The Princeton Shade Tree Commission (STC) and the Town Council are teaming up to combat an infestation of the Emerald Ash Borer (EAB), a beetle that has killed hundreds of millions of ash trees in 25 states since its arrival in the U.S. in 2002.

At Monday’s Council meeting, the STC presented an extensive report, providing information on the tree population, the state’s recommended management options, and cost projections to address the EAB outbreak.

“It’s a huge concern, not just for Princeton, but for the whole United States,” stated Princeton Mayor Liz Lempert. “It will have a huge impact on our ecosystem.”

The STC will hold an information session on the EAB for Princeton residents on Thursday, June 23 at 7 p.m. in the Main Meeting Room of the Municipal Complex.

The emerald ash borer has been found in one ash tree in Princeton and in ash trees in several other nearby communities. It spreads easily to neighboring trees, and all residents are urged to check their ash trees for symptoms of infestation.

“The emerald ash borer will kill 99 percent of all ash trees within the next few years,” said Lorraine Konopka, Princeton municipal arborist. “Residents should identify ash trees on their property and monitor for signs of damage or decline, such as unusual woodpecker activity or missing bark.”

The STC concluded that the municipality needs to decide on the preferred option for action on street trees, then plan and budget for removals, treatment, and/or replacement of ash trees (with different species).

The EAB is a small, metallic green, non-native invasive beetle. It can inhabit a tree for years before the tree begins to show symptoms of infestation, which include canopy dieback, woodpecker activity, missing bark, D-shaped exit holes, shoots sprouting from the trunk, and S-shaped larval tunnels under the bark.

High-value ash trees in good health can be treated before they become infested. But if a tree is already infested or in poor health, it may be best to remove the tree before it dies and poses a hazard.

Implications for Princeton, as outlined by the STC, include safety, particularly with trees that are dead and dying; cost, including the expense of identifying and evaluating ash trees, developing and funding a plan for removal, treatment and/or replacement; and environment, risking impact on storm water mitigation, cooling/shading effect, air quality, property values, and quality of life.

Of approximately 18,800 total street trees in Princeton, according to inventory data from 2010 (Borough) and 2013 (Township), about 2070, 11 percent, are ash trees, but the central business district has surprisingly few (about 60) ash trees.

Some newer housing developments, the STC reported, contain only ash trees and will require treatment or replacement (with different species) to retain their appearance. The majority of street ash trees are located along wooded roads outside of the center of town, and removing them may leave relatively few visually empty areas. Replacement may be unnecessary.

With costs estimated at $425-$1000 per tree for removal, $540-$1305 for treatments per tree over 10 years, and $400 to replace each ash tree with a different species, the total expense for the town over the next 6 years would be approximately $1.7 million for selective management, and $1.6 million for removal of all ash trees with no treatment and no replacement.

The Town Council will be reviewing options in the coming weeks. Homeowners are not required to remove or treat street or public ash trees, but they may request written permission from the town arborist to treat or remove street or public ash trees.

Individuals can contact the Board of Certified Tree Experts at (732) 833-0325 or njtreeexperts@gmail.com for a list of professionals serving the Princeton area or check the directory of Mercer County certified tree experts that will soon be available on the Princeton STC website (www.princetonshadetree.org).

Pam Zipse, outreach coordinator for the Rutgers Urban Forestry Program, will present an overview of the insects as well as recommendations from state agencies at the June 23 information meeting, and members of the Shade Tree Commission will discuss Princeton’s ash trees. Ms. Konopka will respond to questions about the emerald ash borer in Princeton.