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Northern Research Station
One Gifford Pinchot Drive
Madison, WI 53726
(608) 231-9318
(608) 231-9544 TTY/TDD

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Emerald Ash Borer

Predicting Ash Mortality due to Emerald Ash Borer

[image:] This graph shows output from the preliminary model predicting ash decline and mortality for a hypothetical stand of ash trees that becomes infested by emerald ash borer in 2007.  Nearly 100% of the ash trees in this stand are expected to die by 2013.Research Issue

Emerald ash borer (Agrilus planipennis) has already killed 25 million ash trees in Michigan and is expected to kill many more ash trees as it spreads.  Predictions of ash mortality in infested areas would allow managers to plan and budget for hazard tree removal, restoration activities, and pre-emptive harvests.

 Our Research

We are monitoring the decline of over 3000 ash trees in forested areas of Ohio and Michigan.  An easy-to-use rating system is used to classify the health of each ash tree yearly.  Our monitoring sites are on both public and private lands, ranging from 15 acre woodlots to >400 acre stands, in various successional stages, and encompassing all five ash species that occur in the region: white ash (Fraxinus americana), green ash (Fraxinus pennsylvanica), black ash (Fraxinus nigra), blue ash (Fraxinus quadrangulata), and pumpkin ash (Fraxinus profunda).  The data from the yearly ash decline ratings, as well as stand-level and tree-level data, are used to model ash decline.

Preliminary results show that healthy ash stands, once infested, can reach nearly 100% mortality of ash trees >1 in. diameter within six years.  During the first few years, ash decline is very slow and symptoms of emerald ash borer are not obvious.  Later in the infestation, ash mortality accelerates rapidly.

Expected Outcomes

We will make the best model available to managers as an interactive web tool for forecasting ash decline in their forest.  Based on their inputs, the model will predict the percent of the ash trees in their forests that will be declining and dead each year.  This tool will be made available both online and on a CD.  As more data is collected, the model will be revised and improved.  Researchers studying management techniques for emerald ash borer, such as biocontrol or insecticides, will also be able to use the model to understand the effect of the management technique.

Research Results

Knight, Kathleen S.; Brown, John P.; Long, Robert P. 2013. Factors affecting the survival of ash (Fraxinus spp.) trees infested by emerald ash borer (Agrilus planipennis). Biological Invasions. 15: 371-383.

Knight KS, Long RP, Smith A, Gandhi K, Rebbeck J, and Herms DA.  2008.  How fast will the trees die? A transition matrix model of ash (Fraxinus spp.) decline in forest stands infested by emerald ash borer (Agrilus planipennis).  In: Proceedings, Emerald ash borer research and technology development meeting.  pp. 28-29.  Pittsburgh, PA  23-24 Oct. 2007.  Abstract. 

Knight KS, Long RP, Rebbeck J, Smith A, Gandhi K, and Herms DA.  2008.  How fast will the trees die?  Modeling ash (Fraxinus spp.) decline in forest stands infested by emerald ash borer (Agrilus planipennis).  In: Proceedings, Ecological Society of America Conference.  Abstract.  August 2008, Milwaukee, WI.

Research Participants

Principal Investigators

Research Partners

Last Modified: 02/19/2013