Selfie.

As a tree grows the new ring for this year must be on the outside. But as it is also growing upwards all the other rings must be growing vertically too. Moreover the existing bark must be stretching each year to allow for the greater diameter.
Complicated isn't it?

So why is this a selfie. Well if you look carefully you will see why. It would be nice to think that I did that so readers could judge the size of the stump. But really it was just carelessness. And, no, that is not a new boot.