There are at least two points regarding the fundamental mechanism at work in the treeing process. The first viewpoint proposes that tree initiation is a phenomenon in which the mechanical strength of the insulation system is exceeded by an electrical stress induced by the presence of a highly divergent electrical field (see Eq.1, Appendix A). Young's has been rated in an electromechanical relationship, and breakdown field strengths have been calculated (see Eq.2, Appendix A).5