From Sturdy Old Survivor, a Hardier Elm Grows

RINCETON, N.J. — More than 70 springs have come and gone since the first victims succumbed, but grieving friends and brokenhearted lovers have never stopped searching for survivors of one of the worst ecological calamities in American history.

They stalk damp backwoods and prowl deserted country roads looking for rare American elm trees that have somehow managed to ward off Dutch elm disease, which spread in successive waves across much of the country beginning in the 1930's, killing more than 77 million elms in the biological blink of an eye.

They are looking for a noble giant hiding in an overgrown field or standing sentinel over a disappeared farm, an elm that is not just an isolated wallflower that somehow escaped infection, but rather a true survivor that could yield the secret to its indestructibility.

For Roger W. Holloway, a wholesale nursery supplier in Atlanta, the search for super elms has become a consuming crusade that has taken him to an unlikely place to find a survivor: an old graveyard here.

Five years ago, Mr. Holloway, 49, drove into Princeton through a long allée of elms — most of them planted just before Dutch elm arrived. The size, shape and sheer beauty of the 70-year-old trees arching gracefully over the road convinced him this was indeed the place to look.

Now Mr. Holloway says he is certain he has found the mother of all those elms: a majestic giant standing in a prominent spot in Princeton since before it became a cemetery in 1757. About 100 feet tall, this noble elm bows gracefully over the corner of Witherspoon and Wiggins Streets, not far from Princeton University, and shades the grave of Dr. Thomas Wiggins (1731-1801), who donated land for the cemetery and for whom the street is named. The tree's gnarled base is so massive that it has crept over part of Dr. Wiggins's grave marker and nearly swallowed the white marble tombstones of three of his grandchildren.

Mr. Holloway believes — and others have confirmed — that this hardy survivor in Princeton Cemetery is the progenitor of a whole generation of disease-tolerant elms that growers have been shipping around the country for the last few years. His thesis is supported by tests conducted a few years ago that show that a significant sequence of the Princeton giant's DNA is an exact match with the trees planted along the entrance to Princeton.

"Long story short," said Joseph C. Kamalay, a molecular biologist at the Donald Danforth Plant Science Center in St. Louis, Mo., who performed the genetic sleuthing several years ago when he worked for the United States Forest Service, "the cemetery tree was likely the maternal parent of the Princeton elm, at least in the lineage, because their chloroplast DNA is identical."

Even a disease-tolerant tree does not have total immunity. Last year, a much younger elm half a block from the cemetery tree was infected with Dutch elm disease. It had to be cut down, but not before the leaves on two huge branches of the cemetery tree turned brown, a sign of the infection. The branches were pruned, and the tree seems to be fine.

Mr. Holloway said he did not believe that the infection had upended his theories about the tree's ability to tolerate the disease that has killed so many others. "Just because a tree has some issues and has to be pruned doesn't mean the end of its life," he said.

The trees that Mr. Holloway has grown and sold through his business, Riveredge Farms, have been shown in tests by the United States National Arboretum to withstand catastrophic injections of the fungus that causes Dutch elm disease. Two other varieties, Valley Forge and New Harmony, are also highly tolerant, though they are not considered to have the same classic vase shape as the Princeton elm.

In the last few years, Princeton elms have been planted in New York City, at the University of Oklahoma campus and in Washington, D.C., among other places. Soon, they will also will take root on the grounds of the White House and sprout on the pedestrian mall being built along Pennsylvania Avenue.

Other growers are relying on the Princeton elm to revive interest in what used to be America's favorite tree.