A screwjack? Interesting, though the size trees they show being done in the photos, it seems a guy can get the same lift with wedges. Actually I wouldn't mind trying it on leggy small diameter Alders, and Firs instead of setting a tagline from the ground or putting a backcut and wedge in first.
I met this guy at the Ohio Forestry show, Nice enough tree guy the product looked like it would work great in the right situations. he had some videos where he pushed leaners back over center. One of those tools that would be nice to have in your long toolbox. We don't get that many floppers where it would be real nice - if you are clearing a bunch of bean poles, probably work real good for pushing that big ole spar over - oh but you probably left a bullrope up there b4 you came down. If your not very smart with your notching you could get in alot of trouble with it
not to cheese out but you could almost Fab up one of those Basement floor jacks to do the same thing