Tu B'Shevat, the 15th day of the Jewish month of Shevat, is a holiday also known as the New Year for Trees - Chag Ha'elanot. The word "Tu" is not really a word; it is the number 15 in Hebrew.

            Tu B'Shevat is the new year for the purpose of calculating the age of trees for tithing. See Lev. 19:23-25, which states that fruit from trees may not be eaten during the first three years; the fourth year's fruit is for G-d, and after that, you can eat the fruit. Each tree is considered to have aged one year as of Tu B'Shevat.

There are few customs or observances related to this holiday. One custom is to eat a new fruit on this day. Some people plant trees on this day. A lot of Jewish children go around collecting money for trees for Israel at this time of year. That's about all there is to it.