Michelia chapensis, also known as Michelia jinglie, Michelia australis and Michelia macrophylla, is an evergreen tree of Michelia in Magnoliaceae. Its trunk is straight, its crown is beautiful, its flowers are elegant, and its seasons are lush. It is widely used in street trees, courtyard shade trees and landscape trees, especially suitable for the configuration of landscape forests, and it is favored by landscaping departments. Michelia Lechang also has the characteristics of straight dry shape, straight wood grain, low density, small difference between drying and shrinkage, easy drying, no warping, no bending and cracking, and rapid growth, which conforms to the cultivation goal of timber forest and is an ideal substitute for coniferous plantations such as Pinus massoniana and Chinese fir. However, due to the predatory utilization of Michelia Lechang natural forest for a long time, the natural resources of Michelia Lechang in the southern forest region have been seriously damaged, and the natural resources of Michelia Lechang have been exhausted day by day. Therefore, it is of great practical significance to speed up the afforestation of Michelia Lechang and promote the development of its industrial raw material forest for adjusting the tree species structure of plantation in South China. The author summarizes the afforestation techniques of Michelia Lechang as follows.

1 Bio-ecological characteristics

Michelia Lechang is an evergreen tree with a diameter of _15-3m and a DBH of 1m; Bark grayish white to grayish brown, smooth. Except that the buds and nodes are gray-brown and prostrate and fine hairs when they are young. The leaves are thin leathery, obovate or oblong obovate, the apex is acuminate or nearly acuminate, the petiole is 1.5~2.5cm long, and there is no stipule mark. Tepals 6.2 rounds; The gynoecium stalk is 7mm long. Aggregate fruit is about 1cm long, oblong or oval, flat and slightly oblique, with sparse and inconspicuous lenticels. Seeds ovate or oblong-ovate. The flowering period is 3 months and the fruiting period is 7~8 months. Michelia Lechang is widely distributed in China, which starts from the mountainous area in southeastern Guizhou in the west, reaches the evergreen broad-leaved forest in Yifeng hilly area in Jiangxi in the east and reaches Huaiji in Guangdong in Pingting, Hunan in the north, including Jiangxi, Hunan, Fujian, Guangdong, Guangxi, Guizhou and other places. It is equivalent to the range of 2 55' ~ 28 42' N and 17 14-114 47 E, with a north-south longitudinal direction of 4. 37, things span 7. 33,。 Its natural distribution is the densest in Nanling area, with the central distribution area. Due to the influence of man-made deforestation, Michelia Lechang is mostly distributed intermittently at present. There are still small communities of Michelia Lechang in Zixing, Liling, Yifeng, Jiangxi and Shaowu, Fujian, but in other areas, it is mostly scattered or small clusters.

Michelia Lechang in Fujian is mainly distributed in the northern part of Fujian. There are a large number of Michelia Lechang natural forests in Shaowu, Fujian, which generally grow naturally in V-shaped valleys and streams with high air humidity and good water and fertilizer conditions. Most of the soils distributed are mountainous yellow-red soils with developed soil-forming materials such as granite and sand shale, and the soil thickness is thin, but the soil organic matter content is relatively low. Most of them are scattered in the valley evergreen broad-leaved forest between 35-45m above sea level in northern Fujian, and their main associated trees are Cyclobalanopsis glauca, Cyclobalanopsis microphylla, Shidong and Bitter. Fund Project: Science and Technology Extension Project of Fujian Provincial Forestry Department "Promotion of Native Broad-leaved Tree Species such as Betula luminifera and Liriodendron chinense" (No.1, Minlin 24). Broussonetia papyrifera, Uncaria pinnatifida, Schima superba, Ilex macrophylla, Ilex latifolia, Du Ying, Monkey Happy, etc. The young Michelia Lechang forest is a deep-rooted tree species with obvious taproots and developed lateral roots, which is not tolerant to drought and flooding and has germination characteristics. I like the warm and humid climate with abundant rainfall in subtropical areas, and adapt to acidic to slightly alkaline soil, requiring loose and deep moist soil, which is suitable for the lower part of the hillside in the lee of valleys, ravines and depressions. Lechang smiles like wet soil, afraid of stagnant water, and even more afraid of drought. Severe drought can lead to large-scale death.

2 kinds of techniques

There are significant differences in fruit and seed yields of Michelia chapensis at different ages. The results showed that the seed yield of Michelia chapensis at different ages was the highest at 29a, followed by 41a and 18a. The seed quality of the mother tree institute of 29a was the best, and its 1-grain weight, indoor germination rate and field germination rate were 64.26kg, 86.79% and 83.49%, respectively, which were higher than those of the mother tree institute of Michelia chapensis born in 18a and 41a. Under normal circumstances, the average parent tree of Michelia Lechang can produce 16~19kg of spike fruit, about 8kg of fruit can produce 1kg of seeds with shells, and the seed yield of single parent tree is 2~2.5kg. The embryo of Michelia Lechang seed is very small, and the seed has a high water content, which has a dormant period and is easy to lose its vitality during drying and dehydration. If not treated in time, not only germination is slow, but also germination rate is low. Because its seeds contain fragrance and oil, it is necessary to guard against rodents during storage.

Michelia Lechang _ species should be selected from the mother tree _ set, which is about 3 years old, robust and free from pests and diseases. Its fruit ripens that year, and the fruit ripens in early October, so it is advisable to gather it in time around October every year. If the seeds are swept before maturity, the maturity of the seeds is poor and the germination rate is very low. Because the market situation of Lechang Michelia is optimistic in recent years, many forest farmers are worried that the seeds will be taken away by others, so they start when the seeds are not mature, and the skins of the seeds are all blue-yellow, so the seeds will hardly germinate. Therefore, Michelia Lechang must change the shell of aggregate fruit from green to light yellow to dark brown when the seed is mature, that is, from the beginning of October when the seed is about to mature, observe the seed morphological changes every 3 ~ 5 days to master the maturity, and harvest the seeds in time. Different site conditions (altitude, slope direction, etc.) of Michelia Lechang have different seed maturity. In Shaowu, Fujian, the seed maturity is around October 1th in the sunny low mountain area at an altitude of 5m, and it will be delayed for 5~1d in Zhongshan area above 5 m. Moreover, the seed maturity of Michelia Lechang growing on sunny slopes is early, while the seed maturity in shady slopes, valleys and damp environments will be delayed accordingly.

3 seedling raising techniques

Michelia Lechang can be raised by sowing and asexual cutting. Seeding can be used to raise seedlings in areas with guaranteed seed sources. The key technology of planting Michelia Lechang seedlings is to collect the seeds in time after the seeds mature. In order to reduce the waste of seeds and cultivate large seedlings, it is advisable to choose close sowing in winter in late December, and transplant the seedlings with soil 15 ~ 3 days after they are unearthed in March in spring. When transplanting, plant them first and then water them. The row spacing of transplanted plants is 1cmx22cm, and the transplanting density is 45 plants /n? , per hn? 225, seedlings were produced. Through these key measures, not only seed waste can be reduced, but also large seedlings can be cultivated, which basically solves the technical problems of sowing and seedling raising that restrict Michelia Lechang afforestation, and can provide enough seedlings for large-scale Michelia Lechang afforestation in southern forest areas. In areas where the source of seeds is difficult, asexual cuttings can be used to raise seedlings. The key technology of asexual transplanting seedling of Michelia Lechang is to select the top and middle cuttings of Michelia Lechang seedlings, and transplant them in winter after rooting in spring. Cut off 1cm long branches in mid-H, trim 2/3 leaves, dip them in the mud of plant root promoter, and post them on sandy loam seedbed in winter, with the row spacing of 4cmx5cm and 25 plants per row. In mid-March, all rooting cuttings were transplanted into the field for seedling raising, and the row spacing of transplanted plants was 1cmx22cm. The transplanting depth is 1/2 of the seedling height, and the seedling yield per hm2 is 225,.

4 afforestation techniques

Michelia Lechang has strict requirements on forest land, and Michelia Lechang grows well on the deep, moist and fertile shady slope, so Michelia Lechang should choose forest land with better site for artificial afforestation. Michelia Lechang has a large seedling size and a well-developed root system, so artificial afforestation can be prepared with holes of 6cmx4cmx4cm. According to different management purposes, Michelia Lechang can be used for afforestation and bud regeneration. Planting seedlings should be carefully prepared for afforestation, and the afforestation density should be 2-3 plants /bn? . According to the characteristics of shade tolerance of Michelia chapensis young forest, the afforestation density can be appropriately increased. Before planting seedlings, the branches and leaves of seedlings should be trimmed to reduce the water loss of seedlings. Choose cloudy or light rain days for afforestation, dip the root system in mud, plant it deeply, tighten it, strengthen it, and plant it deeply to more than 4cm at the root neck. Generally, the survival rate of Michelia Lechang afforestation is above 8%-9%. On the deforested and burned land, Michelia Lechang can be used to make use of its strong germination ability, and to close the mountain to facilitate afforestation and regenerate naturally, so that it can germinate into a forest or artificially promote natural regeneration. Tending of Michelia chapensis young forest is very important for its growth. Tending should be strengthened before the young forest is closed, and the soil should be loosened and weeded twice a year in the first three years after afforestation, and the redundant budding branches should be removed in time. Weeding should be done once a year in the fourth and fifth years after afforestation, and if it is not nursed in the fourth and fifth years, the growth of young trees will be seriously affected. Therefore, young Michelia Lechang forest must be nursed for five years. After the stand is closed, combined with the growth status of trees, appropriate pruning and timely cutting are carried out to promote the growth of trunk.