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Design of a tree as a structure / inspectors gone wild
15

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.

RE: Design of a tree as a structure / inspectors gone wild

If the tree blows over in a strong wind, it would not be the first to do so. Why is that a concern?

BA

RE: Design of a tree as a structure / inspectors gone wild

What if the tree grows another limb; will the inspector demand that it be removed?

RE: Design of a tree as a structure / inspectors gone wild

I would contact his boss. More often than not i have had rough times with the inspectors and even the main BCO but the head of the department is reasonable. Or contact BCOM. Discuss with them and see what they can do to over rule.

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

2
This might be the most ridiculous thing I've read on this site and that's saying something.bigsmile

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

I was expecting to see a comic strip.

RE: Design of a tree as a structure / inspectors gone wild

(OP)
Good reference, Archie264, thank you. As for going to higher ups, that is easier said than done. Third party inspection agencies are given a lot of latitude and no one really wants to take them on. Something concrete is needed if anyone is going to get involved. This is one of those situations where there is probably more to the evolution of this story behind the scenes, but the debate has become about light fixtures and their perceived ability to cause trees to fall over.

RE: Design of a tree as a structure / inspectors gone wild

Why is it that the Building official job attracts this type of individual and where has practicality gone? It always amazes me that none of these characters ever appreciate the cost of engineering for an oddball item such as this. Maybe a wire rope attached to the tree would suffice. If the tree falls over I suspect the owner appreciates he has bigger problems than a 25lb elec fixture.

RE: Design of a tree as a structure / inspectors gone wild

Is that tree attached to a planet? I've seen the movies over and over where Krypton just up and explodes, leaving all its trees unsupported. In fact, in our own solar system most planets aren't solid enough to have trees stand on them, and on two of the eight (used to be nine, but planets aren't as permanent as they used to be) trees would explode into flames in seconds.

RE: Design of a tree as a structure / inspectors gone wild

2thumbsup

RE: Design of a tree as a structure / inspectors gone wild

Load test the tree. Maybe the building inspector can serve as dead weight for the test.

RE: Design of a tree as a structure / inspectors gone wild

4
Tell them that since the tree is an existing structure, you need the plans to be able to properly analyze the tree, but so far God has not provided them.

RE: Design of a tree as a structure / inspectors gone wild

OMG! I just realized I need to provide a full set of calcs for my Christmas lights in the trees and bushes this year!

RE: Design of a tree as a structure / inspectors gone wild

Ya, EngineeringEric..., but if you use flood lights, then you’ll have the Corps. of Engineers, FEMA, Flood plane studies involved, just adding to the mess. I’d use LEDS, and call it green, and if you leave the light on 24 hours per day you’ll be saving even more money, and everyone will love it and nail a silver plaque to the tree which will cause it die and fall over on the bldg. inspector, killing him. And, your community’s problems will be solved.

RE: Design of a tree as a structure / inspectors gone wild

Dont go to his boss, goto the town council, news papers, tv news, embarrass the shit out of this guy.

RE: Design of a tree as a structure / inspectors gone wild

Sorry, but you missed April fools by 196 days...

Great spirits have always encountered violent opposition from mediocre minds - Albert Einstein

RE: Design of a tree as a structure / inspectors gone wild

I have noticed that a Structure is defined as "that which is built", which is irritatingly vague, but seems like it should be sufficiently clear to eliminate a tree from the definition, if not much else.

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

Sounds like someone ticked off the inspector, so he is getting his pound of flesh.

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

Isn't there some guy on TV that builds tree houses (He is on the Discover Channel or Animal Planet or something). I wonder if they have ever experienced a similar problems?

RE: Design of a tree as a structure / inspectors gone wild

(OP)
hawkaz, JStephen, others - these avenues have been pursued but with no luck.

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

Tell the guy that if the tree falls, no one will hear it...

tg

RE: Design of a tree as a structure / inspectors gone wild

Our government running wild..........(protecting us from ourselves????)!

RE: Design of a tree as a structure / inspectors gone wild

Does he require a permit for a growing tree or tree trimming? Both can cause major structural changes in the load path.

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 stated, this guy obviously has some personal issues here.

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

Can you take the light down. Shut him up, then put it up in a week?

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

Going way back to the beginning, why do you need his blessing? Just ignore him and let him look like an idiot persuing your client.

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

A few more thoughts:

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

We have had the building debate with BI in Canada on signs. If you are governed by the IBC, the definition of a building is below. I wonder what type of assembly he thinks this exterior light fixture is sheltering? Has he suggested what type of proof he might be looking for or is this just his way to say no to anything attached to a living tree? If your owner is principled it seems the appeal process is the only option.

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

This issue has nothing to do with what is right or wrong. It has become an issue of "pride" or "losing face" for the building inspector.

RE: Design of a tree as a structure / inspectors gone wild

jwilson33,

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

Well, not a good situation.
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

call Channel 5 on your side

RE: Design of a tree as a structure / inspectors gone wild

(OP)
I don't know the exact sequence of events, but a total of eight or so lights are installed around a parking lot serving a small business. The business is in a heavily wooded area where mounting lights on trees is the obvious best way to do it. This is holding up issuance of a C.O. for a building that has already been otherwise approved for use.

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

Regarding the inspector's response about would you design a pole- If we were replacing an existing fixture with a new one on an existing pole, and the load is not increased by more than 5% for gravity or 10% for lateral- no, we would not re-design the pole. Reference the IBC Existing Building Code- section 707.4

RE: Design of a tree as a structure / inspectors gone wild

(OP)
hawkaz- This was the logical approach that I took but was denied on. He is claiming that the trees is being reclassified as a structure if lights are added and therefore it needs to meet current Codes and ASCE wind loads for this. If left without lights, then no issue because it is not being reclassified. That is his argument, not mine.

RE: Design of a tree as a structure / inspectors gone wild

(OP)
I have to believe that this is also setting a dangerous precedent and creating a potential liability for the township. What if someone installs a ropes course (either officially, or just as a backyard play structure) as suggested by Archie264 and a tree falls over and injures someone or worse? A good attorney would find that the township banned lights in trees for structural reasons, but allowed far worse to take place. I would think the township could be held culpable for not enforcing their own ban, unless they enforce this requirement universally. Perhaps they should even issue citations to current property owners who have anything substantial hanging from trees for fear of pending collapse?

RE: Design of a tree as a structure / inspectors gone wild

demand to see the permit on the existing structure, maybe it was never permitted in the first place.

RE: Design of a tree as a structure / inspectors gone wild

The question the BI asks is "why do you believe the trees does not" have to be engineered. The answer is that nature has done this job far better than we can ever do. Surely there is somewhere in the code about use of "structures" which have stood the test of time - several billion years would seem a long enough time to me....

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

It makes you wonder why everyone hates people with positions of authority. This guy should absolutely loose his job over this. Waste of everyones time.

RE: Design of a tree as a structure / inspectors gone wild

Quote (cvg)

demand to see the permit on the existing structure, maybe it was never permitted in the first place.

Priceless !

RE: Design of a tree as a structure / inspectors gone wild

Not sure if this will help, but check out http://treehouses.com/joomla/index.php/building-sp...
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

Supposing you have an area with NO building codes at all, and they establish a building code. Are existing structures grandfathered in? And are these trees older than the local building code?

RE: Design of a tree as a structure / inspectors gone wild

More than anything i am worried about the precedent this case is going to put on rest of community if you allow such light fixtures be installed on trees in such heavily wooded area. What is there to stop others from adding more of it on rest of the trees as time progresses. How would you eventually control and say enough is enough. If it was one off case i would shoot the inspector and rest the case, however as you said this a heavily wooded area and people prefer this method. There has to be a limit on such applications or periodic check stipulated on this area as CANPRO stated to make sure you do not endanger public safety at large. I think inspector's main concern here is what is the proof that the system would work. Like building which require 40 year re-certification to justify that they are still structurally safe and can be operational, what is there for trees on same lines?

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

I don't think adding lights qualifies as major modification of an existing structure per the International Existing Building Code. Therefore it should be acceptable as is without design.

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

Never mind, just saw above that you tried that.

Maine EIT, Civil/Structural.

RE: Design of a tree as a structure / inspectors gone wild

send him some ridicoulous calcs, with some made-up factoring of all kinds, showing the structure is fine with the additional lights. As no-one did this before, he can't dismiss them on the basis of being wrong. And if he asks where your calcs came from, say you'll redo them when he shows you the appropriate code.

RE: Design of a tree as a structure / inspectors gone wild

Coolad, what if the transformer is struck by lightning and the lights go off? Not the end of the world. Not a reasonable argument.

RE: Design of a tree as a structure / inspectors gone wild

(OP)
Coolad- The precedent was set long ago that it is okay to mount small fixtures in trees. Preventing fixtures in trees by asking for structural calculations on a whole tree is akin to preventing roadside sign structures by forcing people to design them to resist impact forces from a tractor trailer. If a local governing body wants to control or prevent this condition, then they need to write it into their local zoning ordinances so everyone is on the same page.

RE: Design of a tree as a structure / inspectors gone wild

It sounds like the inspector's request is to justify the wind resistance of the "structure" as opposed to its ability to hold up a light.

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

Play him at his own game. The key is in this sentence for me "By mounting the lights to the tree you are making them a structure; therefore they are not existing structures" - utter rubbish.

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

Along with LI's last post, I had this train of thought:

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

Quote (You cannot "make" an existing thing a structure just by saying it is one and then ignoring the fact that it is already there.)

Excellent point. A thing can't be and not be at the same time. Where's St. Thomas Aquinas when we need him? Or for that matter Mike McCann?

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? bear

RE: Design of a tree as a structure / inspectors gone wild

Quote (btrueblood)

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.

Pay attention, people. This is how it's done.

RE: Design of a tree as a structure / inspectors gone wild

Maybe this is a suitable response to the Inspector:

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

What is the occupancy category of a tree?

"We shape our buildings, thereafter they shape us." -WSC

RE: Design of a tree as a structure / inspectors gone wild

According to the inspector's letter, the act of mounting the lights to the tree makes it a structure. Well they are already mounted, so the trees have already been transformed into structures.

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

Ask the inspector which section of the IBC applies to landscape/walkway lighting? In Arizona an building inspector is required to state the code section.

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

Also,since people/kids can crimb the tree ask what the building code required live loading on the tree limbs are for your calculations.
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

Is it possible to get the total response from the officials at the hearing? Call TMZ

Richard A. Cornelius, P.E.
WWW.amlinereast.com

RE: Design of a tree as a structure / inspectors gone wild

"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."

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

My office once received a review letter, similar in absurdity. The request was to provide calculations confirming how much the lake level would drop when running snow making pumps for the local ski hill at full volume. The lake was 15,000 sq.km (5,800 sq.mi.) with a volume of about 10350000000000000 cubic metres of water (directly connected to another much larger body of water). I recommended a very professional response containing the calculations showing how miniscule the drop would be .... something in the order of millionths of a millimeter.

RE: Design of a tree as a structure / inspectors gone wild

While not a structural engineer, I regularly look at this forum and learn lots of interesting things here.

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

long term health of a tree is certainly not within the realm of the inspectors or the cities jurisdiction. failure of the mounting might cause a light fixture to fall off the tree, certainly no a public safety issue. building departments are supposed to protect public safety. this is not a safety issue.

RE: Design of a tree as a structure / inspectors gone wild

I tend to agree with Spartan5. They don't have a law against mounting lights on trees, so they are using what powers they have. But I don't think trees are suitable as light poles, as they blow over and fall over. Oaks have shallow root balls.

Not often I support obstinate inspectors, so preparing for abuse...

RE: Design of a tree as a structure / inspectors gone wild

so does mounting a single bulb, 12" security light on your garage require a permit? or on your backyard shed? or anywhere on a pre-existing structure or not? I fail to see why this is an unsuitable use. Not much larger than a medium sized bird house.

RE: Design of a tree as a structure / inspectors gone wild

I see little to no difference between a wooden post and a living tree. They're both wood and both anchored into the ground and both susceptible to the same failures and damage (rot, insects, etc.).

Maine EIT, Civil/Structural.

RE: Design of a tree as a structure / inspectors gone wild

They may be more worried about the wires than the fixtures. If they were solar powered, maybe the issue would go away.

RE: Design of a tree as a structure / inspectors gone wild

Maybe a good question for the inspector is what if the tree was dead? Then it's just unsawn lumber and should be no different than any other post supporting a light.

Maine EIT, Civil/Structural.

RE: Design of a tree as a structure / inspectors gone wild


TehMightyEngineer -

Quote:

Maybe a good question for the inspector is what if the tree was dead? Then it's just unsawn lumber and should be no different than any other post supporting a light.

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

(OP)
Well, it hasn't been confirmed in writing yet, but the client was told verbally that the inspector has backed off and is accepting the fixtures as they are. I was almost looking forward to seeing this debate go public at a town meeting but it seems that isn't going to happen. I will share any more insight, for whatever it might be worth, if I get any. Thanks to everyone for sharing in this post, it has been interesting reading all the comments and perspectives.

RE: Design of a tree as a structure / inspectors gone wild

Raplh, those are some good points and I agree those should be considered.

Maine EIT, Civil/Structural.

RE: Design of a tree as a structure / inspectors gone wild

Call it a wood pile, there are easy calcs to copy and use. At this point you have spent more time fighting it than giving him a 3 line calc.

RE: Design of a tree as a structure / inspectors gone wild

I wonder how Tarzan got past the building inspector?

RE: Design of a tree as a structure / inspectors gone wild

Although the comments are all over the place - the one thing that I would be looking for is the connection of the light to the tree itself. It might last a year. I would rather see a band of some sort around the girth of the tree with a positive connection. I don't know how long the screws are in the photo - but sometimes where the screws go in, there may be eventually rot. Others may have a different experience - and now there is a liability problem if the fixture drops off the tree.

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

The title reminded me of a project my company did a while ago,but it was a tree made of Steel sections, not a real tree!!!

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

I had a blast reading this thread. Now I don't feel so bad about the inspectors I deal with.

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