As Bill G alluded to... we used to use a bow saw to buck logs on the landing, was much easier on back and knees than using standard saw when doing it all day long. We used that spike at end to find the dirt before the chain did when you started cutting, and as kindof a lever to "pry" the bow into the log. Added benefit as I recall... on a landing with several skidders working, when you were hunched down bucking a big log with regular saw, you were not as visible to skidders, they didn't see you right away, and you couldn't't see them until they were right on top of you. When using that bow saw, you never knelt down far, and could watch and see the skidder coming from way back, and they could better see you.
Yes... severe kickback... one of our guys was limbing with one, and was reaching up high with it (I know...stupid) and it kicked back into his face. The bow hit his hard hat right in front of his forhead, sawed a big gash in the plastic before the teeth grabbed it and pulled the hard hat off. He got away with some stiches on nose and cheek and was back to work the next day, shaken but alive. Had he not been wearing headgear, I think he would have died that day in the woods, seeing what the saw did to the hard hat. Dangerous business. No room for stupid mistakes.
Dave