When studying tree rings, why is simply counting the rings not an effective method of study?

Simply counting the rings is not an effective method of study, as natural events can influence the sizes of the rings. Tree rings are supposed to give ideas on the environment's climate, as well as changes to nutrients provided. Some rings may be thinner or thicker depending on if there was a beneficial or negative impact from the environment, as well as human interaction. Instead, the user should not only count the rings, but also take note of each individual thickness, any scars, the color or the ring, and any other that can imply some sort of out-of-the-ordinary events that should have occurred.