Trees under power lines

Trees Beneath Power Lines: Should You Be Planting Trees Around Power Lines

Drive down any city street and you will see trees hacked in unnatural looking V-shapes around power lines. The average state spends about $30 million a year trimming trees away from power lines and in utility easements. Tree branches 25-45 feet high are usually in the trimming zone. It can be pretty upsetting when you go to work in the morning with a beautiful full tree canopy on your terrace, only to come home in the evening to find it hacked into an unnatural form. Continue reading to learn about planting trees beneath power lines.

Should You Be Planting Trees Around Power Lines?

As mentioned, 25-45 feet is usually the height utility companies trim tree branches to allow for power lines. If you are planting a new tree in an area beneath power lines, it is suggested that you select a tree or shrub that does not grow taller than 25 feet.

Most city plots

also have 3-4 feet wide utility easements on one or more sides of the plot line. While they are part of your property, these utility easements are intended for utility crews to have access to power lines or power boxes. You can plant in this utility easement, but the utility company can trim or remove these plants if they deem it necessary.

Planting near utility posts also has its rules.

  • Trees that mature to a height of 20 feet or less should be planted at least 10 feet away from telephone or utility posts.
  • Trees that grow 20-40 feet tall should be planted 25-35 feet away from telephone or utility posts.
  • Anything taller than 40 feet should be planted 45-60 feet away from utility posts.

Trees beneath Power Lines

Despite all these rules and measurements, there are still many small trees or large shrubs that you can plant under power lines and around utility posts. Below are lists of large shrubs or small trees safe to plant under power lines.

Deciduous Trees

  • Amur Maple (Acer tataricum sp. ginnala)
  • Apple Serviceberry (Amelanchier x grandiflora)
  • Eastern Redbud (Cercis canadensis)
  • Smoke Tree (Cotinus obovatus)
  • Dogwood (Cornus sp.) – includes Kousa, Cornelian Cherry and Pagoda Dogwood
  • Magnolia (Magnolia sp.) – Large-Flowered and Star Magnolia
  • Japanese Tree Lilac (Syringa reticulata)
  • Dwarf Crabapple (Malus sp.)
  • American Hornbeam (Carpinus caroliniana)
  • Chokecherry (Prunus virginiana)
  • Snow Fountain Cherry (Prunus snofozam)
  • Hawthorn (Crataegus sp.) – Winter King Hawthorn, Washington Hawthorn and Cockspur Hawthorn

Small or Dwarf Evergreens

  • Arborvitae (Thuja occidentalis)
  • Dwarf Upright Juniper (Juniperus sp.)
  • Dwarf Spruce (Picea sp.)
  • Dwarf Pine (Pinus sp.)

Large Deciduous Shrubs

  • Witch Hazel (Hamamelis virginiana)
  • Staghorn Sumac (Rhus typhina)
  • Burning Bush (Euonymus alatus)
  • Forsythia (Forsythia sp.)
  • Lilac (Syringa sp.)
  • Viburnum (Viburnum sp.)
  • Weeping Pea shrub (Caragana arborescens ‘Pendula’)

Originally Posted to www.transitionpgh.org on April 2, 2012 @ 4:30PM

Utility poles create garden opportunities in space that would otherwise just be filled with grass and weeds. My street has a “Hell-Strip” also known as the little strip of grass between your street and sidewalk, it extends from one side of my street to the other… except in front of the house I live in for some reason. Anyway hell-strips create a unique gardening opportunity, there have been books written on the subject detailing many aspects of gardening in these strips.

One of my original “dreams” I had for our street was to garden the entire strip from one end to the other. This dream was soon broken with the realization that since we only have on street parking anything that I planted was soon trampled. This left me to the places you could’nt open a car door like utility poles and traffic signs.

I wouldn’t recomend planting anything you were planning on eating next to a utility pole given the fact that these poles are soaked in creosote which is a product obtained from the distillation of a tar that is heavier than water and is used to preserve wood. Creosate contains many toxic compounds and I don’t recommend eating anything grown in close proximity to it. Creosote was also used to treat railroad ties so caution should be taken any time you are working close to them.

If you have access to bricks use them to make a nice little defining border around the garden. This gives you a visible line showing where the garden is but also defines where the lawncare should end. Most landscapers fail to ever look down and unless you have a clearly defined line where your plants start then they will be destroyed. Another thing to take into consideration is the hardiness of your plants, even though people won’t be directly walking on the garden… dogs will still walk through it, they may do worse if their masters aren’t vigilant… Salt can wreak havoc on your plants as well… Also the creosote on the pole itself acts as an herbicide and keeps plants from growing to close to it. I dig and replace the soil closest to the pole to be safe and add as much organic material as I can fit.

Pick the hardiest most drought tolerant plants you can find like mints, lavendar, sages, echinacea, day lilly, iris or anything that is very hardy. Remember that these plants are really not protected by anything and other than the first month or two you will not want to be dragging water out to the garden daily. You want to only have to deal with it once or twice a year once it is built.

Another cool part of gardening in these long lost areas is they make great places to plant spring bulbs. I find tulips are the only plants that do not do good in these areas. They usually look stunted and never bloom. Daffodils on the other hand will take incredible amounts of torture and will bloom for years. Daffodils are also sold in bulk and if you wait for the right time to ask most places will have extras at the end of the year they will sell to you at a drastic reduction in price. If you want to plant bulbs in grass then just cut and tear up a section of sod, place your bulbs wherever you want them and replace the piece of sod. Sometimes I don’t remember all of the places I put them and find myself surprised every spring. Be creative with them, you can sneak them into somebodies yard and not tell them until they come up in the spring… Hence my nickname for bulbs “Hippy Hand Grenades”

Trees and power lines: When is it OK to plant a tall tree under power lines?

A power pole with secondary and primary power lines. (FOT File)

By Brighton West

In my last post, I pointed out that the rule ‘The Right Tree in the Right Place’ tells us to plant small trees under primary lines. But not all overhead wires are primary power lines. Those “telephone poles” hold primary and secondary power lines, cable lines, telephone lines, and other lines.

Trees growing into primary power lines present a serious safety hazard, so the power company clears trees around these lines. But the other lines can run right through the center of a tree without causing problems. Sometimes the line owner will install some additional protection on the line if it’s rubbing against the trunk, but they usually don’t prune the tree for clearance.

Friends of Trees and most urban foresters believe that planting the largest tree that fits the planting space is the right thing to do—more stormwater captured, more carbon sequestered, more energy benefits to the adjacent property, and higher property values, among other reasons. So if the “telephone poles” don’t have primary power lines and the planting strip is wide enough for a tall tree, then the city policy calls for a tall tree.

That’s one great reason to get a free urban forestry inspection to plant a tree. (It’s also required by the city.) The inspectors are trained to identify primary power lines and the other more rare situations that can restrict tree growth, such as uninsulated secondary power lines.

But I know you are curious to see what the difference is. The photo at the top of this page is the “telephone pole” outside my bedroom window.

Large tree hiding secondary power lines

To the right of the pole, we have primary power lines. They are at the top above the transformer. Below are secondary power lines. So at this location, the houses to the right would need to plant small trees, and those to the left would plant tall trees.

Here is an example of a tree growing through secondary power lines. Imagine if this entire street had large street trees. The ugly power lines would be completely hidden.

Coming next Monday: Trees and Powerlines: Should we plant tall trees under primary power lines?

West is the programs director at Friends of Trees: [email protected]; 503-282-8846 ext. 19

planting Power Lines street trees

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The battle of power lines and the urban forest

Washington area residents tend to think about the metropolis’s imperfect system of electricity delivery when it fails, as it did spectacularly on the night of June 29 with the arrival of a broad, fast-moving storm we now know as a derecho.

Todd Bolton, as the arborist for Takoma Park, is mindful every day of the precarious coexistence of the urban forest and the power lines strung up on poles 25 to 35 feet in the air. On some corners in this historic little city, so many wires seem to be held aloft that you might think you are looking up to some mystical dreamcatcher, though one that seems to prefer collective nightmares at times of hurricanes, tornadoes, derechos, wind shears, ice storms and the occasional Snowmageddon.

We don’t perch domestic gas lines or water mains up in the elements — they’re snugly buried beneath the road — so why power cables? The short answer is that it’s expensive to bury them, but it has to do with history, too. Bolton eyed a map of Takoma Park on his desk computer that shows how the suburban community on the northern tip of the District grew from its incorporation in 1890.

Many of the city’s oldest neighborhoods received basic electricity supply in the first decades of the last century at a time when trees that grew from the mid-19th century were already of great height and girth. A single, innocuous power line brought power well below where these lofty giants began to branch. But during the course of the 20th century, homes became loaded with air conditioners, refrigerators, washer-dryers and other appliances, requiring an increasingly powerful network of electricity transmission and distribution. At the same time, new development led to wholesale removal of old trees and the planting of new ones that were destined to grow amid the utility wires.

Takoma Park, with its leafy neighborhoods of old houses, is like so many other communities of suburban Maryland, the District and Northern Virginia — cozy and settled but with an uneasy alliance of deciduous shade trees amid the aerial power grid. (Telephone and cable lines piggyback on the poles, themselves the carcasses of old pine trees.)

A yoschino cherry tree along Takoma Park Ave. It’s a good example of a small tree that doesn’t interfere with power lines. (Adrian Higgins/THE WASHINGTON POST)

If you live in one of these neighborhoods, you don’t have to go far to see that in the struggle between shade trees and power lines, the trees might win the storm-by-storm battle, but they’re losing the war with the utility companies’ tree trimmers. In my neighborhood in Alexandria, which lost power for six days after the derecho, I can look out to an old oak tree whose central leader has been removed to leave lower branches that have turned skyward to the light to form a 60-foot “U.”

A few blocks away, there is a Chinese elm that has been rendered as a Texas longhorn. Nearby, two silver maples in someone’s front yard have lost their natural canopy, replaced by a towering, crescent-shaped hedge that curves around the power line of Dominion Virginia Power.

Check out Pepco’s Web site and you will find a guide to line clearance that sugarcoats the necessary butchery by conflating universally correct pruning techniques with dismemberment, namely the sawing off of a tree’s central leader or the removal of a whole side of a crown. This might be necessary to keep tree limbs away from lines, but it leaves the oak or maple or sweetgum — name the species — in a state of mutilation. The guide has wonderfully upbeat and persuasive language and compares the radical pruning regime with an older approach of topping trees — reducing a canopy to an arbitrary size. This worked for one season, until the tree responded with a mass of weak wooded shoots from the area of the cut — suckers or, more accurately, watersprouts.

Pepco is surely right when it says that sometimes it is better simply to remove the tree and rethink the equation, but others don’t necessarily agree, believing that a mutilated big tree still provides environmental benefits of providing shade to people and cooling the urban heat island.

Another complexity arises when the power company’s theory of skilled pruning doesn’t always translate into practice. Bolton took me to see a mature redbud to the side of a power line where a Pepco contractor took out the leader two years ago in a way that spawned a mess of suckers, “which absolutely defeated what they tried to do.”

The desire to do it right “doesn’t always get down to the minimum-wage guys in the bucket,” he said. Bolton also took me to the city’s swank Takoma Avenue, where a broad street runs between big lots with large, period houses.

On one end of the block, he pointed to two oaks, one 25 years old, the other 40, now disfigured where they had been cut away from the power line. “Somebody planted the wrong tree,” he said. At the other end of the block, he has installed a row of four Japanese flowering cherry trees that seem destined to coexist with the lines, at least for most of their lives.

This is an obvious solution: Get the local government to replace oversized shade or canopy trees with understory trees that reach between 20 and 30 feet at maturity. (See the accompanying list of suggested varieties.) These selections are the bailiwick of your local government. In the District, you can request the Department of Transportation to take down an ailing shade tree and replace it with an understory tree on the city’s Urban Forestry Administration-approved list. The smaller trees also make sense on private property that abuts power lines. Power companies have the right to cut back private trees that could interfere with lines.

Dominion Power (motto: “Look before you leaf”) doesn’t want any trees under its power lines, suggesting instead planting shrubs. I just don’t see folks wanting to get out of their cars to brush against spireas and viburnums.

Gradually replacing mutilated shade trees with understory trees solves one problem but creates others — one side of the street with 15-foot trees, the other side with 50-foot trees. Also, utility contractors have been known to cut back even the understory trees. In addition, the smaller trees don’t shade and cool as canopy trees do. “Planting small trees comes at an environmental cost,” said Maisie Hughes, director of planning and design for the District-based nonprofit Casey Trees.

Nor should we take down every shade tree that might fall on a power line, says Dean Amel, a member of Arlington County’s Urban Forestry Commission. “I don’t think it’s reasonable. We wouldn’t be able to plant canopy trees pretty much anywhere in Arlington if that was the case.”

In Arlington, where the county government no longer plants trees on strips that are narrower than four feet, the answer might lie in getting residents to revegetate the urban forest on their land. The county funds tree planting on private property by community groups.

“We see private property as having the most area for large shade trees,” said Jamie Bartalon, forestry and landscape supervisor for the county parks department.

For District residents, Casey Trees works with the city to provide residents with shade trees for $50 — that’s a real bargain, by the way. Still, Hughes hankers for a world of grand old street trees without the worry of the power lines. “If we didn’t have power lines, we could have these amazing oak-lined or elm-lined streets,” she said. (If you want to see such a canopy in the offing, check out the young disease-resistant varieties of American elm in front of the White House.)

Bolton says his ideal solution would be to bury the main lines when highway departments rebuild roads, reducing the aerial system to simple, localized power lines that need only three or four feet of tree clearance. “Then if they’re taken down, you only lose a block,” he said.

10 understory trees that coexist with power lines

Small, upright trees make great alternatives to old, mutilated shade trees that have lost their battle with overhead power lines and the utility company’s tree “trimmers.”

Municipal arborists call these alternatives “understory trees” because in nature the trees grow below the forest canopy. Pressed into street tree service, they need to be upright in habit and tolerant of all the ills of growing in a narrow curbside strip, among them poor soil, heat stress, limited root space and road salt.

The trees listed at the bottom of these pages also make good candidates on the edge of private lots where shade trees might, in time, grow into power lines.

Crape myrtles might seem a perfect choice but aren’t on my list: The popular variety Natchez grows to 30 feet with a 20 feet spread, and smaller, multi-stemmed varieties need skilled, annual pruning when young to create a tree form.

1. American hornbeam (Carpinus caroliniana): This small tree with beech-like leaves and silver bark deserves more use. Not a showy bloomer, it develops an upright rounded canopy and grows to a tidy 20 feet. The upright form of the European hornbeam is more common, used as a screen in tight spaces.

2. Crab apple (Malus): It is important to pick a variety that is both upright in growth habit and bred for disease resistance. The crab apple is gorgeous in bud, flower and fruit, though its dropped fruit can be messy. Suitable street tree varieties include Adirondack, Donald Wyman, Autumn Glory, Naragansett and Professor Sprenger, all white-flowering. Prairifire has magenta flowers. Takoma Park arborist Todd Bolton plants a variety named Thunderchild, a 15-footer with pink blossoms.

3. Eastern redbud (Cercis canadensis): This beloved native woodland tree functions nicely as a street tree, growing to 15 to 20 feet when pressed into curbside duty. Somewhat short-lived in a stressed environment, but worth replacing every 20 to 30 years.

4. Flowering cherry (Prunus): The classic Tidal Basin variety is Yoshino, fine for street use, rarely growing to more than 20 feet. Kwanzan, with magenta-pink double flowers, is another stalwart small street tree. Bolton also likes a newer variety named Snow Goose. White-flowered and upright, it grows to just 20 feet.

5. Flowering dogwood (Cornus florida): Like the redbud, this iconic native tree is unlikely to reach great, spreading age at the roadside. Particularly suited to front yards near power lines. Dogwood alternatives include the more upright and larger kousa dogwood (Cornus kousa).

6. Japanese tree lilac (Syringa reticulata): Upright, tree form of lilac that blooms in early June with white flowers. Not particularly fragrant, but a sturdy tree suited for street use.

7. Sweetbay magnolia (Magnolia virginiana): Small, native magnolia growing to 20 feet, with attractive gray-green leaves. The white blossoms appear in late spring. It likes moist conditions but can endure drought once established. An alternative is the entirely different magnolia Galaxy, stouter and symmetric but still sufficiently upright and short for street use. Its strong pink blooms appear in early spring.

8. Serviceberry (Amelanchier): Amelanchiers grow as large shrubs or small trees, depending on species and individual form. Select one that has a single trunk. Autumn Brilliance is a hybrid favored for its tree form and red fall color.

9. Trident maple (Acer buergeranum): Asian maple that grows to approximately 20 feet with great fall color. Woody plant expert Michael Dirr writes: “Small, dapper, handsomely clothed trees are a rarity, and trident maple qualifies as one of the best.” An alternative might be the paperbark maple (Acer griseum), slow growing, with beautiful peeling cinnamon bark, but hard to find and somewhat expensive.

10. Washington hawthorn (Crataegus phaenopyrum): Heat-tolerant species of hawthorn that grows to about 20 feet in a street setting. Princeton Sentry is a near-thornless variety. A suitable alternative is the Winter King variety of green hawthorn.

POLL | How to fix the street tree-power line conflict

Preparing your home for a hurricane

Read past columns by Higgins. Follow him on Twitter @adrian_higgins.

Planting near power lines

Plan ahead when planting

Trees make our yards and neighbourhoods beautiful and they can solve practical problems, too.

We ask that when you’re about to plant a tree that you plan carefully. Be aware of power lines and consider the final height of the tree when it’s fully grown. Planting a tree that will grow taller than the utility pole directly under the power line can lead to issues, like the tree falling on the power line or growing into the line.

Right tree, right place

There are three zones around overhead power lines:

  • Low zone: This area extends 5 metres on either side of the power line. Trees planted here should have a maximum mature height of 6 metres or less.
  • Medium zone: This area extends from the edge of the low zone to a distance of 10 metres from the pole and power line. The maximum, mature height of trees in this zone should be 12 metres.
    • Overheight trees in the medium zone cause the majority of power outages. Falling branches and toppling trees can bring down power lines, causing power interruptions and creating severe safety hazards.
  • Tall zone: Once you’re in an area more than 10 metres from power lines and poles, virtually any strong, healthy tree is fine to be planted in this area.

Overheight trees in the medium zone cause the majority of outages. Falling branches and toppling trees can bring down power lines, causing power interruptions and severe safety hazards.

Use our handy guide to find the right tree

Our Planting Near Power Lines guide includes detailed information on vegetation height restrictions and identifying types of power lines along with recommendations for selecting the right plants and trees for your region.

Hedges

Hedges are not recommended directly under power lines. However, they’re acceptable if they’re the right species and if they’re planted far enough away from power lines.

It’s up to the homeowner to maintain hedges, and annual pruning is required to keep hedges healthy and vibrant.

A property referral is required to determine the maximum allowable height of hedges. Email [email protected] or call 1 800 667 1517 for more information.

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