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The natural history of wooden utility poles.

This post is part of a series entitled ‘Nature and Society’ which touches upon the relationships between mankind and the surrounding natural world. This post deals with the consumption of nature, specifically the fact that an entire tree is required to make a single wooden utility pole.

Weekdays, on my way into work, I drive through a forest of tall trees. There are Douglas Firs, Western Red Cedars, Southern Pines, Jack Pines, Lodgepole Pines, and Pacific Silver Firs. Most of them have been standing there for 30 years or less, but some have been there for far longer. They stand in long, neat rows bordering roadways and residences amidst the urban sprawl.

View west down the Carlin Canyon from the hill above the Carlin Tunnel in Elko County, Nevada. (Image: Famartin)

But these trees aren’t really proper trees. They’re just shadows of trees. Their branches have turned to wire conduit and their roots to thick anchor cables driven into concrete.

Of course, as the title of this post makes clear, I’m talking about wooden utility poles. You can find them everywhere, particularly in developing areas that don’t enjoy the widespread implementation of underground conduit.

It’s probably a consequence of that ubiquity that these omnipresent posts aren’t typically given much thought. They have a tendency to just blend into the background of daily life and you don’t really notice them all that much until they happen to fall across a road during a storm or spoil some picturesque scenery.

Even when you do notice them, it’s easy to forget that each of those towering wooden figures were all once individual trees. That’s right. Every time mankind needs to erect a wooden utility pole, it has to do so at the expense of an entire tree.

And the trunks of those trees remain largely intact. Cut open a wooden utility pole and you’ll find the same growth rings and the same pith, heartwood, and sapwood that you’d find were you to do the same to a tree in a forest.

So since we’re dealing with trees and this is a blog for naturalists, it’s only fitting that we approach the topic of wooden utility poles from the standpoint of their natural history.

According to the North American Wood Pole Council (because, yes, there is a wood utility pole lobby), the life cycle of a wooden utility pole begins in a (presumably managed) forest. For what may be decades, the trees go about their lives like any other tree. They proceed from seed to sapling and so forth until one day a harvester comes along looking for what the NAWPC refers to as “the only 7 percent of the trees” which possess the qualities needed to make a utility pole and chops it down.

Incidentally, if you haven’t visited the website of the North American Wood Pole Council (NAWPC), you’re missing out on an opportunity to witness some delightfully saccharine spin.

For instance, take the following line from this page, “With an estimated 130 million poles in place in North America, wood poles have become so ubiquitous that they even inspired poetry.”

The poem they’re referring to is an ostensibly satirical poem by John Updike entitled Telephone Poles which the New York Times once described as an expression of Updike’s opinion that telephone poles are “a sort of robot-tree appropriate to a people with no gods.” Yet, the NAWPC seems to think that the poem is some sort of affectionate ode to these instruments.

But I’m getting off-topic. Back to the forest…

Out there amongst the conifers and cedars, the trees selected for harvest are felled, stripped of their limbs and crowns, and trimmed to standard lengths with the median length being the “Class 4” 45-foot pole.

The trimmed logs are then trucked to a yard and dried. According to a life cycle assessment by the engineering firm AquAeTer, Inc.,

“The most common means of drying poles include the Boulton process (poles are boiled in the treatment cylinder using the preservative liquid while under vacuum), steaming (poles are heated with steam in a cylinder under low pressure followed by a vacuum to flash the superheated wood moisture), kiln-drying (poles are placed in racks in kilns with heat, and air drying (poles are stacked in the open yard in dry climate areas until dry).”

Afterward, the poles are transported to a facility where they are treated with preservatives. After all, at this point, these poles are essentially just massive logs standing on their ends and there are innumerable insects, collembola, fungi, and other life forms that love to use logs as shelter and/or a source of food.

Since these logs are expected to be sturdy and strong for a lifespan of at least 30 years, decomposition just isn’t acceptable so some powerful preservatives are put in place.

Chamber for chemically-treating utility poles. (Image: Tzaneng Treated Lumber corporation)

In the words of the NAWPC, “the preservatives are not just on the surface, they are infused deep into the wood to provide long-lasting protection.

These preservatives typically take the form of:

  • Pentachlorophenol (Penta) [PubChem]
  • Chromated Copper Arsenate (CCA) [PubChem]
  • Copper Naphthenate (CuN) [PubChem]
  • Creosote [PubChem]
  • Ammoniacal Copper Zinc Arsenate (ACZA or Chemonite) [MSDS]

After the poles have been sufficiently treated, they are sent off to the distributors that will get them along to their ultimate service destinations. Some stand in long lanes of conduit stretching through fields or (ironically) forests, others become one of the common urban poles that I see each morning on my way to work, and some are destined to spend their days being lifted and lowered above the heads of military trainees.

Plebes carry a modified telephone pole during the log PT station of Sea Trials. (Image: US Navy)

Regardless of their destination, the poles are set deep into the ground and there they stand for a functional lifespan of 30 years or more. While there, they may hold everything from electrical lines to telecommunications equipment and might even play an inadvertent role in the local ecology.

The fox squirrels in my neighborhood, for instance, use the ones on my street to cross the street in much the same way you see small mammals utilize wildlife bridges. Large birds like ospreys commonly construct nests atop them (at great risk to the birds and electrical network stability) and, of course, everyone has seen small to medium-sized birds use the ubiquitous conduit between poles as places for perching.

An osprey nest on a utility pole. (Image: Wikimedia Commons)

After a few decades the poles reach the end of their service life. They are then removed from their anchor points and here’s where their lifecycle get a bit less clear.

It appears that little thought was given to what society does with wooden utility poles when they are no longer able to fulfill their original function.

Being that they’re wood, one possibility for end-of-life treatment that immediately comes to mind is recycling, either as lumber or as some form of wood byproduct. Unfortunately, the chemicals mentioned earlier that are used to preserve the wood make that process difficult.

All of those chemicals, while deemed safe by the EPA for their use in wooden utility poles, do pose risks to human health and to the environment. There is enough concern about those chemicals leaching into the environment and potentially contaminating human habitation and the environment that states such as Washington, Connecticut, and California have determined that they must be disposed of as hazardous waste. For instance, in Connecticut,

“Treated wood of all types can be most responsibly disposed of as follows: Homeowners engaged in small projects should take treated wood to their local landfill or transfer station and place it in the designated location (i.e., the non-clean wood pile). Contractors, utilities, and manufacturers should contract directly with a DEEP permitted bulky waste landfill, or send it to an out-of state wood burner facility appropriately equipped and permitted to burn treated wood.”

There are examples of companies offering recycling services for wooden utility poles, yet even they are bound by the same disposal procedures for any contaminated wood they can’t re-use and it appears that even the re-usable portions of the poles are universally considered unacceptable for interior use.

And there it is. The life cycle of a wooden utility pole.

The fact that we have to cut down a whole tree every time we need a utility pole seems downright archaic in an era in which we have an abundance of long-lived materials at our disposal and in which advancements in materials science are making headlines at a rate of about every few weeks. Aside from the environmental cost, I can only imagine the enormous sums of money that must be spent on storing and transporting these poles; particularly given the hazardous waste handling requirements.

Yet, there are many other variables to consider when thinking about the overall impact of a product on the environment and the economy. There are costs to be calculated at each stage of a product’s life cycle and you really need a full cradle-to-grave analysis of wood poles and their alternatives to explore justifications for using such an ostensibly wasteful material.

Unfortunately, that kind of data seems hard to come by and my research turned up a collection of material from overtly biased sources like the NAWPC or the American Iron and Steel institute and organizations with less overt conflicts of interest like Environmental Literacy Council (which was bankrolled by Koch and Exxon.) Each biased source, of course, purported that their product was the all-around best in terms of monetary cost, environmental impact, etc.

It seems there has yet to be a bona fide and sustained independent investigation into the life cycle and environmental/economic impact of wood utility poles, but given the fact that they each represent an entire tree, that they require a considerable amount of toxic material to make them functional that can subsequently leach into the environment, and that they often wind up in massive piles within hazardous waste landfills, I would venture that there are much better alternatives. With climate change and deforestation continuing their rapid and deleterious progression, the trees we really need lining our streets are the ones that have leaves.

 

 

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