JOURNAL ENTRY FOUR: Time for a Little Math

The great conservationist, Aldo Leopold, in his Sand County Almanac once wrote of trees as a time capsule of sorts — noting how these elder statesmen of the woods have the power to remind us of our history as we imagine working our way across their rings from the outside to the core.

With this in mind, I found myself today standing before one of the true giants of these parts, its importance apparent by the many life forms that live on its branches and trunk. If Leopold was right, then there must be amazing stories held within this oak tree. Perhaps if I could calculate its age, I could better appreciate all this tree has seen, survived and provided.

Alas, I find myself without a measuring device. But if my memory serves, a person's arm span is roughly the same as their height. Looks like it's time to give this tree a few hugs.

SOLVE THIS GEOADVENTURE MYSTERY:

What is the approximate age of the tree?

(clue: Triple digits)