Sarah Kirchner, staff writer

Emerald ash borers are a growing concern among many environmentalists, campers and campgrounds, causing millions of ash trees to die in the Midwest area.

Many campers have surely heard the &8220;Buy it where you burn it&8221; firewood campaign. Over the Memorial Day weekend the Minnesota Department of Agriculture and other groups throughout neighboring states had a campaign temporarily tagging ash trees in parks and public areas to raise awareness of the growing epidemic that has destroyed 20 million ash trees already.

Adult emerald ash borers lay eggs on the bark of ash trees and when those eggs hatch the larvae bore under the bark and into the tree completely destroying the tree&8217;s circulatory system and killing the tree. The insects themselves can only travel a few miles, but firewood sales, nursery stock and lumber transportation has increased the spread.

Fortunately, the emerald ash borer hasn&8217;t yet reached Minnesota, as far as experts know, but many campgrounds and environmentalists are taking extra precautions to make sure the pest stays away. The MDA said Minnesota is more at risk than other states because of the large population of ash trees. Over 850 million ash trees could be at risk.

&8220;We&8217;re doing the best that we can as a tree company to be conscious of what we&8217;re doing and where our firewood goes,&8221; said Jay Sullivan, owner of Harmony Park in Clarks Grove and a self proclaimed environmentalist.

Sullivan and those at Harmony Park aren&8217;t required by law to limit where the firewood used in the camp comes from, but they are anyway.

The emerald ash borer, which originated in Asia, was first discovered in Detroit in 2002. Since then, the beetle has shown up in the rest of Michigan, Ohio, Illinois, Indiana and Maryland. Experts and the MDA say it is only a matter of time before it ends up in Minnesota.

&8220;Minnesota is a sitting duck for EAB because we have a huge population of susceptible ash species such as green, white and black ash,&8221; said MDA Commissioner Gene Hugoson in a press release. &8220;In many cases, these ash trees are prized shade trees in our urban lawns and parks. The bottom line is that EAB could rival Dutch elm disease as the worst thing to hit Minnesota trees in our lifetime.&8221;

Since its discovery, there has been a federal quarantine around the known affected area, prohibiting the removal of firewood and lumber.

Adult emerald ash borers can be characterized by their bright metallic green color. They are half an inch long with flattened backs and purple abdominal sections beneath the wing covers.

Larvae are creamy white and legless, have flattened, bell-shaped body segments and the terminal segment bears a pair of small appendages.

Trees infected by emerald ash borers show many symptoms. The most obvious is the canopy dieback of leaves starting in the top third of the tree and progressing until the tree is bare. Epicormic shoots also start to grow as the top of the tree declines, causing new shoots to grow lower on the tree with leaves often larger than usual.

Upon further investigation, evidence of infestation can be found under the bark and even through bark splitting. When the larvae start to bore into the tree, bark splitting occurs with vertical fissures from callous tissue formation, while exposing S-shaped galleries where the bark split.

As the larvae eat through the tree they leave behind serpentine-shaped galleries packed with a mix of sawdust and excrement that weaves back and forth across the woodgrain. As adult emerald ash borers emerge from the tree they leave a D-shaped hole.

Many species of woodpeckers feed on the emerald ash borer, causing woodpecker damage as well, such as large holes when they extract the bug.

Freeborn County has a moderate risk of infestation, but the risk increases in the Twin Cities and surrounding area. The insects prefer white, green, blue and black ash and usually leave mountain ash alone.

Since 2005, the MDA has run a statewide monitoring program to ensure the safety of the state&8217;s ash population. The organization hopes to find the infestation as soon as it enters Minnesota, to quell the spread.

Currently state parks have regulations on firewood, but smaller parks aren&8217;t mandated by law although many are working to prevent the spread by taking precautionary measures anyway.

Most firewood must be purchased at the park where you are going to burn it. The best plan of action is to create awareness, Sullivan said.

&8220;Don&8217;t move your firewood,&8221; he said. &8220;Buy your firewood where you plan to burn it. That seems to be the best way to keep it from spreading.&8221;