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.
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: brightonw@FriendsofTrees.org; 503-282-8846 ext. 19