For centuries that monarch has been slowly growing taller and more massive. It appears likely to continue there long after we are dead and gone. We wonder what occurred during those centuries. The outward appearance of an old tree may indicate what happened to it during recent years but seldom more than that. If it is cut down with a saw, those rings can be counted and compared.
All trees are truthful but some kinds tell their stories more plainly than others.
That is true of most cottonwoods. Oaks, hickories, walnuts and sugar maples leave complete records but, because those are slow-growing trees, they are rather difficult to read and interpret. Pines are the best. In 1947 a big white oak in one of the preserves was removed because it was dead and a public hazard. It had 430 annual rings.