ACcording to the first Mishnah of RH, Hillel and Shammai disagree regarding the new year for trees. What are the sources for their respective opinions (15th and 1st shevat) and why do they disagree with one another?
Joel Morris, Winnipeg, Manitoba, Canada
Hello
The Gemara (14a) explains that the determining factor for the New Year of trees is the fact that the majority of the annual rainfall has been received. Tosfos (ibid.) explains that according to both Beis Shammai and Beis Hillel, the reason is that from then on, the Chanata (blossoming) is a result of the rain from the current year. Until now, any tree that blossomed was living off the rainfall of the previous year. According to Beis Shammai this begins on the first of Shevat, while according to Beis Hillel it occurs on the fifteenth.
On a simple level, one could say that this factor cannot be precisely determined each year (as the amount of rain fluctuates), thus our sages have decided on these dates based on a law of averages, hence the origin of the disagreement. [In the Kabbalah seforim, there are much deeper explanations.]
All the best.
Y. Landy