One such item is the Axe, which you may have already obtained in Chapter 2.
Now, in chapter 5, you'll obtain the Pickaxe. It's an item that replaces the HM Rocksmash.
Works similar to the Axe, except you may or may not have noticed the coloured bar underneath the rock picture. This is a new mechanic im adding to both the axe and pickaxe.
The red icon will move on the bar and you must press enter to make it stop. Depending on the colour it stops at the faster you'll break the rock. Hitting on green will smash the rock(or chop the tree) instantly, while yellow will require 3 hits and grey, 7 hits.
But it also serves a secondary purpose. If you land on the yellow or green sections, you'll get items. (sawdust for the axe, pebble or iron ore for the pickaxe). These items can be refined into more useful items or sometimes required in sidequests.
These items can be used in some sidequests or refined into more useful items. In any case, this adds a little bit more depth to a fairly mundane thing.