Here are sources for a shiur on the cusoms of Tu Bishvat and their sources:
– Why do some people not say tahanun on Tu Bishvat?
– Why do some people eat fruits on Tu Bishvat?
– Why do some people have a Tu Bishvat seder?
– Why do some people plant trees on Tu Bishvat?
Sources of Tu Bishvat minhagim
al capone bemidbar biodiversity Bnei Beteira Burning of the Talmud Chesed death ecology emily dickinson emor Evolution fats waller Hillel King David Limmud Malchut mashiach messiah Noah's Ark parsha Parshat Chukat Parshat Noach Pirkei Avot Rabbi Eliezer Rabbi Yehuda HaNasi rosh hashana sacrifices science Science and Judaism unetane tokef yom kippur yosef and his borthers