1.7 A Question of Climate

Vitis vinifera L. is a temperate-climate species which cannot stand extreme winter cold and requires long, hot summers in which to ripen its fruits. In general, the main areas  of viticulture are to be found between the latitudes of 30°N and 50°N and between 30°S and 40°S i.e. approximate to the 10°C and 20°C isotherms

Within these zones there are major climatic variations caused by mountains, large masses of land or water and ocean currents which greatly affect the distribution of vineyards in the different  continents.

 

In Peru (above), for example, grapes are grown between 12°S and 15°S but the vineyards are to be found in coastal areas which are subject to the cooling influence of the Humboldt current.  

Similarly, the Gulf Stream has a warming effect on the climate of Western Europe and grapes are grown in Germany (50°N to 51°N) on the south and west-facing slopes of the valleys of the Rhine and Moselle.

The Southern Hemisphere is generally cooler than the Northern due to the greater surface area of water; the Southern limit of viticulture in Chile and New Zealand is around 40°S generally. The world's most southerly grapevine plantings are to be found in the South Island of New Zealand (below left) around the 45th parallel.

Towards the Equator the major factors limiting viticulture are the extreme heat, inadequate winter chilling and a shortage of water. In the humid tropics Vitis vinifera L. behaves like an evergreen but, with careful management, can be induced to produce satisfactory crops and the production of table grapes is a small, but growing industry in several tropical countries.

The grapevine flourishes in Mediterranean climates with warm, dry summers and cool, wet winters and it is hardly surprising that the countries of the Mediterranean basin constitute the World's main producers of grapes. Similar climates are also found in the coastal areas of South Africa, Southern Australia, California and Chile.

Oceanic climates can also be suitable for the growing of grapes providing summer temperatures are not too low. Summer rainfall is the major limiting factor here and, in these conditions, fungal diseases and pests make viticulture a difficult undertaking.

Within the temperate zone successful viticulture can be limited by altitude since with increasing elevation one finds lower temperatures and a shortened growing season.  At higher altitudes, therefore, one must select vineyard sites with great care in order to maximise the effect of microclimate and incident radiation for the benefit of plant growth.

The highest vineyards in Europe are to be found at around 1 200 m in Andalusia (Spain - top overleaf) and Val d'Aosta (Italy).

At lower latitudes, high elevation may be an distinct advantage because such conditions provide a more equable environment.  In Bolivia  (18°S) for example, grapes are grown at above    3 000 m but not at lower altitudes.

We see then, that Vitis vinifera L. is a highly adaptable species and that grapevines can be grown successfully in a very wide range of environments; wine grapes are cultivated in the deserts of California and Australia and in Eastern England, table grapes in the mountains of Indonesia and at sea level in Thailand (below right and left).

In each case the limiting factors imposed by climate are mitigated by high standards of husbandry and/or technology. These inputs include irrigation in California and Australia, labour for plant manipulation in Thailand and Indonesia and the addition of sugar to the grape juice for wine making in England.

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