The Battle vs. Rockland Lake’s Deadly Invader


Rockland Lake State Park, where hundreds of trees have been lost to the emerald ash borer, on Sept. 28, 2021. Photo by Robert Brum

A group of preservationists will take up shovels later this month to do battle against a deadly invader that has laid waste to hundreds of Rockland Lake State Park’s white ash trees.

The tiny emerald ash borer, which arrived in Rockland County some half-dozen years ago, has torn through the handsome hardwoods that have shaded the park’s groves and pathways for years.

About 1,300 to 1,400 dead or dying trees have been cut down for safety at Rockland Lake and adjacent parks. Roughly 300 to 400 more are expected to meet the same fate this year, according to Matthew Shook of the Palisades Interstate Park Commission. Those trees are marked with an orange slash on their trunks.

The ash borer’s destruction doesn’t end at Rockland Lake: It’s a major problem throughout the PIPC system, including in Harriman State Park, where thousands of trees are standing dead and in need of removal, Shook said.

The infestation has been blamed at least in part on climate change that has created a more suitable environment for the metallic green beetle, which arrived from China around 2002. The bug’s larvae bore into the ash trees and feed under the bark, slowly starving their hosts to death.

Roots of revival

The slow and expensive effort to replace the white ash trees, delayed by COVID, will take root later this month with the planting of 200 native species through the state’s “Trees for Tribs” program. The new arrivals will be placed along a stream that flows from Rockland Lake’s Nature Center.

Organizers including the state Department of Environmental Conservation, state Parks Department and the PIPC are seeking volunteers to help with the project. Most of the holes will have already been dug; volunteers will primarily be planting, filling in the holes, raking and watering.

In the future, the PIPC hopes to restore some of the trees that were lost along the lake’s shoreline, and in areas to the south and west of the Nature Center, Shook said. The picnic areas also will likely be a priority.

The infestation isn’t confined to the parks.

The village took down an ash tree that was in danger of toppling onto the power lines in front of Bob Stien’s home in Upper Nyack. Stein, an avid hiker and board member of the Friends of Rockland Lake and Hook Mountain, has also seen the damage on the nearby Long Path.

His group has been recruiting volunteers for the October planting program, with an eye toward preserving the park for the next generation of visitors.

“I bicycle around Rockland Lake, walk around there, and I have seen the trees stacked up in the parking lot,” said Stien. “It’s noticeable. There are hundreds of trees that they've had to take down, and I’m grateful that something’s being done about it.”

How to volunteer

  • What: “Trees for Tribs” tree planting program
  • When: 9 a.m. Sunday, Oct. 17
  • Where: Near the Nature Center at Rockland Lake State Park in Valley Cottage
  • Registration: Volunteers (must be age 13 and older) should register in advance by contacting Matthew Shook at or 845-786-2701, extension 252
  • Details: Volunteers must sign a service agreement; those younger than 18 will need a parent to sign. Dress for hard work, wear sunscreen, bring gloves, a snack and water. Refreshments will be provided as well. Masks are recommended when you cannot maintain social distance.
A white ash tree marked for removal at Rockland Lake State Park on Sept. 28, 2021. Photo by Robert Brum
Rockland Lake State Park, where hundreds of trees have been lost to the emerald ash borer, on Sept. 28, 2021. Photo by Robert Brum
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