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Ewing, NJ 08628

Emerald Ash Borer

Photo credit: Steven Katovich, USDA Forest Service,

Got Ash Trees? What You Need to Know

The Ash trees in Ewing have been invaded by an invasive Asian Beetle, the Emerald Ash Borer (EAB), which attacks and kills our native ash trees.  “The emerald ash borer will kill 99 percent of all ash trees within the next few years,” said Bill Brash, the NJ State Certified Tree Expert with whom the Township has been working on the EAB threat to the municipal tree canopy.  “All Ash trees should be considered at high risk.   This will not only cause potential devastation to our tree canopy but also create hazards on your property.  The branches of dead Ash trees are particularly brittle and have high potential to fall and hit people, structures, or cars.”


Eradication is not feasible.  The pest has killed millions of Ash trees since it was accidentally discovered in Michigan in 2002 and its spread (to over 25 states) has been extremely rapid.  It was first discovered in NJ in 2015.   As this invasive pest can easily spread to neighboring trees, all residents should identify Ash trees on their property and monitor for signs of damage or decline. 

What to Look for in Infested Trees

Early detection is difficult as the exit holes are tiny and the infestation starts from the crown of the tree.  However, since trees only live an average of 3 -4 years after infestation, it is important that you contact a qualified arborist as soon as possible to determine if the tree can be saved.

  • Woodpecker damage is often the first sign- the outer bark is scraped off, leaving smooth light colored patches
  • Crown dieback – thinning starts at the top of the tree and becomes progressively worse as more nutrients are cut off
  • Bark splits – these are vertical and result from the callous tissue that grows around the EAB feeding galleries (see S-shaped galleries following)
  • Epicormic branching – sprouts or suckers at the base of the tree grow when a tree is stressed
  • S-shaped galleries weaving back and forth on the surface of the wood will be seen under the bark
  • Small D-shaped exit holes (in contrast to the round or oval exit holes from other insects)
  • You may see the beetle itself from May thru August

 What You Should Do

  1. Determine if you have ash trees (or white fringe trees) that are susceptible and can be saved.

    To identify a tree as ash, it has a compound leaf with five, seven, nine or 11 leaflets.  Use the links below to assist you in determining if a tree is an ash.  You may also contact your local Rutgers Cooperative Extension office.
  1. Assess the condition of your trees
  • Áre they healthy and vigorous?
  • Do they have more than half their leaves?
  • Do you see any sign of insect damage?
  1. Are your trees in a good location away from utility wires and other obstacles?
  • Is there enough room for the tree to grow to its full potential height of abt. 50′?
  • Is there enough room to accommodate its full crown spread of 45′?
  1. Is your tree a specimen or heritage tree?
  • Is the circumference more than 60″ (measured at 4.5′ from the ground)
  1. Treat and Monitor
  • Call a Tree Professional to apply a preventative treatment to your ash tree with a circumference of less than 60″.   Be sure to get at least two estimates and ask for insurance and references.
    • I. Timing – April 1 – May 15 
    • II.Treatment – Soil drench – see licensed Tree Professional for details 
    • III.Precautions – Follow label directions 
    • IV.Reapply – Annually for 20+ years. (See Rutgers infographic for options at a glance)
  • Be sure to work with a Certified (Licensed) Tree Expert or Approved Consulting Forester to help determine whether your ash trees are good candidates for a treatment program, or whether tree removal is the most appropriate response.

Emerald Ash Borer

Emerald Ash Borer

Ewing Municipal Response

More than 890 trees have been identified on municipal lands in a 2015 Rutgers Study.  (link)  Following receipt of the study, the Township applied for a grant in early 2016, Partnering for the Restoration of the Community Forest: The 3P Plan, Partnerships-Plan-Planting to support development of partnerships to manage this threat to our tree canopy.

Members of Ewing’s Green Team and Environmental Commission have been working under the direction of NJ State Certified Tree Expert Bill Brash to administer the grant.  They have formed a partnership called the Ewing EAB Partnership with representatives from Mercer County, Rutgers University and PSE&G to further identify ownership and manage the spread and removals of trees infected with the Emerald Ash Borer on Ewing municipal lands. 

Work in Process

  • A homeowner information session was held in February 2017. 
  • Additional Ash tree data collection is ongoing
  • A small replanting program was conducted in the spring of 2017 as part of the grant.

Additional Resources