ot and disease.

3. All mature apple trees should be so pruned as to keep them in the
most easily manageable shape and to facilitate in every possible way
the operations of tillage, spraying, and harvesting. It is most
important to have the tree low enough down so that spraying and
picking can be easily done. It is difficult to spray properly a tree
which is more than twenty-five feet in height. Even this height
necessitates a tower on the spray rig and the use of an extension
pole. An apple tree should be so pruned that all the fruit can be
readily picked from ladders not longer than eighteen to twenty-two
feet.

Of course, if the tree has been allowed to get higher than this under
previous management, sometimes we have to make the best of a bad
situation. If the trees are too high head them back by cutting off the
leaders, but it is not always wise to lower all trees to twenty-two
feet. Heading back of old trees will be more fully discussed in the
chapter on "Renovating Old Orchards." Ladders longer than twenty-two
feet are heavy and clumsy to handle.

If cultivation is to be carried on close up under the tree the lower
limbs must be pruned so as to allow this. It is not necessary,
however, to drive a team closer than twelve or fifteen feet from a
mature tree, contrary to the common belief and practice. Cultivation
is least important in the first few feet of space around a mature
tree. By the use of set-over tools, all that is necessary can be well
cultivated without crowding the team under or against the branches.

4. As has been pointed out in the discussion of the pruning of young
trees, in humid regions where the sunlight is none too abundant
through the growing season, the open head is most desirable. Sunlight
on the leaves as well as on the fruit is essential to good color of
the fruit, and good color is a very important factor in the flavor and
attractive appearance of the fruit. An open center with upright
growing leaders removed gives the greatest opportunity for sunlight to
penetrate through the tree.

5. As we have seen, pruning in the dormant season tends to increase
the vigor of the tree. Thus winter pruning serves to secure a normal
and vigorous wood growth, which is most essential to a healthy
fruit-bearing tree. On the other hand, such pruning may be excessive
and produce wood growth at the expense of fruit buds, throwing the
tree out of bearing.

6. The sixth and last reason for pruning is to