Download Liquid Geography: Geography of Vine and Wine

Liquid Geography: Geography
of Vine and Wine
David R. Green
Physical Geography
• Vines grow virtually anywhere in a wide
range of natural environments
• But there are limitations which include:
– excessive cold (kill or damage particularly in
Spring)
– excessive heat (when combined with
humidity can lead to wilting of the vine and
fungal growth)
– drought (inhibits growth)
Physical Geography
• Vines therefore are not found everywhere!
• But they do grow in parts of Canada – short
growing season / very cold; lowland Peru –
extreme heat; arid climates - Australia
• In part this is the versatility of the plant
• But also human intervention
• Management techniques that include burial
under soil and sprinkling during frosts; sulphur
dusting and shading to reduce the problems
with high humidity and heat; use of trickle
irrigation where soil/climate too dry during the
growing season
Physical Geography
Trickle Irrigation
Plateau above the
Columbia River Gorge, USA
Physical Geography
• What are the main factors that affect
viticulture?
• Climate and soil? Critical factors
• But there are others also e.g. slope
(seepage and drainage)
• Aspect: orientation to the daily path of
the sun e.g. east, southeast – sun, warm
soils, shade, cooling
Physical Geography
South Facing - Aspect
Physical Geography
Physical Geography
Physical Geography
• Diffusion of vines and viticulture in countries
around the World is evidence that vines can
survive almost anywhere – and especially as
much of this was before human intervention
• But spread was often a case of trial and error
as well as trial and success
• Long before sciences of climatology and
meteorology!
• But in the C20th elements of weather and
climate began to be recorded in increasing detail
• Regional classification of global and local
climate and weather
Physical Geography
• Two systems of note: Koppen (later Geiger) –
regional framework (based on vegetation
classification, synthesis of climatic parameters,
recorded temperature, and precipitation data) –
simple and clear but little about moisture
available for crop growth
• Modified by Thornthwaite – regionalisation of
climates based on four factors: annual moisture
(water need); temperature efficiency; seasonality
of moisture; seasonality of temperature
• Useful as a predictive device for calculating the
availability of moisture for plant growth during
the growing season
http://koeppen-geiger.vu-wien.ac.at/
Physical Geography
1.1 GROUP A: Tropical/megathermal climates
1.2 GROUP B: Dry (arid and semiarid) climates
1.3 GROUP C: Mild Temperate/mesothermal climates
1.4 GROUP D: Continental/microthermal climate
1.5 GROUP E: Polar climates
Physical Geography
Physical Geography
• At the global level of generalisation
Koppen’s
maps
adequately
reveals
preferred environments for Viticulture
• Between 30 and 50 degrees north (LAT)
and 30 and 40 degrees south (LAT) in
Zones C and B – temperate, moderate or
mesothermal and arid
• Although similar temperatures the C
Climates show widely varying precipitation
regimes
Physical Geography
• Even in areas where temperature is
affected by altitude, vines can still be
grown
• Some varieties of Vitis vinifera can be
grown under colder conditions
• Frost hardy varieties (vinifera, hybrids,
and American varieties) survive in
Canada’s Niagara peninsula
• Some vines survive in the D zone
Physical Geography
• Of major importance is the pattern of
temperature and the rainfall during the
growing season (e.g. summer warmth and
modest rainfall)
• Some
areas
experience
maritime
influences (warm, cloudy summers)
• Too much rain can weaken the grape
crop
• Excessive heat/cold can damage the
plant/crop (the harvest) so moderation is
important
Physical Geography
• Sun ripens the grapes to produce the ideal
balance between acid and sugar
• A cooler area needs more sunny days for
ripening
• A delay in the harvest could be affected by rain
and even early frost
• Too much heat will lead to leaf burn, and drying
out of the grapes, and occasionally fungal
growth
• Where rainfall is limited and irrigation not used
then grapevines can be at risk during the
summer
Physical Geography
• Generalisations, however, conceal
microclimates (level of the vine)
• Rains may affect local areas and not others
• Different microclimates may exist within very
small areas
• Winkler – a well known viticulturalist –
classified the climates of California on the basis
of temperature
• Used the concept of ‘degree days’ or ‘growing
degree days’ (GDD)
Physical Geography
• A degree-day is measured by recording the
average daily temperature and counting the
number of degrees that average exceeded 50
degrees Fahrenheit (F) (10oC) – the level of
dormancy
• For example: if the recorded temperature on a
certain day averaged 75 (24 C) degrees F – then
this day measured 25 degree-days
• See Table 2 from De Blij
• Also view this from the perspective of moisture
supply, soil conditions, and other elements as
well as human skills
Physical Geography
Cardinal temperatures
– ~90° F - optimum for single leaf photosynthesis
– ~70 - 80°F - probable optimum for whole vine
accumulation of photosynthates
– 50°F - base temperature for accumulating degree
days. At lower temperature photosynthesis and
respiration cease for all practical purposes
– 32°F - freezing point of water
– 28°F - freezing temperature of most green grape
tissue
Physical Geography
• Growing Degree Days (GDD)- are an
attempt to quantify heat available for vine
development during the growing season.
• By convention grape degree days are
tallied between April 1 and October 31, and
the base temperature of 50°F is used.
GDD = Sum of ((Daily Max Temp - Min
Temp) / 2 ) -50) for all days April 1 to Oct
31
Physical Geography
The book "General Viticulture" by Winkler et. al. defines five grape
growing regions based upon seasonal degree day accumulation.
Region I <2,501 degree days Winkler suggests early ripening
varieties achieve high quality
Region II 2,501 to 3,000 degree days Most early and mid-season
table wine varieties will produce good quality wines.
Region III 3,001 to 3,500 degree days Favourable climate for high
production of standard to good quality table wines.
Region IV 3,501 to 4,000 degree days Favourable for high
production, but table wine quality will be acceptable at best.
Region V >4,001 degree days Usually only table grape varieties
destined for early season consumption are grown.
Physical Geography
Examples of seasonal degree day accumulation in high latitude vine growing districts
Latitude
Seasonal
Degree Day Accumulation
(50°F base)
____________________________________________________________________________
Reims, France (Champagne)
Zurich, Switzerland
Würzburg, Germany
Dijon, France (Burgundy)
Genève, Switzerland
Roseburg, Oregon
Penn Yan, New York
Bordeaux, France
Geneva, New York
Fredonia, New York
Keckskemét, Hungary
Cutchogue, NY
Canberra, Australia
Bolzano, Italy
Glenham, New York
Udine, Italy
St. Helena, California
Fresno, California
49° 20‘
47° 23‘
49° 48’
47° 15‘
46° 12‘
43° 20‘
42° 30’
44° 50‘
43°
42° 30‘
46° 54‘
41°
36°
46° 30’
42°
46° 04‘
38° 30’
36° 40’
1,756
1,874
1,908
2,084
2,090
2,115
2,390
2,464
2,519
2,531
2,588
2,676
2,714
2,985
2,992
3,168
3,302
4,684
Physical Geography
Four growing degree day suitability classes shown below
Class
Degree Day
Ranking
1
1390 and above
most suitable
2
1165 to 1389
good suitability
3
945 to 1164
fair suitability
4
less than 945
questionable
suitability
Physical Geography
• But success does depend on matching
grape varieties with specific environments
• Different vine varieties grow better under
certain conditions
• Soils (Pedology) also important in where
vines and varieties grow best
• Vines often thrive in different soils:
thick/thin; fertile/less fertile; good/poor ..
And fail in some soils that other plants
grow well in!
Physical Geography
Physical Geography
• Grapes grow on steep, thin, rocky soils
• Some grow on gravels (Graves – in the
Bordeaux region)
• Hard to predict how a vine will grow in a soil
• World Soil Regions – shows different soils in
which vines thrive – most of the major viticulture
regions lying in zones of Alfisols (Pedalfers),
Udalfs, Xeralfs, and Mollisols, and Aridosols
etc….
• Soil texture: gravel, sand, silt and clay – loams
( a mixture of sand,silt and clay – see soil
classification triangle) is important as it
indicates a number of things relevant to the
growth of the grapevine
Physical Geography
Physical Geography
Physical Geography
Physical Geography
Physical Geography
– Quantity of water that a soil can hold
– Effectiveness of access of nutrients to roots
– Capacity to contain air
– Capacity to retain warmth
– Effective drainage e.g. loams drain better than silts or clays
(slope may also play a part in this)
• Root systems spread with time and travel
deeper where possible in search of moisture and
nutrients
• Access to minerals and other nutrients is what
gives the grapes their particular character and
the wines their distinctive taste and their
individual aroma
• Fertile soils may lead to leaf growth but not
necessarily a good harvest of grapes!
Physical Geography
• Soil poverty is even sometimes acceptable
• Most vine varieties have ‘soil preferences’
• Some
varieties
like
lime-rich
soils,
calcareous
clays,
sandy/gravelly
soils,
granitic and shale soils
• Like
micro-climate,
micro-pedology
determines the characteristics of the grape
and the wine
• Micro-climatology
and
micro-pedology
together
Physical Geography
• But sun angle, soil, slope, drainage,
orientation and spacing of vine rows as well
as other environmental factors – in
combination – ultimately determine the
grapes grown in a particular location
Other factors: Frost – especially when the
vine is in budding or flowering stage – little
chance of recovery
In Canada and Germany a number of studies
in the 1980s with the aid of thermal remote
sensing
Physical Geography
Physical Geography
• In the Niagara Peninsula – CCRS –
undertook an airborne thermal survey to
produce a map showing potential ‘frost
pockets’ where cold air might flow from
the Niagara Escarpment onto the plain
below (adjacent to Lake Ontario) –
revealed many previously unknown
areas where vines might be affected by
frost – and also helped to provide a
means to match hardy vine varieties to
locations on the plain
Physical Geography
• In Germany, large areas of grapevines are
grown on terraces – which can potentially act
as frost pockets / traps as cold air sinks into
the valleys at night (katabatic air flow)
• Produced a thermal map of the areas where
different vine varieties can grow best
• Terracing is a necessity in areas of steep
slopes for viticulture – but terraces can prove
an economic disaster if vines die from frost
Physical Geography
• Hail can occur with storms and can
severely damage a vine plant and the
grapes leading to loss of harvest
• Hail can also be localised – best to
scatter vineyards across an area to
avoid complete economic disaster!
• Associated wind gusts can also
damage vines (they are fragile plants
where the branches are easily broken) –
hence owners usually plant shelter belts
Physical Geography
Domaine de Fontlade vineyard , Provence
A thousand hectares of vineyard in Provence was literally
shredded by hail stones, sometimes the size of golf balls.
http://societygrapevine.com/2012/06/catastrophic-hail-damage-in-provence/
Physical Geography
Physical Geography
• Salt air in vineyards (e.g. Chile) having
close proximity to the sea – so called
salt-dew – even a long way from the sea
– can be bad for a vintage
Physical Geography
• In some parts of the World e.g. Australia
(Perth) bush fires bring heat and smoke
damage, and may even drive flocks of birds
and animals looking for a food source (de Blij)
Physical Geography
• River valleys have historically been the location for
many vineyards – water supply, transport, but also
areas of fertile soils, microclimatic variation, slope,
aspect etc., as well as a water table, and the
moderating effect of the river in times of cold or
drought
Physical Geography
• Rivers are also a source of water for irrigation (local
or channelled to the vineyard by artificial irrigation
canals); even from mountain streams and snowmelt –
transform an arid area!
• Natural water is favoured however as this brings
character to the grape and the wine – how
comparable is the wine from areas with natural water
supply and those where irrigation is necessary!
Vineyard Siting
Site
• Geology (soils)
• Soils (nutrients / free draining)
• Aspect (south facing)
• Slope (workability of site / drainage)
• Climate / Microclimate
• Shelter (wind)
• Human Intervention / Knowledge /
Common Sense