We recently got a combustion fireplace  put in and just assumed that you can put any dry (dead) wood in it. In reality,  most wood needs  at least a year to dry right out and be ready to burn. Then for it to burn well and produce decent coals, it needs to be a dense type of hard wood like ironbark or the likes. I wake up to no hot coals, even when i load it up,and have to relight it every morning. I'll have to bite the bullet and buy a load of quality hard wood i think.

Yep, have to agree any sort of wood needs to be pretty dry. But having said that, wet dry wood (is that an oxymoron?) can also generate a lot of heat, I think by virtue of the steam adding oxygen to the combustion.

When it comes to coals, most smooth bark eucalypts are pretty low density with a fast burning low ash content.
A good mix is white/yellow/grey box, stringybark/messmate. These can usually be depended on to give you a coals bed for a kick start in the morning.

In my experience, ironbark and river redgum are pretty good for burning grates out!
mikel

I'm still learning the different types of wood and what burns the best.  We have the nectre n60 fireplace and its a beauty. I've since learned that i certainly needed better quality wood to get the most out of it. Money well spent.