I have a few more thoughts to share, aside from falling and bucking timber, I also did extensive urban removals with a local arborist. PROFESSIONAL Arborists use a throw ball to get a line high up into a tree. Basically it is a big bean bag with shot gun shot in it. The bag is nylon or kelvar and has ring on it. The ring gets attached to very light but strong line that is a hundred or so feet long. Often it is thrown up there by hand, other times with a giant, pole mounted sling shot. It's called a Big Shot. Anyway lots of ways to get the line up in the tree, . As the bag goes over a major limb, the thrower works the line so the bag drops. The other end of the line is attached to a stronger rope, ie a Bull Line, or Climbing Line.
You pull the weighted end until the working line goes over the limb and comes down. Then you can proceed to use that line in the way you want. If it is a climbing line, you attach your apparatus, Prusik, or belt. If it is a bull line, you put a loop in it, run the other end through it, tighten up and you have your pulling line.
Jacks are sketchy in small diameter tree felling. I wouldn't use a jack under anything under two feet. yah you can do it, but larger diameter trees gie more working space for the jack AND wedges to use to back up your jack. Cutting a small wedge shaped shelf for your jack is the safe way to do it and you have room to put in your wedges to stay up with the jack in case it fails.
Some people cut the whole back side out and stick the jack in there. They presume the jack won't ever fail and put all their eggs in one basket. It aint the smart thang to do. Even with big double pumper old growth jacks, we cut two wedges out instead of involving the whole back.
A shortee bottle jack is better to use than a tall one in my experience. As the jacking process goes, you need a thick steel plate to go over the jack head. As you jack, you will notice that the angle of the plate riding on the jack head changes and "might slip" the higher you go.
It's best if you are using some doofer jack to have a circle welded on the plate that slips over the jack head. That way as the jack goes up, the head stays secure in the confines of the circle.
Having an under performing jack is risky at best. We never used anything less than twenty ton shortee Duff Norton railroad jacks until Silvey began building a line of aluminum jacks. "just my two cents" for what it's worth
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