August 21, 2017


Millions of N.J. trees are going to die and we're powerless to stop it. That sounds like a dramatic headline from NJ.com, but the situation is very serious.


This is our third article about dangers to several tree species. Last October we introduced the issue with this article:  
Ash, Pin Oak & Red Oak Trees at Risk. We followed it in March 2017 with Update on Trees at Risk.  This July, theStar Ledger released their article, hopefully bringing the issue to a wider audience.

The local update:  As of 2017, the Emerald Ash Borer (EAB) has been detected in Hunterdon County, but not yet in Readington Township.  However, it is only a matter of time, as the 
borer is typically present for about six years before it is first detected.  And 99% of ashes in infested areas die.  Once dead, ash trees rapidly become brittle and prone to failure of branches and of entire trees, making them a liability along roadsides.

During the past dormant season, a number of volunteers helped identify and count ash trees along township roads.  Identifying ash trees in the winter is not easy, but the volunteers provided an estimate that the Open Space Advisory Board could present to the township committee as a first step towards dealing with the emerald ash borer problem.  The township committee has authorized the funds needed to assess and deal with the EAB issue.

The next step will be to get an accurate inventory of ash trees on township roadsides by Raritan Valley Community College students so that the township committee and residents can make informed decisions on which roadside trees to keep and treat, and which to remove and, in many cases, replace.

There is hope for the future, in that the state of NJ is releasing parasitic wasps that attack and kill the EAB at different stages of its life cycle.  Since stem injection treatments to control EAB last two years, it might be that after several two-year cycles of treatment, the beneficial wasps will provide control and chemical treatment can be gradually phased out.

Be aware that not every declining ash is under attack by EAB.  Ashes have been somewhat randomly but frequently declining and dying for many years due to a disease 
known as ash yellows, which looks similar to EAB and cannot be treated.  In the last year, an outbreak of ash bark beetle has occurred in scattered locations and has killed many trees.

As mentioned in an earlier article, Pin and Red Oak (the NJ state tree) are at risk from Bacterial Leaf Scorch (BLS).  Our wet spring and summer might help to reduce the damage caused by BLS this year.

Last, one good bit of news is that the Asian Longhorned Beetle, which was larger, slower and 
more easily
detected than the EAB, was eradicated in NJ in 2013.  That’s one less problem to worry about.

Update:  Ash, Pin Oak & Red Oak Trees at Risk