Serious DBH.

Ancient forests may be closer than you think. Here's a guide to camping and backpacking in trees so tall they'll give you a neckache.

Foresters have a term for it: dbh, or "diameter at breast height," a numerical figure that correlates to the size of a particular tree at just below eye level.

But a few summers ago, as my friend Bill Leonard and I tramped through the ancient forests of the Pacific Northwest, we restated this formal phrase in simple laymen's terms. Far up the Enchanted Valley of Washington's Olympic National Park, our translation rang through the forest as we passed tree after tree as high as football fields are long. Simply put: "Good-godawmighty-lookit-that-TREE!"

Dbh, indeed.

For hours we had hiked up the East Fork of the Quinault River, feeling the strain of our backpacks as we stepped up the flanks of Mount La Crosse. Huge Sitka spruce rose above us, draped in old-man's-beard, spike moss, and sword fern; western hemlock upwards of 20 feet in circumference loomed like great Greek columns. Deep in the temperate rainforest--a habitat type found only in New Zealand, Chile, and in the valleys formed by Washington's Quinault, Queets, and Hoh rivers--we came face to face with the old-growth giants that stimulate the national headlines and our own imaginations.

To a couple of eastern boys weaned on woods of white oak and yellow poplar, the Douglas-fir and Sitka spruce of the western shore were otherworldly, shattering our precepts of a mature forest landscape. And because we were hiking into the Olympic backcountry with tents, sleeping bags, and cookstoves, we were alone in the forests of ancients. We shared the trees with no one.

Old-growth. Ancient forests. Virgin timber. There are many terms for trees of awe-inspiring size, and many definitions for what truly constitutes a forest of significant high-octane dbh to wear the old-growth star. To make the cut by the Society of American Foresters' definition of old-growth, an acre of trees must have at least 10 living trees with a dbh of 40 inches or more, plus other requirements pertaining to downed logs, snags, and woody debris. But by the time a stand of trees reaches an age of 200 years or so, it begins to take on the characteristics of old-growth forest.

For campers in search of serious shadows in which to pitch a tent, the differences between virgin timber and old-growth aren't as important as the similarities, and the campers' minimum requirements are virtually identical: trees with more girth than the collective wingspan of a Boy Scout troop, with crowns so tall the top of your head touches your shoulder blades each time you try to see the sky. When gawking at old-growth, be prepared for a neckache.

Granted, nationwide there are dozens of day hikes and plenty of nature trails that wander through stands of old-growth forest. Trouble is, you're likely to be wandering with a half-dozen other wondering souls. Under those conditions, it is somewhat difficult to react to the majesty of old-growth as you'd like, namely by oohing and aahing like a child, feeling the deeply furrowed bark of an ancient living thing, stretching your arms wide and bear-hugging a giant with a grip that extends only a tenth of its circumference. These are appropriate, if publicly embarrassing, responses.

The solution: Lace up the hiking boots and hoof it to old-growth backcountry, where you can pitch your tent where the sun never shines, and marvel at an old-growth forest up close and personal. Since my introduction to old-growth on the Olympic Peninsula, I've traveled far and wide to camp among, backpack into, and paddle through some of this country's finest ancient forests. I've cooked dinner in old-growth fir stands on the spine of the Appalachians and searched for dry ground under anvil-topped cypress trees. And along the way I've learned that you don't have to be in 10,000 acres of virgin timber to feel the thrill of ancient forests. Sometimes just a patch will do, for in words of this stature, you often can't see the forest for the trees.

I can personally vouch for the awesome camping to be found in the following forests; I've pitched a tent in all of them. Following this detailed list is a roundup of other old-growth sites where s'mores and sleeping under the stars are de rigueur. So I've done all your homework; the footwork is up to you.

MOUNT RAINIER NATIONAL PARK 

While Mount Rainier Park's incredible alpine meadows draw huge crowds in the summertime, there's plenty of leafy landscape where you can walk softly under big sticks. The old-growth western hemlock and Douglas-fir forests of Mount Rainier were ancient when the park was established in 1899. Today these extensive stands are a rare and priceless national treasure, and one campers should have no trouble accessing, whether by lugged sole or family van.

To camp as close as possible to Rainier's old-growth stands, check out the Ohanapecosh River Valley section of the park. The Ohanapecosh Campground is a quick mile hike from the river, whose waters flow gin-clear from an inactive glacier and snowfields. Lower-elevation old-growth is also found around Longmire and Carbon River. Backpackers can obtain overnight permits from the Longmire Hiker Information Center.

Some stands in the park are estimated to be well over a thousand years old, so it's a good bet yours won't be the first shelter pitched under a gnarly Sitka spruce--other campers may have pitched deerskin shelters under your trees 300 years ago. While there, keep an eye open for the northern spotted owl. Some 60,000 acres of Mount Rainier forests are considered suitable habitat for this endangered species cause celebre.

For information, contact Mount Rainier National Park, Tahoma Woods, Star Route, Ashford, WA 98304; 206/569-2211.

OLYMPIC NATIONAL PARK

In many ways the forests of Olympic National Park define western old-growth. The park is home to the world's largest Douglas-fir, western hemlock, subalpine fir, and yellow cedar. But to see any of them, you'll have to don hiking boots and likely hoist a pack. There are more than 95 backcountry sites in the sprawling Olympic Park, and your passport to this wilderness is a backcountry permit, issued free of charge.

Best bets for big trees are the Enchanted Valley Trail, which can be heavily traveled, and the Ancient Groves Nature Trail and Soleduck Falls Trail in the Soleduck Valley. If your idea of roughing it is rocks under your pop-up, there are 16 established campgrounds in the park, many located near trailheads to serious trees. Try the second half of the Marymere Falls Trail near Lake Crescent (no backcountry camping) and the Heart O' the Forest Trail at Heart O' the Hills Campground.

Wherever you go, the tree to watch for is the Sitka spruce, an indicator species of the temperate rainforest. As you hike, watch for nurse logs, the fallen trees that host sprouting seedlings; colonnades, a line of trees standing all in a row from sprouting on nurse logs; and stilted trees, where seedlings sprouted on stumps that eventually rotted away, leaving the tree "standing" on its roots. Pretty cool stuff.

The Olympic forests on the western side of the mountain range are fed by 12 feet of rain per year, so don't forget the high-tech waterproof membrane outershells. And be aware that much of the high ground in Olympic is a stoves-only zone, closed to open fires. Make plans accordingly.

For information, contact Olympic National Park, 600 East Park Ave., Port Angeles, WA 98362; 206/452-4501.

SHENANDOAH NATIONAL PARK 

A small fraction of the visitors to Virginia's Shenandoah National Park venture out of sight of the scenic Skyline Drive. that's good news for backpackers who seek a little weekend wilderness. There are no huge stretches of old-growth forest here, but 200 acres of old-growth hemlock and white oak await in the Limberlost section of the park, near White Oak Canyon and just off the Appalachian Trail.

With a backcountry permit there are an additional 150,000 acres of backcountry at your lug-soled feet. Just camp out of sight of any trail or other camping party, 25 feet away from any stream, 250 yards from any paved road, and half a mile from any developed park area. For urbanites ensconced in the East Coast's concrete valleys, Shenandoah offers an easily accessible big-tree excursion.

For information, contact Shenandoah National Park, Route 4, Box 348, Luray, VA 22835; 703/999-2229.

MOUNT ROGERS NATIONAL RECREATION AREA 

One of my favorite backpacking trips is the hike through the Lewis Fork Wilderness of Virginia's Mount Rogers National Recreation Area, where a patchwork of virgin and non-virgin spruce and fir lies across 2,000 acres of trail-etched forest. It's also a favorite of countless others, so try to get there during the week. Still, I've spent many a night in the area without a campfire in sight, and Mount Rogers offers super winter backpacking.

Many hikers bypass the trail to the 5,729-foot Mount Rogers summit, for there is no sweeping panorama to reward the intrepid. Their loss is any tree aficionado's gain, for the top of the peak is mantled in old-growth spruce. For a complete experience, put in at Grayson Highlands State Park, climb Wilburn Ridge, and ascend Mount Rogers. Along the way you'll pass through hardwood forests, cross wide-open balds kept in wind-swept condition by semi-wild ponies, and burrow deep into the fragrant forests of the Mount Rogers peak. It's one of the finest backpacking experiences in the region.

For information, contact Mount Rogers National Recreation Area, U.S. Forest Service, Route 1, Box 303, Marion, VA 24354; 703/783-5196.

GREAT SMOKY MOUNTAINS NATIONAL PARK 

Ninety percent of the old-growth forest remaining in the eastern United States is found in the Great Smoky Mountains National Park. About 100,000 acres of the park--some 20 percent of its total area--have never been cut, due to the rugged 6,000-foot-plus mountain crest and historic inaccessibility. Even today only one road traverses the park. It's a big-time smorgasbord of serious dbh, featuring massive poplar, oak, and hemlock stands, and the Smokies offer superlative camping and backpacking opportunities.

There are 900 miles of trails in the park; for the best old-growth routes, try the Gregory Ridge Trail, Ramsay Cascades Trail, and Baxter Creek Trail. Still, you're likely to find old-growth throughout the central interior and northeast corners of the park, so don't limit your exploration to the known occurrences. You might just stumble across a secret corner of neck-arching oaks. Free backcountry permits are required for overnight use of the trails; call the Backcountry Office at 615/436-1231 Monday through Friday, 8 a.m. to 6 p.m., EST.

For information, contact Great Smoky Mountains National Park, Gatlinburg, TN 37738; 615/436-1200.

JOYCE KILMER MEMORIAL FOREST/NANTAHALA NATIONAL FOREST

Nearly 4,000 acres of virgin forest in the Little Santeetlah Creek watershed of North Carolina's Slickrock Wilderness have been designated a living memorial to the author of the famous poem, "Trees." Massive yellow poplar, hemlock, sycamore, basswood, and oak punctuate the wilderness area, which was once part of the vast Cherokee Indian Nation.

There is superlative backcountry camping. The loop formed by the Naked Ground and Jenkins Meadow trails ferries backpackers from streamside to mountaintop and back again; leave time for the short hike along the Joyce Kilmer Memorial Trail. But be prepared. Except for the memorial trail, the hikes in the wilderness area are all rated "more" to "most difficult." But then, that's why these forests are virgin.

For more information, contact the U.S. Forest Service, Route 1, Box 16-A, Robbinsville, NC 28711; 704/479-6431.

A SAMPLING OF THE REST

These are old-growth possibilities I've only read about, but they're at the top of my list for exploration. Give them a try; perhaps we'll cross on the trail.

Redwood National Park, 1111 Second St., Crescent City, CA 95531; 707/464-6101.

Sequoia and Kings Canyon National Parks, Three Rivers, CA 93271; 209/565-3456.

Five Ponds Wilderness/Adirondack State Park, New York State Department of Environmental Conservation, 30 Court St., Canton, NY 13617; 315/386-4546.

Big Bend National Park, TX 79834; 915/477-2251.

Tongass National Forest, 204 Siginaka Way, Sitka, AK 99835; 907/747-6671.