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<John Paul Sanborn>
posted
The limb in the pictures is from a white ash. Property belongs to the mother of one of the people I subcontract to.

Limb was approximately 14m up, 11cm dia and 4.6m long.

Top 2cm shearded off near clean the rest peeled off.

No defects in the sheared area were noticable on the ground portion or the aerial stub (which got lost in the jungle below, no pics of it.) With the exception of a small patch of whiter wood, that resisted probing with a steel tool, somewhat visable in the sheared face JPG.

Limb drop occured aproximately 2 am on a calm night in the high 80s, daytime temps have been in the mid-high 90's.

pictures were taken approximately 15 hours after limb drop.


IMO the visual data seem to support the theory of ray cell collaps being a major factor in SLD.
 
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<Russ Carlson>
posted
Reply to post by John paul Sanborn, on July 04, 2002 at 16:13:24:

I have a few questions about the limb and what I am seeing in the images. The resolution is not the best.

In the two shots of the broken and cut ends, I see what I think are some ring anomalies. On the cut end, top, it looks like there is wider than normal growth ring the second year back (last year- 2001, if the outer edge is the cambium). On the other photo (broken wood), it appears that this may be a discontinuous ring, perhaps wound wood?

The growth rings (cut end) were narrow for several years until that wide year. What caused thaat change in growth at that point? There was a response to some event of factor.

The nature of the break (broken wood image) suggests the wood was brash at that point, broke rather cleanly across the grain. This can be caused by many things, including nutrient levels, fungal infection, growth patterns and othe envirnmental factors.

Timing- not too surprising to me. The tree loses water in the high temps of daytime, then replenishes during the night if moisture is available. Tissues shrink, then swell, dehydrate, rehydrate, lose weight, gain wieght. Stresses change, and if the limb has a weak point, such as brashness, it will fail when stress exceeds the reduced strength.
 
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<JPS>
posted
Reply to post by Russ Carlson, on July 04, 2002 at 16:13:24:

with the fracturing and saw artifacts (I'll get a badsaw one of thes day)
 
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<JPS>
posted
Reply to post by Russ Carlson, on July 04, 2002 at 16:13:24:

with the fracturing and saw artifacts (I'll get a badsaw one of thes day) I can't really tell but it does appear that the wide outer ring diminised with proximity to the small embedded stub seen in the backside pic.

Next time I'll try to hold on to the aerial portion better. [roll eyes]
 
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<Carl Absher>
posted
Reply to post by John paul Sanborn, on July 04, 2002 at 16:13:24:

Do you have more information on the theory of ray cell collapse as a cause of SLD?

Carl
 
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