You can use a thick hinge and a pull line, plus a hold-back line, cut with a big open-face/ birdbeak face-cut. Slowly tip the tree.
As the tree trunk and the hold-back rope become more parellel, the load will exponentially increase. If you have the hold-back in a Portawrap, a mid-line tie to the tree can allow (arbitrarily let's say) 20' of standing-end/ tail of the rope. As the tree tips, using up the 20', and the load starts increasing significantly, the end of the rope can be let to go through the POW.