I dispute the point that the tree nodes didn't have any other details on them, https://www.openstreetmap.org/node/12135349872 had leaf_cycle=deciduous which was lost in this change.

Regardless I agree with others points here that in this case the individual trees should be retained, even if they were just natural=tree.

I agree that it's useful to map tree rows as features especially the kind in the photo at https://wiki.openstreetmap.org/wiki/Tag:natural=tree_row

I have at times combined both methods using mapping a way with natural=tree_row with the nodes along the way set at the position of each tree within the row and then applied natural=tree to those nodes. That captures both the individual trees and the "tree row". This approach is described on the wiki.

I'm not sure if these trees should be considered a tree row though.

What shouldn't be individual natural=tree nodes? a dense hedge.