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Originally Posted by Sean Freeman  Certainly got some ideas views on it Cassian, but want to back it up with some pics so prob won't be able to post a meaningful reply for a week or two (down GC next week)...I think it is self optimization in a sense but driven more by the canopy movement above than the defect/weakness below, which is why you're only seeing this in a few Eucs....like I said I want to illustrate this and bung some pretty lines etc. |
Sean the way I see it the turnbuckle is occuring (like the wood ribs Mattheck describes) as a result of lever arm impacting on the weak link (the V fork), the stress recieved in the fork occurs because of the canopy movement.
In response to those stresses the cambium layer (the stress reciever/recorder) instigates rib formation - in the case of the rolling ribs they are acting in the same way as normal ribs but (due to the physics of the turnbuckle) exert a higher level of pressure on the included crack, therefore making the V fork stronger. This explains the Iron bark (Fig 20/21) the turnbuckle on this tree has held the fork in check for a number of years...
I believe the reason that the turnbuckle (rolling ribs) is random is because this is an example of a snap shot of evolution, that in the future this will become the norm for Eucalypts...........