Tu BiSh'vat or the "New Year of the Trees" is Jewish Arbor Day. The holiday is observed on the fifteenth (tu) of Sh'vat. Scholars believe that Tu BiSh'vat was originally an agricultural festival, marking the emergence of spring. After the destruction of the Temple in 70 A.C.E. this holiday was a way for Jews to symbolically bind themselves to their former homeland by eating foods that could be found in Israel.
NOTE: Each holiday begins and ends at sundown on the days listed.