We’ve all seen it: a tree dreadfully mutilated by the unequal pruning carried out by the local electrical utility company. And you can’t really blame them: when there are medium or high tension wires running above ground, they have to keep all vegetation at a safe distance (usually 10 feet/6 m) and they have no time to beautifully shape the trees they run into. If all the branches on the right side of the tree have to go, that’s what they’ll remove, no matter how ugly the result. For the homeowner with such a tree on their property, the only way to remedy the situation is to entirely remove the offending tree.
While dealing with an existing situation offers no easy solution (eyesore or tree removal: take your pick!), preventing the problem to begin with is a no-brainer: simply avoid planting trees or tall conifers near power lines!
The simplest solution is to plant shrubs instead of trees. By most definitions, shrubs don’t exceed 10 feet (6 m) in height and can therefore grow directly under the power or telephone line without causing problems.
However, every yard needs at least one real tree (and preferably several). Even “small trees” will likely be over 10 feet (6 m) in height at maturity while shade trees will almost all be as high if not higher than the power lines. So, before you plant, plan. And take your choice of tree’s future dimensions into consideration in your planning.
Most people immediately understand they can’t plant a tall tree under a power line, but never seem to consider how wide the tree will become over time. Yet most trees these days are sold with the eventual dimensions clearly printed on the label. Do the math, people: a tree should be planted so that none of its parts will be less than 10 feet (3 m) from a power line at maturity. So take the tree’s eventual width, divide by two (because the trunk will be at the middle point of the tree) and add 10 feet (3 m). That should keep the utility company pruners forever out of your life.
People with small yards may find it impossible to find room for some of the classic shade trees (Norway maple, red oak, silver maple, etc.) when there is a power line nearby. After all, many big trees will need to be planted 45 feet (13 m) from the power lines and your yard may be scarcely that wide! However, you may well be able to grow a tall tree if it has a columnar habit. Think upright English oak (Quercus robur ‘Fastigiata’, ‘Tower’ poplar (Populus x canescens ‘Tower’), or columnar sugar maple (Acer saccharum ‘Newton Sentry’). These can be planted less than 25 feet (7.5 m) from the lines.
Here is a useful tool to help you choose trees according to the minimal distance they need to be planted from a power line: http://arbres.hydroquebec.com/en/index.php?vedette. It was designed for hardiness zones 1 to 5 and takes into account the trees’ mature size in those zones. It will probably not work in warmer climates where trees grow taller and wider than in the North, nor does it include trees of interest for gardeners in warm temperate or tropical zones (not a single palm tree was included, for example!). In warmer climes, I suggest you contact your local electric utility for their suggestions.