This
more than 250 million year old species (!!!) is a deciduous
Conifer and the only one of its' genus that has survived all these
years. It seems to resemble the ancient tree fern family.
Just how much of a survivor this tree is was illustrated by the
fact that two Ginkgo's survived the Atom bomb on Hiroshima: One
one the temple-site of Housenbou (the temple itself was destroyed)
and one in the Syukkeien garden.
Fossil and pollen evidence has shown that at some stage in ancient
history the Ginkgo has lived on all the different continents of
the world and it seems to have gone into decline even before the
Ice Ages. It's last known natural occurrence was in the mountain
forests of Chekiang of Eastern China, but this venerable was
planted frequently in temples and also cultivated widely in Japan.
It is said that some of the temple are several thousand years old.
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Name:
"Ginkgo" is derived from the Japanese
name "gin-kyo" meaning "Silver
apricot", (which is now obsolete in Japan).
"Biloba" means "two-lobed".
The name "Maidenhair tree" is derived from
the shape of the leaves, which resembles a traditional oriental
girl's haircut.
Cultivation:
Propagation is by seed or softwood cuttings. This
remarkable tree is very adaptable. It seems to tolerate all sorts
of climatic conditions (from Helsinki to sub-tropical), can cope
with pollution and has outlived all its possible predators and
pathogens. This makes them very suitable as street trees. Only
trouble seems to be that the fruits of the female trees can be
powerfully pongy when crushed (I'm told reminiscent of dog poo).
There seems to be a street in Cardiff with females!
To prevent this possibility trees are also grafted to ensure they
are male specimens. Figures I've seen for its growth are: 25 ft in
20 years and 33 ft in 30 years. It's full size is thought to be
around 70-80 feet, although there is a Ginkgo tree in Milan of 125
ft.
In autumn the leaves turn a bright yellow-amber colour. In the
winter the tree has been compared in likeness to a Pear
tree. Some narrow upright cultivars have been developed
specifically for use as street trees. One example is the American
male clone, called "Sentry".
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Picture:The
Housenbou Ginkgo tree just 1 mile off the center of the bomb blast
in Hiroshima. The temple was destroyed and a new temple was
rebuild around the tree, which miraculously did not suffer any
malformation
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Medicinal Uses:
The tree does not grow any longer in the wild but its
medicinal properties (as well as good looks and
Super-Venerable status no doubt) had always assured it a
place in many of the Far Eastern Temple Gardens.
Although it was introduced to Britain in 1758, you will
not really find it in any of our British Herbals pre-1990.
All of a sudden it became a very fashionable herbal remedy
in the 1980's, when research had shown that the chemical
constituents in the leaves have a beneficial effect on
hardened arteries (arterisclerosis). They help to widen
arteries by relaxing their muscular walls and thus
stimulate the circulation. And what's more, the herb seems
to have a particular affinity for the bloodvessels of the
brain. Our own dear Hawthorn Tree has similar effects with
a specific affinity for the heart. So Ginkgo became very
popular as a herbal remedy for helping to resist the onset
of old-age senility, for example in Altzheimer's disease.
The thing is that the doses have to be quite large for it
to be effective and the treatment needs to be taken for
quite a while (and is probably best done under supervision
of a trained medical herbalist, who will combine it with
other helpful herbs and make sure the dose is right). A
liquid extract tends to be used (rather than a tincture),
because that is more concentrated.
Anyhow, because of its effect on the circulatory system,
the remedy is also used for other diseases of the
peripheral circulation, such as varicose veins (poor leg
circulation), haemorrhoids, senile macular degeneration
(which causes loss of vision), inner ear disorders such as
tinnitus (only of the type caused by bad circulation) and
in some heart conditions. The ginkgolide chemicals in the
leaves have been used by the pharmaceutical industry to
make a drug for treating irregular heartbeats.
In China itself the herb this
tree medicine (mostly the seeds) was traditionally used for
asthmatic disorders and chesty coughs with thick phlegm and it was
considered to work on the lung and kidney meridians. The seeds
were also used for their tonifying effect on the urinary system,
which is helpful in conditions with excessive urination or in
incontinence.
A modern application of this medicinal action is to use the remedy
in cases of impotence caused by the use of Prozac and similar
antidepressants.
The seeds have astringent, antifungal and antibacterial
properties.
Again, care has to be taken with the dose: one seed is usually
enough for 1 dose (3-4 seeds can be prepared together in a
decoction for a day's use). Too much of this good thing can cause
headaches and skin disorders. Fifty or more seeds eaten by a child
can cause seizures. Ginkgo is a restricted herb in Australia and
New Zealand, which means that it can only be prescribed by
qualified practioners. This is probably also due to the fact that
too large a dose of a leaf preparation may occasionally cause
bleeding and bruising (mini-haemorraghes), especially if taken in
combination with other blood thinning drugs such as Coumadin or
Aspirin.
I've also heard that
Ginkgo
possesses (lots of esses in that word!) some anti-cancer activity,
but don't really have much specific scientific information on this
(oral knowledge obtained from Chinese herbalists).
A few people have been known to
develop contact-dermatitis (= skin inflammation or rashes) due to
handling the fruit pulp. I don't know how common this is.
The seeds are actually edible, but they have to be boiled (or
heated) first to remove toxic components. They seem to be quite
tasty roasted or fried and may make a good breakfast after a
night's drinking since they help to relieve hangovers. The hard
fruits are used roasted for this purpose in Japan.
Ginkgo extract is now among the
leading prescriptions in France and Germany, where it has been
accepted as an approved treatment for poor leg circulation and
dementia.
It ranks 3rd on the list of American best-selling herbal products,
although it is only available in the USA as a dietary supplement
in health food stores, rather than a medical prescription.
Apart from tinctures and liquid extract (the traditional way of
preserving herbal medicines in an easy to take form -rather than
brewing up decoctions) there are now also capsules, pills and
under-the-tongue sprays available.
One of the mysteries to me is
where all the herbal material for all these remedies came from. In
Britain it is grown in parks, gardens and streets (mostly only in
the southern half of the country). I wonder if there are now
commercial Ginkgo plantations on the continent and in the USA,
maybe here as well? Any information on this would be gratefully
received.
The inner bark has been used to
make a pale-brown dye.
Note from webmother to
page visitors:
Many of these pages are still bare bones. Whenever time allows, we
will continue to add information to the Tree Gallery until all the
trees have descriptions of their habitat, characteristics,
cultivation, uses and anything else of interest. Email us if you
are keen to know more about a particular tree and we will do our
best to complete that one next.
Don't miss the
Ginkgo pages!
I found this really
absolutely excellent Dutch website (in English) about Ginkgo,
called the
Ginkgo pages: Well worth a visit. The site is a real
labour of love and very informative.
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