Insert felling wedges into the back cut to prevent the tree from sitting back and pinching your saw.
Look up for "widowmakers" (loose branches that may fall). “Nuts & Bolts” of Tree Felling
I can then provide specific techniques like "bore cutting" or "tapered hinging" for your situation. Insert felling wedges into the back cut to
The strip of uncut wood between the notch and the back cut is the . It should be about 10% of the tree's diameter. “Nuts & Bolts” of Tree Felling