Cutting down a dead tree in South Orange NJ 2017-03-18

I cut down a tree in my mother in-law's back yard!  It was about 12 feet tall and 24 inches in diameter at the base.  I mainly used a chainsaw (16" bar).  I did a hinge cut on the "downhill" side, and a thin back cut on the opposite side.  I then used a mallet to drive a wedge into the back cut to try to tip the tree over (towards the hinge), without any luck.  So I started cutting more away.  After cutting some away I would try to use the wedge again, without any success.  Eventually, it fell over spontaneously.  It was interesting that it didn't fall until it was cut down to about 3 inch diameter section in the center.  In the picture below you can see the small section in the middle that was left uncut right before it fell: