I think the explanation might be a whole lot simpler ...
I suspect that this is the topmost section of a wind-snapped birch tree that hasn't touched down because it has just become entangled and supported by a neighbouring tree (or it may even be the top part of the tree that's now supporting it).
If the birch had been in leaf then a significant gale could have carried it several feet sideways ... the remaining trunk, the top of which would have been somewhat higher than the base of this remnant, will no doubt be nearby, although it may too have toppled and be now hidden by the undergrowth.
