Arbor:

noun [fourteenth century; by pergola (Construction and Architecture)].

1) Pergola, if widespread, even set of pergolas: take the cool under the pergola.

2) system of farming vineyard used particularly for varieties that produce grapes.

The vineyards are kept very high (2-3 m) and branches based on the pergola.

According to this as horizontal or oblique pergolas will have a horizontal roof or sloped roof.
This type of farming has the advantage of keeping the clusters away from the ground, so as to exclude moisture.
The screws kept a pergola, are subjected to long pruning or mixed, in ways that vary according to local custom.