As if pruning a fruit tree wasn't challenging enough, instructions often mention the sap scale. In this guide you can read a practical definition with understandable explanations.
What is the sap scale in fruit trees?
The sap scale refers to the fact that the top buds of the leading branches of a fruit tree are evenly positioned at the same height to allow for an even crown and optimal growth. This prevents unequal supply, shade formation and promotes fruit production of the tree.
Juice Scale – Definition
For an even crown structure, the tip buds of the leading branches must be at the same level. The distance to the tip bud of the main stem must not be too great.
The image below illustrates the ideal juice scale. If the sap balance cannot be achieved through pruning measures, equal leading shoots are brought to the same height by tying or tying.
The uppermost buds of the leading branches must be at the same height so that a fruit tree bears fruit more quickly.
Why is it important to pay attention to the juice scale?
With the help of the juice scale, the growth law of top promotion is put into practice. This law states that a bud always sprouts most vigorously when it is at the highest point of the shoot. An even crown can therefore only develop if the top buds of the leading shoots are at the same height during the tree's youthful phase. In this constellation, the branch tips grow evenly in the direction of the sunlight. The tip of the central shoot should form an angle of 90-120° with the leading shoots.
Conversely, ignoring the juice scale results in an uneven, crooked crown because higher-up buds receive more nourishment than buds further down. At the same time, the stronger growing branches cast shadows within the crown, which leads to premature baldness and senescence. Last but not least, steeply upward competing shoots develop to extend the trunk.
The illustration below uses the example of an apple tree to illustrate how the cultivation of a round crown in succulent scale can be initiated with the help of a planting cut.
To ensure that an apple tree develops a round crown with sap, remove all shoots except for the central shoot with three leading branches. Shorten the leading branches so that their tip buds are at the same height. Overall, the scaffolding branches should form an angle of 90 -120°.
Tip
If a home gardener is familiar with how a juice scale works, he can easily transform unnecessary shoots, such as water shoots, into valuable fruit wood. For this purpose, the branch is tied diagonally downwards. This creates increased juice pressure, which ultimately results in the growth of fruit.