Delco’s Tyler Arboretum to reopen miles of trails closed by devastating beetle attack

Tyler Arboretum in Delaware County was forced to close 17 miles of its popular trails last year after 1,400 trees were killed or severely sickened by the invasive emerald ash borer beetle, creating a public safety issue.

Now, arboretum officials say they plan to reopen 11.5 miles of trails, or nearly 70%, to the public on April 7 in time for spring blooms.

“We are thrilled to report that we are able to safely reopen the trails related to the first phase of the project,” Tyler’s executive director, Mike Skuja, said this week in an emailed statement. “But the public will enter a forest that looks quite different in some areas than they are used to.”

Millions of ash trees have been sickened or killed by the invasive emerald ash borer, a scourge since it began a widespread sweep of Pennsylvania’s private and public forests in the 2010s. The 650-acre Tyler Arboretum in Middletown Township has been at the end of the sweep, with its dogwoods, ginkgo, and maples — and ash trees. Some of the larger afflicted ash trees were more than 120 years old. Smaller ones ranged from 30 to 50 years old.

» READ MORE: Tyler Arboretum loses 900 ash trees to emerald ash borer, forced to close miles of public trails

The emerald ash borer, Agrilus planipennis, is a green, shimmery beetle that begins ravaging trees while still in the larval stage. It feeds underneath bark, disrupting the transportation of water and nutrients. It can kill a tree in three to four years. Signs of an attack include a dying upper crown, splitting or flaking bark, tissue damage, D-shaped exit holes, and S-shaped larval feeding galleries just below the bark.

Adult beetles grow to one-half inch long and one-eighth inch wide. They fly from early May until September. Larvae live beneath the bark until emerging as adults through D-shaped holes.

The best way to stop an infestation is to remove affected trees.

Arboretum officials decided last spring to see how much damage the pest had inflicted on the property and began mapping trees. They found more widespread damage than they expected. The pest inflicts a 99% mortality rate on trees.

Mike Karkowski, the arboretum’s director of horticulture, said it’s been a “substantial challenge” to staff and finances.

“The ash tree removal has been a huge expense, costing about $450,000 to date.” he said, noting a $103,000 grant from the state Department of Conservation and Natural Resources.

Karkowski estimates that Tyler needs $1 million more to complete a comprehensive restoration.

Arboretum officials expect the rest of the trails to be open by the end of 2024. They ask the public to enter the Arboretum property in Middletown Township, west of Media, through the Visitor Center at 515 Painter Rd.

There are still a significant number of hazardous trees in woods by Penncrest High School and in East Woods by the old Black Hawk Spring. The trails between Rocky Run and Dismal Run will reopen soon, according to Skuja.

The next phase of the project includes seeking more funding and creating a plan to help combat the overall threat of invasive plant species.

The emerald ash border is native to northeastern Asia. It was first discovered in the United States in 2002 in Michigan. It’s believed to have come from China in wooden shipping crates.

Pennsylvania’s Department of Conservation and Natural Resources (DCNR) first launched a plan in 2014 to tackle the problem.

At the time, the beetle had already reduced the number of ashes in the state’s forest by 12%. The pest began making its way through Delaware County about six years ago, the last of the remaining counties to see an infestation. Widespread treatment isn’t really an option because it’s so time consuming and expensive.

The U.S. Department of Agriculture blames it for destroying tens of millions of ash trees in 30 states.