These trees were decked out to advertise an exhibit at the Museo de Arte Latinoamericano de Buenos Aires (commonly known as MALBA)
Yayoi Kusama : Obsesión infinita
Last summer (2012) we had seen lots of polka dots in New York to promote what I assume was a similar, or even identical exhibit at the Whitney Museum.
Frankly, neither of us was impressed and we skipped the exhibit.
Here at least, they helped us to get off the bus. Seems we always miss the MALBA stop and have to walk back a bunch of blocks.
MALBA, however. is much cheaper than the Whitney and since we had planned to visit the museum anyway, we checked out "Obsesión infinita" too.
It was much better than we expected.
http://en.wikipedia.org/wiki/Yayoi_Kusama