Chapter 3 - The Growing Environment Flashcards
What are the four key natural resources needed by vines to produce and ripen suitable grapes?
- Warmth (temperature)
- Sunlight
- Water
- Nutrients
What is the primary reason why geographical wine appellations are important?
Vineyard sites provide different growing environments, which significantly affect the natural resources available to vines and therefore the resulting wines
What happens to vines at temperatures around -20°C (-4°F)?
Severe damage to the vine
What happens to most Vitis vinifera vines at temperatures below -25°C (-13°F)?
They are killed
How does a significant rise in temperature at budburst affect the quality of the process?
Budburst is more successful and uniform with a significant temperature rise
Name three physiological consequences of mean temperatures above 21°C (70°F) in the final month of ripening.
- Rapid loss of acidity
- Rise in pH
- Faster sugar accumulation
What happens to grapes when mean temperatures are below 15°C (59°F) in the final month of ripening?
Acid loss is reduced to a point that acidity levels in the must may be too high
What are the two main needs of grapevines in relation to sunlight?
- Photosynthesis for vine growth and ripening
- Direct sunshine on grapes for development of color, tannins, and aroma compounds
At what level does light become a limiting factor for photosynthesis?
Below one-third of full sunshine
What four effects does sunshine on grape bunches have?
- Enhances anthocyanin development in black grapes
- Reduces methoxypyrazine levels
- Increases tannin accumulation pre-véraison and promotes polymerization post-véraison
- Increases levels of some favorable aroma compounds
What are the three main natural factors that affect temperature and sunlight in vineyards?
- Latitude
- Altitude
- Proximity to water
How does latitude affect solar radiation intensity and why?
Lower latitudes (closer to the Equator) receive more intense solar radiation because the sun’s rays travel through less atmosphere and hit the Earth at a more direct angle
How much does temperature decrease with altitude?
Approximately 0.6°C (1.1°F) for every 100m increase in altitude
Name three effects of high altitude on vineyard climate.
- Cooler temperatures
- More intense sunshine (more UV radiation)
- Higher diurnal range (bigger difference between day and night temperatures)
Why are high altitude sites favorable in low latitude regions?
They provide cooler temperatures that would otherwise be too hot for quality viticulture
What is meant by ‘aspect’ in vineyard terms?
The direction that a vineyard slope faces
Which slope aspect receives the most solar radiation in the Northern Hemisphere?
South
In the Southern Hemisphere which slope aspect receives the most solar radiation?
North
Why is aspect more important at higher latitudes?
Solar radiation hits the Earth at a lower angle at high latitudes, so a slope can increase the angle toward perpendicular, increasing heat and light intensity
Name four examples of how proximity to water affects vineyard climate.
- Moderates temperatures (cooler days, warmer nights)
- Creates afternoon breezes that can cool vineyards
- Increases humidity levels
- Can provide protection against frost
What are the two opposite phases of the El Niño-Southern Oscillation (ENSO)?
- El Niño
- La Niña
How does El Niño affect wine growing in California and South America?
Causes high levels of rainfall and risk of hurricanes, which can disrupt pollination, fruit set, and increase disease pressure
How does El Niño affect wine growing in Australia?
Causes warmer temperatures and drought conditions, which can lead to extreme vine stress and damage
What two effects can winds have on vine canopies?
- Reduce humidity and stagnant air, decreasing fungal disease
- Increase evapotranspiration, raising water needs
What colors of soil warm up most quickly in spring?
Dark-colored soils
What is the effect of light-colored soils in vineyards?
They reflect solar radiation, increasing light into the lower parts of the canopy
What is the advantage of stony soils regarding heat retention?
They absorb heat during the day and release it at night, moderating temperature
How do morning fog and cloud cover affect photosynthesis?
They can limit sunlight to the extent that photosynthesis is reduced, delaying warming and potentially slowing sugar accumulation
What is diurnal range and why is it important in viticulture?
The difference between day and night temperatures; it affects acid retention, aroma development, and color formation
Why is high diurnal range beneficial in warm climates?
Cool nights slow the respiration of malic acid and benefit anthocyanin formation, which is inhibited by very hot daytime temperatures
Why might low diurnal range be beneficial in cool or moderate climates?
Night temperatures remain warm enough to allow ripening processes to continue, helping grapes reach sufficient ripeness
How much annual rainfall do vines generally need in cool and warm climates?
Cool climates: minimum 500mm
Warm climates: minimum 750mm
What are three main functions of water in grapevines?
- Providing turgidity (preventing wilting)
- Enabling photosynthesis
- Regulating temperature
What benefit does a plentiful water supply in spring provide?
Encourages growth of leaves, establishing a large leaf surface area to support vine growth and grape ripening
Why is mild water stress before véraison considered beneficial?
It inhibits further vegetative growth, which would compete with grape ripening for the vine’s resources
Name two negative effects of excessive water availability late in the ripening period.
- Dilution of sugars in the grapes
- Grape splitting, which encourages botrytis
What happens to grapes during water deficit in the ripening period?
Early onset of grape shrivel and reduced ability to reach desired ripeness
What is evapotranspiration rate and what factors affect it?
The combined rate of transpiration from the vine and evaporation from soil; affected by temperature, humidity, and wind
How do soil texture and structure affect water availability to vines?
Clay soils hold more water but can become waterlogged; sandy or stony soils drain freely but may not retain enough water; soil structure affects root penetration and water movement
Which soil type warms up more quickly in spring and why is this significant?
Sandy or stony soils warm up more quickly, encouraging earlier budburst and potentially extending the growing season
What happens in waterlogged soils that makes them harmful to vines?
Oxygen is displaced, reducing root respiration and growth, eventually killing the vine
Name the five most important nutrients for grapevines.
- Nitrogen
- Potassium
- Phosphorus
- Calcium
- Magnesium
What effect does too much nitrogen have on vine growth and grape quality?
Causes excessive vegetative growth, diverting sugars from grape ripening and potentially causing canopy shading and poor ventilation
Why do vines with restricted nitrogen supply tend to produce higher quality grapes?
They have balanced vigor, with energy directed toward grape ripening rather than excessive shoot growth
How does high potassium in soil affect wine quality?
It leads to high potassium levels in grapes, which is linked to high pH in the must and resulting wine
What is the effect of soil pH on nutrient availability?
Different nutrients become more or less available at different pH levels; e.g., iron is poorly available in high pH soils, while phosphorus is limited in highly acidic soils
What is chlorosis and what causes it in vines?
A condition where leaves turn yellow and photosynthesis stops; often caused by iron deficiency in high pH soils (e.g., limestone soils)
What is the difference between organic and inorganic nutrient compounds in soils?
Organic compounds contain carbon and must be converted by soil organisms to inorganic forms before the vine can take them up
Name three main components of soil.
- Geological sediment (sand, pebbles, rocks)
- Organic remains (humus)
- Pores containing water and air
What is the difference between soil texture and soil structure?
Texture describes the proportions of sand, silt, and clay particles; structure describes how these particles form aggregates (crumbs)
What are four characteristics of clay-rich soils?
- Fine texture
- Large surface area
- Effective at holding water and nutrients
- Can be sticky and form hard aggregates
What are four characteristics of sandy soils?
- Loose texture
- Limited capacity to hold water
- Poor at retaining nutrients
- Easy for roots to penetrate
What is humus and how does it benefit soil?
Organic matter formed by partial decomposition of plant and animal material; it helps bind soil, retains water and nutrients, and has a spongy texture
What is a climate in viticultural terms?
The annual pattern of temperature, sunlight, rainfall, humidity, and wind averaged over several years (typically 30 years)
How is weather different from climate?
Weather is the annual variation that happens relative to the climatic average; it changes year to year while climate represents long-term patterns
What four climate models for vineyard classification are mentioned in the chapter?
- Growing Degree Days (GDD)
- Huglin Index
- Mean Temperature of the Warmest Month (MJT)
- Growing Season Temperature (GST)
How is Growing Degree Days (GDD) calculated?
Subtract 10°C (50°F) from the average mean temperature of each month in the growing season, multiply by days in the month, and add all months together
How does the Huglin Index differ from GDD in its calculation?
It takes into account both mean and maximum temperatures, as well as increased day length at higher latitudes
What is Growing Season Temperature (GST) and why is it useful?
The mean temperature of the whole growing season; it’s closely correlated to GDD but easier to calculate
What are the three broad categories used to describe vineyard climates?
- Maritime
- Mediterranean
- Continental
What are the characteristics of a maritime climate?
Low annual differences between summer and winter temperatures, with rainfall relatively evenly spread throughout the year
What are the characteristics of a Mediterranean climate?
Low annual differences between summer and winter temperatures, but rainfall concentrated in winter months giving dry summers
What are the characteristics of a continental climate?
Extreme differences between summer and winter temperatures, with short summers, cold winters, and rapid temperature changes in spring and autumn
What temperature ranges define cool climates?
Average of 16.5ºC or below
What is continentality and how is it measured?
The difference between annual mean temperatures of hottest and coldest months; regions near large bodies of water have low continentality, while inland regions have high continentality
What is vintage variation and what causes it?
Year-to-year differences in wine style and quality caused by annual weather patterns that affect sugar, acid, tannin, and aroma/flavor development
Name four effects of climate change on viticulture.
- Rising temperatures accelerating vine cycles
- Greater evapotranspiration increasing water stress
- Changes in rainfall distribution
- Greater weather variability and extreme weather events
How does climate change affect the balance between sugar accumulation and phenolic ripeness?
Increased temperatures speed up sugar accumulation and acid degradation faster than the ripening of most aroma and tannin compounds, potentially leading to higher alcohol wines with less balanced flavors
How might climate change shift suitable growing regions?
Some current regions may become too warm for quality viticulture, while previously too-cold regions may become viable; all regions face challenges from extreme weather events
Name two ways wine businesses are responding to climate change.
- Mitigation through sustainable techniques (renewable energy, protecting ecosystems)
- Adaptation through revised site selection, planting material choices, and vineyard management techniques
How does soil color affect heat retention and release in vineyards?
Dark soils absorb more heat during the day and release it at night, moderating temperature fluctuations; light-colored soils reflect more light back into the canopy
What is the effect of altitude on UV radiation and how does this impact grape development?
Higher altitudes have increased UV radiation, which is thought to promote anthocyanin and tannin synthesis
How does proximity to large bodies of water create afternoon breezes?
Air above land heats faster and rises; cooler air from above water is drawn inland to replace it, creating cooling breezes
What is a rain shadow and how does it affect vineyard regions?
Area on the leeward side of mountains that receives significantly less rainfall because mountains force moist air upward, causing precipitation on the windward side
How does soil structure affect root growth and water uptake?
Poor structure can limit root penetration to cracks between aggregates, reducing the area over which vines can obtain water and nutrients
How does the oceanic influence from the Gulf Stream and California Current affect viticulture in Bordeaux and Oregon?
The warm Gulf Stream gives Bordeaux (45° latitude) a warmer climate suitable for Cabernet Sauvignon, while the cold California Current makes Oregon (also 45° latitude) cooler, better suited to Pinot Noir
What happens to grape compositional balance in excessively hot climates?
Grapes accumulate sugar rapidly but may not develop balanced flavor compounds, color, and tannins, potentially resulting in wines with high alcohol, low acidity, and underdeveloped flavors
What specific temperature conditions are helpful for anthocyanin development in Syrah in the Northern Rhône?
Anthocyanin synthesis in black grapes, including Syrah, is optimal at temperatures between 15-25°C (59-77°F). In the Northern Rhône, the moderate climate provides these conditions during the ripening period, supporting good color development in Syrah grapes.
What is the albariza soil of Jerez and why is it well-suited to viticulture in a dry climate?
A clay soil with good water retention that releases water slowly to vines; it forms a crust when dry, reducing evaporation
What are the effects of the Zonda wind in Mendoza?
It brings hot air that heats the vineyard area, increasing temperature and potentially causing water stress
What are the characteristics of soils in the Haut-Médoc and why are they advantageous?
Gravelly soils that are very free-draining, helping avoid excess water in this relatively rainy maritime climate
How does increased temperature at night affect methoxypyrazine degradation?
Warmer night temperatures accelerate the breakdown of methoxypyrazines, reducing herbaceous aromas in grapes
How does the California Current affect coastal vineyard regions like Sonoma?
It brings cool water that generates fog, moderating temperatures and making these areas suitable for cool-climate varieties
What is the benefit of the Cascade Mountains to the Columbia Valley wine region?
They create a rain shadow effect that blocks much of the rainfall from the Pacific, creating drier conditions east of the mountains
What is difference between the soil water-holding capacity in Hawke’s Bay (Gimblett Gravels) versus Jerez?
Hawke’s Bay has very free-draining gravel soils that require irrigation despite high rainfall (1000mm), while Jerez has albariza soils that retain water well despite lower rainfall (650mm)
What is the relationship between ocean currents and continentality in wine regions?
Ocean currents can significantly modify continentality; warm currents reduce continental effects while cold currents can enhance them
How does high diurnal range affect vine physiology differently from consistent temperatures?
Significant temperature differences between day and night create distinct metabolic cycles, with different processes prioritized during warm days versus cool nights
What effect does altitude have on vine dormancy and budburst in high-latitude regions?
Higher altitude delays budburst, which can help avoid spring frost damage but may reduce the length of the growing season
How do vineyard microclimates differ from regional macroclimate?
Microclimates can vary significantly within short distances due to slope, aspect, soil type, and proximity to water, creating conditions that may differ substantially from regional averages
What effects can reflected light from water surfaces have on grapevines?
Reflected light increases total radiation reaching the vines, especially at high latitudes where the sun’s angle is lower, increasing photosynthesis and grape ripening potential
How does topography affect rainfall patterns in vineyard regions?
Mountainous areas force air upward, creating more precipitation on windward slopes and rain shadows on leeward sides; valleys can channel rainfall differently than surrounding areas
What role do windbreaks play in vineyard management and what are their potential drawbacks?
They reduce wind damage and evapotranspiration but may compete with nearby vines for water and nutrients, and require maintenance
How does the conversion of organic to inorganic nutrients occur in soil?
Soil organisms (bacteria, fungi, earthworms) feed on organic matter, breaking it down into inorganic compounds that roots can absorb
What is an important difference between maritime and continental climate effects on vine phenology?
Maritime climates have longer, more moderate autumns that extend the ripening period, while continental climates have shorter growing seasons with more abrupt temperature changes in autumn
