fruit, trees, and earth - stira in rambam from hil brachos to hil bikurim

The Mishna in Brachos (40a) writes that if one says the bracha of borei pri ha’adama on a fruit, one is yotzei and need not repeat the bracha because “ikar ilan ar’a hu”, a tree is nourished by the ground. The gemara explains that the Mishna is R’ Yehudah’s view l’shitaso: There is a dispute whether the parsha of bikurim may be recited over fruit from a tree which has since been cut down – Tanna Kamma says no, because once the tree is removed one can no longer refer to “ha’adama asher nasata li”, as adama refers to the tree itself, but R’ Yehudah says yes, because adama refers to the earth which nourishes the fruit tree. Here too in hilchos brachos, R’ Yehudah holds adamah refers to the earth which nourishes the fruit and b’dieved one is yotzei with such a bracha.

Many Achronim asks: The Rambam in hilchos brachos (ch 8) paskens like the stam mishna in that one is yotzei by reciting borei pri ha’adama on a fruit, indicating (per the gemara) that he accepts the reasoning of R’ Yehudah. Yet, the Rambam in hilchos bikkuim (ch. 4) paskens like the Tanna Kamma against R’ Yehudah, that if a tree has been chopped down the parsha of bikkurim cannot be read. Thoughts?