Esprit Bonsai International – August 2019

#101 EspritBonsaiInternational - 39

Taxonomy

Albrecht Wilhelm Roth

(1757–1834) classified the

silver birch in 1788. Albrecht

Roth is less well known

among the famous naturalists

such as Linnaeus, Siebold,

Thunberg or Kaempfer,

possibly because his name is

only associated with Rothia,

a genus of tropical flowering

plants, named belatedly in

his honour. Nevertheless, he

made a valuable contribution

to botany at the end of the

18th century, to the extent

that Goethe (1749–1832)

nominated him for a chair at

Jena University, a great centre

of intellectual emulation in

Germany at that time.

The small leaves of the silver birch grow
alternately on fine pendulous branches.

This young

birch

demonstrates

the species

need for light.

It seems to

be fleeing a

dark forest

of spruce.

duction, the birch tree pays the price as far as age

is concerned. In a temperate climate, its lifespan is

about 50 years; in mountainous areas and northern

forests, it can live for a hundred or so years, which

is not very long for a tree.

From northern Europe to Canada via Siberia,

the birch, in its wider sense, has played a vital role

in our lives – even in the survival of people living in

these cold and hostile regions. A tree with multiple

benefits became an integral cultural element for

the inhabitants of boreal regions. �

very fast growing and its seeds have a great capa-
city for dissemination.
One can find numerous ornamental birch varie-
ties with very attractive shapes and decorative
foliage.

Inside the bark
Humans have made use of birch for centuries,
above all for its wood, for heating and woodwork –
cabinetry, sculpture and woodturning. Its sap has
been harvested for a very long time and was used
as a fashionable drink and lauded, perhaps a little
exaggeratedly, for its mineral and diuretic virtues.
The most interesting aspect of the silver birch
is its bark. Its silvery white colouration is instantly
recognizable in any habitat. The bark is the result
of extremely rapid growth, essential for a pioneer
species which needs to take up space and take
advantage of maximum sunshine, but without
being scorched by it. It has to keep ahead of other
forest species, such as spruce and beech, which
would hinder its growth if allowed to dominate. In
this race towards the light, its most effective arm is
its bark, as it is made up of several chemical com-
ponents that make it unfit for animal consumption.
It contains betulin a molecule, which transformed
into betulinic acid, is used effectively as a treat-
ment against cancer and diabetes as well as obe-
sity and atherosclerosis.

A hundred or so years
What with the synthesis of its organic com-
pounds, its runaway growth and abundant repro-