Right 斤 - the indexing axe-radical. Compound ideograph: tree being struck by axe = freshly cut firewood. The original meaning of 新 was 'just-cut wood, fresh-cut,' which generalised to 'new, fresh, recent.' Same axe-radical anchors 断 (sever), 斯 (this), 斧 (axe).
Left 亲 - historically the phonetic 辛 over 木 (tree), giving the sound xīn exactly. The graph 亲 visible today is itself simplified from 親, but here it represents the ancient 'standing tree about to be cut.' Sets up the image of a freshly-felled tree.
