Hold off pruning ash trees until fall

As our trees, grass and flowers responded to an earlier spring this year, so did a beetle that attacks and kills ash trees. Emerald ash borers are present in Minneapolis and are normally active from May through Labor Day, but thanks to the warm spring this year they are considered active April 18 by the Minnesota Department of Agriculture. If you have an ash tree in your yard, it is important not to prune it this time of year or move any part of an ash tree (firewood, branches, etc.) while the pests are active. Inadvertently moving the pests helps them spread to uncontaminated areas.

Emerald ash borers are a major concern because they have caused the deaths of millions of ash trees in 13 states, and approximately 20 percent of the tree canopy in Minneapolis consists of ash trees. The Minnesota Department of Agriculture has issued a state quarantine on firewood, ash trees, and ash tree products in Hennepin, Ramsey, Houston and Winona counties to slow the spread of emerald ash borers.

Research has proven that trees are a valuable investment and improve urban quality of life. Healthy trees are beautiful, increase property values, help improve air quality, reduce greenhouse gases by absorbing carbon dioxide, save energy, keep the city cooler, provide homes for wildlife and help manage stormwater. If you have space in your yard to plant a tree, consider getting one going so it can get a start on providing shade.

Not sure if you have an ash tree in your yard? See ash tree identification tips (pdf).

For more information on emerald ash borers, visit the Minnesota Department of Agriculture emerald ash borer Web page or the Minneapolis Park and Recreation Board’s emerald ash borer Web page.

Published Apr. 18, 2012