Jayhawk Boulevard once was lined with elm trees that created a soft canopy above Kansas University’s main thoroughfare.

Over time, most of the graceful giants succumbed to Dutch elm disease and were removed. A hardy survivor remained for some 90 years in front of the Natural History Museum.

But now it, too, is on its last limb, and university officials are “reluctantly, regretfully” planning to cut down the ailing tree this month.

“If you tried to cure this particular tree, the tree would be pretty disfigured and wouldn’t necessarily survive,” university spokesman Todd Cohen said. “And you run the risk of the disease spreading to other very mature trees.”

It’s unclear whether the tree is suffering from Dutch elm or another common nemesis of elm trees, elm phloem necrosis, said Cohen, adding that the sickness had become apparent this spring when the leaves on the top half of the tree didn’t grow back.

Dutch elm is caused by a fungus and is transmitted by two species of elm bark beetles, according to the U.S. Forest Service. Elm phloem necrosis is caused by an organism and is transmitted by the whitebanded elm leafhopper, the service reports. Both diseases also can be transmitted between the roots of adjacent trees.

The forest service recommends that trees with elm phloem necrosis be removed because the disease is incurable. Trees with Dutch elm can be treated by removing affected branches and injecting fungicide into the trunk, branches or both to stop infection.

The latter option would leave behind a “very funny looking tree,” Cohen said, because most of the top half of the elm on campus is dead.

“It seemed like the most responsible decision was to take it out,” he said.

Bob Lichtwardt, KU professor emeritus of ecology and evolutionary biology, who studied Dutch elm disease when it hit Lawrence hard back in the early 1960s, said the best method of controlling Dutch elm was to remove a tree as soon as the disease was discovered.

“The use of fungicides  they tried an experiment on campus years ago, and it wasn’t too successful,” he said.

A committee composed of the university architect, the campus landscape manager and the university landscape architect made the decision to remove the tree, assistant provost Jim Long said.

A new tree will be planted in the fall, Cohen said.

Brad Kemp, assistant director of public affairs at the Natural History Museum, said he and other museum staff had noticed the tree was dying. Though Kemp wasn’t aware of any staff members who had a particularly special place in their heart for the tree, he said he would be sad to see it go.

“It’s a gorgeous tree,” he said, “and it’s going to take an awfully long time to replace it.”