Cabling... your opinion?

[John Paul Sanborn]

Silver maples are inherently weak.

BS!

I hate that statement, nothing personal <g>.

Why are there so many big old ones around if they are inherently weak?

IMO it is a result of the population and the tendency for them to be topped.

Most of the "catastrophic" failures I've seen are related to improper pruning of one sort or another and the related decay. Then it is lions tail and leverage then it is poor unions.

In the number of large storms I've worked on this A. sachariniuminuminum has had the least large limb failure, where Q. rubrum was doing major damage to houses.

maybe we should cut all the oaks down? (that was irony for those who cannot see it)

 

[John Paul Sanborn]

Am I crabbing? Maybe so...the style of responses to the question is becoming typical.

I do think your tense is wrong, it's been prevelent for a long time.

since the name change, maybe the forum needs a little more moderation to keep the answeres on topic? or maybe a restriction of responders so only qualified vollenteers can respond?

Not to say that most of you are unqualified yahoos, but that you do not understand the intent of the forum and say whatever you darned please.

I'll take this up with Darin

 

[Trignog]

Wow I love it, you don't like someone's reply and you get all butt hurt and hostile. I assume you are all mature? Try being polite.

 

[Trignog]

I hope pondracer found a local arborist.

 

[Ekka]

Thinning is an acceptable pratice encouraged by our local government to help eucs stand up better to adverse weather conditions.

Thinning is done throughout the crown, from tips to trunk.

Even qualified people have differences of opinion, like this thinning idea. Our max suggested is 25% in any one year.

 

[Old Monkey]

I personally am against it in most circumstances. Silver Maples can get quite large and don't have the most reliable wood. Reduce the weight on those spars with good thinning cuts in the upper canopy. It looks to me like it has been overpruned down at the bottom and in the interior but barely touched in the canopy. I'd want to see a climber up in that tree, making mostly pole pruner cuts. Cabling just allows the tree to get bigger than it should be able to and doesn't replace the need for trimming.

In my own defense the thread title is "Cabling...your opinion." I think no one here, no matter how many nifty titles and abbreviations after their names is more qualified to give my opinion. Your not always going to get great opinions on this site or in the real world for that matter. The title "Certified Arborist," in my opinion, is not a guarantee of good tree knowledge or experience. Its been my unfortunate experience that a lot of folks get their licenses to enhance their business and forget almost everything they crammed into their brains to pass the exam. The rule is still "buyer beware!" when it comes to tree advice. Even more so when its free! As for silver maples, I liked Mike Mass's circuit breaker analogy for how silver maples break high branches instead of major spars.
JPS-How high do you set your climbline in a silver maple? I had two good size branches break out on me last week, sending me flying. From that experience and others I claim that the wood on silver maples is not as strong as other trees.

Respectfully submitted: Experience with trees is as important as reading books and going to seminars.

 

[Tom Dunlap]

Sorry...I get grumpy some times.

It's frustrating to have consumers come here to get advice and they're told to cut the tree down most of the time. Or the advice given isn't accompanied by any reasoning. Who makes any decision "Because I said so" ?

According to studies done in windtunnels thinning trees has little to do with reducing windsail. I wish that I cold site title and verse. There have been some articles in the Journal of Arboriculture I know.

Thinning reduces the dampening effect of the weight on the inside of the tree. The leverage is changed when all of the weight is on the skinny end of the lever.

Studies done by Erk Brudi in Germany shows that reducing the crown diameter has a better effect on keeping trees whole. For more information about this read up on Tree Statics. There is an excellent book from the ISA:

http://tinyurl.com/3k9gv

https://secure.isa-arbor.com/comersus/store/comersus_viewItem.asp?idProduct=4044

Worth every penny of the $35 price to better understand why trees stand up and why they fall down.

There are methods available to give a value of the structural strength of a tree as well as the parts of the trees. If that's known then a plan can be formulated to add in a support system or reduce the load to reduce the risk of failure. What Erk has done is bring in standard structural engineering to arbo work.

This is a pic of a large linden that Erk tested. The farm has been there for 300 years. The current owners were applying to the state to have the tree put under protection. The state needed to have the tree tested and a plan written before they would take on the care and responsibility. Since the winds would come from the Alps, which are to the left of the picture, the strength of the attachment of the right portion is what needed to be tested.

I climbed the tree and set a strap for the hook of the handwinch cable. Then the handwinch was anchored to the truck. The angles were measured to calculate the load on the trunk. The winch only needed a load in the low-hundreds of pounds. Not enough to fracture the tree.

Erk attaches two meters to the trunk that measure the deflection of the wood under a measured load. He also measured the diameter of the limbs at the point of connection. They have calculated the strength of the wood. By putting a known load on the stem and measuring the deflection the computer calulates strength loss.

After Erk has the strength loss number he can design a care program for the tree. The plan for that tree was a three-legged Cobra system as well as some crown reduction to reduce lateral and wind loads.

 

[treeseer]

Tom, thanks for passing along your experience Erk's good work. I especially liked the "some crown reduction to reduce lateral and wind loads."; this is common sense with good science behind it. Can Mr. Maas agree? We are not talkng about hacking or topping or gradual removal here.

Erk presented at the ASCA conference last year; the consultants were all mindblownthat he had the stones to call a tree"safe" when the work was done--no mealymouthed qualifying to placate liability fears.

"Respectfully submitted: Experience with trees is as important as reading books and going to seminars." trignog is right, but hands-on experience backed with books and seminars, like Tom's, is miles ahead of hands-on alone.

Re silver maples' strength, look at the city of Rochester's experience. They had silver maples with 75% crown loss that were still growing 8 years later, with less maintenance than trees with <50% crown loss. Journal of Arboriculture, June 04 I think.

Re the book, it is well worth the $35.

 

[Tom Dunlap]

I think that Erk will be at the WCISA conference in Phoenix in the begining of May.

 

[Old Monkey]

As realtor's say "location, location, location." I would not advocate removing all or even most silver maples. I wouldn't plant one in the following places: my yard, my families' yards, my friend's yards, at a daycare, in a car lot, at any school short of a university, or any place where an occasional 4" diameter limb crashing to the ground would be considered "a bad thing."

I didn't mean to impugn anyones knowledge or experience. It just seemed like there was a riff going on in this thread that those without proper credentials should pipe-down no matter what their personal experience. The "current" school of thought in any field of science always defends the status quo and condemns those outside the fold. Good stuff sometimes comes from outside the fold. This analogy may be far fetched but here it goes: If I was raised in Nazi Germany during the '30's I would have most likely been a Nazi. If I was born into a landed family in the south during the 1800's I would have most likely owned slaves. If I was a tree guy twenty or thirty years ago I probably would have recommended that everyone top their trees. What are we doing wrong now that we'll disavow later?

 

[treeseer]

... those without proper credentials should pipe-down no matter what their personal experience.

I don't want anyone to stay quiet. If someone thinks that a tree should be cutdown, they are free to say so. But if no reason is given besides some vague impression like undiagnosed problems, or species bias, then the opinion to remove the tree doesn't help the homeowner.

And that IS the title of the forum, right?

The "current" school of thought in any field of science always defends the status quo and condemns those outside the fold. Good stuff sometimes comes from outside the fold.

True. In any field you may get condemnation, which is not good. But questioning things is good and necessary, and sometimes condenmnation is felt/imagined when it is not intended or even implied in a question or comment.

A thick shin is useful when throwing out ideas.

 

[Kneejerk Bombas]

Tom, thanks for passing along your experience Erk's good work. I especially liked the "some crown reduction to reduce lateral and wind loads."; this is common sense with good science behind it. Can Mr. Maas agree? We are not talkng about hacking or topping or gradual removal here.

No, probably not gradual removal, more like gratuitous limb removal. Folks want to see brush on the ground. Assuming the dose is kept under 5%, there won't be much permanent damage.
Erk uses sophisticated computer strength loss formulas to come up with scientific proof that the tree is only strong enough to safely stand, once some crown reduction is preformed? Just think about how ludicrous that sounds!
The only implication I can make, if I agree with this crown reduction, is that all mature trees would benefit from crown reduction. That is some thing I don't think I'll ever say.

I do however, see how some cobra cables would add security to the weak looking lower main crotch.

 

[Tom Dunlap]

Erk uses sophisticated computer strength loss formulas to come up with scientific proof that the tree is only strong enough to safely stand, once some crown reduction is preformed?

No, he determines a lot more than that. There are strength coeffecients that have been established for all trees. The perfect tree would score 100%. Knowing how much of a load would cause that tree to fail in it's present status gives a bracket on the other end of the continum. Knowing how much the load can be changed by cabling or pruning makes the report much more scientific. How much crown reduction is needed, if any? What if the winds came from two directions? What would the diagnosis be?

Statics is an engineering discipline. Erk's brought that into treework. The work that he's done has been confirmed by testing trees again after storms.

Read some of his articles:

http://www.tree-consult.org/html/eng/indexeng.htm

 

[Ekka]

I'd be very cautious putting all my eggs into Erk Brudi's basket. His methods are extremely contraversial and in some instance frowned upon.

Forces exerted in weather extremes simply cannot be duplicated with trucks pulling on trees, the same goes for wind tunnels.

No consideration has been given to soil conditions, root attachment, soil compaction/boggyness from rain etc ...

If you think you can get the rated strength of the timber and work out (with a computer) what forces would make it fail ... you are an idiot! Ever heard of summer branch drop? Trees are a living system, changing all the time, they have natural abscission zones, decay etc .... his practices were heavily critiqued by Klaus Mattheck at a recent siminar.

What are his "real" qualifications, does he have a Doctorate?, is he a professor? Does he belong to a university? Or is he a quack making a buck?

Don't believe everything you read.

 

[treeseer]

Ekka, I lke to keep my eggs in a lot of baskets. When the baskets have holes I try to get my eggs out in time.

The Mattheck-Brudi rivalry is extreme and alive; even though Klaus is a Prof. Dr. or whatever you'd best not put all of your eggs in his basket. His theory of Uniform Stress has a few little gaps that are spreading.

University affiliation is no guarantee of competence. In GA and OH and MN and FL and CA etc. there are some brilliant U tree people. In other places there are quacks with degrees who repeat what they heard 20 years ago.. Brudi's background is in trees, first, and yes, he does factor in " soil conditions, root attachment, soil compaction/boggyness from rain " plus wind exposure.

Mike, of all the mature trees I look at, for the great 90%+ majority I would not recommend overall reduction. For many others, it'd be in that 5% window you speak of. Tom and I are not so ignorant of biology that we'd advocate removing food factories and creating wounds for no good reason.

Pondracer, I hope you're not bored by all this, and hire Jason or someone to visit your site.

 

[Tom Dunlap]

Ekka,

Did you take the time to read the attachments? Let's carry on a discussion based on what Erk has written.

Keeping an open mind will serve the trees better than aligning totally with either side of the Mattheck-Brudi rivalry. If you're comparing M's credentials as a way of disqualifying B's, do you know what M's doctorate is in? Do you know his background? It's not valid to use that as too big a platform. Both of them have added a lot to the understanding we have of trees as an engineered system.

Wessolly is a person who understands statics very well. Nothing radical or extreme. Erk has taken W's work and applied it to our favorite topic, Trees.

 

[Pondracer]

Hello to all, I would have posted but it was a busy weekend. First, here is a picture of the maples on the other side of the yard that the arborist recommended that I also cable.

Maples by my shed

Regarding the tone of the responses - its fine. Doesn't bother me as its interesting to see the diversity of opinions even among professionals who do this daily for a living. What is somewhat frightening is that it would be easy to hire someone and believe that their word was gospel (particularly with regards to removal) and never seek another opinion.

Not that I am against removal. Nor do I see the sense in two-legged kittys My wife on the other hand....

We've went through a little too much removal though, and it would be very difficult for me to cut something down unless there is simply no alternative. Here's a picture from our court case last year. This is what I saw the day before we moved into our house.

Tree Destruction

My neighbor took out the back of my lot. Major shock. We bought the house specifically for the yard and the trees. So additional removal, especially of a seemingly healthy tree, is not an option.

Jason, I appreciate the offer and would take you up on it except that the primary reason for calling the arborist originally was to setup a schedule to have my crabapples sprayed. However something else has come up with my magnolia.... and most likely it *will* have to be removed. Once I get some more info I may contact you offline if its feasonable. However you will have to be insured and able to work in IL.

Someone else said something along the lines of "just leave it alone you'll be moved out before it matters" and that may be the advice I take. Problem is I want to park my boat underneath those other maples by my shed.

Thanks to all.

 

[Ekka]

I'm far from putting all my eggs any any single basket, in fact next monday I'm going to another seminar on tree assessment.

In engineering qualifications are everything.

Prof. Mattheck’s curriculum vitae and awards

Claus Mattheck: born in Dresden, Germany in 1947. PhD in Theoretical Physics in Dresden in 1973, qualified to lecture in Failure Analysis at Karlsruhe University in 1985, and now lectures on biomechanics as professor. Head of department of Biomechanics at the Institute for Materials Research II of the Karlsruhe Research Centre, licensed consultant on the mechanics and fracture behaviour of trees, on wood decomposing fungi and on fatigue fractures in engineering components.

Awarded the Science Award of the Industrial Research Foundation for the computer simulation of biological growth in 1991; the Literature Award of the Karl Theodor Vogel Foundation for technical journalists in 1992; the Georg Winter Award of the European Society for Biomaterials in 1993; honorary membership of the ISA Great Britain & Ireland in 1997; the Science Award of the Berlin-Brandenburg Academy of Sciences in 1998 (founded by the Gottlieb Daimler and Karl Benz Foundation); the Chadwick Award of the ISA for arboricultural research in 1998; the Henry Ford European Conservation Award (environment technology), the Inge & Werner Grüter Award for science journalism in 1999, the English Arboricultural Association Annual Award 2002, the Honorary Membership of the Urban Tree Diagnosis Association Japan 2003 and the German Environmental Award 2003 .

 

[treeseer]

Pondracer, those 2 other maples are double-trunked but do not appear from that distant view to need cabling. How about a closeup of the forks?

Ekka, Klaus's bio has little relevance. His books and other work are major achievements, but that does not make his opinion about his rival's work sacrosanct. O and Tom asked a fair question--are you ready to talk about the article he linked? That basket may be strong enough for more eggs.

Who are you hearing from next Monday?

 

[Ekka]

I think his bio has all relevance ... he is qualified in engineering. You don't get to become a professor by talking rubbish and it has to stand up before educated people ... in no time you'd be shot down in flames.

B's theory is not rocket science. Get the relevant density and strength of the timber, calculate the max load for sail area and ht, will the trunk break or not. Not much different from designing a billboard.Crown reduction is not rocket science either, I don't have to get any tools out to tell you that a 50% smaller crown on the same size trunk is less likely to fail ... these are all valid theories ... but I don't agree with the crown reduction theory. Afterall, isn't that lopping and what the "old school" used to do. I get quotes for every day, can you cut that gum tree in half to make it safer!

Also, how many times do you see failures where the sheer root plate has slid, this would be more common than trunk failures. Similar to the photo, how does B figure that one out? what about other branch failures higher in the canopy?

On Monday two speakers, David Evans from England and Jill Pokorny from US.