How to select dawn redwood seeds? What are the seedling raising methods?

The dawn redwood has strong adaptability and prefers moist conditions; in a suitable environment it grows relatively fast, and it is currently cultivated in most areas of our country. The dawn redwood's wood is light and soft, and can be used for construction, boards, papermaking and other applications. The dawn redwood has a certain resistance to sulfur dioxide, and is an ideal tree species for landscaping in industrial zones and mining areas. So how do you select dawn redwood seeds? What are the seedling raising methods? Take a look with the editor below.

1. How to select dawn redwood seeds?

Dawn redwood seeds are few in source and rather small, so for a small quantity of seeds it is best to use nutritional cup seedling raising. Seed-bearing trees of dawn redwood generally must reach 25-30 years of age before they can bear seed. In mid-to-late October to November, the dawn redwood cones mature; when the cone scales turn yellowish brown and slightly split with a small amount of seed falling out, harvest the cones in time, and dry them in the sun for a few days in sunny weather; when most of the cone scales have split open, tap the cones lightly to obtain the seeds. The seed extraction rate of dawn redwood is about 7%, and the seeds are stored dry in cloth bags. Dawn redwood seeds have many empty grains and a low germination rate, generally 9%.

2. What are the seedling raising methods for dawn redwood?

1. Sowing and seedling raising

For sowing and seedling raising, choose a plot with sufficient water, good drainage, few pests and diseases, and fertile, loose soil. Prepare the land and make the beds carefully, and apply enough base fertilizer. The sowing time is generally March to April, suitable when the ground temperature reaches 12°C. Drill sowing (row spacing 20-25cm) or broadcast sowing, with a sowing rate of 1-1.5kg per mu. Before sowing, irrigate enough bottom water, mix the seeds with fine sand and sow, with a covering soil thickness such that the seeds are just not visible. After sowing, cover with grass and sprinkle water appropriately; germination begins in about 10d, and after the seedlings have basically emerged completely, remove the grass covering in time and provide shade. During the seedling growth period, weed, loosen the soil and water in time, and apply several topdressings. After September, the shade shed can be gradually removed. One-year-old seedlings can reach more than 40cm in height. The following spring they can be lifted from the nursery for planting or moved to beds to cultivate larger seedlings.

2. Cutting propagation and seedling raising

The rooting ability of dawn redwood cuttings decreases as tree age increases; generally cuttings are taken from 1-3 year old seedlings.

(1) Spring cuttings

Generally the cuttings are 10-15cm long, with the upper end cut flat 1cm from the bud and the lower end cut obliquely. For the cutting position on the branch, the tip section and middle section of young trees are better; cut and insert immediately. In order to improve the survival rate of dawn redwood cuttings, in addition to treatment with growth hormones, the "winter storage" method for cuttings is generally used. In winter, cut healthy branches from the mother tree into cuttings, tie them into bundles of 60-100 according to thickness, choose a leeward, sunny place with good drainage, dip the bases of the bundled cuttings in slurry, stand them upright and bury them in wet sand, and cover them with a shed mat to prevent the soil from freezing and rain and snow from entering and rotting the cuttings. Practice has proved that dawn redwood cuttings that have undergone winter storage have softened tissue at the base, root easily after insertion, and this helps increase the survival rate and the rate of successful seedling formation. After dawn redwood cuttings are inserted, the temperature rise is not great; as long as they are watered appropriately and the seedbed is kept moist, there is no need to shade immediately, which can raise the soil temperature and help the cuttings root. After late April, begin shading; on sunny days cover early and uncover late, and do not cover on cloudy and rainy days. After the dog days, gradually shorten the shading time, and after early September, shading may be stopped. Loosen the soil and weed frequently. After the cuttings have rooted, apply 2-3 topdressings to promote seedling growth.

(2) Summer cuttings

Late May to early June is suitable, when the highest temperature reaches 27°C-28°C; collect cuttings on sunny days at dawn before the dew has dried, select semi-lignified young shoots 14-18cm long, keep the top tip and the upper 4-5 pinnate leaves, insert 4-6cm into the soil, with 70,000-80,000 cuttings per mu. Young shoots have vigorous physiological activity and strong regeneration ability, and generally root in 20-25d after insertion. After insertion, shade and mist 3-5 times a day to keep the seedbed moist. From late August, gradually shorten the shading time, and after late September the shade shed can be removed to promote lignification of the seedlings and help them overwinter.

(3) Autumn cuttings

This can be done from the end of August to early and mid-October, before the leaves first fall. For cuttings, choose branches with short internodes and vigorous growth, and avoid using long-internode water sprouts to cut cuttings. The cutting length is 12-20cm, preferably with the top tip or terminal bud. When collecting shoots and cutting cuttings, put the shoots and cuttings into a bucket or basin in time to keep the cuttings moist. On the prepared bed surface, cuttings can be inserted in water, or holes can be made with a thin stick and inserted dry, with plant and row spacing of 3cm x 10cm. If not moving to beds, the plant and row spacing can be 5cm x 15-20cm. After insertion, water thoroughly the first time. For early autumn cuttings, the temperature is still high, so shade appropriately and pay attention to frequent watering to keep the seedbed soil moist. For later cuttings, water appropriately and there is no need to shade. In about 1 month the cuttings heal and root. After the first frost arrives, cover with plastic film to keep warm and let light through, which helps the cutting root system develop; in March of the following year, move to beds and plant at a certain plant and row spacing to cultivate large seedlings. Dawn redwood autumn cuttings have a long period, a wide source of shoots, and good results.

The above is an introduction to dawn redwood. Because cutting propagation is relatively easy and the saplings obtained grow vigorously and uniformly, people use cutting propagation more often; cutting propagation and seedling raising is an effective way to speed up the propagation of dawn redwood.