Montgomery Parks this week began cutting down hundreds of dead or dying ash trees the department says are at risk of falling on Rock Creek Trail users near the intersection of Connecticut Avenue and Beach Drive.
Patrick Harwood, horticulturist for Montgomery Parks, said officials have identified at least a couple hundred hazardous ash trees in the last month infested by the emerald ash borer, a beetle native to eastern Asia that has destroyed ash tree populations in much of North America.
The beetles were first detected in Montgomery County in 2012, but it wasn’t until last April that Montgomery Parks found evidence of emerald ash borer on park property.
Harwood said a volunteer trail steward found what looked to be an infected tree in a section of Rock Creek Park near Lake Needwood in the Derwood and Rockville area. Parks officials found 76 ash trees that were severely damaged by the emerald ash borer in less than a year—Parks officials had last inspected the area in the fall of 2014.
Evidence of emerald ash borer beetles in a tree stump along Rock Creek Trail (left) and Montgomery Parks employees removing infected trees Friday (right). Credit: Aaron Kraut
“At that point, it was brought to our attention how quickly the demise of the trees can happen,” Harwood said.
While only 2 to 4 percent of trees in Montgomery County are ash trees and susceptible to infestation, Montgomery Parks estimates 20 percent of those ash trees are on its 37,000 acres of parkland.
“It turns out that most of our parks are within stream valleys and stream valleys are where the majority of the ash population is within the county,” Harwood said.
The emerald ash borer was accidentally introduced to North America in the 1990s and has spread mostly unabated after first being detected in 2002 in Michigan. As opposed to other invasive beetles, such as the Asian long-horned variety, the emerald ash borer can fly about 18 miles away from its original home, which Harwood said makes it difficult to keep infestations contained in a quarantined area.
As many as 10,000 of the beetles can feed on one tree in cases of large infestations.
Credit: Aaron Kraut
In November, Montgomery Parks asked for help from the public to identify ash trees that appeared dead or infested.
Harwood said at that time the ash trees in the area of the Rock Creek Trail near Connecticut Avenue didn’t appear as bad as they are today. But it became apparent to parks officials the trees won’t make it through the winter and many are brittle enough that branches could fall on trail users below.
“We thought we had a little more time,” Harwood said. “It’s moving quite quickly, much faster than we thought.”
Harwood said Montgomery Parks will remove only the trees deemed to be risks to trail users, drivers on Beach Drive or other infrastructure. The tree removal work over the next few weeks could require cranes or other heavy equipment that will force temporary closures of the trail or Beach Drive.
