Ashes to Ashes

     With the leaves down, trees like the one at the left, stand out in the forest.  You can pick them out, even while driving down the road.  Have you seen them?  These are trees that have a very light brown bark.  Actually they are loosing their bark - woodpeckers are rapidly chiseling it off.  These trees are dead, or nearly so. Don't blame the woodpeckers; the tree was already 'mostly dead' and they are just looking for food.  This tree's demise is the result of yet another invasive species from Asia - the emerald ash borer.

    


     Emerald ash borers are small metallic green beetles that appeared near Detroit in 2002.  In the last twelve years, they have infested 18 states and are voraciously devouring our native ash trees.  Emerald ash borers are about 1/2" long and can fit on a penny.

Emerald ash borer exit hole

     A female emerald ash borer lays about 100 eggs on the bark of ash trees.  The larvae hatch and eat through the outer bark.  It is the larvae of the borers that do the real damage.  They eat the inner bark and new sap wood of the ash tree.  The adult beetles emerge from 'D-shaped' exit holes about a year later. Within four years of the initial egg laying, the tree is dead.  So far these insects have killed 100 million trees and there isn't much to slow them down.

     Currently scientist are experimenting with several pesticides that are injected into ash trees or applied to the soil around the trees.  There has been some limited success, but they must be applied every 1 to 2 years and consistent treatment will probably harm the tree.

     Some scientists have experimented with releasing parasitic wasps that control the borers in Asia.  The obvious problem here is introducing another alien insect to deal with the one that we already have. Hopefully, these methods, plus the possibility that some individual ash trees my be naturally resistant to the borer, will enable at least a few trees to survive.
     Ash trees have some of the toughest wood of any North American tree.  For centuries this wood has been used for snowshoes, canoe paddles, sleds, wagons, skis, tool handles, hockey sticks, and (of course) baseball bats.  In fact, the famous Louisville Sluggers, used my most major league baseball players, come from white ash trees in northern Pennsylvania and southern New York. 

     Unfortunately, the future of these trees is very much in doubt.  Many believe that we are witnessing the same devastation that past generations saw with the American Chestnut blight (see my previous post: http://lutherlynnature.blogspot.com/2012/12/100-american-chestnuts.html).  The future of the North American ash species will probably lie in programs many years down the road.  We will have to rely on future generations to bring back our ash trees.

      There is something you can do, though, to at least slow the spread of the infestation:  Don't transport firewood.  The adult borers often hide in firewood and transporting it can cause the devastation to spread.  For more information, please see the USDA website:  http://stopthebeetle.info/

      Also, please don't take out your frustration on another emerald colored beetle.  The six-spotted tiger beetle is one of my personal favorites.  It is a great predator and eats lots of small insects and spiders.



Six-spotted Tiger Beetle