Emerald Ash Borer Detection Efforts

Today DEEP Service Forester Larry Rousseau paid a visit to White Memorial to girdle several ash trees (Fraxinus spp.) to detect the presence of the invasive Emerald Ash Borer (Agrilus planipennis).

The Emerald Ash Borer (EAB) is a small, metallic green color beetle native to eastern Asia. The EAB was officially identified in the U.S. in 2002, and since has been responsible for the death of millions of ash trees. It currently is found in thirteen states and in parts of Canada. Ash trees infested with EABs are typically dead within one to three years. At this stage, the goal of USDA is not to eradicate the EAB, but to prevent additional spread throughout the entire country. Strict quarantines have been authorized to prohibit the movement of firewood out of states where EABs are known to live, as well as the transportation of firewood intrastate. 

Emerald Ash Borer
Photo by the University of Kentucky
http://www.ca.uky.edu/forestryextension/eab/EABindex.php

A technique used to indicate the presence of EABs is girdling ash trees. At White Memorial, four trees were girdled at various points around the property. Girdling is a cost-effective forestry management technique used to cut off the flow of nutrients inside an individual tree, eventually killing it. Girdling is used for this project because although EABs will occupy any Ash tree, they are most attracted to dead or dying ash trees in which to lay their eggs. When looking for the proper tree to girdle, Larry Rousseau and Lukas Hyder tried to find an intermediate size tree, with a DBH (diameter at breast height) of about 7 to 10 inches. They also wanted the ash tree to have a large canopy, reaching above most of the surrounding vegetation. Finally, it was important to locate a tree that far enough from roads and people so that if it was to fall it would not harm anyone and would remain undisturbed during the girdling process.  

Service Forester Larry Rousseau with ash tree after being girdled.

The first step when girdling a tree is to record the DBH using a measuring tape. Next, a shallow ring is cut around the circumference of the tree, which aids in the next step of shaving off the bark to the cambium layer. By the end of this stage there is an approximate 10 inch long ring of bare cambium around the tree. Tape is wrapped around the trunk to indicate that the tree is dangerous and to stay clear of it. Finally coordinates of the site are charted using a GPS. The tree will be left alone until mid-September. At that time it will be cut down, then sawed into bolts (short logs), and stripped of its bark. The logs and bark will be thoroughly analyzed to find if EAB larvae exists on the tree. If it is detected then the proper management techniques will be enacted to contain the EAB from spreading any further. Currently there is not a cure for EAB infestation, only pesticides to serve as a control measure. Therefore early detection is the obvious key factor to successfully contain the EAB.