Winter's coming: got to keep those poor trees warm! (Note the use of warm colors.)
I vote them neither guerrilla art nor crime against nature: instead, pure Whimsy.
[If tree socks are a crime against nature, what do you call the ones on the lampposts -- a crime against technology? Luddism?]
It's art in my book both in itself and as a device to draw attention to the trees, any "but is it art?" question is a good question.
I have one for you Adrienne and this asks the same question but is also inspiring because of its innovation
Here is a link that might be useful: levitation
You're right, mto. Definitely whimsical. I could actually envision a new kind of cottage industry dressing celebration trees for births, weddings, holidays, Robbie Burns Day... And those photos are quite dream-like, ink. Do you suppose that was the original inspiration?
I think just about anything done creatively, skillfully, provocatively is an art. Whether or not it is appreciated is another matter - not a problem on this forum populated by lateral thinkers with a vocabulary expansive enough to include "Luddism" and "wabi sabi" :)
If a toaster can have a cozy than why not a tree ?
I'm a practical person - my first thought was 'how did they pull them on?' :-) I assume velcro or a zipper... They're definitely whimsical - you could color-coordinate them with something significant in the landscape. It brought to mind the Blue Stick Garden for some reason.
Ink - I loved those 'today's levitation' photos!
Here is a link that might be useful: Blue Stick Garden