i pretty much use charcoal for most of my forging. wood, would keep a cooler fire until the impurities burn off leaving sufficient char to attain its greater heats.
i like it as there is only the ash to put through the garden, or make lye, and some(less than coke) gum/impurities, as lumps of clinker.
while the byproducts of timber give flame, for wheatever you want it for, wood gas for powering whatever engines also, and the miriad of other bits and uses, charcoal wood be my pick for forging. (my analogy would be, forging with timber is like trying to run a petrol car on crude oil. better to distill it.)
raw, or undistilled timber for forging, while you get plenty of flame, if air assisted, and at the face layers of the fire some considerable heat (depending on the air, shape of the fire, and type of timber. however ive usualy only managed a red to dull orange heat in steel from air assisted, undistilled timber.
The coals from a fire, transfered to a forge, or dowsed and used later for forging, gives you the, "metal flowing down the drain as you take too long to role your smoke"...effect.