Dead Trees Still Tell No Lies

Recently, I had the good fortune to be interviewed by Bellamy Pailthorp, the environmental reporter at KNKX radio. We chatted about my Dead Trees Tell No Lies essay from my book Wild in Seattle. Because of this, I decided to repeat this essay, which originally made it into your mailboxes in October 2023. I’ve made a few updates in the story. Here’s a link to our conversation.

And, at the bottom of this newsletter is a coincidental connection about berries (which I wrote about last week) and a Union soldier in the Civil War.

Trees die every day of every year but something unique happened late autumn or early spring 1,100 years ago. Numerous Douglas firs perished, not because of disease or fire, the two typical culprits of that era, but because of an earthquake, or quakes, one of the most noteworthy seismic events in recent Pacific Northwest history. Still extant, the dead trees, some more than several hundred years old when they died, occur at six locations across Puget Sound.

Price Lake (just east of Lake Cushman on the Olympic Peninsula) - A quake-induced stream-impoundment submerged a forest. Researchers sampled 21 trees, including several that required an underwater chainsaw, which sounds sort of nutty and fascinating.

Hamma Hamma (Hood Canal) - A rockslide dammed a creek forming a lake that killed a forest that the geologists found.

Dry Bed Lake - Yep, once again the earth shook, rocks trembled and fell, and created a temporary lake. Researchers were only able to collect these trees in a severe drought.

Lake Washington - This time an entire grove slid into the lake, off the SE end of Mercer Island. They are still there, standing upright. In 1916, the top of one tree pierced the 78-foot ferry Triton carrying 25 passengers. It sank but no one was hurt.

Lake Sammamish - Another grove, another landslide, more dead upright trees. Note two clusters on the map below, which may indicate two slides or a loss of trees. Several of the snags stick above waterline.

West Point (Discovery Park, Seattle) - The ground snapped, trees died, and one was carried by a tsunami to a beach. This random event may have been witnessed by people who seasonally camped there to harvest shellfish. Lucky them.

In December 1992, geologists published a series of papers with a startling conclusion: around 1,100 years a massive earthquake whacked the Seattle area, causing uplift of 23 feet. The quake occurred on what the scientists dubbed the Seattle Fault, a 25-mile zone of weakness running from Issaquah through downtown Seattle to the eastern edge of Bainbridge Island. (When you ride the Bainbridge Ferry, you pass by Restoration Point, thrust out of the water when the land shattered.) Relatively shallow, the quake measured about magnitude 7, not much stronger than the 2001 Nisqually earthquake but with much more significant ground shaking because it occurred closer to the surface. When (not if) a similar quake hits again, it will cause billions of dollars in damage.

One question that has long niggled geologists is the specific date (more exact than “about 1100 years ago”) of the quake, or quakes. The more details, such as timing, magnitude, and extant of damage, researchers have, the better they can model and predict future earthquakes and, they hope, help planners prepare for worst case scenarios. Geologists have known since 1992 that the best evidence for a precise date could be found in the annual growth rings of trees, which respond directly to climatic conditions preserving a detailed record of the history of a tree. They further knew that the quake created numerous geological events that killed or buried trees across the region. All the geologists had to do was locate trees, get samples, and read the evidence.

In September 2023, in a research article in Science Advances, an international team reported that they had solved the dating mystery, narrowing the date of the quake(s) to 923 or 924 CE. It is a tour de force and beautiful example of science, taking a unique set of features and combining technology with old school-out-in-the-field, mucky, muddy detective work to answer an essential question.

After the researchers gathered the trees, which they did over the past 30 years, often in less-than-ideal situations, they compared ring-width patterns. They also compared the trees with an absolutely dated reference set of 27 cores from Vancouver Island that spanned the years 715 to 1990. And, finally, they independently radiocarbon-dated the samples. Everything pointed to 923/924 but what was surprising is that the researchers found that there may have been two quakes, one on the Seattle Fault and one on the Saddle Mountain Fault (near Lake Cushman and labeled in the map above as SMFZ), that acted as double-blow, rupturing the ground twice within hours to months.

This is not good news. We all know that one quake is bad. If a second quake struck shortly after, infrastructure and emergency planning, not to forget the landscape itself, would be vulnerable and prone to more catastrophic issues. But now that these scientists have provided the information on what did happen and what could happen, planners have the opportunity to help build in more resiliency. As my pal Scott says, “Get to work you.”

All too often in our modern world (unfortunately, now more than ever) people question science and scientists, claiming that they have agendas or are only interested in making money from their research. Over the past 25 years I have interviewed dozens of scientists—in academia, government, and consulting—and have found all of them to be committed to doing the best work they can without any agenda or financial gain. This study certainly exemplifies the best of what scientists do: solve a mystery to help further our understanding of our world, often with the goal of making a better world.

September 19, 2025 - HistoryLunch - HistoryLink - I have long been a fan and supporter of this fine organization. If you are not aware of it, the website is the site for history about Washington state, often bringing to light overlooked, under appreciated, and forgotten-but-vital stories. HistoryLunch is their annual fund raising event and I am honored to be the keynote speaker this year. The event is titled Is the Mountain Out? So if you want to support a worthy cause, come on by. Here’s the registration link.

September 20, 2025 - Clima Incognita: Planning For An Unknown Climate – Jaipur Literature Festival: Seattle – Town Hall – 12:00 PM – 12:45 PM – I will be in conversation with author John Vaillant (Fire Weather, a brilliant book) and Brinda Sarathy (professor and Dean of the University of Washington: Bothell School of Interdisciplinary Arts and Sciences). Should be fun and interesting, along with the rest of the festival.

October 14 - Secrets of Seattle Botany - 6pm - BirdsConnectSeattle - I will talking about what Seattle looked like botanically when the first white settlers arrive. This is a virtual class. Here’s a link to register.

Just after sending out my newsletter on berries last week, Marjorie was helping our friend Andy Nettell of Stellar Books. He had asked her to transcribe a letter he had from June 12, 1864. It had been written by a Union soldier named Laurenz to his mother. He was located in Georgia and his troop had recently gotten a resupply of rations after minimal food for the previous 12 days. Fun to read of the ripe berries (dew, straw, and mul), and other fruit, that he ate.