March 2021 Letters & Emails

On removing deadwood

In his article, “On Removing Deadwood, Part 1” (TCI, February 2021), Jeremiah Sandler states “… we reduced the length of the dead branches to a safe size. After we finished our pruning …”

Did finishing the pruning involve removing the rest of the dead branches, or did reducing them to a safe size constitute the totality of the pruning? Around here, “[reducing] the length of the dead branches to a safe size” is what some companies do when the bucket doesn’t have enough reach to make a proper pruning cut.

Kurt Woltersdorf, owner
Woltersdorf, Inc.
Sanford, Maine

Jeremiah Sandler responds: We retained some of the parts of the dead branches as habitat for food for woodpeckers. The deadwood had indicators that woodpeckers were utilizing those dead branches, and we didn’t want to negatively impact them. They were retained for their ecological value.

Yellow, not mellow

I find the yellow background of the Accident Briefs pages visually abrasive. Will you please change it to a more aesthetically pleasing white?

I noticed this last month and gave it another try, then thought others may share the same opinion. So I am passing it on. Thank you for the content.

John T. Massing, arborist
Indianapolis, Indiana
Ed: Better this month?

Backpack-blower restrictions

Regarding “Backpack Blowers: Tree Care’s Latest Indispensable Tools” (TCI, February 2021), a lot of the work has been done over the years at the local (municipal) level on banning these preeminent (gasoline-powered) tools used for cleanup. This has mostly involved the noise level and allowed hours for operation (not too early or late in the day), with such restrictions often clearly covered by statutes. And these can be in effect anywhere in the United States. A prudent operation would want to be aware as to the current situation in the areas where they work.

Also, it doesn’t seem there is yet a statewide ban on gasoline engines in California, as stated in the article, though you can bet a lot of cities have banned blowers using them. Generally speaking, CARB (California Air Resources Board), which is the only state and group able to establish emissions regulations more strict than EPA, is looking at both blowers and mowers as high-volume, small, gasoline-engine products they’d like to switch over to electric only.

John Fischer
Engine consultant
Palatine, Illinois

Clarification on tree appraisal

I am writing regarding Lindsey Purcell’s article, “An Introduction to Tree Appraisal,” in the November 2020 TCI Magazine. Lindsey articulated the appraisal process extremely well and accurately, explaining the new material in the Guide for Plant Appraisal, 10th Edition, material that was without historic and legal precedent and not contained in any prior literature or peer-reviewed papers. Lindsey and Purdue University have been a great resource for appraisal education, so much so that some arborists have coined the term “The Purdue Method” of appraisal, a method, I may note, that is not a recognized method of appraisal.

Plant appraisal is a difficult and nuanced part of arboriculture, with many pitfalls for the untrained and uninformed. Imagine being cross examined by an attorney on your pruning or a plant-health-care application. Add in a controversial Guide, with techniques and terms that do not adhere to historic precedent nor have a foundation in legal precedent.

I would also like to reinforce and support Lew Bloch’s letter, “Clarification on The Guide,” in the December 2020 issue of TCI. Lew accurately describes the flawed process that led to the publication of the Guide for Plant Appraisal, 10th Edition. As Lew notes, industry committees – including a review task force involving TCIA – had recommended that the 10th Edition not be published and needed to be rewritten, not merely edited.

The 10th Edition makes notable contributions to plant appraisal but unfortunately contains significant conceptual, logical and technical flaws. There has been opposition to its publication by many experienced and knowledgeable plant appraisers since the 2012 draft was rejected. It is not considered best practice by many experts in plant appraisal.

A group of experienced plant-appraisal experts recently released a position statement on professional use of the 10th Edition, stating: “For the foreseeable future, however, best practice in plant appraisal will require significant professional judgment that is not constrained by the narrow letter of the 10th Edition. To conclude, the undersigned individual plant appraisal practitioners do not accept the 10th Edition, in its 2020 form, as a generally accepted[1], complete[2], or exclusive[3] expression of best practice in plant appraisal.”

The complete position statement can be downloaded from https://10thguideforplantappraisal.info/position-statement.

Robert Brudenell, BCMA, TRAQ, RCA, TPAQ
The Natural Way, Inc.
Englewood, Colorado

Editor’s note: The TCIA Guide for Plant Appraisal review task force is not a standing committee of TCIA. The task force was formed to review the drafts of the Guide and provide recommendations for improvement, and they did recommend after the final review that a number of changes be made before publishing the Guide. Some but not all of the changes requested by the task force were adopted. Based on those changes, TCIA decided to vote with all the other members of the CTLA to approve the Guide for publication. ISA has since provided some additional revisions to the Guide, and the revised version is available for purchase.

RF waves – additional concern

I just read your recent article about the effects of RF waves (“Beware the Dangers from AM Radio and 5G Transmission Sites,” TCI, January 2021). You raise many concerns that need to be addressed quickly to protect industry workers. I certainly did not realize the danger involved until I read your article.

There is one issue that was not addressed in your article and may not be an issue at all, but I just wanted to ask you your thoughts about it. The issue I am curious about is the effects that RF waves may have on the electronics of critical parts of equipment being operated by workers, especially wireless, radio-controlled remote devices that are becoming more common with each piece of new equipment.

This past fall, I was observing a crew member working the grapple of a chipper with a remote device while standing next to another crew member leveling the crane with a different remote device. After reading your article, I was thinking of how disastrous it could be if unexpected RF waves caused the failure of the wireless remote device operating a critical piece of equipment at a critical moment, such as lifting a cut log out of the path of a worker. I must admit that I do not know enough of the specifics involved to know if something like this is even possible, but if there is a chance of there being a problem, then it needs to be addressed due to safety concerns.

Jeff Glatt
Lincoln, Massachusetts

I enjoyed the January 2021 issue of TCI Magazine (nice new format, too), especially the article regarding RF energy burns from nearby AM radio facilities. I am a licensed broadcast engineer and have been zapped more than once throughout the last 60 years of engineering fieldwork, so I know of what the article’s author speaks.

More than once I have seen telephone and power-support poles and structures that are “hot” because of nearness to AM broadcast towers.

Many of the aerial-lift machines in common use can easily reach heights between ¼ to 1 full wavelength of AM operating frequencies. The actual formula for a wavelength is 984 feet divided by the frequency in Mega Hertz. For instance, for an AM station operating at 1,260 kHz (1.26 MHz), a wavelength is just under 781 feet; 1/4 wavelength is about 195 feet.

Even a lesser height of an extended aerial lift can produce a substantial RF burn if the source is of high power or close enough.

Although most AM radio towers and multi-tower arrays are visually obvious, some may be hidden by surrounding trees or other structures.

Each licensed AM radio tower or array is required to have an ASR (Aerial Structure Registration) number affixed to it. If you have the ASR number of a tower in question, both the FCC and the FAA maintain websites with detailed information including ownership, coordinates, height above ground, frequency and such. If you’re working in an area where you’re not sure of nearby AM towers, you can access either of these sites, enter your coordinates and get “distance to the nearest structure” data in case you need to contact the owner/operator to reduce power while you’re aloft in the bucket. Think positive and test negative.

Michael Bradford, CPBE
Broadcast/Audio Services
Jackson, Michigan

Editor’s note: We shared Jeff Glatt’s letter with Mr. Bradford. Here is his response:

Excellent observation by your reader. Cellphones, hand-held communication devices, electronic remote-control devices and even wired communication links are all vulnerable to RF energy causing them to fail in some fashion. Such interference may be frequency related, too. That’s why it’s critical, in my opinion, to determine any and all nearby RF sources and mitigate their possible interference prior to setup or rigging on any tree-maintenance site, regardless of whether or not you will be utilizing an aerial lift or crane. Because RF energy is related to the inverse square of the distance from the source to the target, even a 50% reduction in output power from an AM facility is often sufficient. Trying to find the owner/operator of a 5G cell site may be more difficult; I have seen many such sites with no indication of ownership visible.

Ed: TCIA solicited input from sources familiar with broadcast electronics and received the following information.

There are three different issues involved. The first is induced current, which manifests itself in sparks jumping and shocks felt in the vicinity of a large metallic object in a vertical position (like a crane or lift) near an AM radio tower. The crane acts as a receiving antenna, which usually produces more sparks and shocks the taller it is. That’s because the AM signal being broadcast from the tower is low frequency and thus long wavelength, which couples better to longer antennas (metallic objects), inducing current in them. And the metallic object must be vertical to produce the sparks, etc., because the AM tower produces a vertical wave. A 5G tower should not produce such an effect because the 5G signal is extremely short-wave (microwave).

The second issue would be health effects due to the radiation itself. Even the 5G radiation is not high enough in frequency to cause ionization, so the radiation’s effect is limited to heating bodily tissues. There’s a lot of controversy about whether that could lead to a complication like cancer.

The third issue would be effects of the radiation on other electronic gear. One aspect of that would be whether the radiation is intense enough to prevent the gear from receiving commands sent to it by radio. A second aspect would be whether the radiation is intense enough to temporarily disrupt or permanently damage the gear. A third would be whether the radiation might mimic one of the control commands that might be sent to the gear. Those questions are associated with the extent to which the gear is shielded (in a full-surround metallic cabinet), whether its control signals are hard-to-replicate digital sequences, etc. It is likely that radio-
control frequencies for such gear would not be up in the 5G range, and if that’s the case, then we should not expect direct interference.

These second and third issues would be associated with 5G transmissions, not AM towers. Unlike the AM signals, the 5G transmissions are directional, so your exact location is much more critical.

So, could the heat and sparks from the AM broadcast be enough to interfere with remote or other electronic controls? Or could they interfere only if touching or in close enough proximity to the vertical equipment to receive a spark?

It is unlikely the AM signal would interfere unless it’s causing bad continuous sparking. Sparks, like lightning, create their own radio waves, over a broad spectrum. (Listen to an empty spot on the AM dial during a thunderstorm.) It’s electronic noise, and if the noise is of high enough amplitude, it could possibly interfere with radio remote controls, etc. It is doubtful the AM signal itself would cause interference, because it is at one particular AM-band frequency, which would probably be filtered out by the remote-control receiver (although that depends on the design of the receiver; if it’s cheap, with no filter prior to its first amplification stage, all bets are off – which is one reason discussions like this can’t be definitive).

And all bets are also off if things are actually touching or otherwise physically receiving the spark.

There is related information on the internet. The FCC website might be a good place to start.

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