[quadrifoliate]

> there is a very good English word with this exact same meaning as written in this sentence: grafting.

Grafting is joining cuttings from one tree to a rootstock of another. That is not what's going on here at all, it's limited to a single tree.

Something like "selective pollarding", maybe, but that's very far from being a common English word. And as I said, most pollarding I have seen is nowhere as straight and tall as this.

[ruszki]

Exactly. Which you cannot possibly know from the cited sentence.