Rosh Hashonoh for the trees. The expression initially refers to the reckoning of years in relation to the laws pertaining to terumos and ma'asros for trees.
However, over the years the day has become a yom tov of sorts in connection to fruits, and in particular the fruits of Eretz Yisroel.
Featured here are several minhagim and anecdotes of various gedolim on Tu BeShevat and its fruits.
The Divrei Chaim of Zanz zt"l also used to have a great seudah in honor of the day, and he said that from that day until Shavuos there is a yom tov every fifteen days.
HaRav Reb Yochonon (Yochantche) of Rachmastrivke zt"l, son of the Tchernobyler Maggid, would make sure to have plenty of fruits of Eretz Yisroel on his table. Aside from this he was makpid all year round to drink wines of Eretz Yisroel.
His minhag not withstanding, he was extremely careful not to talk in a denigrating way about the Holy Land or its fruits. Once he was at his brother's, HaRav Reb Yitzchok of Square zt"l. He was served wine that had been produced in Eretz Yisroel, in accordance with his well known minhag. However, R' Yochonon refused to drink it, saying, "I'm not a connoisseur in wine. Perhaps I won't like the taste of this particular wine and I'll choliloh say something bad about Eretz Yisroel or its products."
In a similar vein, HaRav Reb Aaron of Belz too, was very particular. Once a godol from America came for a visit to the Belzer Rov. He was served small apples and, after biting into one, the godol commented, "A small, sour apple."
Quickly, the Belzer Rov zt"l corrected him, "Groise, roite un zisse," and repeated a number of times, "Big, red, sweet apples," so as not to have heard an insult to Eretz Yisroel's fruits.
Reb Dovid Biderman zt"l of Lelov said that Chamishoh Ossor BeShevat is a yom tov with segulos for yeshuos and, "just as a tree is blessed with its fruits, so too is a person blessed with his fruits," i.e. children.
During the First World War, Reb Dovid sat at his Chamishoh Ossor BeShevat tisch. The table was piled high with fruits, but no one came. The danger was twofold. Aside from the fear of the war itself, a deathly disease was spreading and had already claimed the lives of many.
All at once the door opened and a small boy entered, crying to the Rebbe. He was a son of one of the chassidim and between his tears he related how his father and all his family had caught this sickness and their lives were all in danger.
His eyes filling with tears, Reb Dovid cried out, "Ribono Shel Olom, my yom tov joy for Eretz Yisroel has been cut short. Please say `enough' to our tzoros."
Then, composing himself, he turned to the small boy. He took a fruit from the pile on the table and handed it to him. Then, patting him on the shoulder he said reassuringly, "Take home one of the fruits of Chamishoh Ossor BeShevat, and I'm sure that in the zchus of peiros Eretz Yisroel, your father will yet merit to see fruits from you too."
Subsequently, the whole family recovered and returned to their former health.
The story is told of a chossid who blindly copied exactly what his Rebbe did. Once he saw his Rebbe eating an apple at a certain hour. Came that time on the clock again and the chossid made sure to eat an apple. The Rebbe, who had heard of his chossid's custom, called him and asked him, "Why did you eat an apple?"
"I am following the Rebbe's practice," the chossid replied.
"You have it wrong, though," the Rebbe admonished him. "I want to make a brochoh, so I take an apple to eat. Whereas you want to eat an apple, so you take one and say a brochoh. So you haven't really copied me."
Reb Moshe Leib of Sassov zt"l was always very particular to bake his matzos only from flour that he received from his Rebbe, Reb Shmelke of Nicholsburg, who made sure to have shemurah flour from Eretz Yisroel.
After much effort and money spent on this project one year, Reb Moshe Leib finally set off from Nicholsburg for home, the precious sack of flour in his hands.
On the way to Sassov, he passed through a village where the sound of crying could be heard coming from one of the houses.
Reb Moshe Leib looked for the source of the crying and found a family of small children in tears.
"Our parents had to travel to another town, leaving us alone."
"And why are you crying now?" asked R' Moshe Leib.
"There's nothing left to eat and we're hungry already since yesterday."
Reb Moshe Leib made a quick calculation. It is written "ushmartem es hamatzos." Why do I want davka the flour of Eretz Yisroel of my Rebbe? In fulfillment of this mitzvoh. Well, the gemora says, "Don't call it `matzos' but `mitzvos' — a mitzvoh that comes your way don't let it `rise' and jump out of reach (tachmitzenoh). Such a great mitzvah has come my way now, I will carry it out immediately!"
Having finished his calculations, Reb Moshe Leib set down his precious sack of flour. He then proceeded to use its contents to bake bread for the hungry, abandoned children, and gave them to eat. Singing as he gave them to eat he rejoiced in the knowledge that his precious flour was being used for a great mitzvoh.
HaRav Rabbi Yisroel of Ruzhin zt"l used to dress in Shabbos clothes on the fifteenth of Shevat. As on a festive occasion, he would lead a tisch with fruits of Eretz Yisroel. He would repeatedly tell the chassidim to eat of the fruits, quoting the Arizal who said "The fruits of Eretz Yisroel are a segulah for yiras Shomayim."
His grandson, HaRav Rabbi Yisroel of Tchortkov zt"l explained the connection between the fifteenth of Shevat and the future final Geulah.
Yisroel, the Jewish nation, is compared to a tree. As the winter days continue, the tree stands cold and bare, stripped of its green summer beauty. The strong winds blow its unprotected branches, threatening to uproot the tree. The situation seems hopeless, without chance for a future. Yet, just at this time in the depths of the winter, the tree begins to absorb the fresh sap rising from the ground. Somewhere, hidden from the human eye, the life of this tree has begun anew, its results to be seen as the months turn from winter to spring.
So too is the Jewish nation. Thrust into the biting cold of the golus, stripped of our pride, our situation seems bleak and hopeless. However, it is here in the depths of the tzoros, that the light of Moshiach has been sown. Somewhere, undetected by the human eye, it has started to gather sap and soon, iy"H, it will burst forth bimheiroh beyomeinu.