Stormy White Oak

[Rocks_and_Trees]

Nice job Chris. Definately looked safer cutting those from the top than the bottom.

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It looks like the branches fractured but the branch collars held. Is that true? I couldn't see any collar tear-outs. If so, that shows the strength of the tree.

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That’s exactly right Tom. At least I was able to make some decent collar cuts if nothing else. That White Oak is sure strong wood.

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This is what I've heard some researchers call the CFZ or critical fracture zone. There is some formula like two or three times the diameter of the branch out from the collar where many failures occur statistically? I'll try to find a link for more info...

jp

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Interesting. That is certainly true of Eucalyptus, Elms, and some Mesquites around here. But not so much on Palo verdes and Acacias which often fail at narrow branch attachments.

 

[treesandsurf]

"The results of the test of branch reduction under snow loading indicate that a reduction of 15% will reduce load- induced stress in the Critical Fracture Zone by approximately 40%."

Listening to John's talk at the biomechanics symposium was an eye opener for me. He mentioned (along with several other presenters) at one point that defects were NOT a reliable indication of failure. In other words, where we expected branches or trees to fail they did not and where we though the tree was solid it failed. Still a lot to uncover in the field of biomechanics!

jp

 

[treesandsurf]

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Nice job Chris. Definately looked safer cutting those from the top than the bottom.

[ QUOTE ]
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[ QUOTE ]
It looks like the branches fractured but the branch collars held. Is that true? I couldn't see any collar tear-outs. If so, that shows the strength of the tree.

[/ QUOTE ]

That’s exactly right Tom. At least I was able to make some decent collar cuts if nothing else. That White Oak is sure strong wood.

[/ QUOTE ]

This is what I've heard some researchers call the CFZ or critical fracture zone. There is some formula like two or three times the diameter of the branch out from the collar where many failures occur statistically? I'll try to find a link for more info...

jp

[/ QUOTE ]

Interesting. That is certainly true of Eucalyptus, Elms, and some Mesquites around here. But not so much on Palo verdes and Acacias which often fail at narrow branch attachments.

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Andy, he did mention in his report that Guy posted a link for that there are two exceptions to that general rule (CFZ) and those were dead branches and branches with narrow attachments or included bark. Although, nothing is black and white of course.

jp

 

[goodaking]

Nice work chris!