I doubt the girdling effectiveness.
Seems like when I cut up pine, and it sits in chunks isolated from its root system, even a week or two later, there is pitch / sap still oozing from near the bark.
Maybe the girdling changes how fluid the pitch is.
Can you imagine how much pressure would have to be applied to a cable?
Now that I wrote that sentence, I realized that water moves up the inner tissue. No, I don't think someone could wrap a trunk of a tree tight enough to squeeze the wood tight enough to make a difference.
Moisture movement under the bark in the phloem, is downward, not upward.