This fascinating verse is clearly part of a discussion of the Lehites. The Lord is clearing the ground around the transplanted branches, a botanical reference to weeding out plants that would compete with the branches for nourishment and water. Historically, this reference is to a population existing in the New World prior to the arrival of the Lehites—the only explicit reference to a preexisting population of non-Lehites, even in the veiled language of the allegory. Just as Israel entered its promised land of Canaan and needed to “unencumber” its ground of the previous inhabitants, so this passage implies, did Yahweh eliminate local competition on behalf of the Lehites. Of course we have no indication of how this clearing occurred; but every other part of the allegory involving the Lehite “branch” has an identifiable historical counterpart. Therefore, there is no reason to assume that this particular reference lacks one, particularly since there is no compelling literary reason for this verse above and beyond reporting the fate of the Lehite branch.
Ironically, the promise that indigenous inhabitants would be “cleared” to make place for the Lehites comes in ancient prophecy rather than contemporary Lehite records. Zenos tells us, but Nephi does not (explicitly).
Another possible reading of this verse is that all previous peoples will have died out, a possible reference to the Jaredites. However, the Jaredites lasted until after the landing of the Lehites and therefore were not “cleared” from the land for the “planting” of that branch of the house of Israel. Similarly, however, other indigenous peoples who preceded the Nephites continued in the land. The land that was “cleared” appears to refer to the specific land given to the Nephites, not the whole of the hemisphere or even the entire Mesoamerican culture area.