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The Jarrah is one of the many species of eucalyptus. The Jarrah tree
usually grows to about 40-50 meters high, with a trunk diameter of three meters.
The trunk of the Jarrah is long, straight, and has no branches on it. The Jarrah
tree has rough greyish brown bark with vertical grooves, which sheds in long
strips.
The leaves of the Jarrah tree are about 8 to 13 millimetres long. The top of the
leaves are dark green and the bottom side is lighter. The species name of the
plant "marginata" relates to the light coloured vein around the edge of the
leaf. The curved leaves are found at the top of the tree amongst the flowers.
The flowers of a Jarrah tree are white with a cone shaped bud cap, 5-9
millimetres long. The flowers are found in groups of 7-11.
The flowers have a magnificent scent, while the ball shaped fruits grow to about
9-16 millimetres long. It flowers every other year making it a special event for
bees to pollinate it and make honey. The Jarrah tree can live as long as 500
years.
The Jarrah tree usually grows in gravely soil, but occasionally it is found in
sand or loam. The Jarrah tree has widespread distribution in the dry Australian
Savannah. It forms its forests or woodlands ranging from Albany to Gingin, and
there is one very old tree in Manjimup that is dated 500 years old.
One of the adaptations the Jarrah tree has made is called a lignotuber. The
lignotuber is a large swelling underground. This swelling can store
carbohydrates, and can make it possible for a young Jarrah to grow back after a
fire. Another adaptation the Jarrah tree has made is its long roots. This makes
it possible to pull up underground water during a drought. This drought
resistance is helpful in its natural dry habitat.
The Jarrah tree is mostly used for timber. Jarrah wood makes very durable,
strong furniture and building materials, such as wharves, bridges and railroad
ties. Before modern asphalt the streets of Berlin and London were paved with
blocks of Jarrah.
Another use of the Jarrah tree is honey. Every other year when the Jarrah
flowers bloom, beekeepers have their bees pollinate the tree and make wonderful
honey.
To some animals the Jarrah tree is very useful. Birds and other animals use big
holes in the Jarrah tree to nest. Feral bees make their hives in holes in the
tree. Nectar from the Jarrah tree is also a main food source to many insects,
marsupials, and birds
The Jarrah trees population is decreasing because of heavy timbering. It is also
very defenceless against dieback. Die back is a sort of algae that causes
root-rot. This organism is related to the one that killed the potato crops of
the Irish famine. Researchers are trying to make genetic transfers into the
Jarrah trees from the dieback resistant Marri gum, but it will take a long time.
by Celeste B. 2001
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