Split Down The Middle

February 12, 2010
in Category: All About Trees
2 6299 2

Take a look at this Cedar tree! It unfortunately had to be removed due to the deteriorating condition and potential damage to adjacent structures if it fell.

Cedar Tree: Co-Dominate Trunk Split

With our love of trees, this situation poses a excellent opportunity to discuss how the situation occurred and what could have prevented it.

For this tree specifically, it received 360 degrees of sunlight; thus, allowing the tree to grow full foliage and branches out around the entire tree. This created an issue with excess weight being placed on the outer edges of the tree. Now, for most trees, this would seem normal and healthy as it would provide a full balance of foliage. On that same note, healthy trees have a strong structural system with a full trunk to support the weight of the canopy.

The Cedar tree actually had a co-dominate trunk where during a point of its maturation, the trunk split into two leaders; the junction created from this is called the “crotch”. With a co-dominate trunk, neither is supporting the other and thus a weak spot exists at the crotch. Couple this with the excess weight placed on each of the smaller leaders and overtime, the tree’s structure will fail causing it to split.

Prevention is an important factor to consider here. There are steps to be taken to prevent this type of tree failure and a Certified Arborist is trained in the techniques necessary to assist in supporting the tree. The method depends on the age of the tree as well. A juvenille tree can be trained to develop a stronger trunk and can most likely withstand the stress of removing one of the leaders.

A mature tree, such as this Cedar, is much more susceptible to the stress created from removing a large leader. Though it may seem like an obvious choice to remove one of the leaders, this alone can cause it’s own structural damage and could eventually kill the tree.

The technique used for mature trees with a co-dominate trunk is to maintain the weight of the canopy through a pruning process called Thinning. This allows for selective removal of branches to promote an overall healthy shape and weight distribution. Additionally support can be added with a Cabling system at the crotch to alleviate some of the weight placed on the joint.

Healthy Trees = Safe Trees

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  1. marygail rosenstein

    would this condition, co dominate tree trunk, have the same effect on all trees , and require the same type of treatment and perveative measures no matter the tree classification? maple, oak, birch, ect.

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