Thursday, July 21, 2011


Janet writes: Here is another one from my Archive of Oddities, since we
seem to be straying well away from animal tracking these days. Why does
this white oak appear to be engulfing a boulder? It looks like it has
gone out of its way to grow around the rock. What could account for
this? Is it after some mineral? Found at the Ralph Hill Homestead
Reservation in Billerica.


  1. Comment on this from a forest ecologist:

    "Very interesting! When a tree encounters something it can't push out of its way it has to accommodate its growth by growing around the object. In this case there is space between the trunk and the boulder so my best guess is that the boulder was originally adjacent to the tree which started growing around it while pushing it int its current position where it could no longer move the boulder and continues to grow around it. That is my best guess."

  2. And this, from a botanist:

    "Weird photo. My thought is that the tree gradually grew into an immoveable
    object, a point of the the boulder. As it was forced to grow against it,
    callous tissue was formed in reaction to the irritation, and expanded around
    the boulder more each year. It also looks like the tree trunk has grown at
    an angle to avoid the boulder. Otherwise, some previously un-discovered
    vegetable / mineral union!"