Design of a tree as a structure / inspectors gone wild
Design of a tree as a structure / inspectors gone wild
(OP)
A client of mine installed small light fixtures (12" arm, small single bulb light with about .5ft^2 of projected area. The trees are 40ft+ tall oak trees with 12"-18" trunks. The inspector is claiming that the trees become structures as defined by the IBC Code 2009 because of the addition of a fixture. He now wants full calculations to demonstrate the tree will not blow over in a 90mph wind event.
We have gone back and forth, but he has dug his heels in and told the client they have to file for an appeal through the zoning board of appeals. I have demonstrated by calculation that the load added to the tree is less than 2% of the current load on the trunk alone and therefore the added load does not warrant a structural upgrade. But he rejected that argument because this is a change of use and the tree must now fully meet the current Code.
I am looking for something in the Code that might demonstrate that the tree does not become a structure by addition of a light fixture, or some other slam dunk wording. I am sure he knows his argument is foolish, and the reasons for this probably have nothing to do with the lights on the trees.
A picture of the installed fixture is attached.
We have gone back and forth, but he has dug his heels in and told the client they have to file for an appeal through the zoning board of appeals. I have demonstrated by calculation that the load added to the tree is less than 2% of the current load on the trunk alone and therefore the added load does not warrant a structural upgrade. But he rejected that argument because this is a change of use and the tree must now fully meet the current Code.
I am looking for something in the Code that might demonstrate that the tree does not become a structure by addition of a light fixture, or some other slam dunk wording. I am sure he knows his argument is foolish, and the reasons for this probably have nothing to do with the lights on the trees.
A picture of the installed fixture is attached.






RE: Design of a tree as a structure / inspectors gone wild
BA
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
Do not state that the tree won't fall over, just argue that it isn't a structure. It is a tree. And tell your client to use flood lights next time, one's without arms.
RE: Design of a tree as a structure / inspectors gone wild
I agree with Eric: see if you can go around this fool. The sooner he's reined in the better for people in your area.
That said, out of curiosity I searched for standards for ropes courses, which are often attached to trees. I found this, in case there's something in there that you could use to placate the Building Official Gone Wild.
http://www.prcainfo.org/ansi%20standards/ansi-prca...
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
Great spirits have always encountered violent opposition from mediocre minds - Albert Einstein
RE: Design of a tree as a structure / inspectors gone wild
Go look around City Hall, see if they have any light fixtures, birdhouses or anything else attached to trees.
Unrelated to this, the current leading candidate for governor apparently was paralyzed when a tree fell on him sometime back, and he successfully sued the landowner for ten million dollars. So there is some liability involved.
Have you tried asking the person in question what the design wind load is for a tree?
RE: Design of a tree as a structure / inspectors gone wild
Run a calc showing that you have not increased the load to the tree by more than 5%- so the tree is acceptable under the existing building code provisions
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
This is the body of the inspector's rejection letter, written verbatim:
"While I admire your try to say that the trees are existing structures, I disagree and your letter is rejected for the following reasons:
1. The trees are existing as a tree.
2. By mounting the lights to the tree you are making them a structure; therefore they are not existing structures.
When you mount a light fixture to a pole, doesn't the pole have to be engineered? Yes it does. Then why do you believe the trees does not?
If you disagree with my decision you are welcome to go to the Building code board of appeals. You have 30 days to do so."
The inspector already hung up on me once when I asked him if he required a calculation to put a light fixture on a 100-year old barn. Unfortunately, reason is not an option at this point.
RE: Design of a tree as a structure / inspectors gone wild
tg
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.
RE: Design of a tree as a structure / inspectors gone wild
as ridiculous as this is, lets get back to a real solution. You said you already proved the increase is less than 2%. Considering all of the natural forces encountered by the tree I would suspect that the increase in load on the trunk due to the light would be a small small fraction of a percent. Maybe if you show that to him it may put things in perspective. As he knows this is ridiculous, that may do nothing...but at least you have another bit of evidence to show you're trying to be reasonable with his unreasonable request.
As for his argument that this is a "building"...are you to go back and check this tree every time it grows a new leaf? Is he proposing the tree be surveyed and periodically checked for growth to ensure it hasn't maxed out its capacity? It looks like this is in a park...is there a danger to the public if this tree blows down in a storm? Is "occupant" safety a consideration? If he wants to stick to the books and be an ass I would put it back to him and have him specify all of this crap...otherwise you're reaching in the dark trying to find a solution that satisfies him.
As funny as it is to read the comments on this, I feel your pain, I think we've all been in this situation dealing with an unreasonable building official (although I doubt anyone has had anyone this unreasonable). Best of luck sorting this out.
RE: Design of a tree as a structure / inspectors gone wild
This is the most ridiculous thing that I have ever heard come out of an inspector
RE: Design of a tree as a structure / inspectors gone wild
What jurisdiction is this? we can all spam his phone with calls about "we want to put a light on a tree, but not sure what code reference to follow, can you help me?"
RE: Design of a tree as a structure / inspectors gone wild
Does a lightpole fall under IBC? It is not a building.
You could consider the tree an "existing structure". You can increase the load by 5% with no repairs.
I assume his silly sticking point is that the support for a light should be a designed structure. I think he is looking for a real pole rather than calcs on a tree.
If you need a light, stick a 4x4 in the ground and mount the light. If you don't need a light, take it down. Once he signs off, do whatever you want.
RE: Design of a tree as a structure / inspectors gone wild
BUILDING. Any structure used or intended for supporting or sheltering any use or occupancy. [A]
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
If it is worth the effort, I would appeal the ruling. Hopefully, members of the appeal board will have more sense than the inspector.
How did it come to light in the first place? Did your client apply for a building permit? Or was the inspector just making a courtesy call?
BA
RE: Design of a tree as a structure / inspectors gone wild
If you leave the lights up and don't do anything, what happens? Do you get a fine or citation or what? That might be the simplest way to handle it, by letting him try to assert that it is a structure, rather than you having to defend that it is not.
Is the guy a PE? If so, do you have grounds for an ethics complaint?
I remember years ago, hearing about a certain inspector in Plano, Texas, that cost the city millions and millions of dollars on stuff that was just absolutely stupid like this (a chain link fence rejected because the squares weren't square enough comes to mind). There is not always a good solution.
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
The appeal will likely happen, there is no choice at this point. It is just a matter of collecting enough convincing evidence to help that part of the process.
Manstrom- The inspector has already seen my calculations demonstrating well less than 5% effect. He has denied that approach since the trees would need to be re-classified as structures in accordance with the Code, whereas before they were only trees. Yup...
Temporarily mounting on wood poles, then putting them on trees later would be a big issue. Wires are already run and I believe the lights are operational as is, just rejected for concerns that they will cause the trees to blow over.
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
This definitely reminds me of the "damn beaver dam" letter - I'm sure you know it and maybe there's some choice phrases in there you could use....
The picture you have on the front cover of the appeal file should do the trick though.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
Priceless !
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
This article describes story of the Out 'n' About, a treesort located in Takilma, Oregon and the process to verify the structural use of live tress.
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
You all may kill me for this but i am all in to support the inspector's comment. I think he is not asking for calculations to prove that tree can take such load but he is asking what if the tree falls and you entire grid fails. NOTE: I have seen a lot stupid contractors and clients who do things which eventually help lawyer's make a killing out of it.
--ad
RE: Design of a tree as a structure / inspectors gone wild
Seriously; cite the inspector the IEBC and let him chew on it.
Maine EIT, Civil/Structural.
RE: Design of a tree as a structure / inspectors gone wild
Maine EIT, Civil/Structural.
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
I don't know how one would create calcs for a tree. I have some ideas, but I don't think calcs are the answer. Precedent may be the best bet. I wonder if there are any lights mounted in trees in parks or other government property. The inspector would have a hard time arguing with that.
RE: Design of a tree as a structure / inspectors gone wild
If, for the sake or argument, by adding something (the light fixture) to something else already existing (the tree) you now look at that thing as a "structure" it simply must have been a "structure" before you added it. You cannot "make" an existing thing a structure just by saying it is one and then ignoring the fact that it is already there. Therefore the existing structure rules come into play about not needing any change if within a certain percent. This is pure logic.
I can see to a certain extent that if you add something really big to a tree it could affect its strength / ability to stand up, but clearly within the size of the light fitting he is being extraordinarily belligerent.
Good luck and please come back and tell us what the result is in due course.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Design of a tree as a structure / inspectors gone wild
Modifying the tree has caused the tree to become a structure (a device providing a support function for human use) (inspector's argument).
Therefore, any modification of trees must come before the city planning department for approval/review. Existing trees must be structures, since they often provide support for shading purposes, or to hold ornaments (leaves) for human enjoyment, or as recreational structures for kids (tree climbing rug monkeys).
Therefore, all changes to all trees must be reviewed by the city planning department.
This would include, presumably, modifications that reduce the tree's structure, whether pruning/trimming, or naturally caused detachment of parts of the tree as well, i.e. wind damage, just as you would inspect a house that lost some siding in a windstorm. Limbs - hmm, well sure that sounds reasonable. But what about annual massive loss/replacement of sail area in the form of leaves?
Start sending him pictures of every tree on the property for review and approval. Ask if the existing structure (tree) should be demolished, as they do not meet code.
Better if you can send pictures and questions regarding the trees in the inspector's own yard.
RE: Design of a tree as a structure / inspectors gone wild
What happens if a bear climbs into the tree; are we exceeding the live load capacity of the tree? What if there's snow on the tree along with the bear?
RE: Design of a tree as a structure / inspectors gone wild
Pay attention, people. This is how it's done.
RE: Design of a tree as a structure / inspectors gone wild
Mr. Inspector, what you've just said is one of the most insanely idiotic things I have ever heard. At no point in your rambling, incoherent letter were you even close to anything that could be considered a rational thought. Everyone who has heard of this issue is now dumber have having heard of it. May God have mercy on your soul.
Almost certainly the 1st and only time the movie Billy Madison will be referenced on this website.
RE: Design of a tree as a structure / inspectors gone wild
"We shape our buildings, thereafter they shape us." -WSC
RE: Design of a tree as a structure / inspectors gone wild
So remove the lights and apologize for unknowingly transforming the trees into structures, have inspector agree in writing that this is the case, and by removing the lights it is resolved.
Then mount the lights again, to the now "existing structures" as acknowledged by the inspector, with your minimal load increase calculations.
RE: Design of a tree as a structure / inspectors gone wild
Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.
RE: Design of a tree as a structure / inspectors gone wild
Any answer (or non-answer) should give your something to take to the Building Official or City.
Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.
RE: Design of a tree as a structure / inspectors gone wild
Richard A. Cornelius, P.E.
WWW.amlinereast.com
RE: Design of a tree as a structure / inspectors gone wild
OH PLEASE OH PLEASE OH PLEASE do this. I would LOVE to hear what happens at this meeting.
Please remember: we're not all guys!
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
That said, and to play devil's advocate a bit; maybe the inspector and/or permitting agency desire that trees not be used for the mounting of lights or other structures. I think that the "full calculations" requirement is just the means to that end. Are there real chances that the light will increase the likelihood that the tree blows over? Not even a little bit.
On the other hand, in contrast to a treated wooden pole, this tree is a living organism. Though strong and sturdily mounted now, there does exist a measurable potential for the multiple puncture wounds to contribute to disease or insect infestations which could lead to the failure of the mounting of the light or trunk upon which it is mounted.
Just a thought.
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
Not often I support obstinate inspectors, so preparing for abuse...
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
Maine EIT, Civil/Structural.
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
Maine EIT, Civil/Structural.
RE: Design of a tree as a structure / inspectors gone wild
TehMightyEngineer -
Perhaps - but does the "post" have a proper foundation?
I would go the appeal route as soon as I received the letter from the inspector. However, if the inspector were to require annual inspection of the "post" and the light fixture's anchorage to said "post", I could support that.
Living in a rural area, I have used trees for the support of a variety of things. Long-term attachments to trees can suffer from one or more of the following problems:
- as the tree grows, the live portion may grow around the attachment making its removal difficult;
- depending on the size of the attachment, the growing tree can literally 'push' the attached item off its connectors, or;
- the attachment can facilitate the ability of rot and/or disease to enter the tree.
Structurally, I do not see a problem here. It really is a long-term performance issue, and from this perspective only the inspector may have legitimate concern. Otherwise, I think he's being a bureaucratic ass.
Ralph
Structures Consulting
Northeast USA
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
Maine EIT, Civil/Structural.
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
RE: Design of a tree as a structure / inspectors gone wild
But putting a band around tree presents a problem also - as the trunk will get larger and may grow over and around the band. (Have an example in my rear property where we put up a hammock and over the years got an ugly growth where the rope was present.) Probably have to adjust the band each year - or at least look at it.
Being a pole guy, estimating the size of the tree and the various shape and coming up with a structural analysis (which is probably only good for next year) is pretty easy. The real hard part is verifying the foundation or the roots. Are the roots spread out or does it go straight down? Then there's the problems of the Woodpeckers which in my area are riddling many of the trees. I've also got boles problems over almost all of my property - they kill the roses - but I don't think that will affect you. If the tree is a digger pine, then you don't know when they will come down. Had one on my property (about 200 feet) that fell across the road. The county cut it up and dumped it on my property and it took about a year to cut it up and burn it. (Tree was originally hit by lightning and lasted about seven years before it fell).
Come to think of it, the electric company and the telephone company put their lines on some of the trees on a property in the forest that I know about. Maybe they get away with this because they are utilities and don't have to conform to the building code. This area gets some big winds and sometimes the lines snapped off the trees and you lose your power. Then it might be tough when the telephone company gets the lines mixed up and your getting your neighbors telephone calls. And the telephone fix-it people swear that you have no problems because it says so on the computer in front of them. Looks like a bug in that computer program. You know, I don't think their computers programs are as good as Risa or SAP2000, but that's their problems and for us to sit through the night with no power. Which means that your light on the tree that the inspector has dinged you for, may be just for spite, might not go on.
Almost forgot - ground penetrating radar can probably show you where the roots are.
RE: Design of a tree as a structure / inspectors gone wild
Please go to the building code board of appeals i would really like to see how this goes :P .
“If you don't build your dream someone will hire you to help build theirs.”
Tony A. Gaskins Jr.
RE: Design of a tree as a structure / inspectors gone wild
There are practical & durable ways to structurally attach to a tree trunk. oldrunner mentioned possibilities.
My experience has found the following:
- Banding around the tree is risky - it may effectively girdle the tree and kill the portion above the band.
- The tree's living band (bark + sapwood) will grow around and embed some attachments, usually when the entire perimeter of the attached item is in full contact with the trunk.
- Items like signs and other broad surfaces tend to get pushed outward as the tree grows, straining and ultimately failing the fasteners.
In my opinion, the most reliable fastening method is through-rod(s) - and it causes the least trauma to the tree. This is what arborists use to strengthen a "Y" branch. Stainless steel is best for the long-term. The tree will ultimately grow around the edges of the attached item if its contact area is reasonably small - perhaps a width <= 15% of the tree's diameter. A large contact area runs the risk of the outward growth of the tree pushing with a force greater than the capacity of the fasteners.My comments are based on first-hand experience over the course of my life. From tree-houses to running phone lines to attaching flood lights, I've been there, and I've seen the long-terms results of various fastenings.
Now, the engineering stuff aside, perhaps this is more of a liability concern for all involved. If the light and its attachment can remain secure, the falling fixture hazard is mitigated. But how is power supplied to the fixture and what is the associated hazard if a storm takes down the tree? Who is exposed should the unthinkable happen - the inspector or the owner or the designer? Probably all who were involved, since "accidents" and "acts of God" can still blamed on some specific person or persons. Common sense does not apply.
While the comments provide numerous opinions and suggestions, I look forward to what the final outcome will be.
Ralph
Structures Consulting
Northeast USA
RE: Design of a tree as a structure / inspectors gone wild