BLACKSBURG -- It was 9 a.m. on a recent Tuesday, and already the temperature had risen to 85 degrees on the open ground of Virginia Tech's Drillfield.

But under the branches of the big bur oak, a cool and gentle breeze encouraged passers-by to linger.

Beneath it, five of Tech's tree experts gathered. Represented among them were three generations of tree scientists -- some of the youngsters having studied with the elders.

Jay Stipes, Tech's retired "tree doctor" and a plant pathologist who developed an injection technique to both vaccinate and treat trees for various diseases, was there to herd them on a tour of the campus' oldest and largest trees.

All the professors in attendance -- Stipes, Mike Weaver of entomology, Gary Griffin of pathology, John Seiler of dendrology and Eric Wiseman of urban forestry -- use or have used the campus' urban forest as a living classroom.

The felling of the 143-year-old Henderson Lawn sycamore off College Avenue last month has called attention to the health of other, older campus trees, many of which stand on both sides of West Campus Drive.

Stipes, with help from several colleagues, counted the rings from a slice of the old sycamore and dated it to just before the founding of what is today Virginia Tech.

Weaver is an expert on the history of the big bur oak near Burruss and is writing a book about the man who is thought to have planted it in 1900, pest management professor W.B. Alwood.

Alwood is known as the savior of the Virginia fruit tree industry because of his work on pest management science at Tech, Weaver said.

Today, the tree Alwood imported from his native Ohio sits by the April 16, 2007, memorial and is a member of a special class of the campus' oldest and largest hardwoods.

Although imported, the bur oak thrives in the Virginia climate and is not bothered by lack of rain or blazing heat waves such as the one toasting Blacksburg this summer.

At 110 years old, it's still a youngster compared with its elders, some of which have stood on campus grounds for nearly 500 years. But with a trunk girth of 4 ¹₂ feet, the bur oak is the second largest tree on campus, Wiseman said.

Wiseman, Seiler and their students over the years have inventoried every tree on the campus and entered the data into a comprehensive searchable database. It lists 4,800 trees representing 145 cultivated and native species. Some, such as the bur oak, are bigger than the venerable white oaks, but none is older.

Griffin has researched Tech's white oaks and has dated one to 465 years ago.

He says the white oaks are remnants of a vast forest dominated by that species that stretched across the limestone plains of the mid-Atlantic from present-day Knoxville, Tenn., through Virginia to Harrisburg, Pa.

Looking across campus Griffin sees the landscape -- not just as it is today, but as it was in centuries past, when the white oaks ruled the hillside in front of Hillcrest Hall and the president's house.

"There were a lot of colonist-Indian battles fought under these trees," Griffin said.

In fact, "Mary Draper Ingles would have known these trees," said Stipes, who has given tree tours to groups for years.

Indeed, the white oaks stood on this land in 1755, when Shawnee warriors intent on driving English and Scots-Irish invaders from their traditional lands raided the Draper's Meadow settlement near the duck pond.

Ingles, a young mother at the time, and other captives were taken to the banks of the Ohio River. Ingles eventually walked back nearly 600 miles through the wilderness and reunited with her family. She and her husband went on to operate the Ingles Ferry on the New River in present day Radford.

In 1774, the enslaved people who built Smithfield Plantation -- land on which the campus now sits --and their white owners trod among the white oaks.

The trees were there when local boys marched off to fight, first in the American Revolution, and then in the Civil War.

They were already old in 1872, when 16-year-old William Addison "Add" Caldwell walked 30 miles from Craig County to Blacksburg to enroll as the first student at Virginia Agricultural and Mechanical College.

Every campus president from the early days of Preston and Olin College to Tech's Charles Steger would recognize them.

Stipes wrapped a metal tape measure around the trunk of one of the largest of the oaks in front of Hillcrest.

"Sixty-one-and-a-half inches," he said.

But the Henderson Lawn sycamore was not the only one of Tech's tribe of Ents facing an uncertain future.

Some of the old trees die of natural causes, such as the ancient white oak that stood, Wiseman said, "like a giant sequoia" in front of Hillcrest until 2005, when it was struck by a lightening.

Today a vast stump sits like a gravestone in its place.

All five of the tree scientists lamented the condition of another nearly 500-year-old white oak in front of Seitz Hall. Wiseman said he thinks it will be the next to go.

Construction around it has severed the tree's root system and traffic under its canopy -- several trucks were parked near its trunk -- have caused soil compaction.

In fact, surveys of the health of the campus' trees list 7 percent of them in poor condition, and 34 percent in fair condition.

Some of that is due to natural disease. An American elm on the Drillfield suffers from Dutch elm disease. A Chinese chestnut near the president's house is fighting chestnut blight.

But development is the major threat, the scientists agreed.

Preserving the trees will take planning and care as the university pursues building expansions and changes to its landscape.

Those who care about the trees can help them by sharing their stories with friends and family, Wiseman said.

By advocating that the university can provide funding for care of campus trees and adopt policies that protect them during construction and maintenance.

Browse the Tech tree inventory database at www.dendro.cnre.vt.edu/campus_trees/welcome.html.