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Trimming vegetation away from power lines rarely leaves an attractive result. Unhappy property owners are often left with half-trees, Y-trees and other bizarre shapes. However, even a single tree branch in coming in contact with high voltage lines can scream and explode…

The tree trimming crew from our electric company, CenterPoint Energy, has been in the neighborhood recently. Some people see their activities as an imposition; some see it as a welcome service, but everyone appreciates having uninterrupted electricity. Safety standards being the priority and with limited time and resources, crews often can’t trim your trees with quite the finesse you might prefer. 

Obviously, the best plan is to not plant a tree or large shrub that will outgrow the designated safe space under or near power lines. CenterPoint has detailed brochures available which explain these clearance standards. Click here for CenterPoint tree guides and information. These guides include diagrams about tree placement and some lists of suggested plants and their full-growth sizes.

You can request tree trimming!

Many people are not aware that CenterPoint will come out, inspect, and trim problem trees away from power lines on your property at no cost to you. The numbers to call are 713-207-2222 or 800-332-7143. However, if the CenterPoint representative determines that the plants in question do not pose an immediate hazard, you may have to wait for the regular area-wide trimming schedule to come around to your neighborhood.

Trimming vegetation away from power lines rarely leaves an attractive result. A few somewhat standardized names for the bizarre results are Y- or V-cut, L-cut, and side-cut. Most of them fall into the Please Put It Out of Its Misery cut category.

The used-to-be-a-tree form.
The V-cut.
These two nice trees snuggled under the power lines are heading for...
The Where-is-the-other-half? form.
These are sad pictures, but it’s important to remember the lessened fire risk. According to CenterPoint, distribution lines, which are generally located on wooden poles along roadways or in easements along property lines, carry 12,470 or 34,500 volts of electricity.

Here is a video of what happens when a palm tree tangles with a high voltage line. Note the sparks and debris shooting in every direction and those high tension lines are still live. 

Trimming palm trees away from power lines is problematic, though. Palms have a single growth point so cutting off the top usually is fatal. Simply trimming back the fronds may not be satisfactory either as they can regenerate quickly and become a hazard again before a scheduled trimming cycle. Often the simplest solution is to remove the palm tree. 

CenterPoint tracks whether a service interruption is due to weather, equipment failure, or trees. The company trims 700,000 to one million trees on its distribution system every year and there are 3.5 million trees which periodically require trimming. Eighty-five percent of this vegetation management is planned, circuit-wide to maintain reliability and performance, and the remaining 15% is unplanned, local emergency maintenance. This work is routinely performed by over 100 contractor crews. To put this in perspective, after Hurricane Ike in 2008, there were 4000 tree crews brought in to pair up with an equal number of line repair crews to restore electric service.

How can wood conduct electricity?

Lightening (electricity) strikes trees because they are connected to ground. Under the right conditions, even air can be an electrical conductor. Just because trees are green and leafy, doesn't make them a safe combination with power lines. We are used to thinking of wood as an insulator, but watch and listen to what happens when this one tree branch hits these two lines.
Photo credits: Lauren Millar

Video credits: 
blazing palm: https://www.youtube.com/watch?v=vksMkoKMSHA
screaming branch: http://io9.com/this-tree-branch-hits-a-power-line-screams-and-then-e-1693511312

Sources for this post:
"Power restoration slows as crews go house to house" Houston Chronicle, September 20, 2008.
I am often asked about toxic plants and what plants are pet safe. I always flash back to my elementary school in Kemah which was surrounded by huge hedges of oleanders. We kids knew not to eat them. In fact, we knew not to eat anything unless our Moms said it was all right. We didn’t go around chewing on the shrubs. 

Flash forward to horticulture lab in graduate school and the teaching assistant warning everyone to not eat the bean pods of the Texas mountain laurel (Sophora secundiflora) because they had powerful psychotropic properties. 


Nerium oleander is a beautiful, tough, low maintenance tropical shrub. It’s originally from northern Africa, the Arabian peninsula and southern China. Oleanders have been flourishing here, especially in Galveston, Texas, The Oleander City since 1841, when they were first brought to the island from Jamaica by Joseph Osterman. Pretty, but pretty toxic. All parts of the plant are poisonous. 

What makes the oleander toxic? 

Oleanders contain cardenolide glycosides. According to the NIH, the specific poisonous ingredients are digitoxigenin, neriin, oleandrin, and oleondroside. Possible clinical effects include blurred vision, rash, nausea, vomiting, abdominal pain and as one source puts it “bowel evacuation”. Neurological effects are tremor, drowsiness and lack of muscle control. The cardiovascular symptoms of oleander poisoning are particularly dangerous. Depending on how much is ingested, the toxins in oleander will cause rapid heartbeat (tachycardia) and irregular and uncoordinated contraction of the cardiac muscle (fibrillation) leading to cardiac arrest.

Sago Palms and Stone Fruits

Oleander sap is very bitter, like rotten lemons, according to the International Oleander Society. However, you can’t count on something tasting bad to warn off children or pets. Sago palm seeds, which are the most poisonous part of the plant, are quite palatable to dogs and they have a completely different effect. Ingestion of cycasin, the toxin in the seeds, can cause bleeding and bruising due to slowed blood clotting. Within 24 to 48 hours there may be severe liver damage, probably fatal in the long term. 

Contrary to popular belief, the seeds of stone fruits such as cherries, plums, peaches and apricots do not contain cyanide as such. They do contain a cyanogenic glycoside, specifically amygdalin, which is concentrated in the kernels within the fruit pits. Digestive system enzymes will over a few hours, if these kernels are chewed or eaten, transform the cyanogenic glycoside into cyanide, which is of course, poisonous. According to the Canadian Food Inspection Agency, a lethal dose of cyanide is 0.5 to 3.0 mg per kilogram of body weight or about 13 to 15 raw peach pit kernels for an adult. Only 15% of that amount, say two, could be fatal for a child. Cyanide kills by blocking the ability of cells to use oxygen. One of the characteristic signs of cyanide poisoning is the presence of bright pink mucous membranes; abundantly oxygenated blood has no cells taking up the oxygen. Cells rapidly die resulting in cardiac arrest, coma, and death, essentially by the same mechanism as suffocation

A plant with a descriptive name

Yaupon holly (Ilex vomitoria) is native to the southeastern United States. In spite of their reputation, hollies aren't particularly poisonous. The Yaupon does contain a significant amount of caffeine and antioxidants and the leaves have been used by Native Americans for centuries to make a type of tea (black drink). They also held male-only purification rituals which involved fasting and ingesting great quantities of a much stronger version of the drink, throwing up, or who could keep from throwing up the longest. Some things never change.

The truth about poinsettias

Traditional Christmas flower poinsettias (Euphorbia pulcherrima) have a poisonous reputation, but in reality are not particularly toxic. The average person would have to eat 500 to 700 leaves or a 50 pound child would have to eat 500 leaves before any harmful effect and the leaves taste terrible. The sap, however, may cause skin irritation for those with latex allergy as latex and poinsettias share several proteins. 

Sources of information for this post: