Leading Professionals Issue Emerald Ash Borer Statement

A statement about Emerald Ash Borer

Below is a statement issued by leading industry researchers and professionals.


We the undersigned strongly endorse ash tree conservation as a fundamental component of integrated programs to manage emerald ash borer (EAB) in residential and municipal landscapes. Cost-effective, environmentally sound EAB treatment protocols are now available that can preserve ash trees through peak EAB outbreaks with healthy canopy intact. Used in association with tree inventories and strategic removal / replacement of unhealthy ash, tree conservation will help retain maximum integrity and value of urban forests. This integrated approach to urban EAB management is supported by university scientists with expertise in EAB management, commercial arborists, municipal foresters, public works officials, and non-governmental organizations (NGOs). Emerald ash borer has killed millions of ash trees since its discovery in 2002 and the number of dead ash is increasing rapidly. Ash species are abundant in planted and natural areas of urban forests, representing 10 - 40% of the canopy cover in many communities.
Ash trees provide substantial economic and ecosystem benefits to taxpayers, ranging from increased property value, to storm water mitigation, to decreased energy demands (http://www.coloradotrees.org/benefits.htm). Consequently, widespread ash mortality in urban forests and residential landscapes is having devastating economic and environmental impacts. Indeed, EAB is predicted to cause an unprecedented $10-20 billion in losses to urban forests over the next 10 years.

After its initial discovery, regulatory agencies attempted to eradicate EAB through removal and destruction of all ash trees in infested areas. Unfortunately, this proved unsuccessful and was soon abandoned. Since then, university scientists have developed and refined treatment protocols that can protect healthy ash trees from EAB and help conserve the urban forest. However, despite availability of cost-effective treatments, many municipalities, property managers, and homeowners continue to rationalize tree removal as the only viable management strategy for EAB. This is based on erroneous beliefs that tree removal slows the spread of EAB, or that treatment is not effective, economical, or environmentally sound. Current science supports conservation via treatment as a sensible and effective tool for managing healthy ash trees in urban settings. In many cases, tree conservation is economically and environmentally superior to tree removal. Based on research conducted by university scientists, and
careful review of the potential impacts on human health and the environment, the Environmental Protection Agency (EPA) has registered three systemic insecticides for control of EAB – dinotefuran is registered for basal trunk bark or soil application, emamectin benzoate for trunk injection only, and imidacloprid for soil application or trunk injection. When applied using formulations, products, and protocols documented as effective by university research, these treatments can provide environmentally sound control of EAB, sufficient to maintain a functional and aesthetically pleasing ash canopy.

Treatment is most appropriate after EAB infestation has been detected within 15 miles, and is most effective when applied before trees are infested. However, treatment can also save ash trees with a low level of EAB infestation. Spring is the ideal time for treatment, but soil application in fall can be effective in some situations. Different treatment regimens will be optimal under different situations -- no one treatment plan or application method is best under all circumstances. A program of sustained treatment will be needed to conserve trees through peak EAB infestation. However, as the local EAB population declines due to death of untreated ash, it is possible that treatment frequency maybe reduced. Research on this question and other aspects of EAB management is ongoing, requiring practitioners to stay current.

In summary, urban ash conservation can be less costly than removal, especially when the significant environmental and economic benefits of established trees are considered (www.treebenefits.com, http://extension.entm.purdue.edu/treecomputer/). Furthermore, ash conservation can circumvent the
substantial environmental impacts caused by wholesale deforestation of the urban landscape, as well as
the documented public safety risks associated with standing dead ash trees and their removal.
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