Some are low, others the height of a man, others again on pergolas or, more often, stretched horizontally along wires. The ways vines are treated are very different from one to another; all, however, have a decisive influence on the quality level of the final product. Vitis vinifera is a climber, a little like ivy and it is possible to make a route for it to grow along so as to optimise ripening of the grapes and make picking easier.
The choice of system used depends on many factors; firstly the climate - in some areas it is necessary to try to have the maximum exposure to sun or air and in others it is necessary to protect the fruit from excessively strong sunlight a too high humidity level. Much depends on the type of terrain, the features of the variety planted, the type of wine to be made and the mechanisation of the vineyard. There are about ten most widely used systems. That of the bush - a small plant kept at a height of 30-40 centimetres from the ground - is a system normally used in hot areas where water is scarce or in cold areas to make the most of the heat of the land.
The 'Guyot', one of the commonest vine-treating systems, uses a 5-60 centimetre-high bush with horizontal wires between supports, to the lowest of which the fruiting shoots are tied. The other branches are tied to the wires above. This is a system which lends itself to a number of variations. In the spur cordon the trunk of the plant is allowed to reach a metre in height. It is then pruned in such a way as to encourage horizontal sours (shoots) to grow along the wire.
The 'Cazenave' is similar to the previous system; it provides for creation of new shoots which start horizontally and are then treated upwards. The 'Sylvoz' system is suitable for large systems; this has a horizontal shoot from which fruiting branches curve downwards. A variant of the Sylvoz is the 'Casarza' system, where tow vines are planted against the same support and the woody shoots are treated horizontally. They form a permanent cordon with considerable foliage which protects the grapes well.
Under the name 'pergola' there are a number of forms of vine-treated system which differ from region to region. The one used in Triveneto has the basic characteristic of forming a real roof of foliage. The 'Geneva double curtain' was specially developed for use with grape-harvesting machines; this allows the plant to grow to a height of one and a half metres and creates two corridors perpendicular to the wires from which the buds (and shoots) descend.