Standing on a stump at the edge of a burned-out tract in the otherwise thick forest of Hopeville Pond State Park in Griswold, Bill Reid held up a squat brown pine cone.

"We're looking for these," Reid, chief ranger with The Last Green Valley, told 32 hikers gathered at the park last week for one of the organization's Walktober events. "These are pitch pine cones."

While the charred landscape might be a cause for concern to the untrained eye, Reid knows that it actually tells a hopeful story. Looking across the open landscape now carpeted with ferns turned to autumn gold, he pointed out a lone tall pitch pine, the "mother tree." From the cones of that tree, he explained, a forest of pitch pines could regenerate, now that the seedlings wouldn't be shaded out by faster-growing white pines and hardwoods.

"Pitch pine ecosystems are imperiled habitats, that support unique plant and animal communities," he said. "It likes acidic, dry sandy soils."

Before Colonial settlement, pitch pine forests were more common, sustained by naturally occurring fires that thinned out other species and opened area for the slow-growing, fire-resistant pitch pines. The sap of pitch pines also provided an important raw material for Colonial economies, used in the making of tar, turpentine and pitch. Also called candlewood, its branches were used as torches and candles. But today, 95 percent of the pitch pine forests are gone, felled for gravel mines and housing developments.

At Hopeville Pond, the state Department of Energy and Environmental Protection saw a chance to help restore the imperiled habitat with a prescribed burn, an effort, Reid explained, to do what nature used to do on its own. In modern times, forest fires have been suppressed, but historically, they played an important role in maintaining diverse habitats, he explained. The burn at Hopeville took place in April, covering about 20 acres, according to DEEP spokesman Dennis Schain.

Reid's lesson on prescribed burns and the importance of pitch pine forests was just one of the features of the park he highlighted that bright October morning. Hopeville Pond, busy on summer days with swimmers and fishermen, is actually a section of the Pachaug River that was once a favorite spot for the Mohegan tribe to gather salmon and shad, until it was dammed by Colonists in the 1700s for a sawmill and gristmill. A succession of textile mills operated in the area through the late 1800s, including the Hope Mill that wove satinette fabric — a wool-cotton blend — that gave the area its name. A fire destroyed the mill in the 1880s.

In the 1930s, the federal government acquired the land around Hopeville Pond, using it as a camp for the Civilian Conservation Corps. In 1938 it became a state park, adjoining to Pachaug State Forest, the state's largest, just to the east and south. The park, with 80 campsites, picnic areas and a ball field, is also the northern end of the Nehantic Trail, a 13-mile pathway that's part of the Connecticut Forest & Park Association's blue-blazed network.

Starting from the trailhead on Route 201 just across from the pond swimming area, the trail goes through mostly flat terrain with a few short climbs. After about a mile, the trail leaves the state park and enters the Chapman Area and Mount Misery section of the Pachaug State Forest. It continues southeast, eventually ending at the Green Falls Pond section of the Pachaug in Voluntown. Along the section of the trail through the park, the group trekked past old stone walls and cart paths, reminders of the farms and houses that once stood on land that is now permanently protected forest, enjoying the sweet smell of pines and the colorful leafy splendor of fall along the way.

"The reforestation of the Northeast in the 20th century is one of the great ecological success stories," said Reid. "No where else in the world has this happened."

Hiking the Nehantic Trail, Reid explained, is a good way to appreciate the significance of the forests of The Last Green Valley, a 35-town region that extends into southern Massachusetts, a unique rural landscape in the highly urbanized northeast.

"We're producing oxygen in our forests for eight million people," he said.

Hopeville Pond State Park

Name: Hopeville Pond State Park

Town: Griswold

Directions: 395 north to Exit 86; left off the exit; follow Hopeville Road or the park signs until the Y intersection. Proceed to the right. The park entrance is a half mile to the right, off Route 201.

Parking: There are several parking areas along the main park road.

Description: The 550-acre park, located around a popular swimming and fishing pond, is also the northern end of the 13-mile Nehantic Trail, one of the blue-blazed network maintained by Connecticut Forest & Park Association volunteers.

Regulations: Open 8 a.m. to sunset; dogs must be on a leash.

Amenities: Bathrooms and outhouses; picnic tables and picnic shelter; pond with swimming area and a boat launch; campground and ball field.

Natural Features: Pitch pine and scrub oak forest; Hopeville Pond is a dammed section of the Pachaug River.

Fees: There is a weekend/holiday parking fee and a campsite fee.

Things to Note: Trailhead for the Nehantic Trail is located along Route 201, just across from the swimming area at Hopeville Pond. The 13-mile trail extends about one mile into the park, then crosses into the Chapman Area-Mount Misery section of the Pachaug State Forest, and eventually ends up at the Greenville Falls section of the forest.

Owned by: Connecticut Department of Energy and Environmental Protection

More information: http://www.ct.gov/deep. A hiking map can be found at: http://www.ct.gov/deep/lib/deep/stateparks/maps/hopeville.pdf