Climate Flashcards
Winkler Scale
Degree Day = temperature summation over 50F between April 1 and Oct 31
(or between Oct 1 and April 30)
**Updated by Greg Jones in 2010 (added 1a, extended V)
1,500 - 2,000 = Region Ia 2,001 - 2,500 = Region Ib 2,501 - 3,000 = Region II 3,001 - 3,500 = Region III 3,501 - 4,000 = Region IV 4,001 - 4,900 = Region V
Temperature
Spring Awakening: 50F (soil temp, varies by variety)
Peak plant functions: 70-80F
Total Range: 59-95F
Upper Limit: 95F (inhibits photosynthesis)
Lower Limit: **
Fruit Set Disruption: under 32F
Killing Freeze: ranges by variety - **
Bud Freezing Temps: Concord -18F; Riesling -10F, Cabernet Sauvignon -8F
Dormant **
**Bud killing temp
- 1980 Christmas Massacre in FLX -20F, widespread vine death
Frost
Types of frost:
(sunrise is the most damaging time, when warm air starts to rise)
- **
- **
Ways to fight frost:
- Burners
- Candles
- Smudge Pots
- Overhead sprinklers
- Helicopter
- Dig trenches (FLX)
- Fans
- Hot wires
- Burying vines (FLX)
Note:
- After frost, great care must be taken while pruning to avoid Esca and excess scar tissue.
- Also, the year after frost damage, the vines will throw a ton of shoots and canes
- specialist pruners dealing with frost damage can often charge 20-30% premium
- Added benefit of deeply cold temperatures are killing overwintering pests like phylloxera
Hail
Hail damage:
- early season (incl bud break and bloom): break off shoots, shred leaves and shoots, second buds will produce new growth but 2-4 weeks behind (and generally sport a diminished crop load)
- late season (apr-oct): defoliation (can affect fruit and shoot maturation), injured vine wood (young vines especially at risk), damaged clusters (sensitive to rot).
Note: Can affect the following year’s crop load as well.
Ways to fight hail:
- cloud seeding with silver iodide
- hail nets (INAO legal as of July 2018)
- hail canons (a shock wave generator that elicits an explosive charge of acetylene gas and air)
- crop insurance
- leaving extra buds on vines
- after hail, must cut away or retrain scarred wood
Note: not all varieties have fruitful second buds. Nebbiolo secondary buds don’t set fruit.
Previous exam questions
2018: Referencing at least three wine regions, discuss how climate change is influencing grape growers’ viticultural practices.
2016: When and how can hail cause damage at various stages of vine growth? What methods are most effective for preventing or responding to such damage?
2016: What practical options does a viticulturist have at his disposal to address long term changes in climate in an established vineyard?
2015: When and how does frost pose a risk to grape production? Evaluate the different methods of frost protection available to the grape grower.
2010: How would you manage an established vineyard in a hot climate?
2009: Using relevant examples, outline the problem and advantages of “marginal climate” vineyard sites for quality wine producers.
2008: What consequences for viticulture does climate change present globally, and what can viticulturists do to exploit and moderate its effects?
1997: In the final weeks before and during harvest, a vintage may be spoilt by adverse weather conditions. To what extent can a producer adapt techniques in order to meet the problems that arise?
1994: What do vineyard owners, from various parts of the world, do about the effect of weather problems? Illustrate your answers with particular reference to heat and drought, rain and humidity, hail and frost.
1992: The 1991 vintage in Europe was affected by various climatic disasters. Discuss their impact on the vineyards and on the wines produced.
Extreme weather events
- Heat
- Fire
- Drought
- Freezing temperatures
- Flood
- Rain
- Humidity
- Frost
- Hail
Examples
Frost:
- Finger Lakes
- English Sparkling House (Ridgeview) uses heated trellising wires that automatically turn on when the temp drops to 0F.
- Loire
- Burgundy
- Akitu in Central Otago uses helicopters (didn’t Petrus?)
- WALLA WALLA: dramatic freezes can damage vines, so a reserve cane is buried underground each winter.
Crop loss due to frost:
- 2017 Bordeaux lost 40% drop in production
- MONTLOUIS: Jacky Blot in 2016 lost 75% of crop. So in 2017 hired helicopters at dawn. Can raise temp 3 degrees and dry moisture. Spent $2,170 on candles. Bought wind turbines for $32,500.
- BARSAC: 2017 Ch. Climens produced no lead wine
Hail:
- BURGUNDY: Thiebault Huber, president of Volnay, uses Hailston Shield hail canon. Silver iodide stops formation of hail stones.
- Torres family uses the laborious and expensive hail nets for their top plots
- July of 2018 INAO decreed that hail nets can be used (but they are difficult and expensive)
- hailnets used extensively in Argentina
Climate Change:
- The Torres and Jackson Families created climate change workshop group International Wineries for Climate Action
with goal of reducing carbon emissions by 80% by 2045, sharing best practices, establishing a 3rd part verified baseline of current carbon emissions, using at least 20% renewable energy
- Jackson Family reduced glass weight , saved $
Rain
Rain can cause runoff and erosion
Ways to fight rain:
- ryegrass in Oregon
- cereal crops form a fibrous root system
Humidity
Ways to fight humidity:
Climate change
Budbreak: some producers say it is moving budbreak up and making it more susceptible to black frost
Ways to combat climate change:
- rootstock selection
- water and canopy management
- disease and pest control
- frost/hail controls
Consider:
- both hot and cold areas
- economic pressures
- legal aspects especially RE AOPs
Light
Per Rebecca Gibb MW:
Marlborough = 2,475 hours
Sancerre = 1,800 hours
