The Ginkgo and the Dawn Redwood
Nature Bulletin No. 247-A December 3, 1966
Forest Preserve District of Cook
Seymour Simon, President
Roland F. Eisenbeis, Supt. of Conservation
THE GINKGO AND THE DAWN REDWOOD
a mile or more along each side of Harlem Avenue, one of the main
thoroughfares on the west side of Chicago, there is a row of small
graceful trees which were planted there as seedlings about twenty years
ago. At this season their leaves have fallen and they appear much the
same as other trees in winter. But looks are deceiving because this is the
Ginkgo, or Maidenhair Tree, and one of the strangest trees in the world
-- a living fossil.
Until their seeds were brought to Europe and this country, this tree had
been known only in the sacred groves around temples in China and
Japan. All of its wild ancestors seem to have disappeared. We know
that back in the age of dinosaurs there were many kinds of maidenhair
trees because, throughout the northern hemisphere, we find their
curious fan-shaped leaves in the same layers of rock as the fossils of
those reptiles. Of all that large group, the ginkgo remains as the only
tree of its sort living in the world today, and the fossil record shows that
it has survived, unchanged, for at least a hundred million years.
The ginkgo is not a fern, nor a pine, nor a hardwood tree, but a
combination of the features of all three. Its small yellowish plum-like
fruit has a foul-smelling pulp enclosing a silvery nut with a sweetish
resinous edible kernel. The fruit and the pollen-bearing catkins are
borne on separate trees. The ginkgo has smooth light-gray bark and
attains a height of 60 to 80 feet. Because it is hardy and remarkably free
from pests, it has become increasingly popular for shade-tree planting
on city streets and in parks.
Only a few years ago, another "living fossil" was discovered in a remote
bandit-infested mountain valley of Central China. It has been named the
Metasequoia, or Dawn Redwood, because it appears to be the ancestor
of the Redwood and the Big Tree, or Giant Sequoia, of California. It
was supposed to have become extinct many millions of years ago, but,
from fossil remains of its leaves, twigs and cones found in rocks often
100 million years old, it was known to have been widespread over the
temperate regions of the northern hemisphere.
The discovery, in 1944, of a living dawn redwood -- 64 inches in
diameter and 98 feet tall -- towering above a small temple in the midst
of rice paddies more than 100 miles northeast of Chungking in
Szechwan Province, reads like a fiction thriller. Many people if
different races and classes played a part in this most outstanding
botanical discovery of the century. In March, 1948, Dr. Ralph W.
Chaney, a specialist on fossil plants at the University of California, flew
with a companion to Chungking. From there they traveled by boat down
the Yangtse River, and then inland over rocky trails under the
protection of armed guards to see this tree. Later, they found small
groves of dawn redwoods growing in sheltered mountain ravines in
company with birches, chestnuts, sweet gums, beeches and oaks -- the
same hardwoods we have here in our country.
The most surprising feature of the dawn redwood is that, unlike the
evergreen sequoias, it sheds its leaves in autumn. Further, its cones are
borne on long naked stems and the leaves are arranged in opposite pairs
on the twigs instead of alternately. Their branches slant upward instead
of growing horizontally and turning down at the tips, as do those of the
sequoias. Its seeds are small wafer-like discs similar to a flake of rolled
oats. Some of these seeds were brought back, have been planted, and
young dawn redwoods are growing in several places in the United
States, including Cook County.
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Update: June 2012