Historic Bascom elms getting special treatment

Mark Wever, of Rainbow Treecare (Minneapolis, Minn.), taps T-connectors into a pre-drilled injection site around the base of one of Bascom Hill’s grand American elm trees. The tubing delivers a fungicide treatment into the tree’s roots to help prevent Dutch Elm Disease.

A towering stand of American elm trees on Bascom Hill that has survived the ravages of development and Dutch Elm Disease are being rewarded with some preventive medicine.

Where there were once more than 1,000 elms on the UW–Madison campus, a new management plan focuses on keeping the remaining 68 survivors in the green. Campus landscape managers believe that with proper treatment, these 80- to 150-year-old trees can be kept healthy for at least another century.

Daniel Einstein, UW–Madison’s environmental management coordinator, says the first big step in the management plan begins June 15-16 with a new strategy for Dutch Elm Disease treatment. They are replacing the aerial spraying of Methoxychlor with a fungicide treatment that’s directly injected at the root of trees.

Bascom Hill visitors who happen on the scene might find it strange-looking. Einstein says a tentacle-like collection of 20 to 30 hoses will be arranged around the base of the tree, while a tank slowly pumps the fungicide into the roots. “It looks like the tree is getting an intravenous transfusion,” he says.

In a way, it is. The fungicide should be absorbed into the vascular system and spread throughout the tree, killing the Dutch Elm fungus before it spreads.

Einstein says it has many advantages over Methoxychlor, which people protested because of its putrid smell. That chemical kills the elm bark beetle, which carries the Dutch Elm fungus on its legs. The new treatment kills the fungus itself for up to three years. And since it is applied at the root, it provides zero risk of any human exposure.

In all, 29 trees will be treated at a cost of $11,000, including 24 on Bascom Hill. Another notable elm getting the protection is next to the new Biochemistry building, and is the largest tree on campus.

Because the Dutch Elm epidemic decimated trees nationwide, Einstein says it is rare to find a thriving stand of trees as large as the one on Bascom. Stands are especially vulnerable because the fungus spreads from tree to tree through the roots. Chemical treatments on campus date back to the 1960s.

Daniel Einstein

“You don’t see lots of elms together like this,” Einstein says. “There’s something very appealing about a concentration of elms, because they are so big and they form these huge arboreal arches. We’ve got something very special here.”

The management plan also gives each elm tree the equivalent of a patient record. It lists the overall condition and a course of action, which ranges from doing nothing to intensive treatment. Others carry notations for care such as “need to fertilize/aerate” and “prune ragged branch wound.”

It’s worth noting that many Bascom elms are among the oldest living things on campus. The first recorded planting of more than 800 elms across Bascom Hill was done in 1851, making them only two years younger than the university itself.

Ironically, Einstein noted that the campus has lost more elms in the past five years to the bulldozer than to disease. Some new building construction has caused irreparable damage to root systems, he says.