Longan is a fruit tree that is grafted and propagated under high pressure. It has passed its infancy and can blossom and bear fruit at any time under appropriate conditions. However, from the time of planting, the characteristics of growth, flowering and fruiting are different according to the age of the tree, which can be divided into juvenile stage, growth transition stage, adult stage and aging stage. \x0d\\x0d\( 1) Young longan is called young longan, which lasts for 4-5 years from the year when seedlings are planted to the first fruit. It is characterized by the nutrient competition between the top branch and the lateral branch, which makes the lateral branch in a relatively hungry state and lacks the material basis needed for flower bud formation. Secondly, buds germinate many times, grow vigorously, have few roots, are shallow in distribution and have weak resistance to stress. In the later stage, the tree began to have the ability to blossom, but it was difficult to bear fruit. The purpose of young tree management is to improve the survival rate, expand the growth range of roots, increase the number of roots, cultivate strong and evenly distributed backbone branches, expand the crown and increase the green leaf layer, laying the foundation for the formation of flower and fruit organs and early fruiting and high yield. Standard of fast-growing and early fruiting: crown width of 5-year-old longan 1.2 m× 1.2 m, average yield per plant of 8 kg, average yield per plant of 6-year-old longan 15 kg and average yield per plant of 7-year-old longan of 20 kg. \x0d\\x0d\ In order to make longan trees bear fruit ahead of time and have high yield, the cultivation management requires that: firstly, the orchard land should be comprehensively improved and soil and water conservation should be carried out, so as to create good nutrient and water supply conditions for longan growth and fruiting, prevent and control various diseases and pests in time, and make young trees grow healthily. Secondly, on the basis of cultivating young trees with three or four main branches, plastic pruning technology is applied to promote the vigorous growth of young trees, rapidly expand the crown and lay a good tree frame foundation for early fruit. Finally, inhibiting the growth of the top branches, such as treating with ethephon and B9, cutting off the upright branches and girdling, will slow down or stop the growth of the top branches, help the side branches to obtain sufficient nutrients, change the balance of endogenous hormones and promote the formation of flower buds. \x0d\\x0d\(2) The growth transition period is the period from vegetative growth to reproductive growth, also known as the growth transition period. It can blossom and bear fruit during this period, but the growth is still dominant. The vegetative growth of branches and leaves is too vigorous, and the shoots are vigorous. Especially in the warm winter climate, it is easy to shoot winter bamboo shoots, with high nutrient consumption, and it is difficult to accumulate assimilates and carbohydrates, or it is difficult to form flower buds, or spikes are easy to "shoot". The quality of flowers is poor or the proportion of female flowers is low (generally below 4%-6%), and only a small amount of fruit can be produced or it is difficult to set fruit. Therefore, measures such as increasing branching angle, opening crown, increasing phosphorus and potassium application, controlling late fertilization and controlling emergence of winter shoots should be paid attention to in cultivation to slow down vegetative growth and make it enter reproductive growth smoothly, thus improving yield. \x0d\\x0d\(3) The mature period is the most vigorous period for longan to blossom and bear fruit, and it can blossom and bear fruit normally after 20 years of planting. This period is dominated by reproductive growth, and the flowering is not limited by the age of the tree. The flowering is more regular than that of young and strong trees, and the yield per plant is from low to high, and then it is relatively stable at a certain level. However, in the one-year growth cycle of longan, the tree does not have the inherent ability to adjust the balance of vegetative growth and reproductive growth, and fails to maintain the physiological basis of relatively balanced and coordinated growth and fruiting. So year after year, it follows the phenomenon of results every other year. The fruit in the second year is the inherent nature of mature longan trees, and no human intervention measures such as thinning flowers and fruits can change its nature. \x0d\\x0d\(4) Weak trees can be divided into three types according to the degree of aging: the tree is weak, but the trunk is normal, which is an early decline type; Branches and leaves are sparse, there are many dead branches, and the trunk is damaged, which is a middle-declining type; There are few leaves, the trunk is seriously damaged, some xylem decays, and the trunk bark falls off, which is close to death, which is a serious decline type. The reason for the aging of longan trees is natural aging. After years of flowering and fruiting, the longan tree consumes a lot, the branches and roots are too high, and the distance between roots and leaves is long, which leads to more nutrient loss in long-distance transportation, decreased soil fertility, root recession, less nutrient absorption, less and tender germination of new shoots, more dead branches, and obvious decline or even no fruit. Second, extensive management and natural disasters, such as frost and typhoon, can also lead to premature aging. Therefore, it is necessary to renew and renew trees, restore their vitality, prolong the bearing age and increase economic benefits. \ x0d \ x0d \ After longan begins to age, the growth of new shoots tends to be centripetal, the germination ability of new shoots around the crown is poor, and some branches die. When adventitious buds distributed on the main and lateral branches in the crown often pull out the growing branches, attention should be paid to renewal and rejuvenation. Regeneration and rejuvenation work includes two parts: root rejuvenation and crown regeneration. The time of regeneration and rejuvenation is better before spring shoots germinate, and after regeneration, new shoots are required to germinate 2-3 times in the same year, which is beneficial to the recovery of tree potential. After longan regeneration, it should be allowed to bear no fruit for one or two years to speed up the recovery of root system and crown, otherwise it will lose the effect of regeneration and rejuvenation. Regeneration methods: root regeneration, crown shortening and pruning.