Police were notified of the situation around 6:05 a.m. Tuesday when they received a cell phone call from a girl at the campsite, located in Bull's Island State Park in Delaware Township, Hunterdon County.
The tree fell on the tent where the man, identified as William Arias of Bound Brook, NJ, and his 42-year-old wife, Elcetia, were staying. Both were trapped by the tree.
People from nearby campsites came to help but couldn't move the tree.
"A couple of my friends went inside to try and help, to see if anyone was in there, and we saw the lady down there," said camper Tuan Luong. "We tried to lift the tree up but it was too big."
William died of his injuries.
Elcetia was freed and transported by helicopter where she underwent surgery. She was last reported to be in guarded condition.
The couple had their two children with them - a 10-year-old boy and a 12-year-old girl. Also with them was a 9-year-old boy cousin. All three children escaped injury and were taken into the custody of park police while awaiting relatives to pick them up.
"We were really lucky, but we feel really bad for the kids. We tried to comfort them the most that we could, but there was nothing we could do," said camper Quang Phem.
The tree is described as a huge, heavy sycamore estimated to be 40 to 50 feet high and weighing some 2,000 pounds.
Park officials say the trees are inspected every year before camping season and the tree that fell appeared to be healthy.
Police are calling the incident a tragic, freak accident.
"This will be a full-blown investigation. All of the trees will be examined again but as we said this is a freak accident," said Rick Arroyo of the N.J. Park Police.