A fire that consumed 741 acres of French Creek State Park after burning for five days and nearly reaching two dozen homes and a fireworks manufacturer may turn out to have been a good thing for the popular Berks County recreation area.

"Understory fire is actually beneficial to the ecology of oak," said Marc Abrams, a professor of forest ecology at Pennsylvania State University, referring to the ground-level growth beneath the forest canopy. "It gets rid of competing plants, it keeps the forest more open, and oak can regenerate better in those conditions. It also releases nutrients from the burned foliage and branches that go back into the soil."

On a windy April 9 as flames sparked by a downed electrical wire shot 30 feet in the air and whipped through the Sahara-dry forest, the silver lining to one of Pennsylvania's largest forest fires wasn't evident.

"You don't see flames like that in Pennsylvania," said park manager Eric Brown, standing under a leafy green canopy that still bore scorched trunks in the far west end of the 8,000-acre park. Six- to eight-foot-high flares are "pretty significant," he added.

Just outside the park perimeter, faded red barns and verdant horse pastures made for a bucolic scene, one that could have gone up in smoke if the inferno hadn't been contained.

Though not the biggest forest fire in the state — the Poconos and western regions have lost 1,000 acres or more in devastating infernos — the five-day blaze was extraordinary for this region.

In fact, it beat the biggest fire at French Creek by about 740 acres — the most that has burned is an acre or so, Brown said.

The stage for the April 9 fire was set in October, when a freak snowstorm toppled trees and loosened limbs. On the first day of the blaze, 45 m.p.h. winds knocked a branch into a power line that fell and lit up the dry foliage.

"It was a perfect storm," Brown said. He estimated the cost of the fire so far at $770,000.

Firefighters from 33 companies battled the flames, starting a little after noon near the intersection of Route 345 and Hopewell Street in Union Township, just south of Birdsboro. It quickly spread into North Coventry Township in Chester County.

Smoke could be seen as far away as Reading and Pottstown.

The fire got within 50 to 75 yards of 27 houses — those on St. Peters Road were evacuated for a day — and about 100 yards from the International Fireworks Manufacturing Co. on Sycamore Road.

Several large buildings had professional-grade fireworks and one building was filled with black powder.

"That was a bit of a concern," Brown said.

Firefighters on ATVs shuttled equipment and personnel through the burning forest.

Flames were contained after the first day, but the fire burned for four more days, Brown said. It wasn't completely doused until rain fell the next week.

The charred forest is in a remote part of the park and contains hiking and biking trails. French Creek also has a popular lake for canoeing and sailing, a swimming pool, cabins, and camping groups. On hot summer weekends, the park is crowded with picnickers.

A month after the fire, new signs of life could be seen where bulldozers had carved a path to contain the blaze. Only a few trees were still charred, and canopies were leafy and green.

"Fire," Brown said, "is actually a cleansing-type thing."

According to Abrams, most fires in central and Southeastern Pennsylvania are not catastrophic because the forests are dominated by hardwoods, particularly oak, whose leafy foliage is not that flammable. Fires generally stay on the ground and do little damage.

The disastrous fires in Arizona and other Western states are in forests dominated by evergreens, which are extremely flammable, and the fires are more difficult to control.

However, without periodic fires in Pennsylvania forests, nonnative species such as red maple invade and start to replace the oak. But with a fairly dense population, it's hard to use controlled fires to manage forests because of smoke and the risk of secondary fires, Abrams said.

Contact Kathy Boccella at 610-313-8123 or kboccella@phillynews.com.