Pruning

Japanese: 剪定 - せんてい

It refers to cutting branches of flowering trees, fruit trees, garden trees, etc., for the purpose of promoting overall harmony and healthy growth, flowering, tree shape, and fruit set. Since it also includes the task of shaping the tree, pruning and trimming are sometimes not distinguished because they are two sides of the same coin.

Pruning is an important maintenance task, especially for fruit trees and flowering trees, and is especially essential for fruit trees to allow flower buds to form and fruit to set. Removing unnecessary branches increases the amount of light received by the branches and leaves, which increases the yield of fruit, and improving ventilation reduces the occurrence and damage of pests and diseases, and prevents alternate yearly bearing. Pruning also helps to reduce the labor required for management such as spraying pesticides and harvesting.

[Yasuo Hori]

history

It was during the Meiji period that pruning techniques began to be considered important in Japan, and the spread of fruit cultivation was a major driving force. In particular, the influence of the techniques of the Europeans invited by the Hokkaido Development Commission along with the introduction of fruit trees from Europe was significant. Prior to that, pruning techniques, including pruning, had been developed for garden trees and bonsai, but it is said that they were not linked to production techniques as they are today.

Meanwhile, in Europe, as the decorative pruning of trees in gardens developed, fruit trees also began to be trained into specific shapes, which is said to be the origin of pruning techniques. In particular, it is said that the practice of training trees into geometric shapes to increase their ornamental value while also allowing the enjoyment of the harvest began around the 17th century.

[Yasuo Hori]

When and how to prune

Although there are some differences depending on the type of tree (deciduous, evergreen, climbing plant), the training method (shape), and whether it is a trained tree or a finished tree, they are generally broadly classified as fruit trees, flowering trees, and garden trees, and the timing and method are determined according to the purpose.

(1) Fruit trees: Pruning is done to improve sunlight to the entire crown, to develop fuller branches and leaves, to increase fruit yield, improve quality, and to prevent alternate yearly bearing. Depending on the severity, it can be divided into heavy pruning, in which several buds are left at the base, and light pruning, in which only the tips are cut.

(2) Flowering trees: Most flowers cannot be pruned heavily because they are pruned to make them bloom well. For seasonal flowers that bloom mainly from spring to early summer, light pruning should be done after the flowers have bloomed, while for seasonal flowers, light pruning should be done to prune the branches.

(3) Garden trees: For trees that have been fully trained, light pruning, mainly consisting of pruning, is used to maintain the tree shape, but vigorous trees trained from rough trees (unfinished trees) are often pruned heavily.

[Yasuo Hori]

season

Pruning can be broadly divided into winter pruning, which is carried out during the dormant season in winter, and summer pruning, which is carried out in early summer during the growing season. Winter pruning is carried out immediately after the leaves fall and before the sap starts to flow in early spring. For evergreen trees, it may be better to avoid the harsh winter months and carry out pruning from late February to mid-March. Some deciduous trees, such as maples, which start to flow sap early, are better off pruning in early spring. Summer pruning involves removing overgrown branches and sprouts from the trunk and unnecessary parts around the time of the rainy season, and mainly cutting off those that are impeding the growth of the framework branches.

[Yasuo Hori]

method

There are two types of pruning: thinning, which involves cutting from the base of the branch to enrich it without creating unnecessary branches, and cutting back, which involves shortening the branch by cutting it halfway down, leaving only a few buds, as strongly growing branches are apically dominant and therefore less likely to sprout from the bottom.

[Yasuo Hori]

Points to note when pruning

(1) How the branches grow. In the case of cultivated trees, the future shape of the tree is decided, so for ornamental trees where the beauty of the trunk and twigs is desired, many twigs should grow at once, while for flowering trees, it is better to grow 2 to 5 twigs at once. Also, for fruit trees, there are fence training, open-center natural training, irregular trunk training, etc., and each has its own characteristics in how the branches grow.

(2) Branches that require pruning. Although there are differences depending on the tree species and the purpose of the pruning, generally, branches that require pruning include elongated branches, stumpy branches, trunk-spread branches, saplings, inverted branches, parallel branches, wheel branches, and barred branches.

(3) Pruning tools. Tools must be selected according to the thickness of the branches and the method of pruning, but commonly used tools include pruning shears, tree shears, tree pruners, saws, and accessories such as stepladders, ladders, footstools, ropes, and supports.

[Yasuo Hori]

Name of the branch that needs pruning
©Shogakukan ">

Name of the branch that needs pruning

How to prune
©Shogakukan ">

How to prune

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

Japanese:

花木、果樹、庭木などの生育、開花、樹形、着果促進のため全体の調和を図りつつ、健全に育てる目的で枝を切ることをいう。また樹形を整える作業も含むことから、剪定と整枝は表裏一体であるため区別しないこともある。

　剪定は主として果樹や花木では重要な管理作業で、とくに果樹では花芽の着生、果実の結実上欠かせないものである。むだ枝を取り除き樹枝や葉に受光量を増すくふうにより果実の増収を図り、また通風をよくすることで病害虫の発生や被害を少なくしたり、隔年結果を防ぐなどの効果がある。剪定することにより農薬散布、収穫などの管理の省力化にも役だっている。

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歴史

わが国で剪定技術が重要視されるようになったのは明治時代に入ってからで、果樹栽培の普及が大きな原動力となった。とくにヨーロッパからの果樹導入とともに開拓使に招かれた欧米人たちの技術の影響も大きかった。それ以前には庭木や盆栽などで整枝を含めた剪定技術として発達していたが、現在のように生産技術に結び付いたものではなかったといわれる。

　一方、ヨーロッパでは庭園の樹木の装飾的整枝の発達に伴って果樹についても一定の形に仕立てることが行われるようになり、剪定技術が生まれたといわれる。とくに樹形を幾何学的に仕立てることによって観賞価値を高めることとあわせて収穫も楽しむことが17世紀ごろから始まったとされる。

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剪定の時期・方法

樹木の種類（落葉樹、常緑樹、つる性植物）や仕立て方（形）、養成木・完成木別によって多少異なるが、一般的には果樹、花木、庭木に大別し、その目的により時期、方法を定める。

（1）果樹　樹冠全体に日当りをよくし枝葉の充実と、果実の増収、品質向上、隔年結果を防止するために行うもので、程度により、基部より数芽を残して切る強剪定と、先端部のみを切り詰める弱剪定に分けられる。

（2）花木　花をよく咲かせるための剪定なので、強剪定はできないものが多い。主として春から初夏に咲く一季咲き性のものは花後に、四季咲き性のものは整枝を兼ねて弱剪定とする。

（3）庭木　仕立ての完成した樹木では、整枝を主体とした弱剪定で樹形の維持を行うが、荒木（未完成木）から仕立てる樹勢旺盛(おうせい)なものは強剪定によることが多い。

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時期

冬の休眠期に実施する冬期剪定と、生育期間中の初夏に行う夏期剪定に大別できる。冬期剪定は、落葉直後から早春の樹液が流動する前に行う。また常緑樹では厳冬期を避けて2月下旬から3月中旬にかけて行ったほうがよい場合もある。なお落葉樹でも樹液の流動開始の早いカエデ類では早春がよいものもある。夏期剪定は、梅雨前後の時期に幹や不要部分からの徒長枝、ひこばえ（やご）などを除去するもので、主として骨組枝の成長を妨げるものを切り取る。

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