No More Learning

It remains, then, only to show how the seed is transported from where
it grows to where it is planted. This is done chiefly by the agency of
the wind, water, and animals. The lighter seeds, as those of pines and
maples, are transported chiefly by wind and water; the heavier, as
acorns and nuts, by animals.

In all the pines, a very thin membrane, in appearance much like an
insect's wing, grows over and around the seed, and independent of it,
while the latter is being developed within its base. Indeed this is
often perfectly developed, though the seed is abortive; nature being,
you would say, more sure to provide the means of transporting the
seed, than to provide the seed to be transported. In other words, a
beautiful thin sack is woven around the seed, with a handle to it such
as the wind can take hold of, and it is then committed to the wind,
expressly that it may transport the seed and extend the range of the
species; and this it does, as effectually as when seeds are sent by
mail in a different kind of sack from the Patent Office. There is a
patent office at the seat of government of the universe, whose
managers are as much interested in the dispersion of seeds as anybody
at Washington can be, and their operations are infinitely more
extensive and regular.

There is, then, no necessity for supposing that the pines have sprung
up from nothing, and I am aware that I am not at all peculiar in
asserting that they come from seeds, though the mode of their
propagation _by nature_ has been but little attended to. They are very
extensively raised from the seed in Europe, and are beginning to be
here.

When you cut down an oak wood, a pine wood will not _at once_ spring
up there unless there are, or have been quite recently, seed-bearing
pines near enough for the seeds to be blown from them. But, adjacent
to a forest of pines, if you prevent other crops from growing there,
you will surely have an extension of your pine forest, provided the
soil is suitable.

As for the heavy seeds and nuts which are not furnished with wings,
the notion is still a very common one that, when the trees which bear
these spring up where none of their kind were noticed before, they
have come from seeds or other principles spontaneously generated there
in an unusual manner, or which have lain dormant in the soil for
centuries, or perhaps been called into activity by the heat of a
burning. I do not believe these assertions, and I will state some of
the ways in which, according to my observation, such forests are
planted and raised.

Every one of these seeds, too, will be found to be winged or legged in
another fashion. Surely it is not wonderful that cherry trees of all
kinds are widely dispersed, since their fruit is well known to be the
favorite food of various birds.
Many kinds are called bird cherries,
and they appropriate many more kinds, which are not so called. Eating
cherries is a bird-like employment, and unless we disperse the seeds
occasionally, as they do, I shall think that the birds have the best
right to them. See how artfully the seed of a cherry is placed in
order that a bird may be compelled to transport it,--in the very midst
of a tempting pericarp, so that the creature that would devour this
must commonly take the stone also into its mouth or bill. If you ever
ate a cherry, and did not make two bites of it, you must have
perceived it,--right in the centre of the luscious morsel, a large
earthy residuum left on the tongue. We thus take into our mouths
cherry-stones as big as peas, a dozen at once, for Nature can persuade
us to do almost anything when she would compass her ends. Some wild
men and children instinctively swallow these, as the birds do when in
a hurry, it being the shortest way to get rid of them. Thus, though
these seeds are not provided with vegetable wings, Nature has impelled
the thrush tribe to take them into their bills and fly away with them;
and they are winged in another sense, and more effectually than the
seeds of pines, for these are carried even against the wind. The
consequence is, that cherry trees grow not only here but there. The
same is true of a great many other seeds.

But to come to the observation which suggested these remarks. As I
have said, I suspect that I can throw some light on the fact that when
hereabouts a dense pine wood is cut down, oaks and other hard woods
may at once take its place. I have got only to show that the acorns
and nuts, provided they are grown in the neighborhood, are regularly
planted in such woods; for I assert that if an oak tree has not grown
within ten miles, and man has not carried acorns thither, then an oak
wood will not spring up _at once_, when a pine wood is cut down.

Apparently, there were only pines there before. They are cut off, and
after a year or two you see oaks and other hard woods springing up
there, with scarcely a pine amid them, and the wonder commonly is, how
the seed could have lain in the ground so long without decaying. But
the truth is, that it has not lain in the ground so long, but is
regularly planted each year by various quadrupeds and birds.

In this neighborhood, where oaks and pines are about equally
dispersed, if you look through the thickest pine wood, even the
seemingly unmixed pitch pine ones, you will commonly detect many
little oaks, birches, and other hard woods, sprung from seeds carried
into the thicket by squirrels and other animals, and also blown
thither, but which are overshadowed and choked by the pines.