3. The Growing Environment

Question 1

How much sunlight does the vine need for photosynthesis?

Answer 1

At least one third of full sunshine.

Hence, fog can slow photosynthesis, but an average cloudy day will not.

Question 2

How do solar radiation levels decrease in intensity before reaching the earth’s surface?

Answer 2

Solar radiation is absorbed (held by water droplets, dust and ozone) and scattered as it travels through the Earth’s atmosphere, decreasing its intensity.

Question 3

How does the earth’s curvature influence solar radiation levels in regions at high latitudes?

Answer 3

Nearer the poles solar radiation must travel through a larger section of atmosphere to reach the Earth’s surface. It also means that the radiation hits the Earth at a low angle, so the radiation is spread over a larger area (it is more diffuse).
If all other factors are equal, this generally means solar radiation is less intense at higher latitudes.

Question 4

How does the earth’s curvature influence solar radiation levels in regions at low latitudes?

Answer 4

At the Equator the radiation travels through a smaller section of atmosphere and hits the Earth’s surface at a larger angle (nearer perpendicular), so that solar radiation here is more powerful.

Question 5

How does a high latitude influence daylight hours?

Answer 5

High latitude regions have longer daylight hours in the summer and shorter daylight hours in the winter. This permits a longer duration of time over which photosynthesis can take place in the growing season.

Question 6

Why is grape production rare at latitudes below 30°C?

Answer 6

Regions nearer the Equator are usually too hot during the day. Vines transpire to regulate their temperature and if water is not readily available, this can cause water stress. Grapes can also suffer from sunburn.

Question 7

Why is grape production rare at latitudes higher 50°C?

Answer 7

Regions near the poles are simply not warm enough during the growing season (despite long daylight hours) for enough sugar to accumulate in the grapes.

Question 8

How much does temperature change with altitude?

Answer 8

Temperature falls by approximately 0.6°C (1.1°F) over every 100 m increase in altitude.

Question 9

Why is sunshine more intense at high altitudes than low latitudes?

Answer 9

Because solar radiation travels through less atmosphere to reach the surface.

Question 10

What is ultra-violet radiation?

Answer 10

Radiation with a lower wave-length than visible sunlight.

Question 11

What helps promote anthocyanin and tannin synthesis in high altitudes?

Answer 11

More intense levels of sunshine and ultra-violet radiation

Question 12

What is diurnal range?

Answer 12

The difference between day and night temperatures.

Question 13

Why do high altitude sites typically have a higher diurnal range?

Answer 13

The ground absorbs energy from solar radiation during the day and releases energy into the atmosphere during the night.

At high altitudes the air is thinner and holds less moisture and therefore heat rapidly escapes, leading to relatively cool night-time temperatures.

Question 14

Why do sites at lower altitudes typically have lower diurnal range?

Answer 14

The ground absorbs energy from solar radiation during the day and releases energy into the atmosphere during the night.

At lower altitudes the air in the atmosphere (particularly the water vapour) absorbs some of this energy, meaning some heat is retained at night

Question 15

Why does the importance of aspect and slope steepness increase at high latitudes?

Answer 15

Solar radiation hits the Earth at a low angle at high latitudes. In the context of the vine growth cycle, the angle is lowest in the spring and autumn (compared to the summer).

The slope increases the angle (nearer to perpendicular) at which the solar radiation hits the Earth’s surface, hence increasing the intensity of heat and light.

A good slope and aspect in cool climates located at high latitudes can ensure the full and even ripening of grapes.

Question 16

What are the advantages of east-facing slopes?

Answer 16

Slopes facing east benefit from morning sunshine that can heat up the atmosphere when air and soil temperatures are at their lowest. This can extend the hours of vine growth and grape ripening each day, especially in cool climates.
The grape canopy, which can be covered with dew in the morning, also dries out earlier in east-facing vineyards, reducing the spread of fungal disease, which is beneficial for grape quality and yields.

Question 17

What must a grower consider before planting vines on a west-facing slope?

Answer 17

Slopes that face west receive the afternoon sun and may become too hot, especially in warm climates, and risk of sunburnt grapes is increased.

However, in areas with coasts to the west, e.g. California and Western Australia, cool afternoon sea breezes may alleviate this.

Question 18

Other than heat and light, what are the benefits of planting vines on slopes?

Answer 18

• Shallower, poorer soils and better drainage
• Shelter from winds and rain
• Protection from frosts (air movement down the slope prevents frosts from forming)

Question 19

What are the two main disadvantages of planting vines on a slope?

Answer 19

Soil erosion and the inability to use machinery on steep slopes can be problematic.

Question 20

How do nearby bodies of water influence temperature?

Answer 20

Water heats up and cools down more slowly than land.

**During the day ** The water and the air above a body of water remains relatively cool and lowers the average temperature in the local area. Air directly above dry land heats up more quickly than that above the water, and this warm air rises. Cool air from above the water is drawn to the land to replace the warm air as it rises, resulting in cool, humid afternoon breezes.

During the night The water retains the warmth gained during the day, whereas, without solar radiation, the land loses heat relatively quickly. The warmth of the body of water keeps the local area warmer.

The same effect can be experienced over the year, with large bodies of water giving cooler summers and milder winters.

Question 21

Give two examples of how ocean currents can moderate temperatures.

Answer 21

Margeaux, Bordeaux and Willamette Valley, Oregan are both at 45° latitudes. One produces cabernet sauvignion (late ripening) and one produces pinot noir (early ripening).
Bordeaux’s climate is warmed by the Gulf Stream, an ocean current flowing from the Gulf of Mexico.
Oregan’s temperature is cooled by the California current, which flows from the northern pacific.

Question 22

How does El Nino start?

Answer 22

El Niño starts when warm water in the western Pacific Ocean moves eastwards along the Equator towards the Caribbean.

Question 23

How does El Nino affect regions located in the eastern Pacific Ocean?

Answer 23

The eastern Pacific Ocean becomes warmer than average and this tends to cause high levels of rainfall and risk of hurricanes in South America and California. Rainfall can disrupt pollination and fruit set and lead to excessive water availability, which can increase vegetative growth and hinder ripening. And hurricanes clearly have a destructive influence.

However, El Niño brings warmer than average temperatures and drier conditions
to the more northerly states of Washington and Oregon.

Question 24

How does El Nino affect regions located in the western Pacific Ocean?

Answer 24

On the western side of the Pacific Ocean in Australia, El Niño tends to cause warmer temperatures and drought conditions, which can cause extreme vine stress and vine damage.

Question 25

How often does El Nino occur?

Answer 25

El Niño events typically occur once every 3–7 years, with extreme El Niño events being rarer. It is thought, however, that these extreme events are becoming more frequent as a part of climate change.

Question 26

How does La Nina start?

Answer 26

La Niña is caused when the eastern Pacific Ocean is cooler than average.

Question 27

How does La Nina affect regions in the eastern Pacific ocean?

Answer 27

La Nina tends to result in cooler, wetter conditions in Washington and Oregon, but warmer, drier conditions in California and South America

Question 28

How does La Nina affect regions in the western pacific ocean?

Answer 28

La Niña causes wetter and cooler conditions in Australia

Question 29

In what ways do bodies of water influence heat and sunlight available to wine growing regions?

Answer 29

* Moderating effect. Bodies of water are slow to warm up and cool down. * Ocean currents * Water surface can reflect solar radiation * El Nino and La Nina in the Pacific Ocean

Question 30

How to winds affect vineyards and wine growing regions?

Answer 30

* Winds can cool or warm regions (for example, the cold Mistral in the Rhone Valley, and the warm Zonda in Mendoza. * Winds and breezes can reduce the occurence of humid, stagnant air in the vine canopy that encourages the development of fungal disease. * Wind increases evapotranspiration of the vine, meaning vines water needs may be higher in windy areas. (If water isn't readily available, wind can lead to water stress). * Strong winds can cause damage to vines and vineyard trellising.

Question 31

What can be implemented in the vineyard to minimise the damage caused by strong winds?

Answer 31

Rows of trees can be planted at the edge of the vineyard to act as wind breaks (these can compete with the vines for nutrients and water). Fences can also be used, but are less aesthetic and require maintenance.

Question 32

What factors of the soil influence the warmth of the vineyard?

Answer 32

The drainage of the soil, texture and colour.

Question 33

Why is it desirable for cool-climate vineyards to have free-draining soils?

Answer 33

Soils that drain freely, for example sandy or stony soils, warm up more quickly in the spring than damp soils. Rising soil temperature encourages the breakdown of starch in the roots, which stimulates budburst and shoot growth.

Question 34

What are two factors to consider when planting vines in free-draining soils?

Answer 34

Although free-draining soils are typically beneficial in cool climates, there is a risk of early budburst, which increases the risk of harmful spring frosts damaging young buds and shoots. Warm soils also encourage root growth, which means the vines can absorb more water and nutrients.

Question 35

How do light coloured soils influence temperature?

Answer 35

Light coloured soils can reflect some energy from solar radiation to the lower parts of the canopy (which may recieve little light). This can increase photosynthesis and grape ripening in cool and cloudy climates or where late-ripening grapes are used. In warm climates, light coloured soils can increase temperatures in the warmest part of the day.

Question 36

How do dark colour soils influence temperature?

Answer 36

Dark-coloured soils, such as some of those from volcanic origin (e.g. as found in Etna), absorb more energy and re-radiate most of it when temperatures are cooler, for example at night. This can be useful, especially in cool climates or for late-ripening grapes, allowing the development of colour and degradation of acid to continue during the night.

Question 37

How do stony soils influence temperature?

Answer 37

Stony soils, especially if the underlying soil is slightly damp, are also very effective at absorbing heat and releasing it at night. This is because stone and water are good conductors compared to air.

Question 38

What is mist and fog? How do they form?

Answer 38

Mists are formed by tiny drops of water collecting in the air just above an area of ground or water. They are usually formed when warm air is rapidly cooled, causing water vapour in the air to condense. This may occur, for example, at night when warm air over a body of water meets cooler conditions above the land. Fog is dense mist.

Question 39

How do mist, fog and clouds influence the heat and light available to the vineyard?

Answer 39

Depending on the density of the mist, fog or amount of cloud cover, sunlight can be limited to such an extent that photosynthesis is reduced. With less solar radiation, temperatures can be lower, particularly if morning fog or cloud delays the time at which the morning sun begins to warm the land. Where mists, fogs and cloudy conditions are regular, this can slow down sugar accumulation and acid degradation in the grapes, which may be beneficial in warm regions or when growing early-ripening grape varieties.

Question 40

Why is a high diurnal range considered beneficial in warm and hot climates?

Answer 40

In these climates, a relatively cool period during the night can slow the respiration of malic acid and be beneficial for the formation of anthocyanins (day-time temperatures are too hot).

Question 41

Why is a low diurnal range considered to be favourable in cool to moderate climates?

Answer 41

A low diurnal range may be favourable so that night-time temperatures still allow ripening (e.g. acid degradation, anthocyanin synthesis) to continue, which may be needed for grapes to ripen sufficiently.

Question 42

How does a region's diurnal range influence a grape's aroma compounds?

Answer 42

It is thought that night-time temperatures can have some influence on aroma compounds. For example, warmer night temperatures are associated with a greater breakdown of methoxypyrazines, which may be important in cool climates, and cooler temperatures are associated with a greater retention of some other compounds, such as rotundone.

Question 43

What are the natural factors that affect temperature and sunlight?

Answer 43

* Latitude * Altitude * Slopes and aspect * Proximity to water * Wind * Characteristics of the soil * Mist, fog and clouds ## Footnote + diurnal range, however this is associated with latitude and altitude.

Question 44

How much rainfall do vines typically need per year?

Answer 44

500mm in cool climates 750mm in warm climates

Question 45

Why do vines need water? (4)

Answer 45

* Turgidity (keeping the vine from wilting) * Photosynthesis * Temperature regulation * Uptake of nutrients (water acts as a solvent for nutrients in the soil)

Question 46

What is transpiration?

Answer 46

Water vapour diffuses out of the stomata (tiny pores) on the underside of vine leaves. The loss of water from the cells in the leaf causes water to be pulled upwards from the soil, through the roots and the above-ground parts of the vine.

Question 47

What happens when the stomata is open?

Answer 47

Open stomata allow the free exchange of water vapour out of the vine and also let carbon dioxide and oxygen diffuse in and out of the leaves. If the vine has sufficient water, it can keep its stomata open all day.

Question 48

Why would stomata close or partially close? What can this lead to?

Answer 48

A lack of water causes the vine to close its stomata partially, an effort to conserve water. Closed stomata can also reduce or stop photosynthesis due to the lack of carbon dioxide entering the leaves.

Question 49

What are the risks of closed stomata?

Answer 49

Closed stomata reduces or even stops photosynthesis. As photosynthesis is the way that the plant makes sugars for energy, this causes the vine’s growth to be stunted and ripening to slow down. Extreme cases of water stress can lead to leaf loss and vine death.

Question 50

When is plentiful water desired? Why?

Answer 50

A plentiful supply of water in the spring encourages the growth of lots of leaves and hence the establishment of a large leaf surface area to support the growth of the vine and ripening of grapes.

Question 51

When is plentiful water not desired? Why?

Answer 51

If water is too easily available into late spring and early summer, vegetative growth is promoted and prolonged into the period of grape ripening. This acts as a competitive source for the vine’s sugars, which can delay and compromise ripening.

Question 52

When is mild water stress desired and why?

Answer 52

It is thought that mild water stress before véraison is beneficial as it inhibits further vegetative growth, concentrating the vines' energy on grape ripening. Also helps control the canopy to prevent too much shading of the grapes.

Question 53

What are the risks of a canopy too dense in late spring and summer?

Answer 53

Unless adequately controlled, this can lead to reduced formation of anthocyanins, tannins and aroma compounds, less tannin polymerisation and higher levels of methoxypyrazines in grapes. Dense canopies of shoots and leaves also have poor ventilation, which can encourage fungal disease in rainy or humid climates.

Question 54

What happens when there is **too much** water available to the vine between véraison and ripening?

Answer 54

Too much water available late in the ripening period can cause dilution of sugars in the grapes and even grape splitting, which in turn encourages botrytis.

Question 55

What happens when there is **too little** water available to the vine between véraison and ripening?

Answer 55

A water deficit during ripening may lead to the early onset of grape shrivel and reduced ability of the grapes to reach the desired level of ripeness.

Question 56

How does water availability affect soil?

Answer 56

* **Damp soils** are often cold, especially early in the growing season, and can delay budburst, which can shorten the growing season. * **Warm soils** promote budburst and also encourage root growth and therefore the ability of the vine to take up water and nutrients.

Question 57

What are the risks of high humidity in the vineyard?

Answer 57

A humid environment in the vine canopy that can then lead to fungal diseases such as downy mildew and botrytis.

Question 58

What are the risks of low humidity in the vineyard?

Answer 58

Air that is low in humidity can increase evapotranspiration and therefore the potential for water stress. It is also associated with increased grape transpiration and hence higher sugar accumulation in the grapes.

Question 59

What natural factors affect water availability?

Answer 59

* Rainfall * Characteristics of the soil and land * Evapotranspiration rate

Question 60

What causes rainfall?

Answer 60

Rainfall is caused by water vapour condensing and precipitating. Warm temperatures cause moisture from the land to evaporate. As the warm moist air rises in the atmosphere, it cools and condenses into clouds and eventually rain.

Question 61

How can mountains influence the pattern of rainfall?

Answer 61

Mountain ranges can force winds of warm moist air upwards over high altitudes. This causes the water vapour to cool, condense and precipitate. This can mean that the regions on one side of the mountain experience greater rainfall, whereas regions on the other side are sheltered from the rain- bearing winds and often have very dry conditions (rainshadow).

Question 62

How do the characteristics of the soil influence the availability of water for the vines' roots?

Answer 62

The amount of water available to the vine depends on how easily the water drains, the water-holding properties of the soil (a function of the soil’s texture and organic matter content) and the soil depth.

Question 63

Why are water logged soils harmful to the vine?

Answer 63

Water-logged soils (usually as a result of poor drainage) are harmful to the vine, reducing the amount of oxygen available to the roots (which slows their growth) and eventually killing the vine.

Question 64

How do slopes influence water available to the vine?

Answer 64

There will be greater surface run-off in vineyards on slopes. This can mean there is less penetration of water into the soil and therefore less water available to vine roots.

Question 65

How do surface run-off and erosion impact the vineyard?

Answer 65

* Surface-run off causes erosion of the soil and leaching of nutrients. * Erosion (even without surface run-off, the soil on slopes generally gradually falls down the slope), soils on slopes are generally thin, limiting the area over which vines can obtain water and nutrients.

Question 66

What is the evapotranspiration rate?

Answer 66

Evapotranspiration rate is the amount of transpiration from the vine, combined with the evaporation of water from the soil surface. It is therefore the rate at which water is no longer available, either because it has been taken up by the vine or because it has been lost to the atmosphere.

Question 67

What factors influences the evapotranspiration rate?

Answer 67

* Temperature * Humidity * Wind Hot, dry and windy weather leads to the fastest evapotranspiration rate.

Question 68

What are the five most important nutrients for the vine?

Answer 68

* Nitrogen * Potassium * Phospherus * Calcium * Magnesium

Question 69

What are the six secondary nutrients that play a role in vine growth and reproduction?

Answer 69

* Sulfur * Manganese * Boron * Copper * Iron * Zinc

Question 70

Why is **nitrogen** essential for the vine?

Answer 70

Nitrogen is essential for vine growth and can have a major impact on vine vigour and on grape quality. It is a component of proteins and chlorophyll (required for photosynthesis).

Question 71

What is the effect of **too much** nitrogen in the soil?

Answer 71

Too much nitrogen in the soil causes **excessive vegetative growth,** which leads to: * Sugars being diverted to the shoots and leaves rather than grapes, hindering ripening. * A canopy too dense causing shading of fruit and buds, and poor ventilation leading to fungal disease.

Question 72

What is the effect of **too little** nitrogen in the soil?

Answer 72

Too little nitrogen results in reduced vigour and yellowing of vine leaves. Grapes that have low nitrogen levels can also be problematic for fermentation.

Question 73

Is more or less nitrogen in the soil thought to produce higher quality grapes?

Answer 73

Less. Vines with a restricted supply of nitrogen tend to produce higher quality grapes.

Question 74

Why is potassium important for the vine?

Answer 74

Potassium is essential for vine growth and helps regulate the flow of water in the vine.

Question 75

What is the effect of **too much** potassium in the soil?

Answer 75

Very high potassium levels in soils can cause problems in the uptake of magnesium, and this may lead to reduced yields and poor ripening. High potassium levels in the soil can lead to high potassium levels within the grapes. This has a significant effect on wine quality, as high levels of potassium in the grape must are linked to high pH

Question 76

What is the effect of **too little** potassium in the soil?

Answer 76

Low levels of potassium can lead to low sugar accumulation in the grapes, reduced grape yields and poor vine growth in general.

Question 77

Why is phosphorus important for the vine? How much is needed?

Answer 77

Phosphorus is important for photosynthesis. Vines require very little, and there is usually enough phosphorus naturally present in the soil.

Question 78

What is the effect of **too little** phosphorus in the soil?

Answer 78

A deficiency in phosphorus leads to poorly developed root systems (and hence a diminished ability to take up water and nutrients), reduced vine growth and lower yields.

Question 83

What is impacted with a calcium deficiency?

Answer 83

Calcium deficiency is rare but can have a negative influence on fruit set.

Question 83

Why is calcium important for the vine?

Answer 83

Calcium has an important role in the structure of plant cells and in photosynthesis.

Question 84

Why is magnesium important for the vine?

Answer 84

Magnesium is found in chlorophyll and has a key role in photosynthesis.

Question 85

What is impacted with a magnesium deficiency?

Answer 85

Deficiency can result in reduced grape yields and poor ripening.

Question 86

What are the natural factors that effect nutrient availability?

Answer 86

* Water availability * Soil PH * Soil organisms * Soil textures * Vineyard topography

Question 87

How does the availability of water influence the availability of nutrients to the vine?

Answer 87

Vine nutrients dissolve in soil water, which is then taken up by the roots of the vine.

Question 88

Give two examples of how PH levels influence nutrient availability.

Answer 88

* Iron is poorly available in soils with high PH, which can cause chlorosis. * Vines can struggle to take up phosphorus in highly acidic soils.

Question 89

What is chlorosis?

Answer 89

A condition in which leaves turn yellow and photosynthesis stops, so grape ripening and yields are negatively affected as a result.

Question 90

What are organic nutrient compounds vs inorganic nutrient compounds?

Answer 90

Organic nutrient compounds found in and added to soil (such as manure or compost) contains carbon, and cannot be taken up by the vine. They need to be converted to inorganic nutrient compounds, which do not contain carbon.

Question 91

What is mineralisation?

Answer 91

Organisms that live in the soil (such as bacteria, fungi, earthworms, etc.) feed on organic matter and converts it into forms available to the vine. (inorganic nutrient compounds).

Question 92

Give three examples of how a soil's texture influences nutrient availability.

Answer 92

* Soils with a high proportion of clay are good at holding nutrients. * Sandy soils are poor at holding nutrients. * Humus can increase the soil’s ability to hold nutrients.

Question 93

How does the topography of the vineyard influence the availability of nutrients?

Answer 93

Soils on slopes are often thinner and less fertile than those on plains or valley floors.

Question 94

What is soil made up of?

Answer 94

* Geological sediment; solid matter that has been moved and deposited to a new location (eg. via wind or water). * Organic remains in the form of humus * Pores in between the sediment that contain water and air

Question 95

What is meant by soil texture?

Answer 95

The texture of the soil describes the proportions of the mineral particles of clay (fine), silt (intermediate) and sand (course, loose).

Question 96

What is 'loam'?

Answer 96

Loam describes a soil that has moderate proportions of clay, silt and sand.

Question 97

How do soils with a high proportion of clay influence water and nutrient availability?

Answer 97

Soils with a high proportion of clay are finely textured; clay particles are very small, and because of this have a large surface area compared to their volume, so they are very effective at holding water and nutrients.

Question 98

How do soils with a high proportion of sand influence water and nutrient availability?

Answer 98

Sand particles are relatively large and have a small surface area compared to their volume. They therefore have limited capacity to hold water and it can drain through them easily. They are also poor at retaining nutrients.

Question 99

How do larger rock fragments in the soil influence water and nutrient availability?

Answer 99

Rock fragments (such as gravel or pebbles) improve drainage, but lower the water and nutrient holding capacity of the soil.

Question 100

What is meant by soil structure?

Answer 100

The structure of the soil describes how the mineral particles in the soil form aggregates (crumbs). The size, shape and stability of these aggregates are important for determining water drainage, root growth and workability of the soil.

Question 101

How does a high proportion of clay influence the soil's structure?

Answer 101

Soils that have a very high clay content are sticky and may form **aggregates** that are hard for vine roots to penetrate and challenging for soil cultivation. The vines’ roots may be limited to cracks or gaps between the aggregates

Question 102

How does a high proportion of sand influence the soil's structure?

Answer 102

Soils that are high in sand or larger particles such as gravels or pebbles are very loosely structured and, in fact, need some clay to help bind them together.

Question 103

What is humus?

Answer 103

Humis is organic matter in the soil that is formed by the partial decomposition of plant and animal material by soil microbes and earthworms.

Question 104

How does humus influence the soil's ability to retain water and nutrients?

Answer 104

Humus has a spongey texture, large surface area and is able to adsorb water and nutrients. It helps to bind soils together and can help soils to retain water and nutrients.

Question 105

What factors define a region's climate?

Answer 105

A region’s climate is defined as the annual pattern of temperature, sunlight, rainfall, humidity and wind averaged out over several years (30 years is the timescale generally agreed).

Question 106

Who was the (Growing Degree Days) GDD classification created by and why?

Answer 106

Amerine and Winkler (1944). It was originally intended for the vineyard regions in California. Also known as the Winkler Scale/Index

Question 107

How do you calculate the GDD (growing degree days) of a region?

Answer 107

* For Celsius, subtract 10 from the average mean temperature of a month in the growing season. For Fahrenheit, subtract 50 from the average mean temperature of a month in the growing season. * Multiply this by the number of days in that month. * Make the same calculation for each month in the growing season (April to October in the Northern Hemisphere, October to April in the Southern Hemisphere) and add together the totals to get the GDD. A region's GDD is then categories into 'bands' ranging from region Ia (very cold) to region V (very hot). | (Any months with a negative value would not be counted.)

Question 108

How does the Huglin Index differ from the GDD model?

Answer 108

The Huglin Index, created by Huglin (1978), uses a similar formula to GDD, but differs in that the calculation takes into account both mean and maximum temperatures and the increased day length experienced at higher latitudes. The index is split into bands, with the most suitable grape varieties mapped to each range. This model is widely used in Europe.

Question 109

How is the Mean Temperature of the Warmest Month (MJT) calculated?

Answer 109

This model, created by Smart and Dry (1980), uses the mean temperature of either July in the Northern Hemisphere or January in the Southern Hemisphere, termed MJT (mean January/July temperature), as well as measures of continentality, humidity and hours of sunshine. Again, the temperatures have been divided into six bands.

Question 110

How is the Growing Season Temperature (GST) model calculated?

Answer 110

This model uses the mean temperature of the whole growing season and, again, these temperatures are grouped into climatic bands ranging from cool to hot. It is very closely correlated to GDD and is easier to calculate.

Question 111

Describe a maritime climate.

Answer 111

Maritime climates experience low annual differences between summer and winter temperatures. Rainfall is also relatively evenly spread throughout the year. An example of a maritime region is Bordeaux.

Question 112

Describe a mediterranean climate.

Answer 112

Mediterranean climates experience low annual differences between summer and winter temperatures. The annual rainfall tends to fall in the winter months, giving dry summers. Examples include Napa Valley and Coonawarra.

Question 113

Describe a continental climate.

Answer 113

Continental climates have more extreme differences between summer and winter temperatures. They often have short summers and cold winters with temperatures rapidly changing in the spring and autumn. Examples include Burgundy and Alsace.

Question 114

What is the average GST of regions classified as a **cool climate**?

Answer 114

16.5°C or below

Question 115

What is the average GST of regions classified as a **moderate climate**?

Answer 115

Between 16.5–18.5°C

Question 116

What is the average GST of regions classified as a **warm climate**?

Answer 116

18.5–21°C

Question 117

What is the average GST of regions classified as a **hot climate**?

Answer 117

21°C+

Question 118

Define continentality.

Answer 118

Continentality is a measure of the difference between the annual mean temperatures of the hottest and coldest months.

Question 119

What is the biggest influence on a region's continentality?

Answer 119

Large bodies of water.

Question 120

How does a region's weather differ from it's climate?

Answer 120

A region’s weather is the annual variation that happens relative to the climatic average. Some regions experience greater variation in this pattern than others.

Question 121

How does vintage variation affect how a wine is made?

Answer 121

The weather in a particular year can influence sugar and acid levels, and tannin and aroma/flavour ripeness. This may have a subsequent effect on how the wines are made in the winery, for example more or less extraction, sugar/acid adjustments, whole bunch usage etc).

Question 122

How is climate change affecting the wine industry?

Answer 122

* Rising temperatures * Greater evapotranspiration * Changes in the geographical distribution of rainfall * Greater weather variability * Greater frequency of extreme weather events.

Question 123

# 5 What are the effects of rising temperatures associated with climate change in viticulture?

Answer 123

* Budburst comes earlier in the spring, thus each stage thereafter becomes quicker. * The increased temperatures speed up the rate of sugar accumulation and reduction of acidity, but do not quicken the ripening of most aroma and tannin compounds. (Grapes may need to be picked later, leading to high alcohol, low acidity, high PH). * Aromas associated with grape varieties may change (e.g the pepper aroma in Syrah). * Some region's may become too warm for certain grape varieties, growers will need to adapt. * It is thought that some wine growing regions (eg parts of southern california, south africa etc) will be abandoned in 50-100 years due to increased evapotranspiration and drier, hotter weather.