Key Technical Points for Winter Pruning of Low-Yield Young Vigorous Apple Trees

For pruning low-yield young vigorous apple trees, one should master the pruning techniques of light pruning of the whole tree, local control, and gradual moderation.

Light pruning of the whole tree. This mainly involves light pruning and delayed pruning of the scaffold extension branches, dense branches, and strong vigorous branches. After 1 to 2 years of delayed pruning, most of them can form flower buds and bear fruit. Once the tree's growth vigor has stabilized, a portion of the weaker branches can then be moderately cut back, gradually training them into large, medium, and small fruiting branch groups. When cutting back weak branches, one must not cut back too many or too severely at one time, otherwise it will cause the tree vigor to become vigorous again and affect yield.

Local control pruning. For trees trained in the small canopy delayed-open center form, during pruning first carry out moderate heading back of the peripheral branches and side branches to promote branching, increase the number of branches on the periphery and sides, so as to restrain and moderate the growth vigor of the branches in the inner canopy and on the back of the scaffold branches. While appropriately thinning out inner canopy branches, dense branches on the back, and strong vigorous branches, methods such as bending, ring barking, or bending branches are used on some auxiliary nurturing branches to moderate their growth vigor and promote flower formation and fruiting.

Gradual moderation pruning. This is an important method for prompting young vigorous apple trees to moderate their growth vigor, form flowers, and increase yield. The specific approach is: through light pruning of the whole tree, slow down the growth vigor of individual branches and increase the total growth of the whole tree. After the overall growth vigor of the whole tree has been moderated to a certain degree, then through local control measures, bring the growth vigor of the strong vigorous parts toward the average growth vigor of the whole tree, so as to facilitate flower formation and fruiting.

Through the above pruning measures, after the tree vigor has been moderated, then appropriately reduce the number of peripheral branches, and head back or thin out some inner canopy branches, so as to maintain good light penetration conditions and promote high quality and high yield. However, for low-yield young vigorous Red Fuji apple trees during winter pruning, the key is to properly deal with the strong vigorous branches that disrupt tree vigor, mainly by light pruning and thinning, without heading back or cutting back the side branches, so as to increase the amount of flowers formed on the side branches as much as possible. When the tree vigor is particularly vigorous, winter pruning can be light pruning of the whole tree, and afterwards, based on the growth amount and the growth conditions of the branches throughout the tree, summer pruning should be carried out promptly to stabilize the tree vigor.

Chai Quanxi, Song Suzhi, Vocational Education Center of Gaocheng District, Shijiazhuang City