It is a kind of tree with a height of 10 meter. Growing in calcium-based soil produced by limestone weathering, it is not cold-resistant. In China, it is only distributed in the lower reaches of the Yellow River basin and the Yangtze River basin, and it is rare in the north of the Haihe River basin, and it can not grow in silicon-based acidic red soil areas. Luan tree germinates late in spring and leaves early in autumn, so the annual growth period is short, the growth is slow, the tree shape is twisted and beautiful, and it is not very successful. Wood can only be used to make small household appliances, and seeds can be squeezed into industrial oil. But it is a good tree for greening.

Koelreuteria paniculata is a plant belonging to the genus Koelreuteria of Sapindaceae, which is distributed in the northern and central parts of China, from the northeast to the Yangtze River valley and Fujian in the north, to the southeast of Gansu and central Sichuan in the west. Deciduous trees, the tender leaves are mostly red in spring, and the leaves turn yellow in autumn, which is very beautiful. They bloom in summer and the trees are golden, which is very spectacular. It is suitable for shade trees, street trees and landscape trees, and can also be used as shelter forest, soil and water conservation and barren mountain greening tree species. Its wood is brittle and easy to process, and can be used as plates and utensils. Leaves can be used to extract tannin extract, flowers can be used to make yellow dyes, and seeds can be used to extract oil to make soap and lubricating oil. The game tree is adaptable and easy to cultivate.

First, reproduction

Luan tree can be propagated by sowing, tillering and root cutting, and sowing is the main method. The sowing method is as follows:

1. Seed collection: Koelreuteria paniculata fruit ripens from September to 10. Select excellent single plants with good growth, straight stem shape, open crown and full fruit as seed-collecting mother trees, and harvest them in time when the fruit is reddish brown or orange and the capsule has not cracked.

2. Fruit treatment: After the fruit is harvested, it should be dried or spread in the shade in time. After the capsule is cracked, it should be knocked and threshed to screen clean seeds.

3. Seed germination: the seed coat of Luan tree is hard and not easy to seep. If the seeds are sown in the next spring without germination treatment, they often do not germinate or the germination rate is very low. Therefore, it is best to sow in the autumn of that year, so that the seeds can complete the germination stage in the soil, which can save the procedures of seed storage and germination, and the seedlings will be unearthed in advance and grow healthily in spring. However, when sowing in autumn, the seeds are placed in the field for too long, and the management of sowing sites is more troublesome. Therefore, the layered method is also used in production. Choose a dry, ventilated room that is not exposed to direct sunlight (it is dry and rainy in the northern region in winter, or it can be hidden in an open pit), and pile the seeds and three times wetter media, such as sand, sawdust and peat, in layers or in a mixed way (the wettability of the media can be kneaded into a ball by hand; Hands spread out, spread out), stacking height of 50 cm to 60 cm, on the stacking bed of about every square meter; Put a straw or bamboo cage for ventilation. At ordinary times, the room temperature should be controlled at 1℃ to 10℃, and the seeds should be checked frequently to prevent from being too wet, overheated and moldy. After 100 days to 120 days (just spring), you can sow. After stratification germination, the seedling stage is short and neat, and the effect is good.

4. Sowing: Luan trees are generally raised in the field. Sowing ground should have loose and breathable soil, good water retention and drainage performance, certain fertility and no underground pests and germs. If sowing in spring, it is best to plow 1 ~ 3 times in autumn and winter to promote soil weathering, store water and conserve moisture, and eliminate weeds and pests; The soil preparation should be smooth and fine, and the bottom water should be poured before sowing in dry and rainy areas. The seed germination rate of Koelreuteria paniculata is low, and the seed consumption is large, generally 50 g ~ 100 g per square meter. Adopting wide-width drilling is not only beneficial to ventilation and light transmission of seedlings, but also convenient for management. After sowing, cover the seeds with a layer of loose fine soil with the thickness of 1cm ~ 2cm to prevent the seeds from drying and losing water or being hurt by birds and animals. Then cover with grass, straw and other materials to improve the ground temperature, maintain soil moisture, prevent weeds from growing and soil hardening. After most of the seedlings are unearthed, they should be covered with plastic film in batches in time.

Second, raise seedlings.

1. shading; After removing the covering, it is necessary to set up a shed to shade the sun in time. Shading time and shading degree should depend on the local temperature and climate conditions at that time, so as to ensure that its seedlings are not damaged by sun burns. In autumn, the time and intensity of light should be gradually extended. Until receiving sufficient light to improve the lignification degree of seedlings.

2. interplanting and replanting seedlings; When the seedlings grow to a height of 5 cm to 10 cm, thinning should be carried out, and about 12 plants should be left per square meter. Intercropping requires small spacing, large spacing, excellent spacing, dense spacing and equal spacing, and it is best to do it in rainy days. Combined with thinning seedlings, the missing plants are supplemented to ensure the uniform distribution of seedlings.

3. transplantation; Luan tree is a deep-rooted tree species; It takes several transplants to form a good and effective root system. Sowing seedlings can be dug into furrows after defoliation in the autumn of that year; Plant separately in the next spring. Because the trunk of Luan tree is not easy to grow straight, it is necessary to cut off the stubble at the first time and strengthen the management of fertilizer and water. In spring, branches grow from the base, and those straight and strong branches are selected and cultivated into trunk, and then the trunk grows quickly and straight. If the first interception does not meet the requirements, it can be intercepted again in the spring of the following year. It should be transplanted every three years or so in the future. When transplanting, the main roots and thick lateral roots should be cut off properly to promote the generation of new roots. The young trees of Luan tree grow slowly, so the first two transplants should be properly densely planted, which is conducive to cultivating straight stems and saving land. After that, it should be properly sparse and cultivated well.

4. Fertilization: Fertilization is an important measure to cultivate strong seedlings. After the long roots of seedlings are unearthed, it is advisable to combine watering and diligent fertilization. At the peak of annual growth; Nitrogen-based quick-acting fertilizer with high nitrogen content should be applied to promote the vegetative growth of plants. In autumn, nitrogen fertilizer should be stopped and phosphorus and potassium fertilizer should be applied to improve the lignification degree of plants and the cold resistance of seedlings. It is suitable to apply farm organic fertilizer as base fertilizer in winter, which can not only provide continuous nutrients for seedling growth, but also play a role in heat preservation and soil improvement. With the growth of seedlings, the amount of fertilizer should be gradually increased to meet the demand for nutrients for seedling growth.

5. Shaping and pruning: the crown of Luan tree is nearly spherical and the tree shape is regular, generally using natural tree shape. Due to different uses, its plastic requirements are also different. Roadside saplings require a straight trunk, the height of the first branch is 2.5 meters to 3.5 meters, the crown is complete and plump, and the branches are evenly distributed. Courtyard shade trees require a large and dense crown, and the height of primary branches is lower than that of street trees. In the process of cultivation, corresponding pruning measures should be taken around the above requirements. Generally, it can be done in winter or during transplantation.

In addition, in the management of seedlings, we should also do a good job of loosening soil, weeding and irrigation and drainage according to the weather and ditch conditions. Luan tree has few pests and diseases, so once it happens, it should be prevented in time.