The Tree Blog

Archive for the ‘South East Queensland’ Category

Some interesting recent articles about animals just falling dead from trees.

A bizarre mix of trees and wildlife incidents have happened in the last few weeks …

The Herald Sun in Melbourne published a story about a massive possum die off in the suburb of Casey, around 70% of the total population, for which a recent heatwave has been blamed.  Also in Victoria, the Herald Sun reported that a large number of koalas had been either killed or badly burned in this week’s bushfires.  Meanwhile in Bundamba near Ipswich in South East Queensland, up to 60 native parrots were falling dead from trees in an unexplained fashion according to the Brisbane Times.

While on the other side of the planet, southern Florida in the United States, the chilly weather has seen a spate of warm blooded iguana simply falling from the trees.

We’ve had a record heatwave in the last month here in Australia and in the 20th century, heatwaves have caused more deaths than any other natural hazard.   I was in Melbourne recently and shocked by just how hot it got and how long the harsh dry heat was sustained.  Not only were there record temperatures, but record dry as well.

Heatwaves can and do effect our  Australian capital cities.  In February 2004 Brisbane recorded a new record of 41.7 °C during a heatwave.  Records were shattered throughout South East Queensland.  Another similar heatwave last year peaked at 36 °C.  In March 2008, Adelaide experienced maximum temperatures of above 35 °C for fifteen consecutive days, seven days more than the previous longest stretch of 35 °C days. The March 2008 heat wave also included eleven consecutive days above 38 °C. The heat wave was especially notable because it occurred in March, an autumn month, in which Adelaide averages only 2.3 days above 35 °C.  More recently Melbourne this month recorded three successive days over 40 °C and peaking at 45 °C and its driest month in recorded history.

The cost is racking up the millions, with power outages, air conditioning systems on the blink and hyperthermia, dehydration and death in people as well as many unforseen effects.  Environmental effects are significant and long term and include bushfire and drought.

One thing that is also overlooked is the effect it can have on your trees.  Drastic changes to temperature can cause trees to go under extreme water stress which in turn causes them to lose limbs.  But unlike a storm, they can do it without warning.  The first sign of water stress is leaf shedding.  Some scenes in Melbourne looked like an early autumn.  Another lesser known side effect is that many trees can become toxic during heatwaves, emitting chemicals like isoprene which increasing ozone and can cause health problems for children and older athsmatics.

Whether southern Australia’s recent heatwave is a result of climate change manmade or otherwise remains to be seen (you’ll find I’m not 100% on that topic either way), one thing is for sure there will be more heatwaves during our lifetimes.

It is very important to be prepared get your trees checked out, particularly those close to your home, to ensure they aren’t vulnerable and before they do damage.

The Flame Tree is native to sub-tropical South East Queensland

Unlike the southern states, South East Queensland’s sub-tropical climate ensures that we never really have a true autumn season.

While we don’t get to behold the spectacular sight of falling red and brown leaves (or fortunately the problems of cleaning them out of gutters and drains), it is still possible to decorate your garden with deciduous trees, but management of them is key.

Beyond aesthetics though, the midday winters in South East Queensland are simply not cold enough for the key benefit of deciduous trees – to let sunlight through.

However the native Brachychiton acerifolius (Illawarra flame tree or Kurrajong) is probably the most popular choice and a rare native deciduous that grows in SEQ.  This tree turns a vibrant red before losing its leaves and makes a great ornamental with its pod like fruits.  However given that the tree grows quite tall, it can be a nuisance in Brisbane.

In terms of non-native or European deciduous trees that will grow in Brisbane, trying to growing Maples or London Planes simply isn’t worth the effort although these trees will grow well in nearby Toowoomba and the high country.  Probably the best bet is the Liquidambar styraciflua (Liquid Amber), which goes a vibrant red in late Autumn in Brisbane and has distinctive starry five point leaves which distinguish them from maple leaves.  It is native to North America, but grows reasonably well in Brisbane and it doesn’t cause too many problems where its growth is stunted in comparison to growing it in cooler climates.  In terms of managing them, the best time to prune them is late in the leafless cycle, just before they are about to get new leaves.

So if you are wondering why your deciduous trees have problems growing in Brisbane or South East Queensland, then the answer is simply climate.