This is a good example of the range of equipment I have seen:

https://www.mainecustomwoodlands.com/maine-custom-woodlands-...

Only thing non-tracked that goes off the gravel logging roads would be the Skidder (it literally drags bunches, or 'hitches' of trees to the transport vehicles). And even that might be partially or fully-tracked.

The feller, slasher, excavator, bulldozer, etc. are all tracked from what I've seen.

Mandatory? Doubtful. But they are most practical in the rough terrain.