THE HEVEA TREE
For the very first of the rubber story we may thank a little
wood-boring beetle, and the way nature has of helping her children to
protect themselves.
The thistle of the meadow is as safe from hungry cattle as though
fenced in by barbed wire. A cow must be starving that would care
to flavor her luncheon with the needles that the thistle bears.
The common skunk cabbage would make a tempting meal for her after
a winter of dry feeding, had not Nature given it an odor that
disgusts even a spring-time appetite. The milkweed welcomes the
bees and flies that help to distribute her pollen where she wants
it spread, but she has her own way of punishing the useless
thieves that trespass up her stalk. Wherever the hooks of an
insect's feet pierce her tender skin, she pours out a milky juice
to entangle its feet and body, and it is a lucky bug that succeeds
in escaping before this juice hardens, and holds him a prisoner
condemned to die.
All over the world there are plants with the same ability that the
milkweed has, but it is especially true of certain trees and vines
of the tropics. As soon as the little beetle begins to bore into
the bark of one of these trees, there pours out a sticky, milky
fluid that kills the insect at once. If this were all, the wound
would remain open, ready for the next robber who came along. In
order that the break may be healed, a cement is necessary, but not
a hard, unyielding one, for that would crumble away with the
motion of the tree in the wind.
So with Mother Nature's perfection in doing things, the very plant
juice that has done duty as a poison is hardened into an elastic
stopper, with the result that, no matter how far the tree may sway
and tug at the wound, the filling gives and stretches, true to the
task it has to perform.
This was the juice the crafty savage induced the tree to give up.
Wherever the bark was cut, the fluid poured forth to heal the
break and hardened like blood on a cut finger. The native caught
it while it was still soft and applied it to his simple needs.
This juice is not the sap of the rubber tree. Sap, which is the
life-blood of the tree, flows through the wood, but the juice we
are describing is contained in the inner bark, a thin layer
directly below the outer bark.
Scientific men call this juice latex. It is like milk in three
ways: it is white, it contains tiny particles that rise to the top
like cream, and it spoils quickly.
The particles in cow's milk are full of fats which make it good
for us to drink. But a rubber tree's milk has tiny atoms of rubber
and resin and other things, and it took time to discover which of
the vines and trees was the prize milker of the tropics and gave
the largest amount of pure rubber. Finally, the Hevea, the very
tree the Frenchman wrote about, proved to be the best, and,
although by no means the only rubber tree of commercial value, it
is acknowledged the greatest of rubber trees.
The Hevea tree grows sixty feet tall, and when full grown is eight
or ten feet around. It rises as straight as an elm, with high
branching limbs and long, smooth oval leaves. Sprays of pale
flowers blossom upon it in August, followed in a few months by
pods containing three speckled seeds which look like smooth,
slightly flattened nutmegs. When the seeds are ready to drop the
outer covering of the pod bursts with a loud report, the seeds
shooting in all directions.
This is Nature's clever scheme to spread the Hevea family. The
tree grows wild in the hot, damp forests of the Amazon valley and
in other parts of South America that have a similar climate. The
ideal climate for the rubber tree is one which is uniform all the
year round, from eighty-nine to ninety-four degrees at noon, and
riot lower than seventy degrees at night. The Amazon country has a
rainy season which lasts half the year, though the other season is
by no means a dry one, and so for half the time the jungles are
flooded.
These rubber storehouses had been growing for thousands of years
in the Amazon jungle with their wealth securely sealed up in their
bark, the peck of a bird, the boring of a beetle, or the scratch
of a climbing animal being the only draft upon their treasure. The
trees around the mouth of the river supplied whatever was needed
for the little manufacturing that was at first done. But the
discovery that made a universal use for rubber changed all this.
Brazil was surprised to find what great treasure her forests
contained. Large rubber areas were found a thousand miles up the
river and she began in a serious way to develop a large crude
rubber business.
Less than twenty years ago Brazil produced practically all the
rubber used in the world. But to-day she furnishes less than
one-tenth of the world's supply. How Brazil, possessing in her vast
forests millions of rubber trees of the finest quality, has been
forced by unfavorable conditions to permit the Far East to sweep
from her in this short time the crude rubber supremacy of the
world is one of the most unusual chapters in modern industrial
history.