If the Ibur will affect the time of Hafrasha, then each year on Tu B'shvat there could be no way of knowing whether the year will become M'ubares unless announced before that date. Otherwise one would be in a quandry as to when the to be Mafrish?
Mendel Balsam, Monsey, New York
Good point! Usually the length of the year was announced well before Shevat, such as Tishrei.
If not, most trees would probably not present such a problem, since the only ones affected by the Safek would be those whose Chanatah was after 15 Shevat and before 15 Adar, and I presume that such fruit did not normally ripen before the end of Adar (by which time it was known for sure how long the year would be). The main quandary, then, would be for those picking Esrogim between those two dates (since they follow Lekitah, and they are picked after they are already ripe, yet their year starts at 15 Shevat, like the Gemara said earlier). Perhaps the Rabanan would rule that such trees certainly follow "Rov Shanim," if the leap year has not yet been announced.