It bears noting that the best way to know the age of any tree is to count its annual growth rings. If a tree has been cut down this task is relatively easy. On living trees a core sample can be taken using a tool called an increment borer, and the rings can be counted in the wood collected in the sample. This is not so easy to do and involves drilling a hole into the living tree. A good starting point is to look at a certifiably old tree and study its characteristics.

Perhaps the most compelling physical feature of old trees is irregularity. Old trees are often crooked, bent, twisted, lumpy, asymmetrical and missing parts. These characteristics are the results of struggles with an unending variety of challenges faced by the individual tree over the course of a long lifetime.

Without the benefit of enormous size to indicate great age, most people would not necessarily recognize an old tree. It is another matter altogether to believe a tree no taller than yourself, with a trunk diameter no greater than the size of your leg, might be several hundred years old or more. Yet these trees do exist. Their size may not announce their age, but close observation of their appearance can reveal them.