to close over it, and the wood ultimately decays and acts as a
medium for moisture and fungoid diseases. The saw should travel from
point A to B, as in the sketch. When a stump is left (as would be done
by sawing off at C D) decay sets in sooner or later. Although the tree
often succeeds in healing over the dead part, it more often fails to do
so until the decay has reached the trunk itself. With the softer-wooded
trees like the Horse-Chestnuts disease frequently reaches the heart of
the tree quickly by these means. A coating of liquid tar over the wound,
renewed once or twice until the new bark has closed over, is a sure
protection against these evils.

A good deal may be done in the early training of a tree to so control
its building up that it may best withstand the violence of gales. And
the most important matter in this connexion is the development of a
strong erect trunk, a central axis of such height and strength and bulk
as to be capable of supporting its head of branches easily. In other
words the leading shoot should always be watched, and, by the repression
of any rival leaders that may appear, allowed to retain its
predominance. In the best English nurseries only trees with good "leads"
are sent out.

[Illustration: When a broken stump, such as is here shown, has to be
sawn off, the proper place to amputate it is from A to B; the wrong
place from C to D.]

Trees decayed in the centre, with only an outer layer of healthy wood,
are, of course, doomed, but by filling up all holes in the earlier
stages of decay, and thus keeping out moisture, their term of life can
be lengthened by many years.

Holes made by woodpeckers can sometimes be plugged up with a piece of
Oak. This, if left on a level with the bark, will often enable the
latter to close over the hole. Large holes may be filled with cement, or
even built up with bricks, the surface being made water-tight and tarred
over.

CHAPTER XVIII

TREES AND SHRUBS FOR WATERSIDE

Many of the brightest garden pictures at the present day are by the
well-planted pond or lakeside, where shrubs of large growth are grouped
to give colour through summer and winter.

The wild plants of the riverside are in themselves for the most part
large of stature and important of appearance. When one sees the upright
growth and large leaves of the Great Water Dock (Rumex) and the broad
round ones (2 feet or more across) of the Butter-Bur (Petasites), and
the beds of