Like the wheat or corn plant, the tree seed require as conditions for
sprouting sufficient moisture, warmth, and air. Tree seeds, however,
differ from grain in that most of the kinds lose their power of
germination easily; with few exceptions (locust, pine, spruce), they
can not be kept for any length of time.
The first leaves formed often differ essentially in shape from those
of the mature tree, which may cause their being confounded with other
plants, weeds, etc.
The little seedlings of many, especially the conifers, are quite
delicate, and remain very small the first season; they need, therefore,
the protecting shade of mother trees, or artificial shading, and also
protection against weeds. The amount of light or shade given requires
careful regulation for some of them; too much light and heat will kill
them, and so will too much shade. This accounts for the failure of many
seedlings that spring up in the virgin forest.
The planter, then, is required to know the nature and the needs of
the various kinds of seeds and seedlings, so as to provide favorable
conditions, when he will avoid sowing in the open field such as require
the care which it is impracticable to give outside of the nursery.
[Illustration: Fig. 2.--Bud development of beech. _B_, as it would be
if all formed buds were to live; _A_, as it is, many buds failing to
develop.]