We use resistograph inspection services when there is a concern that a tree’s non-visible interior structure may be compromised, we use a variety of tools and knowledge to perform a tree hazard evaluation by measuring the soundness of the internal wood tissue. One such tool is the Resistograph that uses a micro drill bit to measure, and simultaneously graph out the density of the wood tissue as it penetrates the tree. Tree decay detection can be monitored since its sensitivity is such that it can monitor pick up the difference between the density of spring and summer wood tissue, otherwise known as the annual ring.