That is, the botanical characteristics of chestnut and its unique biological characteristics. It mainly includes the strength of germination and branching ability, branching angle, branching hardness and the ratio of male and female flower buds. The biological characteristics of a single variety should be fully considered when shaping and pruning, and corresponding shaping and pruning methods should be adopted to achieve the purpose of efficient cultivation.

(2) Tree potential and age

Pruning should be guided by "potential" Each tree age stage has different requirements for tree potential, and the young tree stage requires the tree to be robust and cultivate a good and robust tree structure as soon as possible; To enter the full fruit stage, it is required that the tree vigor is moderate, the fruiting period is prolonged, and the reproductive growth and nutritional growth are coordinated and balanced; During aging, trees should be restored. Therefore, when the tree is vigorous, try to cut down as little as possible, thin branches and leave more branches, so that the tree can relax and reach a moderate state; When the tree is weak, more branches should be thinned and nutrient supply should be concentrated, from weak to strong to medium. In production, even in the same park, the tree potential is not necessarily the same, so it needs to be adjusted appropriately according to the actual situation, and different pruning methods should be applied reasonably to control the tree potential through pruning.

(3) Planting density and management level

Dense planting garden requires low tree body, small crown and few backbone branches, but relatively more fruiting branches; Sparse planting garden requires high trees, large crowns and long trunk branches, which is prone to poor lighting. Sufficient fertilizer and water, but improper management, rapid crown expansion, we should pay attention to crown control.

(4) Natural environment and site conditions

The natural environment and site conditions have great influence on the growth and fruiting of chestnut. There is little rain in the north, the growth period of chestnut is short, the growth amount is small, and the tree body is small, so it is suitable to adopt a small crown tree shape, and the backbone branches should not be too long. Therefore, pruning should be heavy, sparse and less, in order to concentrate nutrients, and pay attention to timely retraction and rejuvenation, so as to keep the growth results relatively stable. The southern producing areas have good site conditions, suitable temperature and humidity, and long growth period of chestnut trees. Under efficient management, chestnut trees have many branches and large growth, which is suitable for being a big crown tree. There should be fewer main branches and more layers. Pruning method should be adopted to disperse nutrients. At the same time, it is necessary to pick the heart many times in summer to promote the growth of branches, form early, bear fruit early, and press the crown with fruit. In chestnut orchards with fertile soil and good water and fertilizer conditions, chestnut trees often flourish and grow vigorously. When pruning, you can use a large crown and a higher trunk, appropriately reduce the number of main branches, appropriately increase the number of layers, and prune lightly; Chestnut orchards with poor soil conditions should adopt a small crown shape, with shorter trunk, relatively more main branches, fewer layers, smaller spacing between layers, heavier pruning, shorter nodes and fewer branches. Where there is wind damage, it is easy to choose a small crown shape, reduce the height of trunk and reduce the amount of branches left.

(5) Reaction force of plastic trimming

It is the basis and standard to test whether pruning is correct or not. The same pruning method will have different reactions when the age, position and growth of branches are different. Local reaction, mainly observing the strength, quantity and branch formation of the cut branches; The performance of the whole tree depends first on the total growth, that is, the average length of new shoots and the growth around the trunk, and then on the flowering, fruit setting rate, fruit size, fruit quality, branch fullness and cold resistance of the whole tree. In production, we should constantly sum up experience according to the pruning reaction, improve the technical level, and sort out a set of plastic pruning methods suitable for various varieties and local environment.

(6) the impact of major pests and natural disasters

In order to reduce the damage of weak insect branches and wind, hail, frost and waterlogging, corresponding pruning measures should be taken. When the red spider is damaged, the mother branch is slender and the tissue is not full, which affects the formation of female flowers in the second year. Pruning in winter should mainly restore the vitality of trees, cut more short and thin branches, and concentrate the nutrition of trees for reproductive growth.