One of the conditions for a man leading a successful and fruitful life is to reflect on the Law of God day and night.
There is a clear instruction that the land of Israel needs to rest and lie fallow every seventh year and no planting of either crops or any new plants are allowed. (Leviticus 25).
Israel observed such a Shmita year last year, and this means that this year's Tu B'Shavat celebrations - the New Year for Trees - will be extra joyful! Tu B'Shvat starts with sunset on January 24th and much tree planting will take place during the day on January 25th!