Brace rods for codominant stems: installation location and breaking strength

This study was conducted to determine the strength of codominant stems with two rod locations and compare them with the strength of codominant stems without brace rods. [UMN] 

"The location at which brace rods should be installed to reduce the risk of breakage in codominant stems traditionally has been below the crotch. In this study, codominant stems were pulled apart with measured force to determine if crotch strength was increased by installing a rod above the crotch rather than in the traditional rod location below the junction. With both red oak (Quercus rubra) and red maple (Acer rubrum), the strength of the codominant stem was increased significantly by installing the rod above the crotch a distance equal to the diameter of one of the stems. Brass rods tended to fail more than steel rods in oak but may be useful in small, weakerwooded trees." [Abstract]