rous vines
can finally be brought into practically perfect shape and the somewhat
larger and more numerous wounds necessary are more easily healed by a
vigorous vine.

_Pruning after the third winter._

For the pruner who understands the pruning of young vines and has
brought them to approximately the form represented in Figs. 29 and 30,
the subsequent winter pruning is very simple. It involves, however,
one new idea--the distinction between fruit and sterile wood.

Up to the third winter pruning, this distinction is not necessary;
first, because practically all the wood is fruit wood, and second,
because the necessity of forming the vine controls the choice of wood.
From this time on, however, this distinction must be carefully made.
At each winter pruning a number of spurs of fruit wood must be left to
produce the crop to be expected from the size and vigor of the vine.
Besides these fruit spurs, it may be necessary to leave spurs of
sterile wood to permit of increasing the number of fruit spurs the
following year.

This will be made clear by comparing Figs. 30 A and 31. Figure 30 A
shows a vine at the third winter pruning with two fruit spurs of two
buds each and one fruit spur of one bud--five fruit buds in all.

If these five fruit buds all produce vigorous shoots during the
following summer, they will supply five canes of fruit wood which can
be used to form five fruit spurs at the following winter pruning,
which will be about the normal increase necessary. Some of these fruit
buds, however, may produce weak shoots or shoots so badly placed that
they would spoil the shape of the head if used for spurs. Other
shoots, however, will be produced from base, secondary and
adventitious buds which, while less fruitful, can be used to form
spurs for the starting of new arms.

[Illustration: FIG. 31. Four-year-old vine pruned for vase-formed
head.]

Figure 31 shows a vine after the fourth winter pruning which had
developed from a vine similar to that shown in Fig. 30 A. From the
three fruit spurs left the previous year four canes have been chosen
for the fruit spurs of this year. The old spur on the left has
furnished two new spurs and the two old spurs at the right each one
new spur. The pruner, judging that the vine is sufficiently vigorous
to stand more wood, has formed two spurs from water sprouts which,
while not likely to produce much fruit the first season, will supply
fruit wood for the following year. The