Summer branch drop phenomenon.

Wesspur
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beastmaster

beastmaster

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UFO's, Bigfoot, and summer branch drop phenomenon. I'll save the first two to when I've had a couple beers in me, but I have seen many examples of SBD. On hot summer days no wind, a perfectly healthy tree will just drop a large limb for no reason. I see it in chineses elms, ash and Euc's out here. I got in a discussion today with someone who says it's a myth. Yet I see several examples each summer. I am just curious has any one else seen it and does anyone have any theorys of their own or know of any new explanations or research that has came out?
About them ufo's.........


http://joa.isa-arbor.com/request.asp?JournalID=1&ArticleID=1877&Type=2
 
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Hey Beast,
I recall another thread about that very same thing. Never heard of it out here, but I seem to recall the previous thread was also started by somebody from the West coast. Try a search and if you find it, link it, so I can refresh my memory.

On a somewhat simular note...... a few summers back, I was over by Dad's place talking with neighbor on a nice sunny afternoon. Then CRASH! A large tree fell in the woods above the other neighbors place. Just a very light breeze was blowing at the time. No idea why it fell. No damage done and no cleanup required as it was back in the woods.

Rick
 
Nature is what Nature does- FG. :tongue2:

Just typed a huge response, then I figured it was a derail so I deleted it all!
 
Some years ago in a city neighboring mine, a rather large limb broke off an oak an fell on some people that were sitting at a picnic table in there back yard. It was a beautiful sunny day with little to no wind. A man was killed and I believe two people were injured. I am certian that it was a green limb from a "healthy" tree. The man actually worked for the same company my wife works for. She didn't know him but I think she had more info than was in the paper. I will ask her later and look online for the article.
 
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I get a couple calls on this each year. Around here in NE it's mostly Oaks & Beeches I see shedding out large limbs. I do find it happening more so when we have a dry spell & then a good soaking rain.
 
I remember reading about this before too and yes it does happen. I find myself examing trees every where I go. Last year we were in the blackhills at this park called story book island and there was a big hanger in a big cottonwood that had to just break it had green leaves on it still. I went and told the management about it and they had the area blocked of in minutes. There are hundreds of kids that walk under it dailey, I know I saved someone that day.
 
We see it in the large black cottonwoods that have the large drooping branches. I don't have any stats, but to me it seems to occur when there is a major air pressure change in the summer.
 
I havent noticed the summer thing so much, but I've often noticed the incredible tension that trunks are put under in late fall/early winter. I guess its got to do with dryness/shrinkage. We took out a turpentine (type of eucalyptus) last week and blocking it down gave me the willies even though it was only about 50 feet tall. I'm in aus, and it's the beginning of winter here just now. It was a wet summer this year with very mild temparatures, maybe one of the coolest summers for years.

As you'd be cutting through each block, it was cracking with so much force it sounded like a detonator going off. Each of the blocks would have 3 or 4 cracks through them from the release of all the strain. I don't ever see this in spring/summer.

Shaun
 
Two things not mentioned
1. the difference between or extremes between the underside or highly conducting water xylem of the branch opposed to the less so h2o conducting xylem of the top side of a branch.

2.Another factor potentially contributing is the number of h20 conducting xylem or rings. some trees may have upto 12 water conducting rings and others only 2.

Species that fail regularly have how many h2o conducting rings?



Food for thought.
 
Treepedo said:
Two things not mentioned
1. the difference between or extremes between the underside or highly conducting water xylem of the branch opposed to the less so h2o conducting xylem of the top side of a branch.

2.Another factor potentially contributing is the number of h20 conducting xylem or rings. some trees may have upto 12 water conducting rings and others only 2.
Species that fail regularly have how many h2o conducting rings? Food for thought.
Click to expand...

I get indigeston from all these theories about wood anatomy and water etc. Trees are not as complicated as we think sometimes: I've NEVER seen SBD where the limb was not overextended, sticking out beyond the crown. So when Harris advises "On mature trees, shorten and lighten long horizontal branches and open up the tree" it is not so much " so humidity is less likely to build up" as it is to lessen lever arm and gravity.

Duh! :buttkick:
 
treeseer said:
So when Harris advises "On mature trees, shorten and lighten long horizontal branches and open up the tree" it is not so much " so humidity is less likely to build up" as it is to lessen lever arm and gravity.
Click to expand...


So when Shigo advises "When more than a third of the leaf bearing branches are cut from the tips of larger branches, the larger branches may wane and die in many species....."

Shigo never gave me bad advice.
 
I just witness this last week....working in an up-scale hood, heard some cracking sounds a few doors down and BAMM 2 big limbs of a bradford pear (no surprise here) tore off the trunk, hit the roof and gutter and completly coverd the front door.

I've noticed here in nor cal, when weather gets hot the tree's seem to take up alot of water, hence the term SBD...just my theory though, but this happend's alot here exp. in oaks.....
 
"So when Shigo advises "When more than a third of the leaf bearing branches are cut from the tips of larger branches, the larger branches may wane and die in many species....."

Sure, that's a good guideline. It might take only 1/10 off to get the job done, get the branch to fit in the crown. but it is not a Rule--2/3 off can work too, depending on the branch, and how much light the remainder gets.

"Shigo never gave me bad advice."

Especially when he said "Rules are too absolute for Mother Nature." ;)
 
treeseer said:
"It might take only 1/10 off to get the job done, get the branch to fit in the crown. but it is not a Rule--2/3 off can work too, depending on the branch, and how much light the remainder gets." ;)
Click to expand...


Hmmmmmmm. Shigo says "Northern oaks can not tolerate the tips being removed" (p.433: A New Tree Biology), and you and I both know (since we are educated idiots), that a common defect of Red Oak is branch breakage. Ed Hayes states in his excellent little field guide "Evaluating Tree Defects" that the risk of branch breakage increases in trees greater than 16" dbh.

So, are you gonna prune those oak branches resulting in their decline, or are you gonna leave them intact to possibly clunk Mrs Smith? Whatya gonna do, Treeseer? :dizzy:
 
Shigo says "Northern oaks can not tolerate the tips being removed" (p.433: A New Tree Biology)...
So, are you gonna prune those oak branches resulting in their decline, or are you gonna leave them intact to possibly clunk Mrs Smith?"

With all due respect to the godfather, his observations of reduced oak branches triggering inevitable intolerance are not nearly numerous enough to cover such a blanket statement. not sure he ever climbed or pruned, either, despite his wise words (most of them) on the subject. Good point about species tolerance, but this can be overcome by pruning above to increase light, etc.

re your a or b question, I choose c. Mrs. Smith would not have to worry about her pretty little head because I would cable the big old branch w $80 mtls and 1 hour time, and make $ doing it. :blob2:

O and yes, Mr. Hayes did a fine job with his little fieldbook, and i recommend his presentations on tree risk as well.
 

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