Good catch, Namelus!
Here’s some more tips (hattip to Dalewick):
When possible use softwoods (conifers) preferably and wood that’s been down long enough to be very dry on the inside. Some tree species, like oak, hickory, ash, etc are way harder to break this way and if it’s green at all, it won’t. Sometimes it’s just easier to start your fire and then just feed your wood into it or burn from the middle for longer pieces that won’t break.