Lemon Tree Pruning Methods; Training Methods

Lemon Tree Pruning Methods; Training Methods:

Today, we are into Lemon Tree Pruning Methods and Training Methods.

Introduction:

Pruning healthy, mature lemon trees will reduce the yield in proportion to the amount of foliage removed and leads to fruit delay in young, nonbearing trees. Pruning ought to so be restricted thereto needed for future cover bearing surface development and for the conduct of economic cultural and gather operations. The pruning adjusts tree shape and the ratio of the framework to the fruit-bearing shell of the canopy alters the top/root ratio and changes the carbohydrate (food storage) status of the tree. Proper management of vegetative growth is crucial for the upkeep of healthy, productive citrus groves. Most groves must be pruned at some time during their development to avoid problems associated with overcrowded, excessively tall trees. When pruning ought to begin can rely to an outsized degree on the initial tree planting density. Crowded conditions end in poor light-weight accessibility, loss of lower foliage and bearing wood, relocation of fruiting to the upper tree canopy areas and reduction in fruit yield, size, and external quality. Good management so dictates the requirement to prune before the incidence of those undesirable effects.

The response to pruning depends on several factors they are, tree age and vigor, fruiting habits, growing conditions, and production practices.

Pruning For Sunlight, Photosynthesis, And Food Storage:

The sunlight is intercepted by the tree canopy, on the production of high yields of good quality fruit cannot be overemphasized. Sunlight is the best source of energy for photosynthesis, in which carbon dioxide from the air and water from the soil are combined in the leaves which produces the basic foods upon which trees live, grow, and produce fruit. Light can be a limiting factor in crowded groves and pruning can help to improve the light access to the trees. You can use pruning to adjust the tree height, row middle width, and hedging angle which will maximize sunlight impingement on the tree canopy. Sunlight has a great influence on flowering and fruit set and enhances fruit quality and color development. In Lemon trees, carbohydrates are stored in leaves, twigs, and branches with only a minor amount going to the root system. 

Lemon Orchard.
Lemon Orchard.

Pruning effect on Lemon Tree Hormones:

Hormones in the citrus tree will mainly affect the fruit set, the effects of pruning on their activities are not well understood. Controlling the lateral bud growth by the terminal bud is called apical dominance. Apical dominance shows a great impact on the growth characteristics of trees and their responses to pruning. Branching is mainly influenced by auxin produced in the terminal bud which moves down the system to inhibit lateral bud break. Pruning the terminal bud will destroy apical dominance so that one or several lateral buds will commence growing and branching results. Vigorous shoots which are called suckers show extreme apical dominance with no side-branch development. Apical dominance varies somewhat with vigor and variety.

Pruning for Bearing Habits:

The balance between tree growth and fruitfulness depends on the relationship between carbohydrates and nitrogenous compounds within the tree. When these compounds are adequate, the tree gets moderate growth and high yields.

When carbohydrates and nitrogenous compounds are low, citrus trees grow and fruit poorly. A tree with low in carbohydrates and with high levels of nitrogen tends to produce vigorous vegetative growth at the expense of fruit production. Since carbohydrates are stored in the leaves, heavy pruning which removes a large portion of the leaf area can result in this condition.

High nitrogen application after severe pruning can increase the problem, which can cause thick and puffy fruit peel. Nitrogen applications should be done based on the severity of pruning. Reducing nitrogen applications will prevent the imbalance during heavy pruning. Avoiding a nitrogen application before heavy pruning and possibly after will reduce both costs and excessive vegetative growth. The time is based on the severity of pruning and the rate of top recovery. Light maintenance pruning should not affect fertilizer requirements. Some citrus trees have a bearing habit with alternating high and low yields. Huge fruit yields tend to deplete carbohydrates and results in a small crop and increased vegetative growth the following year. Pruning after a heavy crop additionally stimulates vegetative growth the following year because the carbohydrate supply has been somewhat depleted and the capacity to resupply has been reduced. This practice results in poor fruit quality. Pruning after a light crop and before an expected heavy crop will reduce alternate bearing. The orientation of branches in space will show a great impact on growth and fruiting. You can observe a decrease in growth rate and an increase in flowering occurs when branches bend to a horizontal position. Improving the horizontal branches over upright ones will give you better growth control and more fruit production.

Basic Lemon Tree Pruning:

Cutting back and thinning out are the basic types of pruning cuts and these are used for somewhat opposing objectives. Now heading back removes the terminal portion of a shoot or branch, destroying the apical dominance and encouraging lateral bud breaks. Which leads to a more bushy, compact tree.. when the individual tree or hedgerow increases in size, internal wood becomes less productive and eventually die. Thinning involves the removal of complete branches to laterals or to the main trunk and with hand-held equipment. This process will increase the longer growth of the remaining terminals and can result in a larger, more open tree. The basic pruning is done for better light penetration into the tree but is generally considered too labor intensive and not much practiced.

Severe Lemon Tree Pruning :

Severe pruning promotes vigorous new vegetative growth when pruning is done before a major growth flush. Severe pruning will reduce the fruiting and increases fruit size and juice content and decreases soluble solids and acid. So, pruning a severely crowded grove may result to crop reduction the first year, and yields are recovered in a second or third year, and higher yields thereafter, although this can vary with tree type, grove conditions, and the size of the previous crop.

Recommended Pruning Practices for Lemon Trees:

Young Lemon Tree Pruning:

Lemon Tree Pruning, Training.
Lemon Tree Pruning, Training.

Severe pruning and training of young, nonbearing trees will delay fruit production and so it should be avoided. Lemon trees usually need no pruning for the first few years in the grove, you just need to prune the sprouts on the trunk. These are easily pruned when they are young and tender, and the wounds will be small. Larger sprouts should be pruned with flush with the trunk. Sprouting on the trunks of young, nonbearing trees can be controlled by using a commercial sprout inhibitor containing naphthaleneacetic acid. Keeping protective wraps around the trunk will reduce sprouting and need constant observation to avoid insect and disease problems under the wraps. Vigorous suckers will dominate a weak tree, or a sucker may arise from the rootstock. These should be pruned of early before they compete with more desirable growth. You need to select the permanent scaffold branches during the first few years. You can observe new growth in unexpected places and become dominant over selected branches. When the tree is 3 or 4 years old, based on its growth, branches that are too closely spaced or are crossed and entangled should be pruned. The pruning should be light, just enough to establish a desirable framework without stimulating excessive vegetative growth. Optional pruning is recommended during the next years for removal of water sprouts, dead wood and occasional branches which interfere with the growth of scaffold limbs.

Mature Lemon Tree Pruning:

Mature trees need little pruning until trees approach containment size. Deadwood should be removed for every  3 to 5 years, based on the amount present and labor supply, since it can scar fruit and be a source causing some infections. This pruning can be done at any time when labor is plentiful and particularly following freezes. Growers should remove dead branches of 1/4 in. in diameter or larger, and the smaller dead wood is often broken off in harvesting and other grove operations. All cuts should be made into live wood when a grove is laid out, each tree will be allotted a unit of space in which to grow. When space is exceeded crowding results in inadequate light conditions, loss of foliage and fruit production in the lower portion of the tree.

Hedging of Lemon Trees:

Hedging is cutting back the sides of trees to prevent crowding, it is a common practice and mechanical equipment are used for this purpose. Hedging leaves to cut wood surfaces along the side of the tree canopy from which new sprouts arise. Middles  (alleys) between tree rows should be given enough width to accommodate grove equipment and to provide adequate light access to the sides of the trees. Middles are hedged to a width of 7 to 8 ft. Hedging can be done when the crowding becomes a problem. Removal of a large portion of the tree can be required,  when pruning is delayed until severe crowding occurs. Excessive vegetative growth can lead to a drastic reduction in subsequent yield. Hedging of severely crowded groves aids will cause restoration of the tree skirts and opens them up for passage of grove equipment.

Hedging is done at an angle, it is done toward the treetops so that the middles are wider at the top than at the bottom, allowing more light to reach the skirts of the tree. Hedging angles vary from 0 to 25 degrees from vertical, with 10 to 15 degrees being more commonly used. Greater hedging angles will result in longer exposure of the sides to sunlight and delayed overgrowth of the skirts by the more  vigorously growing shoulders of the trees

Advantages of hedging at wider angles give a good spray coverage and provide efficient harvesting and give a higher percentage of the fruit is accessible to pickers on the ground.

Disadvantages of hedging, extreme angles are a greater initial yield reduction when they are imposed on older trees, greater stimulation of long, undesirable shoot growth and greater exposure of fruit to possible cold injury. 

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Topping

Topping should be done before trees have become excessively tall and should be an integral part of a maintenance program. The long gap between topping will increase the costs of the operation due to heavy cutting and more brush disposal. High tall trees are more tough and expensive to harvest and spray. Topping will increase light penetration into trees and stimulates intense growth and flush. It reduces harvesting costs and enhance pest and disease control due to better spray coverage and increases fruit quality and size. Topping lemon trees will be beneficial in the long run since it would help them regain their skirt areas and bring them to a more manageable height. Topping will increase the fruit size, fresh-market fruit from topped trees may have a higher packout. The optimum height of the lemon tree depends on the distance between trees, the hedging angle, and treewidth. Topping height is about 10 to 20 ft but is usually about halfway between. It is best to start topping before heavy cutting is required. If heavy cutting is essential, in older groves the initial cuts should be low enough to avoid cutting heavy wood in subsequent topping operations. Retopping is done, above the old cut.

Topping in cold areas until is done after the threat of freezing temperatures is past to avoid possible cold injury. A heavy topping is completed in time for exposed limbs to be covered with new growth before the advent of hot, dry weather in the late spring and summer. Topping in April or May without good soil moisture is not suggested. A light topping is not as important, if little fruit is removed, in case of freeze-prone areas it is best not to top in the fall to avoid possible cold injury to new growth. Regrowth is highly vigorous when the topping is done before major growth flush. Topping before the spring flush results in new growth that is more when it is done at other times. Maintenance topping recommended in the late summer when regrowth is less vigorous.

Skirt Pruning

Pruning to lift tree skirts is highly recommended. Until recent pruning was done due to attainable yield reduction and extra expense. With low tree skirts, the movement of weed killer booms and different instrumentality is obstructed, and the examination of irrigation systems is harder. Fruit and limbs close to the bottom are usually broken by the passage of such instrumentality by weed killer spray and fertilizer contact. Low tree skirts might also increase the incidence of fungus genus parasitic, the entity of footrot, due to poor air circulation below the tree cover. Lower cover fruit is additionally additional liable to plant disease, the results of Phytophthora citrophthora infection below sure environmental conditions.

Pruning after Freeze Damage

Corrective pruning should be delayed till the full extent of freeze damage is determined. Enough time is allowed for new growth to take place and for dieback to cease. Premature pruning will result in removal of some sound wood and not removing some which will die back, both of which can slow tree recovery. Injury to foliage and tender shoots sometimes becomes visible at intervals many days however twigs very little and tiny limbs might show little or no sign of cold injury for 5 to 8 weeks or more. It may be many months before a severe injury to larger limbs will be totally determined. Pruning of mature trees should not be done for a least 6 months after heavy cold damage has occurred. Further light pruning is required to help in forming a replacement framework.

Equipment for Pruning lemon Tree:

Pruning equipment can be purchased or can be used through custom operators. While the other small equipment is more economical for light pruning and in tight areas, and large equipment’s used for heavier cutting at a lower cost. No matter what equipment is used, blades should always be kept sharp as they do a better job and require less power.

Training Lemon Trees:

Central Leader System: In recent years closely spaced plantings of trees should follow a central leader system of tree training. The natural growth habit lemon trees to this form make them well-adapted to the system. Interest in this system is enhanced by the extensive use of size-controlling rootstocks and spur-type trees of certain lemon cultivars. In addition, research has shown that when shaped to a pyramidal form and held within given size limits, the central leader tree will expose a most of its foliage and spur-bearing surface to sunlight than the trees trained to most other forms. In Central leader system, the tree is trained in a manner that permits the development of several scaffolds arranged in tiers or whorls of three to four scaffolds along a central axis, much like a Christmas tree. In these systems, the central leader tree is maintained in a pyramidal shape.

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Spreading — A Training Technique: In this Spreading system, the scaffolds in the young trees can aid in bringing about improved tree form, earlier fruit production, and improved fruit quality. Branches that are growing in an upright position are vegetative and unfruitful for a longer period than branches growing in a more horizontal position. The reason for this is due to natural growth regulators in the tree. Thus, spreading the scaffolds of a young fruit tree will improve the spur growth and flowers. Proper limb position is very important for spreading branches, particularly when heading the scaffold leader. The technique includes, upright growing scaffolds down to about a 45-degree angle and holding them there. If the scaffolds are too flat, vigorous upright shoots will develop along the scaffold and terminal growth will be reduced.

Deshooting — An Alternate Training Technique: this technique is of removing the undesired shoots during the first growing season and is very helpful in the proper training of fruit trees. All new shoots can grow on the tree till early or mid-June, or until they are 4 to 6 inches long. At this time, three to four lateral shoots, well distributed at the proper height, are selected for the main framework. All others are removed or pinched to reduce growth and competition with the selected shoots. The shoots remaining for the main scaffold branches should have the widest crotch angles possible, preferably greater than 45 degrees.

Special Training Techniques

Trellising:

With the advent of size-controlling rootstocks for fruit trees and high-density planting, growers have become interested in trellis support for lemon trees. This is especially true with lemon cultivars on the most dwarfing rootstocks, M 9 and M 26. Dwarf lemon trees are trained and secured to wire trellises have been used in commercial as well as home plantings. This method of growing lemons can accommodate from 400 to 600 dwarf trees per acre, depending upon the planting distances. Training lemon trees to a trellis are quite like training grapevines to the four- to six-arm Kniffen system. The trellis may be constructed to accommodate three to six more wires, depending upon the vertical spacing of the wires and the ultimate height desired.

Espalier: The training of lemon trees to grow in various forms, including picturesque shapes on walls or other permanent structures, is a technique of long-standing use in European gardens. This method is used to grow lemon, where the place is very limited. Implementing proper pruning methods and fastening of shoots or branches in place, the grower can get the desired tree design. Below are some general pruning principles used in espalier training:

  1. Head back the central leader and branch terminals by cutting them, 1-year-old wood at the points where you need additional branching.
  2. the shoots are secured in desired places in the year they first develop. Every year all the new shoots, and the older branches, need to be secured in place and kept there until permanently formed to the shape.
  3. Summer pruning is required for regulating growth. By pinching back young succulent shoots to dwarf the growth. This practice is essential with shoots that grow vigorously.

Slender Spindle: This is a training system that can be used for lemon trees on dwarfing rootstocks that have to be supported in some way. In this system, each tree is supported by a stake. It can be used in commercial as well as home plantings. You can accommodate 400 to over 600 trees per acre. The system requires the least amount of pruning and will bring the trees into production earlier than any of the other training systems. In this system, the dwarf lemon trees are trained to a 6- to 8-foot stake with short lateral branches trained out in a horizontal position around the central leader. Such limb positioning reduces vigor and promotes fruiting. Training begins at planting. As fruiting begins on the lower lateral branches (in the third year for a whip, or second year for a tree with laterals at planting), they may need to be tied up to maintain the horizontal position. When the tree grows to the desired height, the procedure used will depend upon the vigor of the central leader. If the central leader is not vigorous, either nothing is done, or it is headed back to a short lateral shoot or spur. If the central leader is vigorous, it is headed back to the nearest lateral branch that has been tied to the horizontal position. That lateral branch is then tied up to assume the position of the central leader.

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