Mountain Jews יהודי ההרים and Bircat Shehecheyanu on a New Harvest

At times, a good way to find the customs of Jews 2000 years ago is to compare it with the customs of old isolated Jewish Communities in the world. One such community if that of the Mountain Jews which have been living in their remote towns since at least the 5th century. In 1884 in St Petersburg, יוסף יהודה הלוי טשארני Yosef Yehuda Charney published his book of travels and correspondence with the Mountain Jews. The natives, describe their customs and beliefs and one such custom which I had not seen elsewhere was that of making the Blessing Shehecheyanu on the new harvest.

There seems to be no source for such a custom, other than the blessing that was made in Eretz Yisrael on the harvest while separating the Ma'asrot. Perhaps the Jews who emigrated from Eretz Yisrael towards the Caucasus kept the custom of making Shehecheyanu not realizing the reason no longer applied.
There is much discussion in the Poksim today if to make a Blessing of Shehecheyanu when tithing today. The story goes, that when the Imrei Emes visited Israel, he met with Rav Kook and mentioned that he will be making the Mitzvah of separating the Ma'asrot for the first time, if so Rav Kook said, you can make Shehecheyanu as well. After a heated debate in which the Imrei Emes siding with the opinion of those who do not make Shehecheyanu, he got up and said, if the Rabbi of Jerusalem, was Posek that you do make a Beracha, I accept his authority and did indeed make Shehecheyanu.

Another possibility might be that the blessing they made was an extension of the Shehecheyanu made on purchasing a new home, clothing etc which they extended to be any happy occasion. There seems to be a consensus though with the Poskim that on eating a new vegetable or other non-fruit that Shehecheyanu does not apply (BaCH OH 235).