- Australia Day Storm 2013
- One and a Half Trees
- The Long Stump Close Up
- The Point of Weakness
- Extent of the Weakness
- Demolition of the 9m Stump
- The 9m Stump - Felled and Dissected
- Upper End of the 9m Stump
- Gone - No Reminder of the 300 Year Old Monarch
- The Old Growth Ironbark Orphan
Australia Day Storm 2013
The Big Storm of 2013 occurred between the 24-28th January 2013 with a rainfall of 370mm or 14.5 inches in the O'Shea backyard, Virginia.
Downfall creek flooded to the highest level since the 1990s. The concrete bridge on Brickyard Road was covered and acted as a dam wall impounding the water upstream. A counter current developed on the Virginia side (South) sending water back upstream.
One and a Half Trees
Two Eucalypts, an Ironbark and a Blue Gum (Local Name), really a Forest Red Gum, stood for centuries, part of a great forest area of sub tropical rainforest. Long before the Whitefella arrived with his steel axe and saw to clear the land to build Brisbane Town, these trees stood tall.
The Blackbutt, which measures 37m (123 feet) to the crowns, is still standing tall while the Eucalyptus teriticornis was partially demolished in the storm leaving a stump 9m (30 feet) tall. The tall stump, was cut down on about 15th April and the trunk cut into sections. The fallen trunk measured 9m and, assuming the Teriticornis would have been roughly the same height as the Ironbark, it too would have been about 37m to the crown.
METHOD OF MEASURING HEIGHT
I use a 45 degree set square at my eye level holding one side of the triangle level and sight along the hypotenuse. When I reach a point away from the tree where the hypotenuse is pointing to the top crown of the tree I mark the spot and add my height to the distance.
The total distance to the base of the tree is the height of the tree.
METHOD OF CALCULATING AGE OF EUCALYPTS
Measuer the girth of tree at my shoulder height with a tape. One centimetre equals one year.
The question arises why did the break occur nine metres up the tree? Why didn't it uproot the tree and blow it all down? The ground was thoroughly soaked and softened.
The wind was strong, the thunder and lightning were impressive but the wind was frightening. It blew the 'daylights' out of us listening in our frail little houses.
The Long Stump Close Up
Getting closer enables us to see the extent of the stripped bark and the dead wood of this side of the tree.
The splits are prominent and seem to indicate that the bark probably came off in one swipe; possibly when the branch came off the stump at the top right.
The Point of Weakness
Extent of the Weakness
In fact it was a tribute to the resiliance of the tree that it was able to stand so long. Evolution over billions of years has fine tuned the development of trees in our forests to withstand all but the greatest winds. The winds are one way nature uses to cull the forests and make way for new trees.
Tall trees such as these have to be very strong and be firmly planted in the ground to withstand wind because the crown, leaves and branches, acts like a huge sail. The wind is able to exert considerable pressure on this 'sail' and lever the tree over. That is why many trees are uprooted in wind storms. The stronger trees only lose branches in the high winds.
When a large branch falls it often leaves a hole in the trunk of the tree which becomes a home for many types of birds and mammals.
Demolition of the 9m Stump
Finally the remaining stump was cut off at gound leves leaving the small stump for the stump grinder to finish the job.
The stump shown here shows that the bark did not go right around the tree. The bark stops in the lower middle of the photo, goes around clock wise to the middle right of the photo. There is no bark on the trunk in the lower right corner of the photo.
The bark could have been stripped of the tree when a large branch was torn off and brought the bark down with it.
When the bark is stripped off the growth of new wood ceases. That is why ringbarking is so effective in killing trees.
When growth ceases the deterioration or rotting of the wood begins as rainwater seeps into cracks which appear as the dead wood slowly shrinks.
The 9m Stump - Felled and Dissected
This is the 9m length of the trunk that was cut down in April showing the weathered timber where the bark has been stripped away a long time ago. There is plenty of bark on the underside of the the trunk.
The bark protects the outer layer of new timber which the growing tree adds each year, viz: growth rings.
Upper End of the 9m Stump
A narrow layer of dead wood can be seen around the part of the log where the bark was missing. The remaining bark folds in over the still growing wood and frames the dead wood.
Gone - No Reminder of the 300 Year Old Monarch
Because the area is a Municipal Park the natural processes are tailored to suit the human inhabitants of the city.
So the felled tree has been dissected with chain saws, chipped and carted away to finish up on someone's garden.
The wood will not decay in situ and fertilise the soil from which the tree drew its sustenance. The natural cycle of regeneration is broken, but we do our best, I think, I hope!
The Old Growth Ironbark Orphan
Old growth trees are rather rare in 7th Brigade Park we lost one near the World War I memorial gates off Murphy Road only last year.
Riding through the woodlands of the park one has to look hard to find any among the secondary growth and grass that carpets so much of the area. It would be good if the area bounded by the bicycle tracks and Downfall Creek could be protected like Benkie's Bush in the grounds of The Prince Charles and Holy Spirit Hospitals! Just a thought.
In another 300 years we might have a forest of giants! Just a thought - for now!