Arbor Day is a holiday celebrated in many countries around the world to promote tree planting and conservation. In the United States, Arbor Day is celebrated on the last Friday of APRIL. The crossword solutions for the term 'Arbor Day Month' are APRIL (5 letters), Tree (4 letters), and MAY (3 letters). APRIL is the month in which Arbor Day is celebrated in the United States, Tree is the focus of the holiday, and MAY is an alternate month in which some countries celebrate Arbor Day.