Today is Arbor Day, which is always celebrated on the last Friday in April. Although it might not be exactly accurate to refer to the observation of Arbor Day as a "celebration", it is just that for those of us who adore trees and Mother Earth and wish to keep her as healthy as possible and show her all the respect she deserves.
In the words of Julius Sterling Morton, the man who founded Arbor Day (which on the first observed Arbor Day on April 10, 1872, it's believed that one million trees were planted, by the way) “Arbor Day is not like other holidays. Each of those reposes on the past, while Arbor Day proposes for the future.”
You said it, Mr. Morton.