The Secret Life of UW’s Cherry Blossoms—What You Didn’t Know

Every spring, thousands of visitors visit the University of Washington’s campus to witness one of the most breathtaking sights in Seattle—the iconic cherry blossoms in full bloom.

These delicate pink and white flowers transform the Quad into a scene from a postcard, drawing photographers, nature lovers, and tourists alike. But beyond their beauty, these trees have a fascinating history, a dedicated research team tracking every stage, and a future that isn’t as secure as you might think.

In a recent episode of the Exploring Washington State Podcast, Marlee Theil, sustainability coordinator and lead researcher for the Cherry Tree Phenology Project, shared insights into these beloved trees’ science, mystery, and future.

The Mystery Behind the UW Cherry Trees

Many assume that the University of Washington’s cherry trees were a gift from Japan, similar to those in Washington, D.C. While that’s a strong possibility, the whole story is still up for debate. One theory suggests that the Quad’s cherry trees were originally planted at the Washington Park Arboretum and later moved to campus in the 1960s to save them from being destroyed by construction. Another theory, however, points to records from the 1930s suggesting that the trees may have been planted on campus as part of President Roosevelt’s Works Progress Administration (WPA) during the Great Depression.

Despite the uncertainty surrounding their origins, these trees have become an integral part of UW’s identity. Today, over 100 cherry trees stand across the campus, and 107 are currently being tracked as part of a long-term research project.

Predicting Peak Bloom: The Science Behind the Beauty

While most people admire cherry blossoms for their aesthetic appeal, researchers like Marlee Theil are studying them for a different reason—to understand how climate change is affecting their bloom cycles. The Cherry Tree Phenology Project, now in its eighth year, is focused on documenting every stage of the trees’ blooming process to predict when peak bloom will occur.

Phenology, the study of seasonal biological events, plays a crucial role in this research. Like many other plants, Cherry trees rely on a balance of chilling and heating units—cold temperatures that signal dormancy and warm temperatures that trigger growth. If the balance shifts too much due to rising temperatures, it can disrupt the natural bloom cycle.

The data collected by Marlee’s team of 22 student volunteers helps track these changes and allows scientists to predict future trends. With detailed temperature tracking, they can estimate when peak bloom will happen, providing valuable insight into how climate patterns are shifting over time.

Why Tacoma’s Cherry Blossoms Bloom Later

One of the more surprising details discussed in the episode was the difference in bloom timing between Seattle and Tacoma—despite being less than 50 miles apart. According to Marlee, this could be due to differences in tree speciesand local microclimates that slightly alter temperature patterns. Some species, like Prunus serrulata (Kwanzan cherry trees), naturally bloom later than the Yoshino cherry trees in the Quad. This variation is another example of how environmental factors influence these delicate blossoms.

Preserving the Future of the UW Cherry Trees

At nearly 90 years old, the Quad’s cherry trees are reaching the end of their natural lifespan. While they are still thriving thanks to careful monitoring and maintenance, the University of Washington is already planning their eventual decline. A nursery has successfully cloned the trees through propagation, ensuring that identical replacements will be available when the time comes.

This approach means that when an older tree dies, it will be replaced with a genetically identical cherry tree from the same lineage. Instead of losing all the trees at once, they will be strategically replaced over time, preserving the aesthetic and historical significance of the Quad’s blossoms.

When to See the UW Cherry Blossoms in 2025

For those hoping to visit this year, peak bloom is expected during the week of March 23. However, the exact timing depends on weather conditions in the coming days. The blossoms typically last 7 to 14 days, depending on temperature, wind, and rainfall.

UW offers a live cherry blossom webcam for those who can’t make it in person. View the webcam here.

More Than Just a Beautiful Sight

While the cherry blossoms are a beloved spring tradition, their significance extends far beyond their visual appeal. They serve as a living laboratory for climate research, a reminder of the importance of tree conservation, and a symbol of the rich history woven into the University of Washington’s campus.

Marlee Theil and her team continue their work to monitor, document, and protect these trees, ensuring that future generations will have the same opportunity to experience their beauty. Whether you’re planning a trip to see them in person or want to learn more, these blossoms have a story worth exploring.

Marlee Theil Cherry Blossoms University of Washington Epsiode Transcript

Hello, friends, and welcome to the Exploring Washington State podcast. My name is Scott Cowan, and I’m the host of the show. Each episode, I have a conversation with an interesting guest who is living in or from Washington State. These are casual conversations with real and interesting people. I think you’re gonna like the show. So let’s jump right in with today’s guest. Alright. Well, welcome back to this episode of the Exploring Washington State podcast.

Scott Cowan [00:00:29]:

My guest today is Marlee Theil. Her LinkedIn title says sustainability coordinator, graduate research assistant at the University of Washington. But I’m gonna ask her a question that she was totally unprepared for, so this is the sound of the bus backing over you. Alright? I see that you went you you’re a grad student at the UW. You went to Slippery Rock University in in University of Pennsylvania. You also went to college in Florida. That’s not on your LinkedIn.

Marlee Theil [00:00:59]:

So I do I do want to say that I did not attend college at the University of Florida. I was an employee there prior to attending the University of Washington.

Scott Cowan [00:01:11]:

Alright. So for the sake of my sake of this question, you’re gonna have to play along like Florida was college. K?

Marlee Theil [00:01:17]:

Okay.

Scott Cowan [00:01:18]:

Because this is a question for you. You have one in three chance to guess this one right because I don’t think you’re gonna know the answer. I’m setting you up for failure. Just to start the episode, welcome aboard. Alright. Do you know the name Donnie Iris?

Marlee Theil [00:01:34]:

It sounds familiar, but no.

Scott Cowan [00:01:36]:

For the sake of this question, he’s an alumni of which of those three institutions?

Marlee Theil [00:01:45]:

University of Florida.

Scott Cowan [00:01:47]:

It’s Slippery Rock University. He was he was a musician in the seventies and eighties. He had kind of one eighties rock hit. I’ve set it I set you up for colors before your time, before my time, so it’s all good. Alright. So welcome aboard. How did you get to the UW? What’s your story to Seattle?

Marlee Theil [00:02:08]:

Yes. Well, I think if we’re gonna talk about my story and my journey of how I ended up at grad school and my love of the environment. We have to go all the way back to my childhood if you guys are willing to go on that journey with me.

Scott Cowan [00:02:24]:

We’ll do it.

Marlee Theil [00:02:25]:

Amazing. So I I grew up in well, around Pittsburgh about thirty, forty minutes outside of the city in a more suburban rural area. But, really, some of my favorite childhood memories are in Trout Run, Pennsylvania, which is north central in the Appalachian Mountains. So my father is president of a hunting and fishing club that was founded by his grandfather in the nineteen twenties called Trout Run Hunting and Fishing Club, and I was lucky enough to spend my summers there and my childhood on the expansive property. The hunting club originally owned 700 acres of private land, and it grew to its most extensive expanse of 2,800 acres in the early two thousands. And when I was about 11, the Pennsylvania Department of Transportation purchased 200 acres of the property and cleared all the trees for a highway. And that was really my first exposure into seeing the land and trees that I loved being removed and not protected. And it was a really shocking experience for me because I had so many wonderful memories there.

Marlee Theil [00:03:55]:

Like, me and all of my cousins would go up every summer, and we’d swim in the creek, and we’d catch snakes and frogs and ride ATVs and go hiking. And it was it was the best in some of my happiest memories. And to see all those trees cleared, it really showed me that this land and forest that I love, it’s not necessarily protected and preserved the way that I want it to be. And that really set me up on a path to want to dedicate my career to protecting the environment and protecting trees.

Scott Cowan [00:04:34]:

Okay.

Marlee Theil [00:04:35]:

Yes.

Scott Cowan [00:04:36]:

So you went to the university or more slippery you guys on the I’m I’m teasing the East Coast, but they’ve got some really weird names out there. Just like I’m sure they think we’ve got weird names out here, but Slippery Rock University.

Marlee Theil [00:04:49]:

Yes. Reference beer. You know? Yeah.

Scott Cowan [00:04:52]:

What’s going on with Slippery Rock?

Marlee Theil [00:04:55]:

I it’s a small university, but I’m really happy with the education that I got there because my program environmental science was pretty small, some of my classes there would be less than 10 of us in a classroom, which

Scott Cowan [00:05:09]:

Wow.

Marlee Theil [00:05:10]:

That would never happen here at U Dub. But what I think was so great about that is I really got to develop close relationships with my professors and my advisors, and I think I had a lot of really great opportunities because of that. So I’m I’m really happy with my education.

Scott Cowan [00:05:31]:

So you you’re based on your LinkedIn. Right? It says you went there from 2016 to 2019. Now you were an employee at the University of Florida. When did you start working there?

Marlee Theil [00:05:43]:

Yes. So I I started in 2022 and worked there for about a year. I worked in a wildlife ecology and conservation lab, and we were specifically studying reptiles. So I worked with alligators and crocodiles and the Burmese python, which is so iconic and all over the news, this really large non native snake that’s just decimating mammal populations in the Everglades. But so I worked there for a year, and I actually moved there. Prior to that, I was living in in Portland. So I actually to Oregon? Yep. Mhmm.

Scott Cowan [00:06:26]:

Okay. What did you know, Portland, Maine, Portland, Oregon. Okay.

Marlee Theil [00:06:29]:

Portland, Oregon. Yes. Good question. So left Portland and moved to Fort Lauderdale with the idea that I would attend grad school at the University of Florida. And it was a culture shock for me leaving Portland and going to Florida. When I was in Portland, I spent all my time hiking and camping outdoors, and that’s not really too much of an option in Florida. So I was really having to redevelop my hobbies and find new ways to spend my time. And don’t get me wrong, I actually had a blast in Florida.

Marlee Theil [00:07:13]:

I’m actually really missing some parts of Florida. But within weeks of me being there, I knew that I needed to come back to the Pacific Northwest. I was grieving for the forests and mountains here, and Florida just didn’t feel like home for me. It was like a I mean, it was like a fun vacation, but it didn’t feel like home. So

Scott Cowan [00:07:39]:

So why did you select the University of Washington?

Marlee Theil [00:07:42]:

Yes. So I actually I reached out to my adviser, Patrick Tobin. He’s a faculty member at the University of Washington. He is an entomologist. That is the study of insects, and his specialty is working with invasive insects. And so at that point, I had experience working with invasive plants in Portland. I was working with invasive reptiles in Florida, and I thought how interesting to now work with invasive insects. So I reached out to him, and I I was offered a position.

Marlee Theil [00:08:19]:

So the forest service who funds my research, specifically the Pacific Northwest Research Station in Juneau, Alaska, that’s my study region, they have these insects that have been killing trees over the past few years, and they’re not sure if this behavior is normal or unique for these insects. So they basically reached out to my advisor. They were like, hey. We have this problem. We’re gonna give you some money to hire a grad student. Let’s let’s look for these answers. So then when I reached out to him, I basically sent him a cold email. I did not see a job posting for this position.

Marlee Theil [00:09:05]:

Basically, just reached out to him and said, hey. I’m interested in being a grad student. He was like, I have this project, and here we are. And here we are. Yes.

Scott Cowan [00:09:15]:

Alright. So that gets us up to about now.

Marlee Theil [00:09:18]:

Yes.

Scott Cowan [00:09:19]:

Now let’s let’s talk about how I found out about you. And that was an article in the Seattle Times. And you are managing the cherry tree is it Phenology?

Marlee Theil [00:09:35]:

Mhmm. Phenology. Mhmm.

Scott Cowan [00:09:37]:

Phenology. The Cherry Tree Phenology Project. So for those of you that don’t know what that word means, like myself, we’re gonna find out in a second, but what this translates to is that you’re monitoring the cherry blossoms at the University of Washington, which is an iconic thing in Washington State. So first off, what the heck is phenology?

Marlee Theil [00:10:00]:

Mhmm. Phenology is the study of the timing of seasonal biological events.

Scott Cowan [00:10:08]:

So some you put that into layman’s terms now. I mean, that’s pretty layman, but let’s let’s break it down really simple.

Marlee Theil [00:10:15]:

Yes. Well, how about I give some examples? Right. So an example of a phenological trait would be trees losing their leaves in the fall. So the tree experiences environmental and biological cues. The temperature is getting colder, sunlight decreasing, and then it triggers the tree to lose its leaves. So that’s an example of phenology. Another example would be a caterpillar forming a cocoon after a certain after a certain amount of time, after a certain amount of life stages, forms a cocoon to then become a moth or a butterfly. That’s an example of a phenological trait.

Marlee Theil [00:11:00]:

So the phenological trait that we are interested in looking at when studying the cherry trees is the timing of each bud stage before the bud reaches full bloom to become a full blossom.

Scott Cowan [00:11:16]:

Okay. And for these trees at the UW campus, approximately how long does that take?

Marlee Theil [00:11:21]:

Mhmm. So we start tracking at the February, but the buds are usually dormant for about a month while we’re tracking. So the buds, they start to break dormancy at the March. And by the time they’re all all the blossoms are in full bloom to the time that they senesce and fall off and die, it’s about a a two month period.

Scott Cowan [00:11:48]:

Okay.

Marlee Theil [00:11:50]:

I’m sorry. One month. Mhmm. From the March. Yes. Mhmm. From the March to, like, the April.

Scott Cowan [00:11:58]:

So how many trees do you know this answer? I mean, I I would think you might know this answer. How many cherry trees are on the UW campus?

Marlee Theil [00:12:07]:

Over a hundred. Over a hundred. So we are tracking 107 on campus, but I know that there are a few more than that. And the only reason we aren’t tracking all of them right now is because some of them are inaccessible due to construction.

Scott Cowan [00:12:23]:

Got it. Go and this predates you and I, but Mhmm. Hundred and seven trees, those just didn’t randomly appear. Do you know kind of the history of why the UW has these hundred and hundred plus cherry trees on the campus?

Marlee Theil [00:12:40]:

Yes. So there’s a little bit of lore and mystery specifically about the quad cherries, which are arguably the most famous cherries on campus. And there are several theories about their origin because we have no direct evidence for really how they got there and where they came from. So the first theory is that the quad cherries were originally planted at the UW Arboretum. It’s a very strong theory, and this is the one that everyone refers to. It’s the theory that’s all over the UW cherry blossom web page. But then there’s debate about how they ended up at the Arboretum. So in 1930, the city of Yokohama, Japan donated 4,000 cherry trees to the city of Seattle.

Marlee Theil [00:13:35]:

So that donation is a fact, but it has been speculated that the U Dub trees were part of that donation. There’s also just speculation that the arboretum purchased the cherry trees and then they ended up at UW. And so within that theory, there’s a whole story, and there’s an elaborate detail article that was written in 1999 by U Dub Magazine about how the cherries ended up being relocated from the Arboretum to U Dub. So in this in this theory, the quad cherries lived at the arboretum until 1961 until the new five twenty bridge construction threatened to demolish them. So a crew was responsible for digging up the trees and for the relocation, and there’s this whole dramatic story. They were running out of time because construction was imminent, and the the bulldozers were hovering, and the transplant was haphazard, and the trees were damaged. And in near panic, the trees were brought to the quad and planted exactly where they see them today. But even though this article is so detailed and contains quotes from prominent individuals at the time, there is another theory that has discredited this theory of the cherries originally being at the arboretum.

Marlee Theil [00:14:59]:

So a UW student in 2016, Yuki Shiitani, was an exchange student from Waseda University in Tokyo. They cited that the trees were originally planted on campus in the quad as part of the works progress administration during Roosevelt presidency and during the great depression. So this administration provided jobs in construction and public works projects. So that’s the other theory that the the quad cherries were originally planted there as part of of this administration.

Scott Cowan [00:15:35]:

Well, let me ask you this question. I mean, isn’t there scientific techniques that could age these trees?

Marlee Theil [00:15:46]:

Yes. So

Scott Cowan [00:15:49]:

so if the trees were planted during the Roosevelt administration, I mean, that’s eighty years ago. If they were now we don’t know how what you’re not saying is how old the trees were at the arboretum before they were moved to the U Dub, but that’d be sixty five years ago. So these trees are at least 65, probably 70 years old, at least. But wouldn’t has there been any studies to I mean, all I know is, you you know, when you cut a tree down, and I’m not saying we should cut it down, but, you know, check the rings. I don’t know if that applies to a cherry tree or not. But what can you guys do? What can scientists do to date these trees?

Marlee Theil [00:16:26]:

So we do know that the trees are about 90 years old. We don’t know the exact age of when they were planted, but we have been able to estimate 90. And we know that so if they were at the Arboretum, they would have had to have been planted prior to 1936. Because in 1936, the Arboretum, they developed a record keeping system to document new plants, and the cherries are not in that system. So

Scott Cowan [00:17:05]:

Okay.

Marlee Theil [00:17:05]:

If they were at the Arboretum, they were before 1936. But, yes, we’re Interesting. We the estimate is that the trees were about three years old when they were planted at the quad.

Scott Cowan [00:17:17]:

Okay. Do do we have a ballpark of what the average life of a cherry tree of this now this is a particular species of cherry tree. Right?

Marlee Theil [00:17:28]:

Yes. There are a few species on campus. The famous ones in the quad are Prunus gedoensis. The common name would be Yoshino Cherries.

Scott Cowan [00:17:38]:

Yoshino. Do we know what the typical lifespan of a mature tree is?

Marlee Theil [00:17:43]:

Yes. So the lifespan of these trees is usually eighty to a hundred years. So these trees are nearing the end of their lifespan, which is really unfortunate. But it’s kind of interesting because so that article that I referenced a little bit ago about how the the cherries ended up from the arboretum to campus, the title of that article was time is running out on the quad signature cherry trees. And, basically, it was talking about how the cherry trees are dying and they need to be replaced. And like I said, it was this very dramatic article. But that was written in 1999. And here we are over twenty five years later, and we are anticipating a beautiful and full bloom within the next week or so.

Marlee Theil [00:18:32]:

And the trees are healthy, and they are heavily monitored and protected by the grounds management team, which is who I work for as well. So I’d like to shout out Chris Homer, Natasha Lozano, and Sarah Shores. They are responsible for the care of the trees and protecting them from disease and other health concerns, and they know the cultural and ecological significance that these trees hold. They’re these trees get a lot of attention and care to them. So let’s just hope for many more prosperous years, and let’s not write any more articles about the trees dying when they’re not.

Scott Cowan [00:19:13]:

So to put this in to for reference for the listener, we are recording this on March 13. So when she said in in a week, you’re implying around March. Well, I’m gonna put you on the spot. Mhmm. When’s peak bloom gonna be this year?

Marlee Theil [00:19:29]:

Yes. So right now, we are anticipating the week of March 23. I don’t think it will happen on March 23, but I think it will be during that week. So that weekend following the twenty third would be a great viewing time for the cherries.

Scott Cowan [00:19:46]:

Okay. And and the blooms last about

Marlee Theil [00:19:49]:

About

Scott Cowan [00:19:50]:

seven to Mhmm. Seven to fourteen days, if you will, depending on, you know, if it rains and, you know, and, you you know, things out of our control.

Marlee Theil [00:19:58]:

Yes. Exactly. I would say about a week for the full peak bloom, but, really, the the blossom display will be beautiful the week before and the week after. So.

Scott Cowan [00:20:11]:

Alright. To tie back to this conversation about the age of the trees and the maintenance and all of that, has there been discussions about strategically adding trees to the campus to offset the potential, you know, decline in you know, of these existing hundred and seven trees that you’re tracking?

Marlee Theil [00:20:36]:

Yeah. Great question. Specifically for the ones in the quad, the 27 of the original 29 are still there, and two of them have already died and been replaced. So there are still 29 in the quad, but 27 of the original ones. So our

Scott Cowan [00:20:58]:

The two the two the two new ones, are they being bullied by the the the old trees? I mean, are they are they welcome to the to the I’m just kidding. Sorry.

Marlee Theil [00:21:05]:

They’re all welcome. Yeah. So our plan, if any of the other trees do die of old age or disease so a nursery has created clones of those existing trees through propagation. Propagation is basically cutting off a branch or some roots from the tree and replanting that to grow an identical tree. And those clones are actually spread out around campus, And so the plan is that any that if any of the cherries die in the quad, that can be removed and replaced with the largest existing clone on campus. So each cherry will most likely get replaced one at a time, and it’s not going to be this dramatic experience where we lose all the all the cherries in the quad at once.

Scott Cowan [00:22:05]:

That’s a great sounding plan to me. I mean, you know, that just keeps the whole thing, you know, going. I’m surprised actually that, you know, only two you’ve only lost two trees over all this period of time. That’s that’s pretty impressive.

Marlee Theil [00:22:17]:

Yes. And I I think that can be attributed to the the care of the the gardeners and our campus arborists who are hardworking people and passionate.

Scott Cowan [00:22:29]:

So one thing I do know, what little I know about this whole cherry blossom phenomenon in at the UW is that down in Tacoma, there’s number of cherry trees down in Tacoma as well. And that’s, let’s call it, less than 50 miles away. And yet it appears that the trees in Tacoma do not bloom at the same time as the trees in Seattle. They they’re like a week to ten days later in the cycle. So it’s interesting to me that what I think is a very small amount of distance, forty, fifty miles, a week’s worth of change happens right there. Are you familiar with the Tacoma cherry trees at all?

Marlee Theil [00:23:12]:

I’m not, but I have a theory.

Scott Cowan [00:23:16]:

Let’s go.

Marlee Theil [00:23:16]:

So I’m not sure what species of cherries are in Tacoma. Like I said, the species in the quad, that’s Prunus yeidouensis. And also on campus, also really famous, we have Prunus serulata or Kwanzan cherries, and those are actually in the Rainier Vista. So red South of Red Square lining the walkway to the fountain, we have about I think there’s 18 Prunus serulatas there, and they are actually known to bloom a week after the cherries in the quad. So that makes me think in Tacoma, it’s either Prunus serulata or a different species.

Scott Cowan [00:24:03]:

Because I mean, obviously, things as we go to closer to the Equator, further from the Equator, you know, things change. But that doesn’t seem to me like enough of a of a distance to impact a a week’s worth of change, you know, a, you know, 5% change. Okay.

Marlee Theil [00:24:20]:

Yeah. I would agree with that. Bloom, it’s really driven by temperature. So I agree that going just a little bit south to Tacoma, I wouldn’t think would dramatically affect the the bloom peak bloom date.

Scott Cowan [00:24:40]:

So if we were looking for optimal peak bloom experience From a weather standpoint, what do these trees need to really have a substantial impressive bloom?

Marlee Theil [00:24:57]:

Mhmm. So cherries and most flowering species, they have a series of temperature requirements needed in order to progress through the stages and reach full bloom. So they require periods of cold temperatures, which break dormancy and prepare for spring growth. We call that chilling units, and they also require periods of warm temperatures to initiate flower development and blooming. We call those heating units. So for simplicity’s sake, I’m gonna give you guys an example. I’m gonna make up some numbers to explain this process to you. So so let’s say that the buds are dormant.

Marlee Theil [00:25:43]:

That’s their first stage of development. And in order for those buds to wake up and progress to the next stage, they need ten days or 10 heating units of temperatures above 50 degrees. So let’s say on Monday, the temperature is 51 degrees. Great. The buds accumulate one heating unit because the temperature is higher than our hypothetical threshold of 50. On Tuesday, temperature is 55 degrees. Now the buds have two units because the temperature is above the threshold. Wednesday, temperature is 47 degrees.

Marlee Theil [00:26:23]:

That’s below our threshold, so the buds stay at two units. Thursday, temperature is 53. We’re above the threshold again. Now the buds have three units, etcetera. So once the buds accumulate 10 heating units, then they will progress to the next stage of development.

Scott Cowan [00:26:44]:

So let me ask you a question. What happens if we had a unseasonally warm day? Let’s say, you know, you say 50. But what happens if we had a 70 degree day there? Does that count for more than one unit, or is it what does that do?

Marlee Theil [00:27:02]:

Yes. It does. There is a certain level of being higher than the temperature. You do accumulate more units than that. Nice job.

Scott Cowan [00:27:12]:

Well, also, though, would it go the other direction if we had a a an unseasonably late hard freeze? Mhmm. Would would that would would that put them would that hinder development?

Marlee Theil [00:27:25]:

It could

Scott Cowan [00:27:26]:

Let’s say you had, like, three days of 50, just rock solid 50, and all of a sudden, out of nowhere, boom, it’s 32 degrees on a on a Thursday night. What does in your opinion, what does that do to the the development of the of the tree? The

Marlee Theil [00:27:43]:

It would definitely delay peak bloom. So it wouldn’t you know, our units, it wouldn’t subtract any units that it doesn’t wouldn’t subtract units from what it already has, but it would it wouldn’t gain any units that day, and it would push peak bloom back. So So these blossoms have to accumulate these chilling and heating units to reach full bloom. And if these requirements aren’t met, then that can affect the duration of peak bloom. It can affect how many flowers reach full bloom, and they can be weaker and more likely to wilt and fall off. So these units accumulating these units, the the perfect amount of chilling units and the perfect amount of heating units, that’s really what leads to our most beautiful display.

Scott Cowan [00:28:35]:

Got it. Is the you tracking, historically, these units? Like, how many how do I wanna say this? On what day did we get to the 10 units to start the bloom? I mean, are are we is the you tracking all this

Marlee Theil [00:28:54]:

historically? Yes. So that’s so that’s the Cherry Tree Phenology project that I’m monitoring right now. I have about 22 students going around on campus and checking all the cherry trees. So from the February, they go out and document what stage the bud is in, and then we’re able to relate that to temperature data to figure out the temperature requirements needed for the buds to progress to the next stage.

Scott Cowan [00:29:30]:

So why 22 students sounds like a lot. That’s like five trees a student. But why so many students? And are they are they all of a certain major, or is this just an open posting on campus? How do you select the students?

Marlee Theil [00:29:43]:

Yeah. So 22 students is a lot, and they they all are collecting data for about two to eight trees, two to three times a week. And I I bring on so many because they’re volunteering to do this in their free time. They’re all hardworking students studying environmental science or biology, and I’m so grateful that they choose to collect data in their free time and for what they have contributed to the project. So I’m I’m wary of asking them too much. And so I put I set them up into teams, and they’re all assigned to a certain amount of trees per zone. So however they wanna divide it up, as long as every tree is being documented two to three times a week. That’s my goal.

Scott Cowan [00:30:33]:

What is the documentation that they are gathering? What what what are they bringing back to you?

Marlee Theil [00:30:38]:

Yes. So they are they use an a map of an application on their phone that’s a map of all the cherry trees. So they can select the cherry trees and they’ll they’ll enter the data there. And the first thing that they’re documenting is the overall stage of the tree. So they they get up close and personal, checking out the buds, then they take a big step back and they say, what is the current stage? What what current stage are the buds the majority of the buds in. So what more than 50% of the buds are in. And then they divide if the tree up into percentage categories. So if they say that 60 they say the current stage, all the buds are dormant, and they say 60% of the buds are dormant.

Marlee Theil [00:31:30]:

So the current stage, dormant, and then they break it down into percentages. So 60% of the buds are dormant, but 40% of the buds have just started to wake up a little bit, and they’re in the second stage. We also have the option to add photos if they need help identifying any of the stages. I can look at that, but, really, just three or four data entries per tree.

Scott Cowan [00:31:57]:

So they’re taking selfies with the tree is what you’re telling me. They’re

Marlee Theil [00:32:00]:

Yes. Absolutely.

Scott Cowan [00:32:02]:

Posting them on Instagram. Okay. Got it. That’s interesting to me. I mean, so how long so you’re the the group has two two to eight trees. Right? So how how long does it take an individual to, let’s say, just do a tree? Typically, how long are they spending at a tree to do this?

Marlee Theil [00:32:22]:

I would say a few minutes.

Scott Cowan [00:32:25]:

Okay. Not not terribly long, but not just walking by, click, click, move on. It’s they’re they’re they’re they’re stopping. They’re being purposeful. They’re looking at the tree, kind of getting back to you. Okay.

Marlee Theil [00:32:35]:

Yes. Absolutely.

Scott Cowan [00:32:37]:

It can be it

Marlee Theil [00:32:38]:

can be a bit of a challenge to identify the the stage of the buds because some of them are so far away and so high up. And the buds closest to the trunk and closest to the ground usually progress through the stages a little bit earlier because, you know, I think it has to do with heating from the ground. Like, they’re closer to the ground. They’re less exposed from the cold temperatures and the wind. So even though they can see the buds that are closest to the ground and closest to the trunk, When we’re capturing the whole stage, they need to really take a step back and see what’s going on up at the top to get an accurate estimate.

Scott Cowan [00:33:21]:

Well, yeah. And that’s interesting because on on the U Dubs website, there’s this thing here right there. It says tree safety. Please do not climb the trees. So we don’t want we don’t want students going up the tree to look at the buds even if it is for science. Okay. What do you do? Now you take all this data for a hundred and seven trees. We’ve got students out there.

Scott Cowan [00:33:40]:

They’re gathering data. They’re reporting it back to you. What do you do with that data?

Marlee Theil [00:33:45]:

Mhmm. So the goal is to use that data to predict peak bloom on campus. So k. I’m able to review the data that the students have collected, relate that to temperatures. Now that we know the temperature requirements needed to reach full bloom, we’re able to use weather forecast to predict when peak bloom will occur.

Scott Cowan [00:34:14]:

Now in today’s day and age are you a sports fan?

Marlee Theil [00:34:18]:

Not really.

Scott Cowan [00:34:19]:

Alright. But but in today’s day and age, you know, betting on sports is, you know, prevalent. I’m almost surprised we don’t have a, you know, peak bloom bedding pool or something. I’m sorry. Just just the way it comes to mind. But it’s it’s fascinating to me. So you’re taking all this data. You’re looking at weather projections, and you’re you’re kind of going, where are we at in the in the heating units? If we’re at eight and we don’t have a couple more 50 degree days for three or four days, well, we’re not gonna be there, so we gotta push out.

Scott Cowan [00:34:48]:

And it changes. I mean, weather forecast for today could be you know, it’s gonna be 53 degrees and cloudy in Seattle, and and it might only turn out to be 48. I don’t know. We don’t know. You that you don’t control that. That’s really kinda cool, though. This is this is very interesting. So as you as the project continues to develop data over years, you know, and so you have more more data to work with, What is the the hope that this project will lead to? I mean, what’s the what’s the I I don’t wanna say the big goal of it, but what’s yeah.

Scott Cowan [00:35:23]:

But what’s the big goal of it? Not besides just predicting peak bloom for photo opportunities for visitors to the campus.

Marlee Theil [00:35:31]:

Absolutely. Yeah. So our specific narrow goal, predict peak bloom on campus. But the broad goal is really to evaluate the effects of climate change on trees and ecosystems. And, really, the long term goal with this data is to eventually create a computer model or a series of mathematical equations that can be used along with our phenology data with future climate projections to see how peak bloom may change in the future. So, hopefully, once we have ten years of phenology data, this is our eighth year of data collection, we should be able to use that, apply it with future climate predictions to see how peak bloom may be altered in forty or fifty years into the future.

Scott Cowan [00:36:27]:

Now when we started this conversation, you mentioned going to the UW for insects. Yes. We’ve been talking cherry. We we’re talking cherry blossom. So how did you end up on the cherry blossom project?

Marlee Theil [00:36:40]:

Yes. So part of my grad student experience, everybody’s is a little bit different in terms of how they’re funded and what they’re researching and do they do they have to teach classes, do they have to support their adviser in the classroom, things like that. So part of my experience, I actually work for UW grounds management, and my title is sustainability coordinator. So grounds management is a team of about 40 30 to 40 gardeners that maintain all the natural landscapes on campus. And if if listeners have not been to campus, campus is a a really beautiful place and lots of wonderful natural spaces and green spaces on campus. So part of my role as sustainability coordinator, I can help with developing restoration plans, invasive species management. I can help with grant writing to earn money for any sustainable projects that may benefit the grounds team or campus in general. And I also do project management, and that’s where the cherry tree phenology project comes into place.

Marlee Theil [00:37:52]:

So my role as project manager, I I train the student volunteers. I help calculate predictions for when the campus cherries will be in full bloom, And I communicate with the public because the cherry trees are a big deal, and we get a lot of media coverage. So I handle that as well, and that’s really why I’m here today.

Scott Cowan [00:38:13]:

I am looking. So I just did a quick search. I can’t say this is accurate because it’s the Internet. But campus size is approximately 634 acres. You tell me there’s only 40 gardeners?

Marlee Theil [00:38:27]:

I know. Right? It’s they are hardworking. They are stretched thin, really.

Scott Cowan [00:38:35]:

So when you say gardener, like, the person who’s mowing the quad.

Marlee Theil [00:38:41]:

Yep. They’re a part of our team.

Scott Cowan [00:38:43]:

That’s a gardener.

Marlee Theil [00:38:44]:

Yep. Mhmm.

Scott Cowan [00:38:45]:

So so so gardener encompasses all landscaping maintenance.

Marlee Theil [00:38:52]:

Yes. That’s a great way to describe it. And I guess we do have a mow crew, but they they are a part of our team.

Scott Cowan [00:39:01]:

Wow. That’s just but 634 acres with 40 people, that’s Yeah. That’s, like, what, 15 acres a person that they’re made. And then, yes, there’s buildings and asphalt and yeah. We it’s not all landscape grounds, but still. Yes. Every time I’ve ever been on the campus, the grounds have always been I have always been impressed with how how well maintained the grounds are on on the UW campus.

Marlee Theil [00:39:23]:

I agree completely. And k. I think it’s I’m actually really happy that I’m I get to be in this role and I get to work with the gardeners because it has given me a much more intimate relationship with UW campus. Like, I know about the people who planted these trees, and they’re all so passionate. And, like, I I shouted out Chris Homer earlier, taking care of the cherry trees since the early two thousands. And their their work, it’s appreciated by everybody, but I don’t think that they always get the recognition that they deserve.

Scott Cowan [00:40:05]:

Well, only if things don’t look good, then we go, what what happened? What where the what you know, and I’m I don’t you know, that’s just everywhere. It’s like, if something’s well maintained, we just expect that, and we don’t really take into account what it took to keep it well maintained. You drive somebody’s by somebody’s lawn, and you’re like, oh, it’s really it always looks nice. And then one day, you drive by and they hadn’t mowed it that day. Oh, they’ve let it go. What what’s wrong? You know? We don’t tend to appreciate. It’s just still staggering to me, but that number for that size campus. Alright.

Scott Cowan [00:40:36]:

Putting you on the spot. I want you to share a secret about cherry blossoms that you probably shouldn’t tell us. There’s gotta be something you can come on.

Marlee Theil [00:40:49]:

A secret?

Scott Cowan [00:40:51]:

What? Yeah. I mean, where’s where’s the where’s the best place to view them? Oh, okay. Absolute in your opinion, best place. But I also want you to go into detail and say, this is when, like, time of day and all of that. Like, what’s the secret? What’s, like, the I wanna go and I wanna take my camera, and I wanna win an award for the best photo of cherry blossom tree. If you saw my photo skills, you’d know that your your task is impossible because it’s just not gonna happen. But, anyway, where’s the best place and what time?

Marlee Theil [00:41:23]:

Yes. So the best time is definitely first thing in the morning or later in the evening. Like, if you get there early, that’s how you’re gonna beat the crowds for sure, which there will be photo bombers in your in your pictures if you go during the day. So definitely go early or later. And I think a a a lesser known spot that is equally as beautiful behind UW Medical Center, I think there’s a little less than 20 cherries, the Yoshino cherries, the same ones as the quad, all in a beautiful row down the street that really doesn’t get as much attention. So if you went there, you would probably, again, have less crowds, and it would still be a very beautiful display. Everyone is drawn to the quad and the walkway from Red Square. But, yeah, behind UW Medical Center is another great spot to view the cherries.

Scott Cowan [00:42:28]:

Okay. Excellent. What else do we need to know about the the cherry trees? What else have we what haven’t we maybe covered here? Because it’s actually you know, the the history of the trees themselves, the the mystery surrounding was pretty cool. And the study that you guys are doing to predict I don’t wanna say predict, but, you know, estimate peak bloom.

Marlee Theil [00:42:49]:

Yes. Absolutely. So I think it would be it’s important to mention that although so, yes, these cherry trees are beautiful and they draw a crowd and they’re wonderful, but there are other reasons to be studying cherries. So they’re very sensitive to changes in climate patterns and specifically temperature. So tracking the different bud stages can provide insight about the magnitude of the effects of climate change. So changes in phenology, changing in the the timing of the bud stages and when peak bloom occurs, that can affect the natural range of distribution, so where the tree is found. It can reduce photosynthesis in the tree, which is how trees produce food for itself and how it survives. It can affect pollinators, like everybody loves our native bees.

Marlee Theil [00:43:47]:

And another example of a phenological trait is that pollinators have evolved alongside their food source, pollen, to feed when the flowers are in bloom. So if changes in climate affect when the flowers bloom, then there might be a mismatch between the timing of bloom and the timing of when pollinators usually feed. And pollinators are really important. So, yes, the cherry trees are beautiful. Yes, we are interested in predicting peak bloom so that visitors can help plan their trip to campus, but we are also conducting this study to evaluate the effects of climate change.

Scott Cowan [00:44:28]:

You mentioned pollinators. Does the u have any do they do they do they have bees on campus? In other words, do they have beehives on campus, or they do they raise pollinators, I guess?

Marlee Theil [00:44:41]:

Yes. They’re we have pollinator gardens, and we the gardeners actually do their best to nondestructively handle any wasp’s nest or bee’s nest that might appear because they are they are important parts of our ecosystems. And I think a lot of people see a wasp nest and they just wanna spray it with a I

Scott Cowan [00:45:07]:

do.

Marlee Theil [00:45:07]:

A pesticide. Yes. I understand. I have been stung by wasps before and they’re really terrible, but but they are they are important parts of the ecosystems. And wasps are pollinators as well. So the gardeners really do their best to just kind of, like, remediate, and they they’ll put up signs saying, hey. There’s a wasp nest nearby. Like, don’t go into this area.

Marlee Theil [00:45:31]:

So there are indeed pollinators on campus.

Scott Cowan [00:45:34]:

Okay. This has been this is really quite quite interesting to me, and and you’ve done, I think, an excellent job of of explaining the whole project. I mean, you know, from from the beginning what we think the beginning might have been with the with the campus trees and to to today. When you’re done with your graduate studies, what do you hope to do?

Marlee Theil [00:45:58]:

Mhmm. I I’m interested in restoration for sure. That’s that’s actually what I was doing when I was in Portland. I worked for a forest management company developing restoration and reforestation plans, and it was really rewarding to be able to see the change in landscape that I had helped facilitated. So I’m I’m interested in restoration and land management in terms of, you know, working at a working at a wildlife refuge and saying and monitoring the animal population, saying that this is what they need to be healthy and survive, and this is how we protect our trees and looking at the the landscape as a whole and trying to keep it healthy. So I I would like to work for the forest service, but I’m I’m pretty open minded. And something that I am just now learning for myself is that I can’t project too far into the future what I anticipate myself doing because it because sometimes it doesn’t happen that way and your your feelings change. And I could be in school for another four to five years.

Marlee Theil [00:47:24]:

So I’m just taking it one day at a time.

Scott Cowan [00:47:29]:

Okay. Well, about how much longer do you have in your graduate program at the U?

Marlee Theil [00:47:34]:

Yes. So I am a right now, I’m a master’s student, so with an anticipated graduation date of December 2025.

Scott Cowan [00:47:43]:

Okay.

Marlee Theil [00:47:44]:

However, I am potentially interested in staying on and continuing into my PhD. Again, I’m trying to not think too far into the future, taking it one day at a time. But

Scott Cowan [00:47:56]:

Okay.

Marlee Theil [00:47:57]:

But if I do continue and go on to do my PhD, then from today, I could probably have about four four or five years.

Scott Cowan [00:48:06]:

Four more years? Okay.

Marlee Theil [00:48:07]:

Which is a long time to think about.

Scott Cowan [00:48:10]:

Yeah. That that is a long time. Alright. So I asked my guests three questions, but I’ve got a fourth one for you today. So when you’re not on campus, when you’re not tracking peak bloom, when you’re not herding 22 undergrad students who are looking at trees for you, when you’re not interfacing with the gardeners, when you’re not doing all of these other things, what do you like to do for fun?

Marlee Theil [00:48:31]:

Oh, I love hiking and camping. That’s that’s really my passion. I love being outdoors and taking road trips. So that’s really what I like to do in my free time.

Scott Cowan [00:48:44]:

Where was your last road trip? Where’d you go on your last

Marlee Theil [00:48:46]:

trip? Road trip. I know where did I go over Thanksgiving? I always take a a Thanksgiving road trip since I’ve been away from my family for five years. So I don’t I haven’t had Thanksgiving dinner in five years. So if anybody wants to invite me to their house, let me know. But but usually, I take

Scott Cowan [00:49:10]:

a We’re getting that we’re getting that request out months in advance. There’s gotta be somebody. I love that. Awesome.

Marlee Theil [00:49:17]:

Alright. So, usually, I take a road trip. Oh, I drove down the Oregon coast and went to some beaches there, and I went to Mount Hood National Forest and the Columbia River Gorge outside of Portland.

Scott Cowan [00:49:33]:

Okay.

Marlee Theil [00:49:34]:

Yep. That was my last road trip. Mhmm.

Scott Cowan [00:49:36]:

Very important question.

Marlee Theil [00:49:38]:

Okay.

Scott Cowan [00:49:38]:

Super important. Where’s a great place to get coffee around the UW campus?

Marlee Theil [00:49:43]:

Yeah. So me and my me and my lab mates, we usually go to Cafe Solstice, which is on the West side of campus. It’s a really good place to just hang out and study and collaborate. So that’s I’m not much of a coffee connoisseur, though. I usually just drink my coffee black and nothing fancy to it. So take my opinion with a grain of salt, but Cafe Solstice.

Scott Cowan [00:50:16]:

Cafe Solstice. Okay. Alright. You’ve been putting in a hard day looking at cherry blossoms. Where’s a great place for lunch around the campus?

Marlee Theil [00:50:26]:

So Agua Verde Cafe, it’s a Mexican spot along Portage Bay, which is south of campus. It’s one of my favorite places to go. They have a lot of great options, and I’m a vegetarian, and they have lots of great vegetarian options. So that’s what I look for when I pick a lunch spot. I think a lot of

Scott Cowan [00:50:46]:

What’s your what’s your go to there?

Marlee Theil [00:50:48]:

What’s a

Scott Cowan [00:50:48]:

go to vegetarian, dish?

Marlee Theil [00:50:50]:

I love their nachos. They have really good loaded nachos, jalapenos, and guacamole, and peppers, and onions, all good stuff. And I think a lot of students on campus enjoy going there. They have a back patio overlooking the water, so it’s a great spot on a sunny day.

Scott Cowan [00:51:09]:

Yeah. Alright. As we wrap this up, what didn’t I ask you that I should have asked you? What what what do you need to give a shout out to? Where can people find out more about the UW, things like that?

Marlee Theil [00:51:22]:

Yes. So first, I just I just wanna say that I’m so honored to even be involved with the Cherry Tree Project, but there’s an incredible network of people that have contributed to this project over the years. And I just wanna give some people some shout outs, if that’s cool.

Scott Cowan [00:51:41]:

Let’s do it.

Marlee Theil [00:51:42]:

Great. I’d like to thank Sooyoung Kim. He’s a professor here at U Dub, and he studied the Washington DC cherry blossoms that our project is based off of. And then Michael Bradshaw, he was the sustainability coordinator in my role years ago that really spearheaded the development of this project, created the protocols and things like that. I’ve already shouted out Chris Homer and Natasha Lozano and Sarah Shores, all a part of U Dub grounds management responsible for the cherry tree care and making sure the trees are healthy. And I’d also like to shout out Autumn Moss and Patrick Tobin. They reworked the Washington DC equations to create our our prediction equations here on UW campus. So thank I would like to thank all these people for their efforts.

Marlee Theil [00:52:34]:

They’re really the foundation of this project. So I’m I’m happy to be involved. They they all walked so I could so I could run.

Scott Cowan [00:52:44]:

Okay.

Marlee Theil [00:52:45]:

And I think just the other thing that I’d like to like to say, my my takeaway from all this and what I’d like to share with your listeners, as we admire the beauty of the cherry blossoms on campus, I think it’s important to remember that all trees hold incredible value. They clean our air. They provide habitat and food for wildlife and make our cities livable. And climate change and urbanization are putting trees under growing pressure and threatening not just their survival, but the vital benefits that they provide to us in our ecosystems. And protecting and valuing trees means protecting the health of our planet and the well-being of future generations. So my my call to action for everybody, consider supporting local tree planting initiatives, advocating for urban green spaces, and finding ways to reduce your environmental footprint. Every action helps, and I really believe that every person can make a difference.

Scott Cowan [00:53:49]:

Well said.

Marlee Theil [00:53:50]:

Thank you.

Scott Cowan [00:53:51]:

Alright. Now I warned you about this. This this this whole episode accumulates right now. All the pressure’s on you. You have this question you’ve agreed to answer. K? You’ve agreed to answer, and you’ve also agreed to give us your reason why. Are you ready?

Marlee Theil [00:54:06]:

I’m ready.

Scott Cowan [00:54:08]:

You wanna compose yourself? Okay.

Marlee Theil [00:54:10]:

I’m ready.

Scott Cowan [00:54:11]:

Cake or pie?

Marlee Theil [00:54:14]:

Pie.

Scott Cowan [00:54:15]:

Why?

Marlee Theil [00:54:17]:

I like fresh fruit in pies. Apple pie and peach pie, those are my favorite. And especially with an apple pie, you cannot go wrong with, like, the graham cracker and the crumble crust. That is just so ideal for me. I think cake can be a little too sweet and sugary for me sometimes. I do like cake. Not knocking cake, but I am I prefer pie.

Scott Cowan [00:54:44]:

You you you’re throwing some shade at cake. I guess, okay. We’re we’re it’s alright. So some people answer this super easy like you did. Some people like cake and Some people are even more adamant than you are. But I do have a follow-up question. Growing up, what did you have at home? Cake or pie?

Marlee Theil [00:55:01]:

Usually cake. We would have cake, except on Thanksgiving, I feel like we would always have

Scott Cowan [00:55:07]:

Which you haven’t had in five years. So remember, folks, she’s looking for a place for Thanksgiving.

Marlee Theil [00:55:12]:

Oh, that’s so funny. My best friend is gonna laugh at this because she knows how much I love Thanksgiving dinner. So funny. But, I usually had cake growing up. Okay. But I have been an apple pie lover for a long time, so I have been getting apple pies for my birthday for a while. So Okay. But usually cake.

Scott Cowan [00:55:38]:

Okay. Alright. I was just just curious because I we’ve been working kind of on this this premise that our our answers were influenced by how we grew up as kids. You know, if you grew up in a in a household that had pie all the time, you like pie. That is not holding up true. It it really isn’t holding up true. It’s kind of hit or miss. It’s it’s very I don’t think there’s a correlation there.

Scott Cowan [00:56:00]:

I’ve been I thought that for sure there would be, but but not now. I will say, I I keep saying I’m gonna do this. I haven’t. I’m gonna go back through all the episodes and and write down everybody’s answers and, you know, put it into a chart. But I I’m pretty comfortable saying Pai is in the lead and that Apple Pie is the the, you know, the the the big winner there. It’s you know, if it was an election season, apple pie is gonna win. So well, I appreciate you sitting down today. I think, you know, a, the cherry blossoms on the campus are iconic.

Scott Cowan [00:56:34]:

Everybody in Seattle, everybody in Washington I don’t know. Maybe not everybody in Washington state, but most of us in Washington state are very aware of the beauty on the UW campus and other places around The States, not just UW is not the only place with the cherry trees, but it is well documented. And, I think you did a great job. I mean, I really appreciate you explaining it to to me. I learned a lot, and you you broke it down so that that I can understand it. So that’s that’s great. And I hope that you’re I hope this season is successful.

Marlee Theil [00:57:06]:

Yes. Thank you so much. I forgot to mention that the UW Cherry Blossoms have their own website and social media that gives updates on peak bloom predictions, where you can see the cherries on campus, how to travel to campus, history, and much more. And we even have a webcam set up to view the quad cherries so you can see how far along in the bloom process that the trees are to help you decide when to come to campus. So our UW news and marketing teams put together these helpful and creative guides, and they’re definitely worth checking out. So a simple Google search of UW cherry trees, you’ll

Scott Cowan [00:57:47]:

Yeah.

Marlee Theil [00:57:47]:

Find a variety of websites.

Scott Cowan [00:57:50]:

And I’ll put a link in the show notes to it for it as well. So that’s that’s pretty cool that you guys are doing that. So Mhmm. Well, thank you so much for sitting down with me.

Marlee Theil [00:57:58]:

Thank you so much. I’m I’m honored to be here.