To address urban sprawl, educate developers and network with planning and engineering colleagues to balance gray and green infrastructure.

Web Extra

For an example on balancing grayray and green infrastructure, visit the “article links” page under “resources” at www.pwmag.com.

Immune to invasion

Scientists work to develop disease-resistant trees.

In just six years, the emerald ash borer (EAB) went from an emerging pest in Michigan to one of the most significant menaces to North American ecosystems, threatening to wipe out an entire species of trees.

The Ohio State University researchers are working to identify the proteins or metabolites that make ash trees from Asia resistant to the Asian beetle. Meanwhile, the U.S. Forest Service is studying breeding approaches to develop a hybrid between North American and Asian ash species.

“If our approach works we intend to perform backcrosses so that through breeding we get trees that look and act like the North American parent and essentially retain only the resistance from the Asian parent,” says Jennifer Koch, a research biologist with the Forest Service.

Both studies are a long way from bearing fruit. Other studies to watch:

  • The American Chestnut Foundation's effort to restore the tree to its native range. In 1904, an Asian fungal disease killed an estimated 4 billion trees, which once comprised one-quarter of forests in the Eastern seaboard. In 2005 the foundation harvested its first blight-resistant nuts. The foundation anticipates starting reforestation trials by 2010; if successful, this process could set a template for restoring other tree and plant species. For more information, visit www.acf.org.
  • The National Elm Trial, a multistate effort to evaluate and promote commercially available disease-resistant American and hybrid elms. Dutch elm disease was accidentally introduced into the United States from Asia in 1928. Although disease-resistant cultivators are available in nurseries, there's not enough scientific data on growth, form, and pest resistance for these trees to garner broad public acceptance. This study aims to provide that data. Visit http://treehealth.agsci.colostate.edu.
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