Sean, its very interesting to read of tree failures in other regions of the world. A few years back a group of Arborists in the US started collecting data on different types of failures. Apparantley not just anyone can contribute to the database, you are required to take a course. With the regulatory system in Australia, could it be to everyone advantage to have a component on tree failures as part of the educational training. This would allow a a list of tree failure traits to be developed for each region?
It is really interesting to note that in Canada, we use hardiness zones that take into account the lowest temperature a species of tree can handle. Do you folks down there use a sytem that takes into account, say, drought?
The picture of the tree that failed in your original post appears to be windthrown, and I would concur that there doesn't appear to be a lot of major anchoring roots outside the root plate, they may have broken when the tree fell. But the thing that first came to mind was, whow there are a lot of trees nearby. I was at a workshop in which Dr. Kim Coder reminded us that the best thing that you could do for a tree was to give it room. It appears that the tree in the pic had a very dense canopy, that didn't allow the extra wind through. There are so many factors to consider when looking at a tree failure, but a lot of the failures might be prevented IF the people planting new trees knew of the traits of partiular trees to fail in particular enviornments. Proper tree in the right place. (Site appropriate trees)
I am also glad to here that its not just Canadians that put 60' trees under 30' power lines. I figured we were a little shy on the learnig curve.
It doesn't appear that we are alone. While it was interesting to read that you folks have a few species that tolerate harsh crown reduction pruning, wouldn't it be better to control what may be planted under the overhead infrastructure?
Just a few thoughts, carry on!
