"Tu" (the Hebrew abbreviation of 15th) in the month of Shvat was set (Hillel's opinion generally overrules Shammai's) as the beginning of the tithable year for tree fruit: Calculating the tithe on fruit starts again for fruit that sets after that date.
Here is the quintessential Jewish question: How do we emulate God? We are told that we were created by God. We are told that we have a divine spark within us.
"15th of Shevat;" New Year of the Trees; Jewish Arbor Day, which is a minor festival.
Israeli Independence Day, which commemorates the establishment of the modern state of Israel in 1948.
Israeli Memorial Day on which citizens remember the soldiers who lost their lives fighting the War of Independence and other subsequent battles.