Tree City faces serious problem

By Mary Ann Kane

Neighborhoods in Ann Arbor, Michigan have been known for their beautiful trees, creating a tunnel effect over the streets. Currently, thousands of local streets instead, are showing the effects of an invasive pest.

Briarcliff Street, on the city’s northeast side, is one that has been hit hard by the Emerald Ash Borer (EAB), an Asian beetle that has made itself home in Great Lakes ash trees. The infestation was first discovered in metro Detroit in 2002.Ann Arbor’s nickname of “tree city” is seriously threatened by this half inch long, metallic-green insect. To date, twenty-one counties in Michigan have been quarantined, as well as some in the northern Ohio, northeast Indiana, and Ontario.

The theory of how an Asian beetle arrived here in Michigan is that it hitched a ride in wooden packing material from Asia. The adult beetles feed on ash leaves, but the real damage is done by the larvae. In this stage, the insect feed on the inner bark, between the wood and the rough outer bark. This damages the tree’s ability to transport water and nutrients. The infestation is first noticed as dying back in the tops of trees.

Durwin Passsow, 71, a resident of Briarcliff Street for the past 30 years, said his first hint of a problem was when the large ash tree in his backyard started dropping cluster’s of healthy-appearing leaves from the top of the tree about three years ago. He consulted a friend who works for the forestry department, and was told that the tree was trying to save itself by reserving its energy for its main system.

The dying out worked its way down the tree, so Passow had the tree taken down two years ago before it was completely dead. He stated that his street previously was lined with ash trees, which have now all been removed.

It is estimated that the state of Michigan has over 700 million ash trees. Emerald ash borers have infected over 15 million trees, and killed over 10 million in southeast Michigan thus far. The city of Ann Arbor will lose more than 10,500 to the infestation. Hundreds of trees are being removed every week. The city anticipates that tree removal will be completed by approximately December 2007, and stump removal a year later.

Dr. Peter Sutherland, a biology teacher at Ypsilanti High School, stated both he and his parents have lost ash trees that are at least 40-50 years old. When asked if he thinks the emerald ash borer will wipe out all the ash trees in North America, as some have predicted, he replied, “I believe it is very serious threat; however, as is the case in biology, evolution will favor survival of the fittest.”

“There will be trees that survive due to random mutations and will have some resistance to EAB or will be strong enough to survive due to other genetic factors,” Sutherland continued. “I think it is unlikely to kill all ash trees, but it will wipe out most of the population.”

Experts say the most common way that the EAB is spread is through transportation of infested wood, often firewood. The quarantine prohibits ash wood from being transported out of the quarantine area in any form larger than one inch in diameter. It is important to know that even healthy-appearing wood can be infested with the emerald ash borer larvae.

The AAA Great Lakes Camp book for 2006 mentions neither the EAB nor the quarantine on transporting wood outside the quarantine zone. A review of other campground guides revealed that none mentioned the EAB, despite a publication date of 2005 for one guide.

Anyone who inadvertently moves non-coniferous firewood out of the quarantine area should burn the wood completely and report it to the state Emerald Ash Borer hotline, 866-325-0023, immediately.