When digging a place like Vindolanda there is never any certainty about what you will find. So early results always lead to evolving theories. By which I mean logical sounding explanations that quickly get disproven.
Here for instance is a series of images of the same spot.
Here is a view that gives the perspective a little better:
A few years back (2006 and 7) some really monumental bits of wood came up at the far west of the site. Here is a rather youthful looking Justin posing with a gigantic post. Evidently it once supported part of a very large building of unknown purpose:
But getting back to our misplaced tree. Here is a photo from mid season:
I wonder a bit about the solitary tree/shrub. Extensive excavations of the area do not seem to show anything like it. It stood outside the fort proper, and even after the ditches were filled in it would have been standard military practice to keep brush cut to allow clear views. I mean, there could be a hostile Pict hiding behind that bush!
Was this just an isolated lapse? Even the efficient Romans must have slipped up once in a while. Or did this have some purpose, one irretrievably lost to history. A Sacred Yew being started by the local Druid priest? Or maybe just the favored curb side spot for the hunting dogs of the Commander to stop and lift a leg on their way off to the countryside?