Each year there are thousands of search-and-rescue incidents logged across the National Park System. They typically involve missing hikers, visitors who get injured in falls, boating accidents, or climbing accidents.

Far and away the bulk of the incidents quickly are resolved, usually in less than a dozen hours. During 2007, for instance, the National Park Service reported 3,593 SAR incidents. Of those, 2,566 individuals were uninjured, another 136 died.

Rarely do SARs go unresolved, but in 2007 there were 19 cases where the individual who spurred the search never was found. Such unresolved cases grow cold over the years, but never forgotten. One from 1969 in Great Smoky Mountains National Park still seems fresh and painful in the minds of some of the rangers who participated in the search.

"The search in Utah that took place a few years ago, for the Bardsley boy, just brought back memories of Dennis Martin for me. Big time memories of the Dennis Martin search,” recalls Larry Nielson, who was the Cades Cove District ranger in 1969. “It was similar in so many ways.”

Garrett Bardsley was a 12-year-old Boy Scout who vanished without a trace during a camping trip in the Uinta Mountains in 2004. While fishing by a lake with his father he got his feet wet and headed back to camp a short distance away and never came back.

Though a continent and 35 years separated the disappearances of Garrett Bardsley and Dennis Martin, the cases were similar in the frustrations and puzzlement they exacted from those who went searching.

Word that Dennis, a soon-to-be-7-year-old, went missing 40 years ago on Father’s Day spurred one of the largest hunts in National Park Service history. Before it ended the FBI investigated, more than 1,400 searchers combed Great Smokey’s rugged backcountry, an estimated 70,000 linear miles were said to have been walked, and 1,110 helicopter sorties were flown. Noted psychic Jeane Dixon suggested where the boy might be found, the White House monitored the search, and active Army and National Guard troops on summer maneuvers joined the hunt.

For two weeks they searched.

The Martin family, from Tennessee, was celebrating that Father’s Day Weekend as it traditionally had, by heading into the Smokies. On June 13, the Friday before Father’s Day, father William, his young sons Dennis and Douglas, and their grandfather, Clyde, were striding up onto the backbone of the Smokies.

Setting out from the Cades Cove Campground, they moved up the Anthony Creek Trail for little more than a mile and then veered right onto the Russell Field Trail and continued on for several more miles in the warm summer weather.

The Martins moved along Leadbetter Ridge above the Left Prong of Anthony Creek and made their final run of the day to Russell Field. A grassy break in the forest, this clearing offered room for the youngsters to burn off whatever energy they still carried after the long day’s hike. For the adults, the bald offered panoramic views across the Smokies and time to relax, visit, and watch their offspring grow in the mountains. There the Martins spent the night, rising on June 14 for the final 90-minute or so push east to Spence Field and its simple, three-sided shelter, where more relatives were waiting.

While the Martins long had traced this route to Spence Field, for Dennis Martin, whose seventh birthday was but a week away, the 1969 hike and camp-out with his grandfather, father, and 9-year-old brother was his first over-nighter, a passage that would sharply define the separation between him and his younger siblings and mark his acceptance into the mountains.

Arriving at Spence Field, the Martins found a clearing that trends northeast-southwest, one that basks under sunny skies but which also offers little shelter from pounding thunderstorms, which are common in the Smokies come summer. From here the Anthony Creek drainage funnels any rain that falls on the north side of the bald quickly down into Tennessee, while the Eagle Creek drainage does the same for the south side, flowing in crooked and rocky leaps and bounds into North Carolina where it dumps its fill into Fontana Reservoir.

The Smokies are rippled with drainages eroded by creeks that bound over ledges and dart through boulder-choked stretches before coming to rest momentarily in pools. The mountains flanks in many places feature cliffs both steep and cut with crevices.

Roaming these mountains and their shadows are the occasional wild cats that pass through the area and the resident black bears that easily can, and actually do, reach 500 pounds by feasting on the fish and vegetation that are so abundant in the Smokies.

Into this realm of bears, panthers, feral hogs, and rattlesnakes wandered Dennis. The slight, 4-foot-tall youngster and his older brother had been playing with two other boys on the forest clearing. While the adults relaxed on the west side of the bald within view of the youngsters, the whispering boys conspired around some clumps of serviceberry bushes to split up, circle the knob through the cloaking woods, and surprise the adults from behind. Douglas and the other two boys went south and then west, Dennis went northwest, along the Appalachian Trail, and disappeared into the forest.

“We knew what they were doing,” 32-year-old William Martin would say later. “We also knew when they sent Dennis another way, because they thought the red T-shirt he was wearing would spoil their scheme.”

Three minutes, perhaps, but no more than five, passed without anyone spotting or hearing Dennis. At that point his father began calling out to his young son. He then followed the Appalachian Trail west for about a mile before doubling back, thinking Dennis surely had rejoined the others at Spence Field and was waiting for dinner. When William Martin found this hope shattered, he headed west again, this time all the way back to Russell Field, only to return, alone, to Spence Field.

While the boys’ father was making these frantic searchers, their grandfather, Clyde, headed all the way back down Anthony Creek to Cades Cove, a distance of roughly 8.5 miles, and reached the ranger station shortly before 8:30 p.m. to summon help.

Initially, the response summoned by word of Dennis having gone missing was not unlike any other “hasty search” that has been mounted in the country’s national parks and national forests. A small group quickly looks in the immediate area where the missing person was last seen, and if their efforts prove fruitless, the search broadens, both in terms of terrain and searchers.

These days searches have been refined to the point that in 90-95 percent of the cases the subject is located within 12 hours. But 40 years ago searches weren’t so methodical.

Before long the hunt for Dennis Martin turned into the largest-to-date SAR mission in Park Service history. Spence Field would turn into a military base camp, with landing zones cut from the surrounding forest. The Park Service staff quickly became overwhelmed by the turnout of volunteers and struggled to manage them.

Complicating the search for Dennis was rain. More than 2.5 inches of rain – and possibly 3 inches in and around Spence Field -- fell throughout the night. The aftermath not only challenged searchers the following morning, but it would confound them in the ensuing days.

That Dennis Martin became lost was not that unusual. Thousands of national park visitors find themselves lost or injure themselves and need rescuing by rangers every year. More often than not those searches are conducted in mountainous settings above 5,000 feet.

Some settings, such as Great Smoky Mountains National Park, feature dense, confusing and cloaking thickets of vegetation that can trap you if you stray from an established trail. Other landscapes can lead you astray with maze-like canyons or trails that thread through fins of rock or scurry across featureless slick-rock. Some who go lost become confused and disoriented by hypothermia, heat exhaustion, or altitude sickness. And some are trapped by water.

Where had Dennis Martin wandered off, and how come other hikers in the area didn’t see him?

In hindsight, the Martin case came to be the example of how not to conduct a search-and-rescue mission. Too many people were on the ground without proper supervision, a strong overhead team was not in place to direct operations, search training perhaps had not been practiced as much as it is today and certainly was not as perfected.

For two weeks the active search dragged on. At one point 71 Green Berets were engaged, living in the mountains, eating rattlesnakes they came upon in their fruitless search for Dennis.

A park spokesman at one point, no doubt in a moment he later wished he could erase, practically promised that the boy would be found: “He may be a little bit the worse for wear after being out in the open so long, but I’m confident we’ll find him.”

Park Service officials finally had to admit it was fruitless to continue the hunt after crews intensively covered nearly 60 square miles of the park’s backcountry. The boy’s family, refusing to believe the boy died in the mountains, offered a $5,000 reward for information leading to his whereabouts. It went unclaimed.

Ask Larry Nielson today where he thinks Dennis Martin is and his answer is quick, and short: “I think he’s up there,” he replies, referring to the thicket-tangled spine of the Appalachians.