Grasping the Gravity; Emerald Ash Borer

I witnessed an unintended consequence of the global economy as I drove I-80 across Ohio this summer.  I’m not referring to the idle factories left to rust, long abandoned for cheap labor and lax environmental regulations of the ‘global south.’  Nor do I mean the big box stores and Starbuck sameness off every exit that makes one unsure if they ever left home, because no matter where you go, there they are, the  same  seven choices.  No, I’ve gotten over, worse than that, I’ve gotten comfortable with these aspects of globalized American life.

What caught me off guard were millions of dead and dying ash trees.

As an arborist living and working in Central Pennsylvania, I had heard over the past few years the reports coming in with increasing frequency from the Midwest, parts of Maryland, and recently the western part of my own state on the damage inflicted by the exotic insect pest, the Emerald Ash Borer. But until you actually see the damage in person, it is something akin to a Tsunami or earthquake on the other side of the world.  Yeah, you’re shocked, even saddened by the disturbing visuals and grim stats that you catch in the news, but until you see it, tragedy at a distance remains primarily a media event that is easy enough to tune out

Ash Trees die back, some eventually die, after EAB infestation.

I drove in quiet anguish for a hundred miles, my wife and baby girl, sleeping in the back seat.  I knew it was bad before my trip through Ohio, but for some reason, I thought I would have to look closely to see evidence of damage due to the Emerald Ash Borer.  I didn’t expect it to be so obvious and in my face. Periodically, I focused on individual trees flashing across my windshield at 70 miles per hour looking for the stout opposing twig configuration confirming ash. As if just the gestalt of all of those bare trees under the summer sun could have indicated something other than what I knew it was.

The Emerald Ash Borer is a smallish green beetle native to Asia and was first discovered in the US near Detroit, Michigan during the summer of 2002. Since its arrival, the Emerald Ash Borer has killed tens of millions of ash trees in Michigan alone, and spread to 12 states and 2 Canadian provinces.  Although minor foliar damage is caused by the adult beetle, the primary damage is inflicted by the larvae that feed on the inner bark of ash trees.  Before long the infested tree’s plumbing is compromised and the tree quickly declines due to its inability to transport water and nutrients.

Emerald Ash Borer most likely stowed away in solid wood packing material originating from China or elsewhere in Asia.  It takes a fair bit of wood to pack up all of the products that are made in China these days and exported to the US.  It makes good economic sense to use the insect infested low grade lumber from the countries of origin for this purpose.  Who would have thought that the time it takes to log a dead ash tree in China, get it to mill, use it for packaging and load it on a huge container ship would correspond with the larval stage and emergence of the adult beetle? When the container doors swing open in Detroit, Philadelphia, or anywhere else the adults are ready to fly out in search of a fresh Ash to lay their eggs.  Efficient? Yes. Recipe for disaster? Yes.

Larvae create tunnels as they feed in the phloem and outer sapwood, producing galleries that eventually girdle and kill branches and entire trees.

Once here, the rapid spread of the pest is not attributed to the wings of the adult beetle alone, for they only travel up to several miles before mating and depositing eggs on other ash trees. The spread is hastened by interstate transport of infested wood products and nursery stock, and repeated introductions from abroad.

Millions of dollars have been spent trying to slow the spread of EAB with little effect.  However, arborists have had great success protecting ash trees systemically.  EAB can be managed as well as any other insect pest, but it does take preventative and sustained care. Easy enough, for the concerned homeowner with a few ash trees, but not a viable proposition on an ecosystem level.

Returning home, I look at the ash trees in the communities that I service like I do the locally owned coffee shop, book store or grocery store; living relics bracing in a hurricane of change. It is my hope that by the time the the storm finally abates we have come to embrace diversity and complexity with the same zeal that we currently pursue efficiency and sameness.

An EAB larva inside a tree. Adults do little damage.