le and have no
advantages.
The arrangement of the arms of a headed vine may be symmetrical in all
directions at an angle of about 45 degrees. Such a vine is said to be
"vase-formed," though the hollow center which this term implies is not
essential. This is the form used in the great majority of our
vineyards whether of wine, raisin, or shipping grapes. It is suitable
for the "square" system of planting and cross cultivation. Where vines
are planted in the avenue system, particularly when trellised and
where cross cultivation is impossible, the arms are given a
"fan-shaped" arrangement in a vertical plane. This arrangement is
considered to be essential for the economical and easy working of
trellised vines.
On the vertical or upright cordon, the arms are arranged at as regular
intervals as possible on all sides of the trunk from the top to within
twelve or fifteen inches of the bottom. On the horizontal cordon the
arms are arranged similarly, but as nearly as possible on the upper
side of the trunk only.
Each of these systems may again be divided into two subsystems,
according to the management of the annual growth or canes. In one,
spurs of one, two, or three eyes are left for fruit production. This
system is called short or spur pruning. In the other, long canes are
left for fruit production. This is called long or cane pruning. In
rare cases an intermediate form is adopted in which long spurs or
short canes of five or six eyes are left. In cane pruning, each fruit
cane is accompanied by one or two short renewal spurs. These must also
accompany half-long pruning. Systems of pruning, when only long canes
are left without renewal-spurs, are not in use in California. In all
systems, replacing-spurs are left wherever and whenever needed.
Other modifications are introduced by the manner of disposal of the
fruit canes. These may be tied up vertically to a stake driven at the
foot of each vine or bowed in a circle and tied to this same stake, or
they may be tied laterally to wires stretching along the rows in a
horizontal, ascending or descending direction.
The different systems differ therefore in: (1) the shape, length, and
direction of the trunk; (2) the arrangement of the arms; (3) the use
of fruit spurs or fruit canes with renewal spurs; (4) the disposal of
the fruit canes.
The principal possibilities of the pruning are shown in the following
table:
A. HEAD PRUNING: VASE-FORM
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