Tree Power| Voltage Explained

Eric Frei

Scientists have solved a long-standing mystery behind the source of a faint electrical current in trees - and it wasn't as hard as they thought.

Explanations for the power source ranged from a static energy field in the earth's crust, to the possibility it was generated through rust and corrosion, similar to the old do-it-yourself potato clock experiments.

Now, a team of MIT scientists, using platinum electrodes and everyday ficus house plants, have found that the faint current actually comes from an imbalance in pH between the soil and a living tree. And that discovery is already sparking discussions about novel ways to use that electricity - including as a power source for a tree's own fire alarm.

Scientists tap tree power to run devices - The Boston Globe

Tree power could save forests from fires - Discovery.com - MSNBC.com

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newguy18

I would think that if the tree had its own power source that if say a limb were touching a power line that the wire and transformer would short out.

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old schooler

ArborealTerror

Well I must say, this should be filed in the department of the bleeding obvious. If you think about it if there was no potential difference between the tree and the surrounding water soaked soil it would be impossible or at least far more difficult for dissolved ions to migrate into the root structure. Come to that if there was no difference in the salt concentrations it would be very difficult for water to migrate into the trees.

NG - I dont think the micro-voltages involved are going to do much damage to a 240v residential supply. If however a limb is touching an uninsulated line then that limb will become electrified and 'short' to ground. This kind of shorting draws as much current as it can and this tends to make pole top fuses trip or burn out. By this time the tree will have sustained severe damage as will anyone who may have been climbing or touching the limb.

newguy18

I'll have to disagree with that,i've climbed several trees that were touching secondaries and primaries and the limbs had no signs of burn marks and i'm still here and i had to get out on those limbs.

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ArborealTerror

Yes, sometimes you can get away with it. The voltage takes the path of least resistance to earth. I am not sure what you mean by primaries and secondaries. In Oz we have three wires each carrying a single phase (active) and a single neutral (earth) cable with the voltage being 240v between any of the four.basically the voltage in the active cables wants to get to the neutral wire or ground and will take the path of least resistance. If you or the tree are that path then you are fried.

In America I believe you have 110v systems. The good news there is that the as the voltage decreases the liklihood of using a piece of damp wood as an earth conductor decreases. Never the less, it can and does happen.

NewGuy, I have read in many of your other posts that you laugh in the face of danger and read the plea's of many other members asking you to not take so many risks. Mate, don't take chances with electricity. You seldom get a second chance. If a branch is touching a live wire hire a LV insulated bucket truck or tow behind EWP and do the removal using that. Pass the costs on to the customer. If they are not willing to pay for your safety then stuff 'em, they are not worth your life. Take Care, there is more to life than cuttin trees -

OutofMytree

Under no circumstances does anyone in my crew go near ANY tree which is in contact with an uninsulated overhead power line. If there is any doubt we earth the tree with a cable before commencing work.

Less than 12 months ago a local arborist died from an accidental contact with a polesaw. POWER LINES ARE DANGEROUS.

Bill don't fool yourself. Because you have done something risky and survived doesnt mean you or anyone else can do it again and survive. After all, it is theoretically possible to play Russian Roulette and not die.....

Eric Frei

You had it coming to you.

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newguy18

What about all those line clearance guys that did it for years and nothing happened to them.If they are making connection with both wires,no way i won't climb it,if its just touching one,maybe after a good inspection.On the really bad ones,i just call asplunduh,let them fool with it since they're line clearance.

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newguy18

Primaries are the main wires that run through say downtown,secondaries are the wires that carry power to the residential transformers,service drops are the little 240 going to peoples houses.Transmission lines are the ones up on the steel towers.

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OutofMytree

Remember when we kids and Mum used to say "if that idiot friend of yours jumped of a cliff would you do it too?"

I clear residential 240v on a regular basis. I had the unfortunate experience a year back of losing my grip on a Norfolk Island Pine branch. The wind took it sideways and onto the uninsulated 240v 4 strand. The branch cause a wave along one line and even though they didnt touch, the electromagnetic fields around each cable repelled each other. It looked like 4 giant snakes 30m long whipping backwards and forwards. Not only did I blow the houses fuses for the street but the pole top transformer across the road. Fortunately for me, the service guy for the power company made a mistake reconnecting and took out half the suburb and in the ensuing embarrasment they forgot to bill me for my mistake.

My point is that that contact was light and we were in an EWP about 6 metres away. Had we been closer and worse still climbing rather than using an insulated bucket then the story may well have had a different ending.

It is absolutely vital, that novice tree workers reading this post should have no illusions about power lines. They are dangerous. They do kill people and it is often line clearance tree workers who are the victims.

newguy18

i never for a minute under estimate the dangers of power lines or our line of work for that matter,its just a matter of understanding the risks and choosing wether you want to accept or decline the risks,kinda like climbing dead trees,i've climbed a clump of black cherries that were dead for 15 years,i deemed it safe because,i got 2 tie ins from a couple pines,What heart wood was left was some what sound,i've climbed worse.I've only walked away from 3 jobs,one was pruning a tree limb over the suwannee river,my reasoning being that the tree was at a good lean over the river,and on the side away from the river it had extensive root rot and i can't swim.

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OutofMytree

Over here, the lines you describe as secondaries carry up to 3300 volts. There are some truly gruesome training videos of guys with massive injuries and burns. Contact need only be for a fraction of a second to produce a burn so severe that amputation of the limb is the only way to prevent death by gangrene.

Still, you could probably get a job as an extra on the next PotC movie.

newguy18

Oh yeah voltage definatly gets higher with differnt lines,i'm not even going to tell you guys about another job that would make others cringe.I don't like pirates of the carribean.As i've said before,common sense and gut feeling are real important when doing that kind of work,if you doubt it for a second,don't do it.

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newguy18

I see i forgot my flak jacket this morning.

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MTS247

We can work on a tree if it is touching "Low voltage" <1000v 240v in australia, but we contract to the power company.

We aren't alowed to go near a tree that is within 700mm of HV, usually 22000v in victoria. but i know its very diferent in NSW.

apparently branches dont contuct "low voltages" very well. as long as they are not wet.

branches do conduct "high voltages" quiet well so be very carefull.

And remember unless you are "authorised" by the power company you probably are not allowed to work within 6m of powerlines

ArborealTerror

Guys, I used to work for the state power utility many years ago in the high voltage, metering and regulatory section. I mostly worked on metering. The things i learned in the other two sections were chilling.

High voltage used to have massive static electricity generators with wich they would test how easily lines of varying voltages would arc in various conditions.

Regulatory used to investigate deaths caused by electricity and modify the state regulations accordingly.

When you talk about a LV line not conducting down a dry branch you are making some pretty big assumptions. Here are some questions you may want to consider next time:

1. Has contact with the wire damaged the bark such that some moist inner bark is in contact with the wire?
2. What is the water content of the tree and the resistance of that water with all of it's dissolved ions to electricity?
3. What is the current humidity?
4. Are you sweating?
5. What is your personal current static potential?
6. Is the sprinkler/retic system below the tree about to activate?
7. Is a car about to crash into a pole a few blocks over and cause a voltage spike in your line of a few thousand volts?

Ah heck - I'm going back to my game of russian roulette. Less questions to answer.

BTW - I read somewhere that about a dozen people die in the USA each year from lick testing 9V batteries. I have done this hundreds of times with no ill effects. I guess they were just really unlucky but I stopped lick testing 9V batteries anyway.

My advice - unless you have had the specific training for dealing with trees in close proximity to power lines, have the appropriatte equipment to do so, are authorised by you local electricity regulatory authority, and have comprehensive insurance stay well clear of the lightning.

Gunslinger

AT brings up some good points. Here in the US the predominate residential system voltage is 120/240 single phase. One thing that I would clarify is that voltage does not only follow the path of least resistance. It follows all parallel paths regardless of the resistance. Those with greater resistances will have a lower current flow, therefore if a tree were touching an exposed 240 volt conductor the tree could very well be conducting electricity through the earth back to the utility transformer. If you stood on the ground next to the tree and touched it your body would create a parallel path for current flow (think of a bird on a wire). Since the resistance of the tree is high and the resistance of the human body is high not much current will flow through the body. However since these resistances are fixed the current flow will increase proportionately with the voltage. Therefore a tree in contact with a 240 volt conductor would likely pose little threat to a person touching the trunk standing on the ground. But increase that conductor voltage to 7200 volts or higher and the potential for shock will proportionately increased.

Eric Frei

One thing that has to be absolutely clear here is ...

Regardless of the risks you as an individual wish to take regarding electricity there is a strong hierarchy of risk management beyond your personal perception (an potentially ignorant and lethal perception). The 3m rule or 10' rule is for most low voltage lines (up to 1kv)

Here's our rules for Qld.

The air that surrounds an exposed bare wire is like insulation. Observe the distances from the wires to each other, wires to the pole, they are a certain distance for a reason.

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rbtree

Apparantly you do...and you are extremely ignorant, and stupid as wwll...

How old are you again?

Your statements in this thread lead me to believe that you are a candidate for any year's Darwin Award.

newguy18

i'm not going to waste a post on you rbtree,i'll do what i do and thats that.

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OutofMytree

No flaming please.

OutofMytree

And Bill....

Dude....

I don't agree with insulting people in this forum but your comments here undermine the good work you have done in other threads.

If you are going to do irresponsible things please please do not post about them here where your post count suggests a degree of competance the points you have made in this particular thread do not support.

rbtree

My post wasn't really an insult......

Bill's comments on this thread, if to be taken as he really thinks and works, speak volumes.........

The kid needs to wise up, and that's a fact, Jack!


I know whereof I speak...AND have more experience, knowledge, skill and training than 99% of those involved in the industry....

....and, apparantly, an ego too boot.....

Galbee

I work power lines this way:-
If the tree is touching the LV lines call the power co and get a temporary switch off then do the job, if the tree is very close to LV lines call the power co and get a temporary switch off(see where im going with this), if there are HV lines close or touching get the utility co to do it, I have a wife and kids at home and love my job i want to live long and prosper not die hanging upsidedown in a tree and be the next statistic on the news. i watched a tree surgeon use a throw line on a tree that was next to a four cable LV line he missed the tree and hung up in the lines, then pulled really hard to get it down the flash and crack from the lines touching was scary as hell the muppet got away with it that day, but all he had to do was call the utility co and get a temporary switch off and he would have been safe also the guys wouldnt have ripped him for being such a nob for weeks. an ego in the tree is a dangerous thing.

OutofMytree

Must hold on.....must keep control......must not say it.....must not say it.....must not say it......

Ah what the hell.

May I offer you a straw to breath through?

rbtree

Why thank ya, mate!!

Done it

This thread sort of got off topic and I didn't post this.

jomoco's invention just reminded me.

George O. Squier ~ Trees as Antennas ( Scientific American, June 14, 1919 & British Patent Specification # 149,917)

Eric Frei

Trees self-power a wildfire alert network | MNN - Mother Nature Network

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woodmiller

Interesting application...wondering when the authorities here in AUS will trial such a system? Are any of our authorities, power or emergency services, already utilising this style of system...anyone know?

Done it

Just a bit of an update.
Electrical power from trees :: ElectricalSolutions

Tree power is unlikely to replace solar power for most applications, Parviz admits. But the system could provide a low-cost option for powering tree sensors that might be used to detect environmental conditions or forest fires. The electronic output could also be used to gauge a tree’s health.

“It's not exactly established where these voltages come from. But there seems to be some signalling in trees, similar to what happens in the human body but with slower speed,” Parviz said. “I’m interested in applying our results as a way of investigating what the tree is doing. When you go to the doctor, the first thing that they measure is your pulse. We don’t really have something similar for trees"

UW Associate Professor of electrical engineering, Babak Parviz