Heading back to the whites this summer. I’ll be going from Crawford notch to grafton notch using a hammock. If memory serves me right there was a fairly short steep section north of Mizpah hut before Pierce. I believe there were trees suitable for hanging above this steep section. Can anyone confirm? I don’t want to push too far north and run out of hanging trees. What’s the furthest north along the Appalachian trail around Pierce I could hang?

Welcome Dunkard!
Camping above treeline or within 1/4 mile of the hut is frowned upon when there isn't 2 feet of snow on the ground
With that said, Pierce is a somewhat wooded summit. There's split along the Crawford path...right to Mizpah, left towards the summit of Pierce....and there is a trail from Mizpah to the summit. I'd look along that area.
After Pierce there isn't anything for tress except some scrub towards Eisenhower and near the base.