Crop formations in trees?

For a few years I have heard rumours that 'crop formations must be caused by aliens because they have been found in trees' (in Canada I think).  Yes - apparently the appearance of a vaguely similar pattern, in trees, half way round the world makes complete sense of the patterns found in fields of wheat in southern England.

Having had a few posts about crop formations recently, I did a google search to see whether I could find pictures of this phenomenon.  So here it is.  A pattern that looks a bit like a crop formation, and it qualifies for inclusion on this blog because it certainly does look surprising.

I have no idea what the explanation for this is, but I would say the smart money is probably not on the alien hypothesis.

Source of this photo: Enormous tree-circles (like crop-circles) were discovered in the Wabikon lake forest (Wisconsin).  (I actually think it is a Photoshop job as the water in the furthest circle seems sloped.)  You can see this lake on Google maps too.  I couldn't spot any circles like this.  Can you?

Related posts:
'Out' Crop Formation
Cornucopia for Cereologists
Income from crop formations  
Where are the formations?
Japanese Rice Art