The specific time of pruning depends on the specific temperature characteristics of the local winter. For example, in the northern region where the winter is cold, the wound is vulnerable to freezing injury after pruning, so it should be pruned in early spring, usually about 2 months before the juice flows out in spring; However, some flowering shrubs that need to be protected in winter should be pruned before the fallen leaves freeze in autumn, and then buried in the soil or wrapped in tree trunks to keep out the cold.
Plastic road
The main purpose of modeling is to maintain a reasonable crown structure, maintain the subordinate relationship between branches at all levels on the crown, promote the balance of the overall tree potential, and achieve the purpose of viewing flowers, fruits, leaves and modeling appreciation, mainly including:
Natural shaping is based on the crown formed by natural growth, and only the crown growth is adjusted and arranged to make it more beautiful and natural. Maintaining the natural form of trees can not only reflect the natural beauty of garden trees, but also conform to the growth and development habits of trees themselves, which is conducive to the maintenance and management of trees. Studying and understanding the natural crown shape of tree species is the basis of natural modeling. The natural crown shapes of trees are mainly: cylindrical, such as cedar, juniper and cypress; Tower shape, such as cedar, Metasequoia, fir, etc. ; Oval, such as American black poplar and Canadian poplar; Spherical, such as bone shape, heather shape, pittosporum shape, etc. ; Cluster, such as rose, Tang Di, begonia; Arch-shaped, such as forsythia suspensa and winter jasmine. ; Vertical branches, such as locust trees and elms; Creeping, such as Sabina vulgaris, Sabina vulgaris, etc. Pruning needs to be mastered flexibly according to different tree species. For example, for uniaxial branching trees with central leadership, attention should be paid to protecting the terminal buds, preventing the top from destroying the crown shape, inhibiting or cutting off the transverse branches, regenerated branches and long branches that disturb the growth balance and destroy the tree shape, and maintaining the symmetry and integrity of the crown.
According to the needs of landscape configuration, artificial shaping is suitable for boxwood, Ligustrum lucidum, cypress, water wax and other tree species with dense branches and small leaves. Common tree-like geometric modeling, irregular artificial modeling, pavilions, doors and other sculpture modeling, originally used in western gardens, has gradually become popular in China in recent years.
Natural and artificial mixed modeling is a modeling method based on natural tree shape and combining ornamental and tree growth and development requirements.
The cup-shaped tree has only one lower trunk, and there are three main branches on the upper part of the trunk, which are evenly arranged around; Each main branch has two branches, and each branch has two branches, forming 12 branches, forming a tree called "three branches, six branches and twelve branches", which is more common in urban street trees. The cup crown has no upright branches and inward branches, and it must be cut off once it appears.
Natural happiness is suitable for viewing flowers and fruits, such as peaches, peaches and plum blossoms, which are weak and dry, and it is an improved plastic way of cup shape. The only difference is that the branches are low, the chamber is not empty, and the three main branches are distributed at certain intervals, radiating outward from the trunk and developing toward the center.
The trunk shape of the central leadership is suitable for tree species with strong dryness, obvious trunk of the central leadership and capable of forming a tall crown, such as paulownia, ginkgo biloba and coniferous trees. , commonly used in shade trees and solitary trees.
The multi-trunk shape is suitable for tree species with strong germination ability, and 2 ~ 4 trunks can sprout from the base of the trunk to form a clustered crown shape, such as flowering trees and shade trees such as osmanthus fragrans, pomegranate, crape myrtle and begonia.
Shrub type is suitable for small shrubs such as Yingchun, Forsythia suspensa and Huangxin. There are more than 10 main branches at the base of each shrub, and 3-4 new main branches are added and 3-4 old main branches are cut off every year to maintain vigorous growth and flowering ability.
Scaffolding modeling is suitable for the modeling of three-dimensional gardens, such as vines such as grapes, wisteria seedlings, Cinnamomum camphora and Akebia. The specific shaping and pruning methods vary with the frame shape, including fence wall type, scaffolding type, corridor type and so on.
Pruning technique
Short cut, also known as short cut, refers to the cutting treatment of annual branches. After the branches are cut short, the nutrients are relatively concentrated, which can stimulate the germination of lateral buds under the incision, increase the number of branches, and promote vegetative growth or flowering and fruiting. The degree of truncation has a significant effect on the pruning effect.
Light and short shears are used to cut off 1/5 ~ 1/4 of the total length of branches, and are mainly used to trim the strong branches of flowering and fruit-watching seedlings. After the branches are cut short, most of the semi-full buds are stimulated to germinate, forming a large number of short and medium branches, which are easy to differentiate into more flower buds.
Cutting off 65,438+0/3 ~ 65,438+0/2 of the total length of branches in short and medium cutting can concentrate nutrients and promote more nutritious branches under the cutting mouth, which is mainly used for the cultivation of backbone branches and extended branches and the rejuvenation of some weak branches.
Cutting off 2/3 ~ 3/4 of the total length of branches with heavy weight and short length has a great stimulating effect and can promote the bud germination at the base of branches, which is suitable for rejuvenation and renewal of weak trees, old trees and old and weak branches.
Only 2 ~ 3 buds are left at the base of extremely heavy short branches, and the rest are all cut off. After pruning, the short branches in 1 ~ 3 will sprout, which is mainly used for the treatment of competitive branches.
Retraction method, also known as shrinkage cutting method, refers to the pruning method of shortening perennial branches. When the growth potential of trees is weakened, some branches begin to droop, and baldness appears in the middle and lower part of the crown, this method is often used to rejuvenate the aging branches and renew the fruiting branches, so as to promote the vigorous growth of branches below the incision or stimulate dormant buds to germinate and grow branches, thus achieving the purpose of rejuvenation.
Thinning can reduce the number of branches in the crown, make the distribution of branches tend to be reasonable and uniform, improve the ventilation and light transmission in the crown cavity, enhance the assimilation function of trees, reduce the occurrence of pests and diseases, and promote the vegetative growth or flowering and fruiting of branches in the crown cavity. The main objects of thinning are weak branches, pests and diseases, dead branches and cross branches, interfering branches and sprouting branches that affect tree modeling. Especially the upright branches sprouting in the crown are suitable for thinning as soon as possible because of their small buds, long internodes, thick, high water content and insufficient tissue, so as not to affect the tree shape. But if there is room for growth, they can be transformed into branches, which can be used for the renewal and transformation of crown structure and the rejuvenation of old trees.
Thinning can weaken the overall growth of the whole tree, but promote the local growth of the tree. The local stimulation of thinning is different from short cutting. It strengthens the branch below the ipsilateral incision, but weakens the branch above the ipsilateral incision. However, it should be noted that thinning branches will form wounds on the mother branches, thus affecting the transport of nutrients. The thinner the branches, the closer the wound spacing, and the more obvious the weakening effect.
The weakening degree of thinning on the whole tree growth is related to the thinning intensity and the strength of the thinning branches. If the thinning intensity is high and the branches are weak, the growth of trees will be greatly weakened. Thinning perennial branches has a great weakening effect on the growth of trees, and it is generally appropriate to carry out it in stages. Thinning intensity refers to the proportion of thinning branches in the whole tree. When thinning the whole tree, 10% of the branches are light, 10% to 20% are medium, and more than 20% are heavy. In practice, the thinning intensity depends on the specific conditions such as tree species, tree potential and tree age. In general, trees with strong germination rate, weak branching ability or weak germination rate and branching ability should be thinned less, such as Pinus massoniana, Pinus tabulaeformis and Cedar. Trees with strong germination rate and strong branch formation can be thinned more. For flowering shrubs, thinning can promote the formation of flower buds and facilitate early flowering. Young trees should be light and sparse to promote the rapid expansion of crown; Adult trees entering the peak period of growth and flowering should be properly thinned to adjust the balance between vegetative growth and reproductive growth and prevent flowering and fruiting. Trees in aging period have weak branching ability, so in order to keep enough branches to form a crown, they should be sparse as little as possible.