But a 170-year-old eastern sycamore tree that abuts the north end of the stone bridge continues to thrive.
Joe Calzarette, natural resources manager at Antietam National Battlefield, said the tree undoubtedly was hit by gunfire as thousands of Union and Confederate soldiers fought for control of the bridge on Sept. 17, 1862.
“Boy, if it could talk,” Calzarette said of the tree, known as a witness tree because it was there at the time of the battle. “We knew there was heavy action. It’s a relatively healthy tree. It’s in good shape.”
Calzarette said he believed that the tree wasn’t planted, but naturally sprouted near the northwest corner of the bridge about 170 years ago, about the same time the bridge was built in 1836.
In recent years, park officials have grown concerned that a lightning strike or severe winds might topple the massive tree and damage the bridge below.
“You never know which way she’s going to break or where she’s going to go if it happens,” he said. “The bridge can be repaired. The tree can’t.”
To prevent damage to two of the park’s most well-known landmarks, workers have strung metal cables between the tree’s two main branches.
Calzarette said the purpose of the wires, which can support 60,000 pounds each, is to prevent the tree from splitting by reducing pressure on the limbs.
One positive aspect, he said, is that officials believe the roots of the tree haven’t grown under the bridge. As a result, the base of the bridge probably wouldn’t be disturbed if the tree were uprooted by heavy winds.
He said the tree has difficulty getting nutrients because the soil is compacted at the base — caused in part by tourists who stand there to have their pictures taken. The problem might grow even worse in September, he said, when visitors come to the park to attend the battle’s 150th anniversary.
Calzarette said rangers also are worried that the tree might lose root mass as the soil erodes near the bank of Antietam Creek.
“There’s just some work we need to do below the surface,” he said.
Calzarette said the tree was about 15 years old at the time of the battle and could live for another 500 years.
“If you look at trees in human terms, it’s like 30,” he said. “Our job here at the park is to preserve and protect this tree, and keep it as alive as we possibly can.”