENSIS CHENG ET L.K.FU) is mainly distributed in 16 counties in western Yunnan and Dizhou, with a total area of about 90,000 square meters. It is characterized by wide distribution, scattered growth, no pure wood forest, mostly scattered wood in the forest.
3. Tibetan yew (T.WALL ICHIANA IUCC) is mainly distributed in northwestern Yunnan, southern Tibet, and southwestern Yunnan.
4. Chinese yew (. CHINENSIS （PILGER） ROHD）
5. Southern yew (T.CHINENSIS VAR MAIREI (LEMEE ET L'EVL) CHENG ET L.K.FU) is mainly distributed in the pure forests of eastern Yunnan, southwestern Yunnan and eastern Yunnan, and the others are mostly scattered trees in the forest.
6. Mandia yew is a hybrid variety introduced to China at the end of the twentieth century. Its mother is the Northeast Yew (T.CUSPIDATA), and the parent is the European Yew (.T.BACCDFA), which is only 80 years old in the United States and Canada. Mandia yew is mostly a shrub type, because it can only grow into a shrub, can not grow into a tree, so it is a good variety of greening.
Globally, although yew trees are found in the United States, Canada, France, India, Myanmar and China, Asia has the largest reserves of yew trees. Among them, China's yew reserves are more than half of the global reserves, and there are 5 species in China among the 11 varieties in the world.
Fourth, the medicinal value of yew and its environmental protection value
1. The medicinal value of yew. Yew has the effect of diuretic swelling, warm kidney menstruation, treatment of kidney disease, diabetes, nephritis edema, unfavorable urination, gonorrhea and menstrual irregularities, postpartum blood stasis, dysmenorrhea and so on have a good effect.
(1) Anti-cancer and anti-cancer
Paclitaxel extracted from the bark and leaves of yew trees has outstanding efficacy on a variety of advanced cancers, mainly used in the treatment of advanced breast cancer, advanced ovarian cancer, esophageal cancer, nasopharyngeal cancer, bladder cancer, lymphoma, prostate cancer, malignant melanoma and head and neck tumors, upper gastrointestinal cancer, small cell and non-small cell lung cancer. Experience has proven that paclitaxel has a unique anti-tumor mechanism and significant tumor inhibition effect.
(2) Hypoglycemic
The yew in yew has a certain hypoglycemic effect. Suitable for patients with hyperglycemia to assist in hypoglycemic use.
(3) Anti-inflammatory effect
Yew contains a large number of tannins, which have antibacterial and anti-inflammatory effects, and have a very significant therapeutic effect on nephritis, hepatitis, gastritis, laryngitis, gynecological inflammation, prostatitis, hemorrhoids, rheumatoid and so on.
(4) Anti-leukemia effect
Yew contains a large number of yew terpenoids, yew ning, ye shan ning A, ye shan ning H, ye shan ning K, ye shan ning L, paclitine, paclitaxel, paclitaxel and many other elements, has a certain anti-leukemia effect.
(5) Antioxidant effect
Yew is rich in bioflavonoids, which have a good antioxidant effect, effectively maintain organ function, and delay the aging of the body.
2. The environmental protection value of yew trees.
(1) Inhaling carbon dioxide 24 hours a day and spitting out oxygen; at the same time, a negative oxygen body can be released, which can not only purify the air, anti-inflammatory and sterile, but also enhance resistance, prevent diseases and benefit human health after being inhaled by the human body.
(2) Has the ability to repel mosquitoes and avoid insects, it volatilizes odor molecules - citronellal, the higher the temperature, the more volatile incense molecules, the better the mosquito repellent effect.
Since yew has such precious medicinal, ornamental and environmental value, it has been hyped to sky-high prices and vigorously promoted and planted, but now it is rarely artificially planted. The author analyzes from the perspective of personal professionalism and understanding, but there are the following reasons:
First, the natural distribution range of yew is very narrow and rarely distributed in flakes, which proves that yew is very demanding on climate and soil conditions, and is planted in places where climate and soil conditions are uncomfortable, with poor growth and even inability to grow.
Although yew has anti-cancer and anti-cancer, hypoglycemic, anti-inflammatory, antioxidant and other effects, but as a plant to extract these medicinal ingredients is not only a variety of yew, therefore, the use of raw materials is not very large, the price will not be too high, and medicinal material manufacturers generally have formal procedures and large cultivation area of the planting base signed a purchase contract, and scattered growers because they can not provide formal procedures and small supply of reasons are excluded, planting can not find a market.
In addition to the larger plantations, the production site is fixed, the area is larger, it is easy to confirm the source of production and easy to apply for a production and sales license, other sporadic growers are difficult to apply for a production and sales license, even if they are planted privately, they are not allowed to be used privately, once they are found to be illegally logged and sold, the serious ones are even imprisoned.
The market price of yew trees is not as large as when planting was vigorously advertised before, resulting in a decline in the enthusiasm for planting yew trees.
Fifth, some growers have been punished by forestry law enforcement departments for illegally producing and selling yew trees, which has also led to a decline in the enthusiasm for planting yew trees
