What Happened ???

[rahtreelimbs]

Being in trees mostly on weekends my understanding of trees is still limited. I'm trying to learn what I can when spare time makes itself available. A Silver Maple that I did some pruning on ( mostly removal of worrysome limbs for the customers neighbor ) had a lead that just broke off about 2/3's out. Looking at this I saw no decay, wounds or anything. The leaves on the end on the branches are all green. When I did the aforementioned pruning, I was up on this limb. I saw nothing wrong. I did remove several small limbs on this lead to thin it to the customers liking. If I'm not supplying enough information let me know, I'd like to know what might have caused this. Thanx, Rich.

 

[Stumper]

An obvious question is 'were there any high winds?' Assuming that has been eliminated a possibility is that a phenomenom known as "Summer limb drop" may be what occurred. I don't think that it is fully understood but it IS well documented that some trees (certain Eucalyptus varieties, cottonwoods, and Siver maples are more prone to it) may drop apparrently healthy limbs in periods of relative calm during the growing season. Theories abound but "fatigue" and crysaling of the wood from former stresses seem likely.

 

[rahtreelimbs]

Re: stumper

I forgot to add that a neighbor was around when this happened. He told me that no winds were present. Could this have been caused by previous high winds? We have had some bad storms this summer. Thanx, Rich.

 

[treeclimber165]

To this day, I still become highly agitated when I am told to "thin the tree to the customer's liking". I AM NOT SIMPLY A TRAINED MONKEY WITH A CHAINSAW!!!!!!!!!! To have some old lady stand on the ground and tell me which limbs NEED to come off pisses me off to no end! Of course, the customer standing on the ground has a MUCH better idea of what limbs are safe or not, and what is best for the tree. I'm just the #$%^ing idiot in the tree with a saw who has studied and climbed trees for most of my life!

OK, I'm stepping off my box now. Gotta go wash the soap off my boots.

 

[rahtreelimbs]

RE:

I should be more specific. "To the customers liking" was the customer saying: "can you thin this out a little". I removed two small limbs that were causing problems. Rich.

 

[Stumper]

One of the theories( which makes sense to me) is that severe winds, ice loads, etc., iniate a breakdown in the wood which later results in a catastrophic failure when the limb is at rest. it makes sense as an explanaton. The phenomenom itself is weird and spooky.

 

[Nickrosis]

I don't any more about Summer Limb Drop than Stumper does, but I want to confirm that it has been documented, and he is not out on a limb with this.

Unless he has Internet access in his treehouse...

Nickrosis

 

[John Paul Sanborn]

SLD is frequently assosiated with dead calm and high temps. I've read that a theory that is is ray cell collaps.

Quick search spoke of high humidity and calm where evaporation can no longer take place, the limb becomes engoreged with fluid...

http://www.arbormatters.com/arbortimes/arbortimes.htm

Depends on how the wood failed.

Could you have put too much wheight on it and cracked it while thinning the tip?

 

[rbtree]

nick,

Oh it is documented for sure...and silver maple would sure be a species where it can happen.

About 10 yrs ago, I was at Green Lake park in Seattle, when a ~10" black cottonwood limb failed, not far from the kiddie pool.

A few years later, the parks dept removed all the cottonwood around the lake.

 

[Nickrosis]

I knew it was documented - that's what I was saying. No one had replied; a day had gone by. Just wanted to make sure it stayed at the top of the list.

Nickrosis

 

[rahtreelimbs]

Re: John Paul Sanborn

Originally posted by John Paul Sanborn


Could you have put too much wheight on it and cracked it while thinning the tip?



I don't think I put to much weight on the lead. This lead is roughly 12" where it meets the trunk. Go figure, there's no way to tell at this point. I will be going out to clean this damage up in the next few days. I'll take another look at the break. Thanx, Rich.

 

[murphy4trees]

See it pretty often around here.. Nothing at all wrong with the wood and no wind... usually maples.. more Norway than Silver.. Really scares the customers.. they think the tree is dangerous rather than realizing it's a rare phenomenon..
That said I always thought it was related to drout.. and thus low water content in the cells.. reducing their ability to "hold up" the fibers.. Never heard that from anyone.. just made it up..
Maybe JPS is right that it's too much water in wood... but does that make sense?.. as I thought it was the transpiration that draws the water up in the first place.. Maybe there is a lag time...
God Bless All,
Daniel

 

[FBerkel]

Limbs have been dropping around here, extremely dry conditions. I've always heard that's a contributing factor.

May be that there was a preexisting longitudinal crack? Also, silver maples tend to outgrow their own strength. We do alot of light-moderate drop crotching on "leggy" silver maples, and it generally makes a big difference.

A couple of years ago a cottonwood limb fell on a perfectly still summer day, killed a young boy sitting under it in a public park. They did find that some decay was present, though.

 

[treeclimber165]

When I was just starting in treework, I heard (and always believed) that a large tree can take up more than 100 gallons of water per hour in certain conditions. All that water weighs a lot, and can overload marginal strength limbs. This was the reasoning for large limbs splitting out during heavy rain storms, especially following an extended dry period.
I know this doesn't apply here, but thought I'd mention it.

 

[John Paul Sanborn]

What I infered from the paragraph I found on it is that one of the reasons may be that the trasportation of fluid is taking place, then with the calm wind and high humidity the leaves cannot pass it any more, but the flow contiues. Fluid builds up in the branch and the tip becomes too heavy.

The other theory I had heard is that durring a hot spell, the ray cells suddenkly collaps before temporary leaf wilt can shut the system down. this initiates the fibe failure that leads to total limb failure.

I submitted some images of a limb failure to The Knothole. I no longer have the picures, but here is Russ carlsons responce to them.
http://tree-tech.com/board/?topic=topic2&msg=1543

 

[rahtreelimbs]

To add!!!

Another thing comes to mind. I had to get the broken lead on the ground to eliminate the hazard. Once on the ground I looked at the break. All of the wood was real dry except for right under the bark which was moist. Rich.

 

[John Paul Sanborn]

If it has had a few days to sit, this could be spuriouse data.

 

[Treeman14]

No way, Thumper. He didn't even USE spurs. Pay attention next time.

 

[John Paul Sanborn]

Got me!

I had to read it twice

 

[Treeman14]