A New Study of Some Problems Relating to the Giant Trees [pp. 305-316]

Some Problemns Relating to the Giant 7rees.
marked, wide-spread, and minute-seeded
throughout;-the cypress group. for exam ple. It does not spoil it at all for our pres ent purpose, that the Sequoia itself is a mem ber of the group. Cypresses grow well un der human protection in the greatest variety
of situations; but not so in wild nature.
There they might almost be characterized as
the swam p-group of conifers. The cypresses
of our northern States white cedars, as they
are called-and those of the south as well,
growonly in swamps. Our own beautiful Law son's cypress - everywhere cultivated- in
its natural habitat stands with its feet in the
waters of the Shasta streams. Our common
hedge evergreen, the Monterey cypress, is
found only on a narrow strip of seashore ever
swept by the fogs of ocean. But its seed lings, once started. will thrive on the dry
sand-dunes about the Hotel del Monte.
There is not the slightest doubt that it was
once quite widely dispersed; but it has not
been able to hold its own in these dryer
times. The Monterey pine with its heavy
seeds has driven it almost into the sea-not,
be it noted, because it cannot live, but be cause it cannot rmake its children live. The
redwood is more fortunate; it still maintains
itself on a long sweep of coast, and even lin gers falteringly in some favored spots inland.
But its central range, we notice, touches the
region of summer rains. Most significant of
all, however, is the fact that it has developed
a method of reproduction quite independent
of seed; namely, by suckers from the root.
Not merely is this a rare thing among conifers; it would probably be difficult to find
in all the world another forest tree that depends so habitually for the perpetuation of
its race upon this method of reproduction.
One risks little in affirming that the redwood
colonies east of the Bay of San Francisco
could never have lingered on to this present
time, if they had been dependent upon seedlings alone to fill up their ranks, for it may
well be doubted whether seedlings ever spring
there spontaneously. How much this tendency has favored the redwood in its struggle. for life within its proper range, no one
can guess. But the redwood with this
strange aptitude survives; the giant tree with out it has been steadily vanishing from the
earth.
Our brief survey, then, of the great family
of conifers, with its wide diversity of habitat
and of seed, leads us to this conclusion:
that in general those species which maintain
themselves in regions of summer drought
are large-seeded species; while, on the other
hand, the minute-seeded species and groups
of species are either swamp trees, or are so
situated as to be sure of moisture from rain,
or stream, or fog during the growing season.
Furthermore, the necessity of such irrigation
is often clearly limited to the earliest years
of the plant —possibly to its earliest year —
since many of these trees, once started in
life, are able to maintain themselves well in
situations of very scant summer moisture,
either of air or of soil. Evidence enough
has been adduced, perhaps, to establish these
points; but I cannot forbear citing further
one or two familiar witnesses in proof of the
amount and variety of testimony which might
be brought forward, were confirmation nec essary. The willows, a well defined family
with minute seeds throughout, are sharply
confined to marshes and stream-bottoms.
They exhibit, moreover, in a marked degree,
a tendency toward a collateral method of
reproduction; their broken branches and
twigs strike root promptly whenever they effect lodgment in soil, and thus become new
trees. Then, again, the strange Eucalyptus
family affords in mnany ways a striking parallel
to our Sequoias. They rival our trees in
bulk; they excel them in height; they are,
in fact, the tallest trees on the globe. They
have the same tenacious grasp on life- seen
in their prompt recovery from deadly mutilation and in their tendency to start anew
from the root. Their seeds are even more
minute than those of the Sequoia. Their
natural habitat, as I am told, is in wet and
swampy districts. They certainly thrive in
such situations —witness the groves of them
in the fever-smitten marshes near Rome, and
on the islands of our Californian rivers.
But they thrive also, after the start has been
given them in the nursery, on the sunny ex
1886.]
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