EAB girdled Sentinel Tree

For the 6th year in a row NE IA RC&D partnered with the Iowa DNR Forest Health Dept. emerald ash borer sentinel tree monitoring program. Sentinel trees are usually 4-6 inch diameter ash trees (sometimes smaller, sometimes larger) in parks and recreation areas that are at high risk for emerald ash borer infestations. Parks with campgrounds are at risk because the movement of infected ash firewood is the main method of transport for the borer. Depending on the size and number of campsites at each park, 1-5 ash trees are double girdled and the bark removed between the girdles. Each tree is tagged with a notice stating the tree is a part of the monitoring effort and GPSed to assist with locating the tree the following fall. It has been determined the ash borer is attracted to stressed ash trees first, so the girdled trees will be the trees that will attract any borers that may be in the area.

The following fall, the ash trees are cut down and the bark is peeled off in 6-10 areas of the tree, looking for the larva stage of the borer and evidence of it’s s-shaped tunneling activity. If undetected, an infestation of emerald ash borer eventually girdles the tree, essentially starving it of water and nutrients. Infected trees decline and die in 2-3 years.


Bark peeling ash tree for EAB

This year 416 sentinel trees statewide were inspected and all were negative for emerald ash borer. RC&D’s part of the monitoring was 100 trees in northeast Iowa parks and recreation sites.  Due to funding cuts, no sentinel trees were prepared for 2014.  At this time it is uncertain if the program will resume in the future.