It had been contained to about 200 acres by afternoon and would likely be brought under control more quickly than the blazes that had been threatening wildlife and homes in Cumberland, Gloucester, and Ocean Counties since Wednesday, officials said.
All the fires occurred in or on the fringes of the Pinelands National Reserve.
"It seems like a lot of fires, but this is our spring fire season in South Jersey," said Steve Holmes, a spokesman for the New Jersey Forest Fire Service, which had been dispatching crews of more than 100 forest-fire fighters to battle the blazes alongside local volunteer companies over the preceding 72 hours.
Blustery winds earlier in the week, dry weather, and low humidity contributed to the tinderbox situation, Holmes said.
But before firefighters could finish mopping up a blaze that had begun the day before, forcing evacuation of a school and routing residents from 617 homes in Berkeley Township, Ocean County, the fire erupted in Shamong late Friday morning on about 50 acres of state forest land.
"They may say we're safe to be in our homes now, but it's still pretty scary when you can still smell the smoke in the air," said Donna Smith of the Bayville section, whose home was among those evacuated Thursday night. "You never know if it could break out again."
The 500-acre Berkeley blaze and another Thursday on 300 acres in Lacey Township, at Double Trouble State Park, followed two earlier forest fires. The first broke out Wednesday on 1,535 acres in the Bevans Wildlife Management Area in Downe Township, Cumberland County, the second on 550 acres in the White Oaks section of Franklinville, Gloucester County.
"When the conditions are just right, and the weather is as dry as it's been, it doesn't take much for fires to get going," said Holmes, a second-generation forest-fireman, who said such blazes had become less ferocious in recent years.
Holmes said forest fires in New Jersey in the 1970s, '80s, and early '90s were more frequent and often much larger. Agencies such as the fire service were less likely to employ various preventive means, such as controlled burns, in which flammable underbrush is removed from the forest floor before prime fire season.
"Cellphones have also helped a lot, too, because if people see smoke, they can report it right away," Holmes said. "Back then, it could be a while before someone would be able to find a phone to call in a report. By then, the fire would have had a chance to really get going before anyone could get to it."
A lack of leaves and greenery, and low humidity in spring and fall, makes the woods particularly vulnerable to fires, because the sun can more easily penetrate the forest floor and ignite dry leaves and underbrush, Holmes said.
The forest service also staffs 21 lookout towers throughout the state continually during the burn seasons in March, April, May, October, and November. Forest fire observers also calculate fire danger ratings, which are reported as alerts to the public and help the agency determine staffing levels.
"It's a landscape that is full of fire-adapted species, both in the flora and fauna," Holmes said.
Other experts agree.
"In a place like Southern New Jersey, the question is not whether there will be forest fires, it's what type of fire the area will have," said Stephen Pyne, a fire historian and scientist with Arizona State University's Global Institute of Sustainability.
Pyne says a cycle of fire has always been present in the Pinelands. Species in the Pinelands, such as the pitch pine, thrive only after a fire. The earliest explorers of New Jersey smelled its smoke before they saw its shore and "viewed the fire plumes before they knew what those fires were combusting."
Those facts, coupled with the region's "mosaic of land uses" - a 1.1 million-acre land reserve lies within a few hours' drive of 35 million people - have driven the Arizona native to study Pinelands fires extensively.
"The extensive urban development that surrounds the contemporary woods lies next to the biotic equivalent of a munitions depot or an abandoned tenement rotting into combustibles," Pyne wrote in an essay called "Bog and Burn: The Paradoxes of the New Jersey Pinelands," part of a 50-year history he has compiled about the cultural evolution of firefighting in the U.S. since 1960.
Pyne said New Jersey was "very lucky that it has a fire service that really understands the importance of using a device like the controlled burns to prepare for fire danger."
"The vulnerability of some of these areas, of some of these homes, is equivalent to people who live in flood plains," Pyne said. "Planners and others need to consider that in the future."