When I was a young and dumb teenager and didn't know any better I used green hickory for flavor in an ECB. That's what my father advised me to do in a tone that sounded like he had used it before. My father was an ole timer who was raised on a farm, so I expected he had seen some smoke houses in action and didn't argue. I'd go out on the wooded lot next door and cut down a *small* hickory sapling or a branch off a tree and cut it into lengths that would fit in the ECB. Of course these small sticks went on top of a bed of charcoal. The fresh green wood wouldn't burn for a very long time and the aroma was great. This is the ultimate version of what folks try to accomplish by soaking wood.
If I cut too much wood and tried to use it again later it just didn't work as well-as in smell as good or impart as good a flavor. IMO, it's wood that's in between absolute fresh green and not seasoned yet that's the real trick to cook with. My experience with small amounts of cut today and cooked with today hickory was totally positive but when I've tried to burn a normal sized split of less than fully seasoned wood is where I've always had problems.