7.1 The Aims of Canopy Management

Question 1

What are the 6 aims of canopy management?

Answer 1

1. maximise the effectiveness of light interception by the vine canopy
2. reduce the shade within the canopy
3. ensure that the microclimate for the grapes is as uniform as possible so that grapes ripen evenly
4. promote balance between the vegetative and reproductive functions of the vine
5. arrange the vine canopy to ease mechanisation and/or manual labour
6. promote air circulation through the canopy to reduce incidence of disease.

Question 2

Why is it beneficial to maximise the leaf surface area that is exposed to sunlight?

Answer 2

• Increases the vine’s photosynthetic capacity (compared to a vine with a dense, shaded canopy)
• Increased ability to ripen larger yields

Question 3

Why can dense canopies be problematic?

Answer 3

• Poor air circulation
• Dry out more slowly after rainfall or morning dew
• Provide suitable conditions for fungal diseases to develop
• When spraying fungicides, it is more difficult to ensure the spray reaches all areas of the canopy

Question 4

What are the 7 positive effects canopy management has on grape quality?

Answer 4

1. increased sugar levels
2. increased tannin levels (greater polymerisation, leading to less bitterness)
3. enhanced anthocyanin (colour) development in black grapes
4. decreased malic acid – warmer grape temperatures lead to more malic acid being broken down in cellular respiration
5. increased levels of some favourable aroma precursors and aroma compounds
6. decreased methoxypyrazines (herbaceous characters)
7. reduced risk of fungal disease

Question 5

Describe unripe black grape characteristics.

Answer 5

• unpleasantly high levels of acidity
• harsh tannins
• unripe fruit character

(reduced wine quality)

Question 6

Describe ripe black grape characteristics.

Answer 6

• good depth of colour
• ripe fruit aromas
• balancing acidity
• ripe tannins

Question 7

What is the optimal crop load?

Answer 7

Allows grape grower to grow the maximum yield of grapes that have the required composition for the desired wine style and quality

Question 8

Describe a balanced cycle of canopy management.

Answer 8

• After véraison, sugars and other compounds needed for growth are mainly allocated to the fruit and shoot growth is depressed.
• Because shoot growth is reduced, the canopy is less likely to become dense and shady, and light exposure in the canopy is improved, leading to high quality fruit.
• It also results in enhanced bud fruitfulness the next year, and the balanced cycle continues.

Question 9

Describe a vegetative cycle of canopy management.

Answer 9

• If the yield of fruit is too low for the vigour of the vine, shoot growth continues through the vine cycle because there is not much fruit to ripen.
• The growing shoots and leaves compete with the grapes for sugar and other compounds needed for growth and can negatively affect grape formation and ripening.
• This leads to a dense, shady canopy, and hence lower quality fruit due to lack of sunlight interception.
• This may also result in low yields the next year due to reduced bud fruitfulness.
• Low yields in the next season may lead to under-cropping in that year and hence the vine enters what is known as ‘a vegetative cycle’.

Question 10

What is under-cropping?

Answer 10

If the yield of fruit is too low for the vigour of the vine

Question 11

What is over-cropping?

Answer 11

If the yield of fruit is too high for the vigour of the vine

Question 12

What is the ideal amount of fruit on the vine to create the correct balance in a warm climate with ample resources? Explain why.

Answer 12

• Vines can grow vigorously, producing lots of shoots and leaves.
• With many leaves, the vines have a high capacity to photosynthesise and produce sugars and other compounds needed for growth.
• These vines can successfully ripen a large crop load.

Question 13

What is the ideal amount of fruit on the vine to create the correct balance in a climate with limited resources?

Answer 13

• Vines will not grow, so many shoots and leaves will be low in vigour and therefore not be able to ripen the same crop levels.

Question 14

What determines the ideal amount of fruit to achieve a perfect balance?

Answer 14

• Climate
• Resources (Water, soil)
• Grape variety
• Choice of rootstock
• Wine Style

Question 15

Name a variety with high vigour that will grow larger and ripen a larger crop load. Name a low vigour variety.

Answer 15

• High vigour: Cabernet Sauvignon

- Low vigour: Merlot

Question 16

Why can vines producing grapes for rosé wine sustain larger yields that those producing grapes for red wines?

Answer 16

• Tannin ripeness is less critical for roses (very short maceration time)

Question 17

What is the key time when decisions are made that will influence number of shoots and crop load in the coming growing season? What other time could have an affect?

Answer 17

• Key Time: Winter Pruning

- Other Time: Summer Pruning (amend vine balance and enhance ripeness as needed)

Question 18

What is yield?

Answer 18

A measure of the amount of fruit produced

Question 19

How is yield measured?

Answer 19

• per vine (e.g. kg per vine)
  or
• over a set area (e.g. kg per hectare or tons per acre).

Question 20

What types of laws exist over yield?

Answer 20

• In EU countries, legislation may specify maximum yields per set area.
• In these cases, if too much fruit is produced it may have to be removed when ripening or left in the vineyard at picking.

Question 21

Why does the ideal yield-to-fruit-quality ratio vary so widely?

Answer 21

• Natural resources of vineyard
• Planting material
• Wine Style