Why trees with co-dominant trunks are an accident waiting to happen

Posted on: 27 June 2017

A mature tree with co-dominant leads or twin trunks might appear awe inspiring in the height of summer when it is in full bloom, but these trees can be deceptively weak. They do look impressive, but in this case, looks can be deceiving. While they might appear to be towering behemoths that could withstand all Mother Nature might throw at them, the truth is quite often the opposite.

If you have a tree with co-dominant trunks or leaders in your yard, you should assess the risks to you and your home before the next storm season. Here is what you should look for when evaluating your tree.

V or U-Junctions

The first thing to examine is the junction where the trunk divides into two. U-junctions are sturdier because the two trunks do not interfere with each other as they grow. V-junctions on the other hand, begin to compress each other as they grow due to their close proximity. The bark of each trunk builds up in the small space and over time, begins to act like a wedge being driven between the two trunks.

Either time or a severe storm will eventually cause one of the trunks to separate, causing catastrophic damage to the surrounding area. You should seriously consider having your tree removed by a tree removalist and replaced with a smaller, safer one if your tree has co-dominant leads.

Drought Followed by Heavy Rain Increases the Risk

Trees that have previously suffered through prolonged droughts may be structurally unsound and prone to failing in severe storms. In Southern California, during severe storms in January, trees that had suffered through six years of drought were brought down causing havoc. The drought had weakened the trees and made them susceptible to toppling in the high winds.

Since 2013, Queensland, Australia has suffered its worst ever drought. If you live in or around Queensland then, you should be especially vigilant when examining your trees. A tree with co-dominant leads may have a weakened root system as well as trunk damage, both of which may be difficult to spot. Therefore, you should consider contacting an arborist before the next storm season in November.

You don't necessarily have to have the tree removed, not if you are fond of it, but it is advisable. You could also ask your arborist about securing the co-dominant leaders with a steel cable system to provide them with more support during high winds. 


How to Care for Your Trees

Hi, my name is Sophie. Welcome to my tree care blog. I never paid much attention to trees until I was about 32 years old. I mean, I liked trees. I liked sitting under trees in the summer, but I didn't really think about the effort needed to keep them healthy. All that changed when I married a wonderful man and we purchased a big house in the countryside. The property featured a large garden which contained lots of trees. I wasn't sure how to manage them so I called in a tree service. The guys were great and gave me a real education. I decided I would like to share what I had learnt here.


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