Features of canopy formation in modern intensive fruit growing

Features of palmette orchards and planting patterns

Transitioning to flat artificial canopies (palmettes) allows for increased tree planting density and accelerates the onset of their fruiting. Such canopies are better illuminated and warmed by the sun, which activates leaf photosynthesis and stimulates growth. In palmette orchards of apple, pear, and peach, it is significantly easier to care for the trees and carry out harvesting, which reduces manual labor costs.

All types of palmettes are divided into regular and irregular. In regular ones, the main branches are arranged strictly in pairs with specified inclination angles and distances. Irregular palmettes are distinguished by an unpaired (asymmetrical) arrangement of skeletal branches on the trunk. The choice of planting pattern depends on the rootstock vigor and the need for support.

Technology for forming a regular oblique palmette

A regular oblique palmette is formed on apple, pear, and sweet cherry trees grafted on semi-dwarfing rootstocks. During pruning, it is important to correctly guide the branches along the row. To do this, the cut above the bud is always made on the side facing the inter-row. Then, the upper bud will produce a vertical leader, and the lower buds will produce shoots directed toward the row.

• Trunk height of the tree — 60–70 cm
• Cut of the nursery plant above the trunk — 15–20 cm
• Zone free of growth on the first-tier branches — 20–30 cm
• Length of shoots to be inclined in the second year — more than 20–25 cm
• Decrease in distance between tiers upwards — by 5–20 cm

1. Spring of the first year. Unbranched one-year-old nursery plants are headed back 15–20 cm above the trunk level. Shoots from the second and third buds usually grow at an acute angle and are not suitable for skeletal branches. To establish the first tier, shoots from the fourth and fifth buds are used, directing them strictly along the row.
2. Summer of the first year (late June — early July). Two most developed lateral shoots growing in opposite directions in the plane of the row are selected, as well as a central leader. All other shoots in the canopy are bent to weaken their growth.
3. Spring of the second year. Only the central leader and two branches of the first tier are left, while the bent branches are removed flush to the collar. The central leader is headed back: for cultivars with an acute branch angle — 100–110 cm from the top branch of the first tier, for spreading canopies — 80–90 cm. If the leader has not reached this height, it is left untouched.
4. Summer of the second year (July — August). Vigorous competitor shoots on the leader and skeletal branches are bent. On the branches of the first tier, within a 20–30 cm radius from the trunk, all new growth is completely removed. On the remaining parts of the branches, all growth longer than 20–25 cm is inclined.
5. Spring of the third year. Extension branches on the skeletal branches of the first and second tiers are not headed back. Previously bent competitors are completely removed. The central leader is headed back at the height where the next tier of branches is to be established, with the distance between each subsequent tier being reduced by 5–20 cm compared to the previous one.

Completion of oblique palmette formation

In the third year of the growing season, the gardener begins fixing the branches and regulating their growth. In July–August, it is necessary to bend the shoots that develop on the skeletal branches of the first and second tiers. At the same time, the extension shoots of the central leader and the two shoots selected for establishing the next tier must not be headed back. In early autumn, the first-order branches are deflected to the required angle and securely fixed using stakes, anchors, or other devices.

In the fourth and fifth years of the growing season, the summer selection of first-order branches for new tiers continues, bringing the total number to four. In the spring, adjustments must be made: shoots on the leader and branches that were not bent last summer due to their weakness are now bent and tied. By the fifth–sixth years, canopy formation is completed. At this stage, the inclination angles of the first-order branches are controlled: in the first tier, they should be 45–50°, and in the last, they should increase to 60–65°.

• Number of tiers — 3–4 pcs.
• Tree height — 2.5–3.5 m
• Canopy width along the row — 5 m
• Apple tree width across the row — 2.5 m
• Pear tree width across the row — 1.2–1.5 m

Features and step-by-step establishment of the tiered palmette

The tiered palmette is recommended for growing apple trees on semi-dwarfing and dwarfing clonal rootstocks, as well as pears on seedling rootstocks. The canopy consists of a central leader and three tiers of primary scaffold branches. In each tier, two branches are established, directed in opposite directions along the row at a distance of 10–12 cm from each other. The main difference from the oblique palmette is the free growth of secondary branches without forced bending downward or into a horizontal position.

For cultivars with a compact canopy (Wagner, Starking, Starkrimson), the inclination angle of the first-tier primary branches is 45–60°. For cultivars with a spreading canopy (Renet Simirenko, Jonathan, Golden Delicious), this angle should be within 50–60°. On upper tiers, the branch inclination angle is increased to 55–70° for all cultivars.

1. In early spring, before bud break, shorten unbranched one-year-old nursery plants at a height of 70–85 cm from the ground above a bud facing the inter-row space.
2. In spring, when lateral shoots reach a length of 8–10 cm in a herbaceous state, leave only the growth with an emergence angle of 45–60°, and break off the rest. Simultaneously, clean the trunk at a height of 50–60 cm from the ground.
3. In the first year, when growing without support, identify the leader and select shoots for the first tier with a spacing of 10–15 cm (use growth from the third bud from the cut with an emergence angle of 45–50°). On a trellis, select shoots for the first tier from buds below the leader in the second year after planting.
4. In the spring of the second year, shorten the apple tree leader on M9 and MM106 rootstocks at a height of 80–90 cm, and cut out excess shoots in the first-tier zone.
5. Perform green operations at the beginning and end of the second summer of the growing season.

• breaking off vertical growth on first-tier branches;
• pinching of strong lateral growth to convert them into fruiting ones;
• selection of the second tier and the extension shoot of the central leader.

If growth appears between the tiers, pinch or break it and leave it to eventually shade the central leader against sunburn. Simultaneously, remove competitors on the first-tier branches. If the central leader was not shortened in spring due to insufficient length, all shoots formed on its two-year-old part are removed by breaking them off in a herbaceous state.

In the third year of the growing season, in spring before bud break, the central leader, having reached the required length, is shortened at a distance of 70–90 cm from the upper branch of the second tier to establish the third tier. If the length of the central leader does not meet the requirement, it is shortened in late summer or the following spring, as in the third year of the growing season, most apple cultivars on dwarfing rootstock begin fruiting, which weakens the growth of the central leader and the branches of the first and second tiers. Every spring, the emergence angles of the primary branches are adjusted, thereby regulating the growth vigor of the branches not only in the lower tiers but also in those located above, which is of particular importance for optimal tree growth.

In summer, when performing green operations on the branches of the first and second tiers, in the inter-tier space, and in the zone of the third-tier establishment, the same operations are carried out as during the establishment of the lower-positioned tiers.

On the branches of the first two tiers, a great deal of growth forms after spring pruning in the third year of the growing season. Therefore, during green operations on primary branches:

• leave secondary growth at a distance of 30–35 cm from the trunk and 25–30 cm apart on one side of the branch;
• in the gaps, all growth longer than 20–25 cm is shortened using pinching to 10–15 cm, turning them into fruiting ones;
• as they age, carry out renewal of old growth with young one by shortening them to a 3–5 cm stub.

By the fourth year under favorable conditions, or by the fifth year as a mandatory requirement for all trees, the framework of a layered palmette is completed with six main branches, and the central leader is redirected to a lateral branch or tied down at an angle. During this period, the trees have the following parameters:

The canopy width across the row is 1.5–2.0 m, and the height is 2.5–3 m.

After the start of commercial fruiting, part of the fruiting wood is thinned out, and pruning of secondary branches begins with a 3–4 year replacement cycle. At the same time, excessively long two- and three-year-old branches and extension growth in the overlapping zone between adjacent canopies are shortened.

Once the trees enter the period of full fruiting and as growth slows down, the canopy is progressively shortened by pruning primary branches to an outward-facing lateral, and then the central leader is cut back to the base of the second-tier branches.

The free-growing palmette, developed in Moldova, is used for shaping the canopy of apple trees grafted onto semi-dwarfing (MM 106, M4) and dwarfing (M9, M26) rootstocks, and pear trees grafted onto Quince A and C. When shaping a free-growing palmette, trees are planted according to a 4…5 × 3.0…2.5 m spacing. The technique for creating this canopy is largely similar to the oblique palmette, except that only primary branches are subjected to angling. The canopy consists of five to seven main branches arranged along the row. The first tier consists of pairs of branches, while the others are single branches located at a distance of 50–70 cm from one another (on one side of the central leader). Fruiting wood is evenly distributed along the central leader and main branches.

In the first year after planting, unbranched nursery plants are pruned at a height of 70–85 cm, depending on the vigor of the rootstock. In spring, the tree is inspected, and three growths are selected: one at the top as a central leader, and two from those below that are directed along the row, with branch angles of 45–55°. The remaining growths are broken off or pinched.

In the spring of the second year of the growing season, the first tier of branches is established similar to a layered palmette, and the central leader is pruned at a height of 80–100 cm from the top branch of the first tier.

Figure 33 – Main stages of forming a free-growing palmette

During the second and third years after planting, during winter-spring pruning and summer operations, 2–3 primary branches are established, directed along the row, and set at an inclination angle of 45–60° by pruning to a lateral branch.

Secondary branches are placed on the primary branches, and fruiting wood is formed on them. Branches growing on the upper side of the primary branches are removed during green operations or spring pruning.

During the process of canopy formation, the central leader is shortened annually at the height of the next tier or single branch. When establishing main branches, the following operations are performed:

• excess shoots are pinched;
• they are weakened by pruning;
• they are removed using a collar cut.

On the central leader, the space between branches is filled with shorter ramifications, converting them into fruiting ones. Pruning is used to restrict branch growth towards the inter-row space. Optimal tree dimension parameters are presented below:

Formation and pruning of the free-growing palmette

The free-growing palmette is one of the easiest-to-maintain canopy types, which can be managed either with or without a support. The main advantage for the gardener lies in the minimal pruning required during the formation stage. To restrict the tree's height, the central leader is redirected to a lateral branch.

• Leader redirection height — 2–2.5 m
• Clearance zone from the trunk — 30–35 cm
• Fruiting wood replacement cycle — 3 years

During the canopy formation period, pruning is limited to sanitary and corrective measures. At this time, only those branches that interfere with the development of the tree skeleton are removed:

• competitors of the central leader and main branches;
• vigorous vertical shoots that cause canopy congestion;
• branches on primary axes located closer than 30–35 cm from the trunk.

As yield increases and the canopy becomes denser, primary or secondary branches located on the trunk between the main branches are shortened into older wood. They are converted to horizontal ramifications and then into fruiting wood. In cases of severe canopy congestion, weak and drooping shoots are completely removed, and fruiting structures are thinned.