Cultivated form (fruit trees)
The term cultivated form refers to the visible growth form of the fruit trees in question. The desired type of use makes the requirement for different shapes. For the orchard meadow , the trees must be tall and robust and allow easy mowing or grazing of the meadow under the trees. In the garden, trees should often be easy to harvest and are therefore chosen with a shorter trunk and smaller crown volume. The plantation-like commercial fruit growing (for example according to Otto Schmitz-Hübsch ) favorably requires direct access to its plants without using ladders and is dependent on a quick start of the yield phase. The smallest forms of fruit trees are used here.
The forms produced by the nursery, such as the tall and half-trunks , as well as the bush trees , with their combination, the roots, as the performance-determining substrate and the noble rice that determines the variety , provide an initial structure that the owner with the help of Fruit tree pruning is developed and maintained over the entire lifespan of the tree. The cut for all tree shapes naturally uses the same physiological principles, but their implementation must be adapted to the requirements of the respective shapes. In the article pruning (horticulture) , in the paragraph fruit tree pruning , some requirements are mentioned that arise for the high and half trunk. Due to the complex structure of the treetops, however, these requirements must be supplemented by the instructions in appropriate training courses. For cut forms such as slender spindle, columnar trees and espalier fruit , which are also common in shaped fruit growing, there are customized descriptions and associated training courses in the literature.
Tree shapes
Basics
The grafted young tree is repositioned several times during the rearing process using a bale cutter , for example , i.e. “schooled”. Regardless of which form of the roots is sought ( "bare root" , "with ball" (see root ball ) or "in a container" (see plant container )), a concentration of (fine) roots in a compact root ball should be achieved in order to allow growth to improve at the final location.
High trunk
A high trunk is the name given to fruit trees with a crown at a height of at least 180-220 cm (valid nationwide standard since 1995). To achieve this form, are in the nursery in the first years after planting and finishing all the side branches and the third year all the branches below the desired crown altitude.
Between 1950 and 1995 the requirement for tree nurseries was “at least 160–180 cm”. The change in the desired trunk height for the tall trunk corresponds to the changed use or the ever-growing tractors in order to be able to carry out a mechanized cut of the orchard. Trees with a higher crown height (for example for use as avenue trees and a more beautiful crown structure) are often referred to as "solitary".
In tree nurseries, the designation is also given for the qualities of other woody plants. A high trunk here is a single-stemmed, trained wood with a crown at the appropriate height.
For the current infection situation with fire blight , the tall trunks represent a possible way out. While the dwarf forms usually have to clear the entire plant in the event of an infection, a tall trunk can cope with a strong pruning of the affected areas.
Half and low trunk
Half-trunks are trees with a crown between 100 cm and 160 cm. In the case of low trunks, the crown begins at a height of 80–100 cm.
Older forms of use (Y-crown)
The former method of building lower trunks in combination with a strongly growing rootstock are in principle possible, but today there is no longer any need for professional fruit growing. The result would be a tree with the crown volume of a high trunk and a trunk height that is barely recognizable. The old form of the Y or longitudinal crown represented such a use, but the necessary crown cut is more complicated, the start of the yield phase later and the yield in relation to the required area worse, compared to the currently used slim spindles .
Bush tree
Bushes and spindle bushes have a trunk length of about 40-60 cm. This tree shape is achieved by choosing a correspondingly weakly growing base and a training cut to plant the crown-forming branches. Although a lower trunk needs a cut that is adapted to its physiology throughout its life, the overall size of the plant is almost entirely determined by the performance of the root support. In addition, this root is also so weak that the more conventional forms also need a permanent support post or a connection to a wire system.
For use on a trellis , the plants should be selected according to the desired crown volume. Weaker documents are usually used for this. However, if there is enough space, stronger documents are also possible.
A slim spindle is usually finished on a very weakly growing base. The fruit wood is raised directly in the middle, real scaffolding branches (guide branches), as is usual with large-crowned fruit trees , are completely absent. Because of the early onset of yield and the suitability for more efficient work processes, this form has become established in commercial fruit growing.
History of professional fruit growing with bush trees
Low-stemmed fruit trees were only systematically cultivated with the advent of commercial fruit-growing in the 19th century, because they bring (compared to standard trees) earlier and higher yields with better quality; in addition, they are much easier to harvest and maintain, as no ladders are required.
Initially, the slow-growing forms were preferred for espaliers, topiary and allotment gardens with limited space. In some cases, the desired shape of the fruit tree (e.g. U-palmettes) was more important than the yield.
Spindle bush
The German fruit growing pioneer Otto Schmitz-Hübsch planted the first apple and pear plantations with low trunks in 1896 and thus developed what is known today as high-density planting . It was also Schmitz-Hübsch who introduced the Spindelbusch (slim spindle) in Bornheim-Merten in the early 1930s. This work was further developed around 1950 in England by Gordon McLean under the name Pillar . The slim spindle was reintroduced in southern Hesse again in 1960 via Dutch plantings , but this type of cultivation did not gain acceptance worldwide until the second half of the 20th century. Today around nine out of ten apple trees in Europe are spindle bushes.
Other bush tree shapes
For the private garden, pillar trees such. B. Ballerina developed. In principle, these are slender spindles that maintain this growth pattern more or less independently and form short fruit wood. The weak base allows the plant to be held easily in the tub. The disadvantage of many of these varieties is their taste, which is usually not entirely satisfactory. Almost all types and varieties of fruit can be kept as potted fruit with appropriate support and care . Recently, varieties such as Cox Orange have also been offered as dwarf apple trees for balcony pots.
Confusion with other forms of care
Above the trunk height, a bonsai tree could also be viewed as a low trunk , but bonsai are usually not grafted on low-growing substrates. The reduction in plant size is achieved here by means of a much more extensive branch cut and, in particular, an additional root cut. The format of bonsai shows, however, that almost all types and types of fruit can be kept as potted fruit with appropriate support and sometimes very intensive care.
Vulnerabilities of the bush trees
For the current infection situation with fire blight , weakly growing lower trunks are less suitable. In the case of the dwarf forms, after an infection there is usually only the option of clearing the entire plant, as the necessary pruning (starting from the infected area) hardly leaves any remains of the plant. However, a high trunk can cope with a correspondingly massive pruning of individual infested areas relatively easily.
Vigor and refinement
It is a common misconception that tall trunks always develop larger crowns than half or low trunks. All of the above forms form crowns of similar size on the same root material . In practice, however, it is usually so that high strains to rapidly growing base, half tribes strong- or medium strong base and low strains or bushes on the medium to weak-growing location refines be.
A free-standing tree, regardless of its type, will not initially develop a high trunk without human intervention. The first crown attachment arises at the first random branching of the young seedling. However, the effect of self-pruning can be observed in many trees with increasing age due to their own shading of the lower crown areas . Trees in a narrow forest stand, through mutual shading, usually form knot-free trunks up to 10 meters high. Since fruit trees are usually grafted, one cannot speak of a natural crown approach . However, old, unkempt fruit trees also tend to steadily “strain” because the umbrella crowns that are forming shade the lowest crown branches, which means that the tree can no longer sustain them.
In addition, it should be noted that the total size of the trees also always depends on the subsoil and the nutrient supply.
Most of the time, fruit trees on a weakly growing base require artificial support devices (stakes, tension wires, trellis etc.) for their entire life due to their weak root system.
ecology
Standard tree ecology
Large-crowned fruit trees enrich the landscape and are valuable in terms of nature conservation, as they provide a habitat for numerous bird , insect and fungus species that are on the red list of threatened species. This ecological function results from a number of reasons: Firstly, high-stem fruit trees with their rapidly growing roots are getting significantly older. Woodpecker holes and the full variety of lichens can usually only be found on fruit trees over 40 years old - trees on low or medium-growing substrates have usually already been cleared. Second, standard fruit trees have not been cultivated as intensively but more extensively than low -stem plants for decades . The use of pesticides, for example, has not been common in orchards for many decades. This favors the occurrence of insects and fungi in particular. Thirdly, there are studies from various regions of Germany, according to which woodpeckers only build their nesting holes in fruit trees with a trunk height of at least 160, if possible 180 cm, or a crown base. These woodpecker caves are used in the following years by numerous endangered species of the orchards such as the common redstart, wryneck and collarcatcher, but also bat species, hornets, dormice and garden dormice. The deadwood in old trees also creates natural caves and habitats for deadwood-specialized insect and fungus species. And fourth, high tribes are able to cope with greater damage.
Some fruit processors have standard products in their range. In Switzerland, Hochstamm Suisse is responsible for the non-profit promotion of these crops, in Germany this is the NABU Federal Expert Committee for Streuobst , in Austria the ARGE Streuobst .
Bush tree ecology
In contrast to the large-crowned fruit trees, spindle bushes are only little enrichment for the landscape. They only have a limited ecological function, as they offer almost no nesting opportunities. This restriction results on the one hand from the size of the plants, the lack of tall or hollow branches for nests, hardly any old, structured bark that would be suitable as an insect hideout, and the need to manage it efficiently. Such a small tree cannot cope with greater damage, which means that dead wood or knotholes that insects would need can not hold up.
With spindle bushes, there is only intensive cultivation ( monoculture ), as the trees quickly suffer from the surrounding vegetation if used extensively and would quickly become old and die without constant pruning. The use of insecticides in conventional orchards is common, but intensive ecological management is also possible and represents an improvement in the habitat of many living beings.
Web links
- Website Hochstamm Suisse
- Website of the NABU Federal Expert Committee for Orchards
- Website ARGE Streuobst
Individual evidence
- ↑ a b c Hans-Joachim Oczko, 'Die Schlanke Spindel', Office for Agriculture and Rural Development Friedberg
literature
- Agridea : Planning, planting and caring for standard fruit trees , 2012