I am going to post a few pics, you guys that do this "swinging the tree" thing are welcome to tell me if I have this right. This is going to be a bit long, but what the heck? That seems to be my specialty. I will also probably have to edit this a few times to get it all right.
Let us assume that there is a tall tree with a slight lean to the east. We all agree (I think) that a deep face cut could be made that would be less than perpendicular to the lean that would cause the tree to lean in a different direction. For simplicity purposes, I am assuming that there is no back cut, that the wood is flexible enough to allow the face cut to close without breaking. This cut requires that the face closes holding the tree in just the right position, yet has enough holding wood to prevent total collapse of the tree. Picture as shown:
Let us remember that the lean of the tree is now a bit greater than it was before, but we have used gravity to change it's direction to the south east.
Now, either above or below the original cut, we will cut an additional deep face cut. Although it will be installed using the full diameter of the tree, it will only be held securely by the remaining holding wood, and it will be only partially held by the wood fibers that have been undercut in the first face cut. Again, we will be increasing the angle of the lean, using the force of gravity and the strength of our holding wood to change the lean somewhat to the southwest. At this point, the tree has not ever "risen" against gravity, but the lean has increased while it rotated around the vertical axis. The amount of true holding wood has decreased with each cut.
Repeat the process on the third cut, making a face cut that uses gravity to increase the lean while it changes the direction of lean. After the 3rd cut, the tree could be theoretically facing almost opposite the original lean; all by making face cuts a bit less than perpendicular to the existing lean that collectively rotate the tree aound to the SW, having once been leaning East.
At this point, a quick nip into the remaining holding wood and the tree will fall opposite the original lean.
Obviously, this theoretical tree now leaning to the SW is being held by a tiny amount of uncut holding wood, the face cuts would need to be made by an exceptionally skilled faller that could choose the necessary angles very precisely, and each cut would be chopping useable lumber off the end of the log. I'm not so sure how effectively this could be done in the real world, but it is theoretically possible.
Since I have NEVER tried to do this, how 'bout you lumber harvesters tell me if this is about what you have been describing with respect to "swinging a tree" with multiple cuts. Obviously, I have not made any mention of dutchmen, and my drawings almost certainly are not scaled properly to allow a face cut (of unspecified width) to close. Back cuts (that would allow the face cut to close) have not been drawn, mostly because I am not that good at making these drawings.
Let us assume that there is a tall tree with a slight lean to the east. We all agree (I think) that a deep face cut could be made that would be less than perpendicular to the lean that would cause the tree to lean in a different direction. For simplicity purposes, I am assuming that there is no back cut, that the wood is flexible enough to allow the face cut to close without breaking. This cut requires that the face closes holding the tree in just the right position, yet has enough holding wood to prevent total collapse of the tree. Picture as shown:
Let us remember that the lean of the tree is now a bit greater than it was before, but we have used gravity to change it's direction to the south east.
Now, either above or below the original cut, we will cut an additional deep face cut. Although it will be installed using the full diameter of the tree, it will only be held securely by the remaining holding wood, and it will be only partially held by the wood fibers that have been undercut in the first face cut. Again, we will be increasing the angle of the lean, using the force of gravity and the strength of our holding wood to change the lean somewhat to the southwest. At this point, the tree has not ever "risen" against gravity, but the lean has increased while it rotated around the vertical axis. The amount of true holding wood has decreased with each cut.
Repeat the process on the third cut, making a face cut that uses gravity to increase the lean while it changes the direction of lean. After the 3rd cut, the tree could be theoretically facing almost opposite the original lean; all by making face cuts a bit less than perpendicular to the existing lean that collectively rotate the tree aound to the SW, having once been leaning East.
At this point, a quick nip into the remaining holding wood and the tree will fall opposite the original lean.
Obviously, this theoretical tree now leaning to the SW is being held by a tiny amount of uncut holding wood, the face cuts would need to be made by an exceptionally skilled faller that could choose the necessary angles very precisely, and each cut would be chopping useable lumber off the end of the log. I'm not so sure how effectively this could be done in the real world, but it is theoretically possible.
Since I have NEVER tried to do this, how 'bout you lumber harvesters tell me if this is about what you have been describing with respect to "swinging a tree" with multiple cuts. Obviously, I have not made any mention of dutchmen, and my drawings almost certainly are not scaled properly to allow a face cut (of unspecified width) to close. Back cuts (that would allow the face cut to close) have not been drawn, mostly because I am not that good at making these drawings.
