As for hard wood, here is some of my experience:
Hickory is easy to work with, it cuts nicely and splits very easily. It is also usually twist free. Hickory is very hard though, and that wears you down and your blade edges as well, and since it is so hard any sharp angle can cut into your skin very easily. I wear tough goatskin gloves when working with it. The juggles come off very easily if you pop them off from the end.
Ash is pain in the neck. While it often grows straight and has good long lengths on it most of the time, for some reason it just does not like to be hewn. I don't understand this really, it is fairly easy to cut with hand tools, and ash firewood splits very straight and easily. So why does it hew so hard? Ash would not be my first choice, definitely.
Hackberry is another wood I have some experience with. It is actually not as bad as you might expect it to be if you have ever worked with it otherwise. For firewood, hackberry is a pain to split. It is so stringy that it is about impossible to split a good sized chunk in one blow. However it cuts very easily, and if you split of your juggles from above instead of popping them off from the end it is definitely manageable, especially if you split off the juggles a little at a time instead of trying to remove all that wood all at once. This works because if the wood has less resistance toward the splitting side, it will bed out easier, and so require less efort to pull or cut through the grain. The question is does hackberry have enough strength to work for framing timbers?
Cherry is another surprise. Cherry never grows straight (as in not twisted), and if you want to split it don't expect to get a good split off of it, it just doesn't happen. For firewood it splits easily, but in long leangths you quickly see that it does not split straight. Cherry is one of those woods that the old timers avoided because it doesn't split (they avoided it for things like fence posts and riven lumber) As with hackberry, cutting off the juggles from above rather than popping at them from the end is the best approach. If you do this, the twisting of the wood essentially becomes a non-issue. Now cherry is a wonderful wood, it is stunningly beautiful, very strong and durable, and very rot resistant. My experience with cherry comes from hewing out timbers from a long dead tree. The tree had been dead and on the ground for maybe 20 years, yet it had yet to rot beyond the sapwood at all, other than a little tiny bit along the occasional bug hole. That should tell you a little bit about the durability of Indiana black cherry wood.
Now if should explain something in case you didn't catch on. I mentioned 2 different ways to remove the juggles, and so I should talk a little bit about my hewing techniques so you understand what I am talking about.
I always put the log up on high stands, at about waist high. And I always keep in mind to take good, confident strokes with my axes. good confident strokes are less likely in my opinion to come back and hurt me. it's the timed, sloppy strokes that don't dig in to the wood and deflect out with the potential to damage my shin or knee. I don't always score, if the tree is relatively close to the size of the finished timber than it isn't always worth the effort, especially on certain species (ash, for example. I find it is easier to cut ash than to split out pieces of it) If I do score, I do it in 1 of 2 ways. 1: I stand atop the log and swing the axe, using its own weight and perhaps some of my own body weight by bending my knees to make the cut, which is made at a fairly shallow angle (because it will penetrate better at a shallow angle). 2: Me and a partner stand facing the log, taking turns chopping at a specific spot. We work on opposite sides of the notch. Smaller, arrow-bited axes work the best for this. This way is a lot of fun, but requires that 2 people be present. It is faster than scoring from above as well, and probably more precise as well.
Now the question of removing the juggles. For me, this depends mostly on the specific log I am hewing, and maybe a bit on my mood at that moment. For some species, such as those that do not grow very straight (like cherry or perhaps sycamore)or stringy wood (like elms or hackberry) I find it best to work at the juggles from above. I sit straddling the log (I place the logs at the height that allows me to sit on the log with my feet still touching the ground) and chop down at the juggle, splitting it off. This doesn't yield nice big chunks, but it works. a short handled axe works the best for this in my experience.
Now if the wood is straight and splittable, I do it the common way. I stand on top and swing (or rather let the axe fall) at the ends of the juggles, popping them off (hopefully) in 1 to 3 swings.
With both methods, after the bulk of the juggles have been split off, I take my axe and clen off most of the rest of the juggles, my aim here it to bring the face down to about 1/4 inch from the line. It's only then that I bring out the broadaxe, which I think leaves a better finish when it has less wood to cut off and so can be swung in long, sweeping strokes.
Splitting the juggles from the end can be quick and easy, however it requires that the wood cooperate with you. Hard to split or twisted wood just seems to fight against you if you try to split it off from the end.
Cutting of the juggles from the top (it is just about as much cutting through the grain as it is splitting it) in theory should be slower, but if splitting off the juggles requires you to fight against the wood anyway or else place your scores excessively close then this method really does work a lot better. And on some species it's the only way that works at all (and there's not always a logical explanation for this, in my experience. You just have to learn the temperament of different kinds of wood I guess) The Germans seem to always split the juggles from the top, Americans for some reason decided to always do it from the ends. I think it has mostly to do with the kinds of wood they were working with. The colonists learned how to hew with immaculate white oak. If that's what you have then of course you will split from the ends, it's so easy to do! But when they began to move to other wood, either because they moved further west or because they had cut down the old growth oaks, they were used to splitting from the end, and so that's the way we still do it today. Personally, I developed my style by studying techniques from around the world. It's because of the Germans that I split some wood from the top rather than from the ends, and stand beside the log with a partner to score the faces. It's also because of the Germans that I sit on the log while hewing. It's because of the Japanese that I sometimes don't even score at all. It's because of the Americans that I sometimes pop off the juggles from the end, and stand on top of the log to score when working by myself.
