PRESTON - Kneeling in the hot sun beside a long row of 3-year-old white oak seedlings, Frank Gouin took an old paring knife and sliced down into the bark of one knee-high tree, just above the soil.

The blade removed a thin chip of wood and exposed the thin inner layers of the seedling's stem - an oval wound about an inch long in the little tree grown from a Wye Oak acorn.

Into that wound Gouin placed a tiny green leaf bud. The bud was cut from one of the hundreds of footlong shoots, or "bud sticks," that were salvaged last week from the 460-year-old Wye Oak after the great tree fell in an afternoon thunderstorm.

These buds, held in cold storage since the storm, are the last living tissue from the old tree, which was the largest white oak in the United States. Gouin's work yesterday at Maryland's John S. Ayton Forest Tree Nursery was an effort to preserve the genetic secrets that made possible a life that stretched from America's primeval forest into the 21st century.

"The Wye Oak has stood the test of time, 460 years," said Gouin, the retired chairman of the horticulture department at the University of Maryland. "Shade trees on the street last seven or eight years, yet this has tolerated everything. That says something. Let's preserve that, and someday we may be able to utilize it."

Yesterday's was the fourth effort in as many years to produce genetic copies of the Wye Oak.

Though fruit trees have long been grafted, until 1999 it had never been done successfully with white oaks. And the process remains chancy.

About 12 percent of the Wye Oak grafts Gouin attempted in 1999 and 2000 were successful. Thirty of those trees are now about 2 feet tall. Most are growing at the 300-acre Preston nursery; two were planted in April at Mount Vernon, George Washington's home in Virginia.

Last year's grafting of Wye Oak buds was a failure.

"We were too late," Gouin said. The best time to cut white oak bud wood for grafting is between mid-July and mid-August. That's when the buds seem to be at an ideal stage for grafting. Last year's grafting was delayed until late August.

This year, the tree's fall dictated the timing. It was six weeks too early, and initially, Gouin had little hope for the 2002 class of Wye Oak grafts.

But the tree's buds were unusually green and mature for early June. Gouin believes the drought accelerated its bud development. "I got a feeling it's going to be better than we thought it was going to be," he said.

Shaded by a wide straw hat, Gouin held the bud salvaged from the fallen tree against the seedling grown from its acorn, then bound them tightly with an elastic band.

Finally, he covered the band and the protruding bud with "parafilm," a waxy tape that would seal in the moisture for two weeks or so until the wound has healed.

Called "chip budding," it's a technique Gouin learned in England 20 years ago. In his practiced hands, the procedure took little more than a minute.

Before the day ended, he and Suzanne Carmean, a natural resources technician at the nursery whom Gouin trained, would graft as many as 200 Wye Oak buds.

With luck, a year from now the buds will have merged their conductive tissue - the channels that carry nutrients and water up and down the stem - with the host tree's, and begun to grow. The leaves that unfold, and the new shoots that emerge, will be genetically identical to the Wye Oak - clones.

The roots of the host seedling will continue to nourish the new growth, but they will always carry the genetics of the acorn from which they grew - half from the Wye Oak, and half from a nearby tree that pollinated the Wye Oak's flowers.

Once the grafts are established, nursery workers will cut off all the trees' original stems, allowing the Wye Oak grafts to flourish and grow. Years from now, they will provide more buds for grafting, eventually producing enough Wye Oak clones to be offered for sale.

"It's not high-tech, not when you can do it with a pocketknife," Gouin said. "But it's proven. All roses are done this way. All apple trees, all citrus trees are done this way."

That's how we are able to ask for red delicious apples from many different orchards, and get identical, predictable fruit.

But until the nonprofit Champion Tree Project International launched its campaign in 1996 to produce genetic clones of every National Champion tree in the United States, no one had bothered to try it with many forest trees. In six years, the project has cloned more than 70 species - a small step toward its goal of replicating 1,000 National Champions.

In two weeks, nursery workers will cover the Wye Oak grafts with mulch to keep them moist and cool through the summer. When the mulch is removed next spring, the buds should be swelling with new growth scripted by a genetic code first written in the Maryland wilderness 460 years ago.

For information on the Champion Tree Project, go to www.championtreeproject.org