One of Janesville’s biggest, oldest, and arguably most historic oak trees is losing limbs, and the Rock County Historical Society is trying to figure out why—and how to save the tree.
Officials said that during an otherwise windless and quiet night on Saturday, the giant bur oak tree on the northwest side of the historical society’s Lincoln-Tallman Restorations grounds shed an enormous set of limbs. They snapped off and fell to the ground.
The oak tree, known locally as the "Witness Tree," has stood at the Tallman House property since at least the 1850s. The tree is believed to have been living when former President Abraham Lincoln visited the Tallman House in October 1859.
The oak, which is nearly 100 feet tall and has a trunk big enough that two men can’t reach all the way around its girth, is likely the oldest tree on the Tallman campus. In its long life, the tree has witnessed the coming of Lincoln—but also countless weddings, high school portrait shoots, ice cream socials and, more recently, the annual Tallman Arts Festival. All this and more have played out in the shade beneath the stately tree’s massive spread of limbs.
The grounds below the tree are now slightly less shady after the big branch broke off Saturday.
One local arborist driving past the Tallman House on Sunday saw that the tree had a huge limb down, said Tim Maahs, executive director of the Rock County Historical Society.
The historical society and two private arborists looked at the tree Monday and said the limb loss is likely due to a common tree malady called “sudden branch drop syndrome”—a disorder in which healthy, living tree limbs suddenly break off and fall from otherwise healthy trees. It often happens at night and for no clear reason.
The disorder is considered common in large oak trees, although arborists aren’t sure exactly why it happens. Some believe branch drop syndrome can be tied to trees being infected over time by bacteria or fungus.
Maahs said the same tree had shed a couple of large, healthy limbs about three decades ago. Another bur oak nearby has become stunted and has lost limbs similarly over the years.
Maahs said arborists viewing old wounds on the trunk suspect the tree may have been afflicted with branch drop disorder for years.
The oak is believed to have earned its moniker, the Witness Tree, because Lincoln supposedly sat under it and had a picnic sometime in early October 1859 when he visited the Tallman House.
Maahs said it's understood that the tree and other bur oaks at the Tallman property did exist at the time of Lincoln’s visit to the Tallman House 162 years ago. But he said the historical society has no documented evidence that Lincoln actually sat under the big tree to dine during his visit to Janesville.
“They didn't appear to have had a meal out here. That's probably one of those stories that just kind of developed over time," he said. "We were never able to confirm that it actually occurred.”
Maahs said that arborists now are working to properly seal the tree’s new wound and to protect its old scars from fungus, bacteria and insects which can cause blight that can threaten such adult oak trees.
He said arborists are considering drilling holes in the big oak that will allow its trunk to drain water from existing cavities left from old wounds. The arborists also plan to re-connect a set of lightning rods that have been anchored to the tree for years to protect it from lightning strikes, Maahs said.
Maahs said the historical society considered chipping up the huge, fallen branch, which had bows measuring two or three feet thick. But he said that the group has decided instead to send the limbs off to a local wood drying kiln.
Later, Maahs said, the historical society will commission works of art from the tree’s wood that might be sold to those seeking a unique piece of Lincoln lore.
On Monday, only a few stray leaves from the tree filtered down to the ground, but Maahs pointed out that the big oak has several branches that overhang the Stone House, a mainstay on the north side of the Tallman property.
The building is an old, stone shotgun house that was built as an annex to an original, log home built on St. Lawrence Avenue. Two women commissioned moving the house to the Tallman property in 1965. The Stone House has sat at the site, its front porch overlooking Mineral Point Avenue, ever since.
Maahs said the historical society planned this fall to fund a $100,000 project to rotate the home 180 degrees so its porch faces the Tallman House. The plan is to rehab the old house as space for weddings and other events.
It would behoove the historical society, Maahs indicated, to try to maintain a tree that looms over the old Stone House and sat on the same part of the Tallman property for decades before that. It’s a tree that’s associated with the whole Tallman property. But moreover, it's known for the spring, summer and fall events that invariably have drawn crowds who nestle in the shade of the massive, well-known oak.
“I still have older people ask, ‘Are you still going to do the ice cream social under the big oak tree?’” Maahs said. “It’s been years since we did the ice cream social.”