Why a “Y” is Not Good in a Tree

Trees have an amazing ability to keep themselves upright for years, sometimes hundreds of years.

However, a structural flaw called co-dominant stems can cause a tree to prematurely fail.  Co-dominant stems can create a high risk in urban areas where failure can be catastrophic.

This is a Hackberry with a typical co-dominant stem that has failed with the split going all the way to the ground. The tree is amazingly still standing, but it is a matter of time before one or both of the stems break and fall. If this were near a house or where people are frequently present, the results could be devastating.

This problem can be corrected with what is called “Bracing” in the ANSI A300 Standards for Tree Care.  This is simply installing bracing rods through both stems, tying them together.  The rods are normally 3/4 galvanized threaded rod.  They are placed in holes drilled through both stems and are secured on each end with over-sized washers and galvanized nuts.  The tree is not harmed by the drilling and eventually grows over the nuts and washers and hides them. 

This procedure secures the joint, even if it has already split.  Trees that are a high risk for failure can be saved and continue to provide shade and beauty to an urban property.

Tree Shepherds provides this service.  Please call us at 972-317-9598 for an assessment and estimate if you have a tree that has co-dominant stems or limbs.

Scott Geer

Scott Geer

Scott Geer has a master's degree in forestry from Stephen F. Austin State University and is an ISA Board Certified Master Arborist.® He is also a graduate of the American Society of Consulting Arborists Academy.