Detailed Guide to the Cultivation Techniques of the Chinese Yew (Taxus wallichiana var. mairei)

Yew was first recorded in the "Northeast Medicinal Plant Journal," also known as Chibaisong, Yew, and Zibaisong, and is a plant of the genus Taxus in the family Taxaceae. There are 11 species of yew worldwide, distributed in temperate to tropical regions of the Northern Hemisphere. China has 4 species and 1 variety, namely Taxus chinensis, Taxus cuspidata, Taxus yunnanensis, Taxus wallichiana var. mairei, and Taxus wallichiana, distributed in Northeast, South China, and Southwest China. In Sichuan, they are mainly distributed in Maoxian, Heishui, Maerkang, Wenchuan, Luding, Kangding, Xichang, Huili, Miyi, and other areas.

I. Variety Characteristics

Yew is an evergreen tree, about 20 m tall, with a diameter at breast height of 60-100 cm. Branchlets are alternate, leaves spirally arranged, in two ranks, linear, slightly curved, 1-4.5 cm long, 2-5 mm wide. The fruit is a spherical nut, with an aril, and the seed is ovoid. It is dioecious and cross-pollinated. The flowering period is March to June, and the fruiting period is September to November. It grows scattered in mountain forests at an altitude of 500-3,500 m, preferring shady, humid, and cool climates, with an average annual temperature of 11.2°C and annual precipitation of about 487.9 mm. This article mainly introduces the cultivation methods of Taxus wallichiana var. mairei.

II. High-Yield Cultivation Techniques

1. Site Selection and Fertilization

Choose loose, humus-rich, neutral or slightly acidic high mountain platforms, and deep, moist brown earth or dark brown earth along both banks of gullies and streams. Deep plow, level, and dig holes at a spacing of 0.4 m x 1.0 m or 0.4 m x 0.4 m, with a hole depth of 40 cm, ready for planting.

2. Propagation Methods

Seed propagation and cutting propagation are used, mainly through seedling raising and transplanting.

(1) Seed seedling raising

① Seed collection and germination promotion. In mid-to-late October, collect seeds when the fruit turns deep red. These seeds are physiologically after-ripened and require 1 year of wet sand storage before they can germinate. The seeds are often treated by the outdoor natural moist sand storage stratification method to increase the germination rate.

② Nursery selection and land preparation. Generally, raising seedlings and transplanting under pine forests according to local conditions is better. Choose a mature forest land of slash pine or masson pine with a canopy density of 0.6-0.7 and no pests or diseases as the nursery site, requiring a gentle slope, deep upper soil, and good drainage. In August to September, clear the weeds and shrubs in the forest, arrange into horizontal terraces, deep dig 20-30 cm, and in November shallow plow and harrow finely. During land preparation, apply 40-60 loads of decomposed base fertilizer per mu (1 mu = 1/15 hectare, the same below), divide into beds, with a bed height of 15-20 cm and a width of 1.2 m. After leveling the bed surface, use a 15 cm wide wooden board to press out sowing furrows, 2 cm deep, with a furrow distance of 20 cm.

③ Sowing at the right time. Generally sow in early spring. After the seeds have been stored for 1 year, when 30% of the seeds have cracked and shown white, sieve out the seeds in time, disinfect them in a 0.2% potassium permanganate solution for 10 minutes, then rinse them clean with water, and after drying the surface water, evenly sow them in the furrows. Drill sowing is mainly used, with a seed spacing of 5-7 cm. Broadcast sowing can also be used. After sowing, dig up sieved yellow soil with mycorrhizae from under the pine forest to cover the seeds, with a thickness such that the seeds are no longer visible. During the seedling stage, pay attention to shading. When sowing, cover with rice straw so that the soil is not visible. Build a shade shed during the seedling stage, with a light transmittance of 60%. Then lay moss to protect the seedlings, protect the seedbed from sun and rain, and keep the soil loose and moist regularly. The seed emergence rate is above 70%.

(2) Cutting seedling raising

During the tree's dormancy and sprouting period, choose a mixed substrate of sand, sawdust, and perlite as the cutting soil. Select 1-4 year old lignified seedling branches, cut the cuttings into small sections 10 cm, 15 cm, or 30 cm long. When cutting, the cut should be smooth, the lower cut should be horse-ear shaped, and the leaves below 2/3 should be removed. Choose agents such as ATP, ABT, NAA, IBAA, etc. to treat the cuttings, then insert them and cover with film. The cutting survival rate is generally above 85%. During the seedling stage, pay attention to keeping warm and build a low shed for shading. Transplant the following year.

(3) Transplanting

Generally, seed-raised seedlings take 1-2 years, and cutting-propagated seedlings take about 1 year. When the seedlings grow to 30-50 cm in height, they can be transplanted. Transplanting is carried out in October to November or February to March before sprouting, with 1 seedling per hole, water, and appropriate shading.

3. Field Management

After the seeds germinate, weeds must be pulled out frequently. Topdress 1-2 times per year. In rainy seasons, prevent water accumulation to avoid root rot. After planting, cultivate and weed 2 times per year. After the forest land is closed, generally only winter cultivation and weeding are done, and earth up 5 times. Combine cultivation and weeding with topdressing, mainly using farmyard manure. During the young tree stage, remove sprouts and tillers to ensure the trunk is straight and grows quickly.

III. Harvesting and Processing

Artificially cultivated yew can generally be appropriately harvested for branches and leaves after the 3rd year. Fresh leaves can be harvested all year round. However, based on the accumulation of active ingredient content, young branches are better for branches, and old leaves are better for leaves. October is the best harvest period. After harvesting, if not used for fresh processing, they should be spread out in time to dry in the shade with ventilation or in the sun.

IV. Planting Prospects

Yew is a plant left over from the Tertiary Period and is called a "living fossil" in the plant kingdom. Because its resources are scarce, it is listed as a rare tree species in the world and protected. Yew combines medicinal, timber, and ornamental uses, and has extremely high development and utilization value. Paclitaxel extracted from yew bark, branches, and leaves is a globally recognized anticancer drug, priced at 5-10 million USD per kilogram. Paclitaxel is used to treat advanced breast cancer, lung cancer, ovarian cancer, and head and neck cancer, soft tissue cancer, and digestive tract cancer. Yew branches and leaves are used to treat leukemia, nephritis, diabetes, and polycystic kidney disease. Yew natural resources are scarce, and medicinal sources are in short supply, so extensive research and development are being carried out in various places. The whole yew plant is treasured, so the yew tree is also called the "golden tree," and its planting prospects are promising. Areas with mature conditions can develop it appropriately.