Tu B'shvat

Why is Tu B’Shvat in the winter?
In the short dark and cold days of the winter we celebrate four holidays: Chanukah, 10th of Tevet, Tu B’Shvat and Purim.
Chanukah is when גלות and גאולה were mixed together and although the Makabim had won the war, it was one of the last steps before the beginning of the long גלות.
Asara B’Tevet is the day we fast for the beginning of the גלות - the day when Jerusalem was surrounded. It is not only by chance that this fast comes one week after Chanukah so that we put the Makabim’s winnings into perspective.
Then we go in to the coldest and darkest days of the year thinking about how the nation is having a difficult time during the long גלות.along come Ester and Mordechai to remind us that even in the darkest and most difficult days הקב”ה is looking after us and is in control over the world even if his name isn’t mentioned. (Since הקב”ה’s name does not appear in the Megilah.)
In the middle of this waiting for the גאולה to come in the natural way, we celebrate Tu B’Shvat, the New Year for the trees. The prophet Amos promises us that in the days of the גאולה we will all be planted back in Israel like trees. – “And I’ll plant them upon their land, and they shall no more be plucked up out of their land..”. Therefore while celebrating the tree’s birthday we should remember that we are also celebrating that הקב”ה is going to plant us back in Israel and we are reminding him that we still want to come back by planting our trees in Israel and by eating fruit that grew in Israel. All these mitzvoth are to show ourselves, and הקב”ה , that we are connected to the land of Israel like the trees that we are celebrating for.
The Gmara based on the words of the prophet Yechezkel tells us that when we see the land of Israel growing trees and giving fruit we know that the Jews from all over the world are close to coming home “But ye, O mountains of Israel, ye shall shoot forth your branches, and yield your fruit to my people Israel; for they are at hand to come”.
From this we learn that by celebrating Tu B’Shvat during the dark days of winter and of גלות we are doing the first step in reminding הקב”ה that it is time for גאולה. Just like in the עמידה immediately after the ברכה for the land and nature we have the ברכה for the returning of Am Israel to their land, illustrating the Gmara’s explanation based on the same words from Yechezkel, after the trees we will see the nation back in the land of Israel.
The reason this happens in the darkness is because Tu B’Shvat is only the small beginning of the process. If we celebrate correctly and continue by understanding on Purim that during the גלות we were supported by הקב”ה , then we should be able to get to Pesach which is the beginning of the warm summer and feel the warm גאולה.