This article was featured in the 2023 summer newsletter by Johnathon Rosenthal with the Ecological REsearch Institute. 

The Monitoring and Managing Ash (MaMA) program of the Ecological Research Institute (ERI) has made considerable progress in its efforts to detect “lingering ash”, trees that likely have some resistance to emerald ash borer (EAB) and from which material can be used to breed highly EAB-resistant trees. Already, in the Hudson Valley and Catskills, where EAB has long been established, MaMA has enabled detection of over 30 lingering ash.

As EAB’s invasion expands in the SLELO region, participation in MaMA needs to expand as well, so locally adapted lingering ash can be found. Through efforts of partner institutions and citizen-scientists, we are already receiving data from several MaMA Monitoring Plots Network plots across the region. The data are crucial because lingering ash can only be found after 95% of the ash in an area have been killed by EAB, and the plots tell us when this threshold is reached.

Lingering ash in area with almost 100% ash mortality. © R. Wildova, ERI


Monitoring a plot is just one way you can help find lingering trees, which provide great hope for the future of native ash species. ERI has just unveiled a new MaMA component, the Rapid Ash Mortality Assessment (RAMA) project, which takes less time than monitoring plots. An even easier way to participate is using the MaMA Ash/EAB Surveys project to report sites where you do or do not find EAB, enabling us to track EAB’s spread. Finally, after the 95% mortality threshold has been reached, you’ll be able to use the MaMA Lingering Ash Search project to report lingering ash.

Lingering ash are rare for all the native ash – white, green and black. Therefore, if you manage ash, instead of proactively cutting all of them, enough trees should be left standing that there will be a chance one or more will turn out to be lingering trees.

Now, MaMA plays a prominent role in the Tree Species in Peril Collaborative Initiative led by The Nature Conservancy in collaboration with the US Forest Service, through which its implementation is being extended throughout New England.

For more information on the MaMA program please visit, where updated training videos and a SLELO MaMA Action Map prioritizing particular actions for different areas in the region will be posted, or email,

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