Pikes/Pines | The Vancouvers have fallen: Emerald Ash Borers have reached Washington

A little over a month ago, the first Emerald Ash Borer, Agrilus planipennis, was found in Washington State. This is devastating news, because this invasive metallic green beetle is essentially a death sentence for the ash trees of the Pacific Northwest. It may have been inevitable, but that doesn’t mean we can’t mourn the future losses and do our best to slow the expansion of this true disaster.

For those not familiar with the story of the Emerald Ash Borer (EAB), there’s a boatload of information about them online (including this, written by yours truly). However, here’s a brief recap. These little beetles were accidentally introduced to North America from Asia and were first noted in Michigan in 2002. For the past two decades they have been tearing through North America’s ash trees, both wild populations and urban street trees are being devastated by the beetle, which has no environmental controls outside its natural range (trials of biological controls like using parasitic wasps have been largely unsuccessful). Thus far, there are no permanent solutions to EAB, even insecticides are only somewhat useful.

When I call Emerald Ash Borers one of the worst invasive species in the United States, I’m not just being dramatic — millions of ash trees have already succumbed to them across the country. This topic deserves an update on Pikes/Pines because we know this will happen in the near future — earthquakes, volcanic eruptions, and the climate crisis all will too, but they all feel different. We’ll see ashes decline and disappear from our urban and wild landscapes in the near future.

For now, the trees of Capitol Hill are safe, but with detections in both Vancouver, BC and now Vancouver, Washington we are hemmed in and have a pathway of both urban and wild ashes leading right to us. To their credit, the Washington State Department of Agriculture and the Washington Invasive Species Council have been pulling out all the stops possible, spreading the word, providing sound scientific information, and establishing a quarantine that aims to stop untreated firewood from entering the state. There are also pathways for both municipalities to gain assistance for urban forest planning and for citizens to contribute by reporting sightings.

To this last point, without a pair of engaged citizens, we might not yet know that EAB had made it to Vancouver, Washington. They found the beetle on their windshield on August 3rd in a small community just north of Vancouver, and after deciding it was likely the invasive pest, captured it, and got it to the State. While no one was astonished by the discovery because they’d been in the Portland area for several years, it could have been months or even longer before any other means of detecting the beetles proved fruitful. Citizen involvement in reporting potential sightings (there are several lookalikes), could be key to helping municipalities to plan for EAB impacts.

For now the only option may be to turn to pesticides injected into healthy, uninfested ashes. The cocktail of chemicals used as a preventative treatment for EAB requires planning, professional application, and continual reapplication to be even somewhat effective. For the average homeowner with an ash, this might be out of the financial question. For municipalities like Seattle, starting to treat as a way to forestall millions of dollars worth of costly, dead and dying hazard trees hitting the budget all at once, it is likely the best option.

Sadly, we benefit from decades of EAB impacts elsewhere – research has demonstrated the efficacy of the various approaches. Allowing trees to become infested is a guarantee for tree death. According to the EAB Resources & Management Guide for Washington State, “the United States has collectively spent over $900 million in street tree management costs in the last 30 years due to EAB.”  Because we understand the beetle’s biology, their specific impacts on different ash species, and how treatments have worked, Seattle stands to weather the storm, even if the ash trees don’t ultimately make it long term. One thing that’s clear is that aside from pesticides, another preventative measure is discontinuing the planting of ash trees.

If efforts to stop accidentally spreading wood infested with EAB larvae are successful, it could be years before we see them on the Hill. Studies have estimated that the beetles naturally disperse at a rate between 1.6 to 12.4 miles per year, depending upon conditions and available hosts, (which are numerous — there are river valleys and wetlands full of ashes between here and Vancouver, Washington). So maybe we are at least ten years out from touchdown — assuming the beetles haven’t already inched closer than we’ve realized, which is entirely possible.

Losing street trees is a shame, but the real horrific future is one without our native Oregon Ash, Fraxinus latifolia, the only one we have. Trying to imagine our riparian ecosystems without Oregon Ash is gut wrenching because EAB impacts are not just about impacts on trees. Oregon Ashes are vital members of wetland and riparian communities across their range, they are food and shelter for countless species. Indigenous peoples have deep relationships with this tree as well. (The decline of other ash species across the US has taken a heavy toll on various cultural practices most notably in the case of their use in basketry.) We aren’t just losing a tree, we are losing a point of connection, a member of complex communities. It’s hard not to feel helpless knowing that while we might be able to run around and inject street trees to keep them going, we’ll never be able to save entire forests full of Oregon Ash. The repercussions are yet unknown but in places with high densities of ashes (like so many lovely rivers and lakesides across Western Washington, including the watery edges of the Washington Park Arboretum), could see large changes in water and soil chemistry, increased invasive species presence, and declines in native fauna that rely on the trees.

Ecological horrors have already been inflicted upon our region, but I find it very difficult to just sit and bear witness to an essentially inevitable wave of beetles approaching us. I also think it’s important to realize that this isn’t about demonizing the organism, invasiveness is a symptom of globalization and capitalism — the beetles aren’t evil, they are just beetles being beetles. Knowing all this, our job is to stay vigilant, report potential sightings, and stay up to date. There is a strong chance this won’t be the last time I write about Emerald Ash Borers, which is ironic because I have never met one in person. Unless I am somewhere in Eastern Asia, I truly hope I never do.

How to report

• Online at invasivespeciaswa.gov
• The Washington Invasives app available for free on Google Play and the Apple App Store.
• Email screenshots, links, and as much additional information as possible about reports made on social media or other platforms such as iNaturalist or Nextdoor to invasivespeciesinfo@rco.wa.gov.
• Preserve physical specimens as you are able by placing the insect in a plastic bag and freezing it. You may also place it in a vial with ethanol or isopropyl alcohol. Please write your name, the date, and where the insect was sighted (GPS coordinates preferred) on the container.