2013/2014 Winter

In this Newsletter…

– Effect of extreme cold on Emerald Ash Borer (EAB)
– Minneapolis uses new tax levy for Ash tree removal

– Minneapolis recognized for urban forest
– Forest Tent Caterpillar and Gypsy Moth
– Conifer and long term drought effects

Emerald Ash Borer has been in the news even more lately.
Our take on it…

There has been a significant debate on the effect that this years extreme cold temperatures in MN will have on the established EAB population in the Twin Cities metro. Much of this came about from a Minnesota Public Radio story featuring the University of Minnesota’s Lee Frelich, a reputable source and frequent MPR contributor regarding forestry issues. The most significant statement, supported by research from the US Forest Service and the Minnesota Department of Agriculture is that larval mortality can be as high as 97-99% associated with temperatures below -30 degrees Fahrenheit.While the research is not debatable, there are many more variables for trees in the landscape that may affect the actual mortality of EAB larvae. Air temperature varies significantly based on the surrounding vegetation, topography, aspect, and the urban heat island effect. The fact that EAB larvae in our landscape overwinter under the bark of ash trees also mitigates the effect of cool temperatures. The native range of EAB is eastern Asia, which is climatologically similar to Minnesota. Therefore the insect is likely adaptable to the occasional temperature extremes. These factors coupled with the reproductive capacity of EAB will likely mean that despite some mortality, the population will rebound by the summer in the Twin Cities metro. The point taken is that the harsh winter weather may slow the establishment of the EAB population in the Twin Cities metro slightly, but it will not eliminate the insect.

Another attempt to control EAB, in a broader scope, has been the release of predatory wasps by the Minnesota DNR. Sampling is beginning to show that the predatory wasps, which do not harm humans, are establishing a population where they have been released. Since 2010, over 125,000 of the Tetrastichus planipennisi parasitoids have been released to slow the spread of EAB.  Their establishment may help to slow the spread of the EAB population in our area.

At Premium Tree Protection, we are often hired to protect people’s trees as assets in their landscape.   Our treatment protocol to prevent EAB in ash trees will not change unless new scientific discoveries are made or our observations in the field change. To this point, we are vigilant about keeping up to date with governmental and educational updates on the invasive insect that threatens nearly one billion Minnesota ash trees. There are many questions that are still being answered about EAB and the information is mostly new, don’t hesitate to ask Adam or Jason about how EAB might affect your tree or our urban forest in the metro area.

Minneapolis Tax Levy

A new tax levy is being used to remove ash trees in Minneapolis. Over the next 8 years, the city plans to generate $9 million and remove 40,000 Ash trees. Homeowners can personally pay for ash trees on boulevards and in parks to be treated with insecticide, although that requires hiring a Minneapolis Park and Recreation Board approved company to do the injecting. * Premium Tree Protection, LLC is a MPRB approved tree care company