Training and Pruning Basics

Objectives and Tools

Strong Tree Framework

Balanced

Renewal

Facilitate Management

Harvest Sunlight Efficiently

Maintain Productivity

What happens if you do not prune?

Faster growth

Earlier fruiting

Less light penetration

Poor spray coverage

More difficult to manage

Objectives of training A. Establish a strong tree framework

B. Facilitate management of tree and crop

C. Harvest sunlight efficiently

D. Maintain productivity ◦ by renewing fruiting wood

Balanced

Renewal

A. Establish a Strong Tree Framework

Upright vertical trunk

Well distributed scaffolds

Wide crotch angles

Structural Wood

Establish a Strong Tree Framework

Vertical trunk

Well Distributed Scaffolds

Establish a Strong Tree Framework

Wide branch angles are stronger

Narrow angles are weak and increase shading inside canopy

A Strong Tree Framework:

Major objective of the

first three years

Must last the lifetime of

the tree

Structural support for

fruit crop

Should not be crowded

B. Facilitate Management of the Tree and Crop

Height of primary scaffolds

Distribute scaffolds well Tree uniformity Tree size

Facilitate Management: 1. Height of Primary Scaffolds

Access to tree base

◦ Irrigation, herbicides, fertilizers

Allow air movement to minimize disease pressure

Facilitate Management: 2. Distribute Scaffolds Well

Easy entry to tree

Thinning, pruning, harvesting

Good pesticide coverage

Facilitate Management: 3. Tree Uniformity

Easier to train employees

Mechanization possible

Facilitate Management: 4. Tree Size

Small trees are easier to work

No ladders needed

Easy to reach all parts of tree

Better spray penetration

Facilitate Management of the Tree and Crop

Optimize height of primary scaffolds ◦Allow space at tree base

Distribute scaffolds well ◦Do not over crowd scaffolds

Tree uniformity Limit tree size with summer and winter pruning

C. Harvest Sunlight Efficiently

Maximize surface area of orchard covered by canopy

Limit canopy depth

Harvest Sunlight Efficiently: 1. Maximize surface area of orchard covered by canopy

Most rapid in high density plantings

Harvest Sunlight Efficiently: 2. Limit Canopy Depth

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% L

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Canopy Depth (feet)

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30%

Light Intensity Decreases Within the Tree Canopy

Harvest Sunlight Efficiently: 2. Limit Canopy Depth

Photosynthesis Decreases at Lower Light Levels

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% Full Sunlight

Harvest Sunlight Harvest

Efficiently:

Poor fruit color Poor fruit distribution

◦ Less fruit bud development

Poor fruit size Poor fruit flavor

Poor Light Intensity Leads to

Harvest Sunlight Efficiently: Poor Light Intensity Leads to poor Color

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% R

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% Full Sunlight

Harvest Sunlight Efficiently: Light Intensity Affects Fruit Color and Size

Harvest Sunlight Efficiently: Light Intensity Affects Fruit Color and Size

Harvest Sunlight Efficiently: Light

Intensity and Fruit Size

% Light Penetration Fruit size (grams)

Harvest Sunlight Efficiently: Light Intensity and Fruit Distribution

% Light Penetration % Fruit Distribution

Harvest Sunlight Efficiently: Light Intensity and Fruit Flavor

% Light Penetration % Soluble Solids

Harvest Sunlight Efficiently

Maximize Orchard Floor Covered with Canopy

Limit canopy depth to 1.0 m.

Expose all parts of the canopy with at least 50% sunlight

D. Maintain Productivity Sustain maximum bearing area for maximal

time

Balanced

Renewal

D. Maintain Productivity

Maintain light distribution in canopy

Remove unproductive wood

Maintain good vegetative/fruit balance

Maintain Productivity: Maintain light distribution in canopy

Only sun-exposed areas produce quality fruit

Limit canopy depth to 1.0 m.

Control tree size ◦ Unless control tree size

the fruit moves up every year

◦ Lower part of tree will be shaded

Maintain Productivity: Remove Unproductive Wood

Fruiting wood which hangs down

Fruiting wood which is shaded

Water sprouts and root suckers

Diseased or damaged wood

Weak or thin wood

Maintain Productivity:

Remove Unproductive

Wood

◦Remove weak or thin wood

Maintain Productivity:

Remove Unproductive

Wood

◦Remove weak or thin wood

Maintain Productivity:

Maintain good vegetative:fruit balance

◦Thin out excessively vigorous vegetative growth during summer

◦Allows light into center of tree

Maintain Productivity: Maintain good vegetative/fruit balance

Remove excessive fruiting wood In peaches - remove 40-60% of new fruiting wood each year

Conclusions: How should you train your trees?

Many approaches work Open center is most common for peaches Central leader is most common for pome

fruit Find a program that works and stick to it

Conclusions: How should you train your trees?

Keep in mind the four objectives

Establish a strong tree framework

Facilitate management of tree and crop

Harvest sunlight efficiently

Maintain productivity by balanced renewal

Tools used in Tree Training

Manipulation of apical dominance

Controlled by the plant hormone auxin

Produced by actively growing shoots

Moves down the branch with gravity

Effects of auxin

Inhibits lateral bud break

Inhibits lateral shoot growth

Affects branch angle

Pruning Remove the Source of Auxin

Heading Cut

Remove part of the branch

Stimulate bud break near cut

Stimulate localized branching

Pruning Remove the Source of Auxin

Thinning cut

Remove branch at point of origin

Least invigorating cut

Promote light penetration into canopy

Maintenance pruning

Bend Branch Towards Horizontal

Decreases amount of auxin moving from tip

Increase lateral branching

Decrease terminal growth

Bend to a 45 to

60 degree angle

Bend Branch Towards Horizontal

Decreases amount of auxin moving from tip

Increase lateral branching

Buds at highest point break

Decrease terminal growth

Bend below the horizontal

Timing of pruning

Dormant pruning ◦ Most common approach

Summer pruning ◦ Works well in combination with dormant pruning

◦ Open up the tree to allow light into center

Pruning Response Varies with Tree

Different varieties/crops grow differently ◦ Spur types in apples

Vigor level of the tree ◦ Age of the tree

◦ Rootstock

◦ Fertility/irrigation/soil constraints

Small fruited vs. large fruited crops