The Latest Technical Method Tutorial for Winter Fruit Tree Pruning

Pruning carried out during the period from leaf fall to the following year's bud break is called winter pruning. For most tree species, winter pruning is generally done between January and February. The main purpose of winter pruning is to thin out and cut back unwanted branches, such as diseased and pest-infested branches, dead branches, densely growing branches and unusable water sprouts, so as to build a tree canopy of a certain shape, keep the growth of the scaffold branches at all levels of the canopy in balance, develop the framework, promote the formation of fruiting branches, and thereby adjust the relationship between growth and fruiting.

Heading back

Heading back, also called cutting back, means cutting off part of a longer branch. Its main effect is to stimulate the lateral buds to sprout, so that they send out new shoots and increase the number of branches, thereby keeping the tree vigorous and bearing normally. Different degrees of heading back have different effects on the growth and fruiting of fruit trees. Light heading back is cutting off 1/5 to 1/4 of the total length of the branch, moderate heading back is cutting off 1/3 to 1/2 of the total length of the branch, heavy heading back is cutting off 2/3 to 3/4 of the total length of the branch, and extremely heavy heading back leaves only 1 to 2 buds at the base.

Whether light or moderate heading back should be used, and whether heavy or extremely heavy heading back should be used, depends on the tree species, cultivar, tree age, type of branch and the purpose required. Generally, the heavier the heading back, the stronger the stimulation of lateral bud sprouting and growth vigor, but this is not favorable for the formation of fruiting branches. Sometimes, if the degree of heading back is too heavy, the opposite result occurs and growth vigor is weakened. The lighter the heading back, although more lateral buds sprout, the growth vigor is weak, and short branches tend to sprout in the middle and lower parts of the branch, making it easier to form flower buds. The lighter the heading back throughout the whole tree, the more profusely it blooms every year, and the tree tends to age prematurely.

For young fruit trees, the focus should be on developing a good and sturdy canopy and bearing fruit early, so light heading back and light thinning are generally used. Under normal circumstances, heading back the branches of young trees can stimulate the lateral buds below the cut to sprout, prompting them to send out branches, which favors vegetative growth and accelerates the expansion of the canopy. For fruit trees from the time they begin to bear fruit until they enter full bearing, the main aim is to let them bear more fruit and grow well, so when there are a large number of fruiting branches, the method of appropriately heavier heading back combined with branch thinning should be adopted. As for fruit trees entering the aging stage, since they gradually decline and die back and yields drop year by year, the starting point should be restoring tree vigor; when pruning, heading back should be strengthened to prompt the growth of new shoots, so that tree vigor is rejuvenated and fruiting branches continue to form. This is especially true for stone fruit trees, because their flower buds are borne on new shoots of the current year, and almost every node on a new shoot has a flower bud; heading back can prompt them to send out more new shoots and increase fruiting.

Thinning out

Thinning out, also called thinning or thinning pruning, means cutting out the dry dead branches, unusable water sprouts, competing branches, diseased and pest-infested branches, weak drooping branches, excessively dense crossing branches and overlapping branches in the canopy. The degree of thinning can be divided into three levels: removing no more than 10% of the whole tree's branches is light thinning, removing 10 to 20% is moderate thinning, and removing more than 20% is heavy thinning.

The degree of thinning must also be adapted to the tree and the site. Young fruit trees should be lightly thinned to favor the formation of flower buds and early fruiting. After entering the fruiting stage, on the basis of not affecting yield, on the one hand the fruiting branches should be strengthened and on the other hand branch growth should be stimulated to create good conditions for the next year's fruiting, so moderate thinning is carried out more often. For ordinary large trees, because there are more branches, more thinning can be done. After entering the aging stage, there are more short fruiting spurs or bouquet fruiting spurs on the tree and growth is weaker, so these short fruiting spurs or bouquet fruiting spurs must be carefully thinned to promote vegetative growth.

Rejuvenation pruning

Rejuvenation pruning, also called renewal pruning, is used when the tree reaches full bearing: the growth vigor of new shoots gradually weakens, most of the branches produced are short branches, and at the same time some branches begin to droop and bare areas appear in the middle and lower parts of the canopy. In order to improve light conditions, rejuvenate tree vigor and prolong the bearing years, rejuvenation pruning must be carried out so that the short branches can be renewed and rejuvenated, keeping the tree vigorous and bearing heavily. Rejuvenation pruning generally means leaving a vigorous lateral branch at a point on a perennial branch and cutting off the terminal branch. This shortens the length of the large branch and reduces the number of small branches on it, so that nutrients and water are concentrated in the branches that are kept, which is very favorable for rejuvenating tree vigor.

Along with rejuvenation pruning, fertilizer and water supply should be increased to promote normal branch growth and favor the formation of fruiting branches. In addition, for some excessively aged main branches, heavy rejuvenation pruning can be carried out, even leaving only a short section at the base, so that the branches below the saw cut grow vigorously, or so that latent buds are stimulated to sprout water sprouts and a new canopy is formed. This method of heavy rejuvenation pruning is also called canopy renewal pruning.

Notching

Cutting horizontally through the bark of a branch with a knife before spring bud break, deep enough to reach the xylem, is called notching. Notching above a bud can block nutrients from being transported further upward, so that the buds below the notch receive sufficient nutrients, and at the same time, because the buds are stimulated by the notch, this favors bud sprouting and shoot growth. If notching is done below a bud in summer, it will block the downward transport of carbohydrates, which accumulate in the upper part of the branch, thereby inhibiting tree vigor and promoting flower bud formation and branch maturity. Therefore, if you want to supplement branches at a certain part of the canopy, you can notch above a bud, and if you want to moderate the growth vigor of a certain branch or make it form fruiting branches, you can notch below a bud.