The Spiral Tree

I was driving down Penns Creek Road today when I spotted this supremely interesting tree and since I already had the subject of trees on my mind, I decided to make this guy the subject of today's Blip.
Upon pulling over for further examination, I failed to determine exactly what type of tree this is...or, for the life of me, what in the world happened to cause the trunk to grow in such a manner. 
I must say though, that in all the time I have spent roving the forests of Pennsylvania, I have never seen anything like this; so I feel quite fortunate to have even spotted this unique "spiral tree" on a bleak and dreary sepia colored day like today.

"The tree which moves some to tears of joy is in the eyes of others only a green thing that stands in the way.  Some see Nature all ridicule and deformity, and some scarce see Nature at all.  But to the eyes of the man of imagination, Nature is Imagination itself."


~ William Blake, The Letters