Edward Plumb:
Well, good morning, and welcome to the annual webinar about tracking green up in Alaska's boreal forest. This event is being held in the International Arctic Research Center on the University of Alaska Fairbanks Troth Yeddha Campus. The Alaska Center for Climate and Assessment. And preparedness, is also known as ACCAP, is hosting this event. ACCAP is part of the Regional Integrated Sciences and Assessments program. which is funded by the NOAA Climate Program Office. ACEP has been working here in Alaska for over 17 years to improve the ability of Alaskans to adapt to a changing climate. So, a few logistics before we get started today. I have everybody's mic muted and your video turned off. We will have a question and answer session, during the last 10 minutes or so. And at that time, I will allow you to unmute yourself and turn on your video if you want to ask questions directly to the speakers. Otherwise, please feel free to drop questions into the chat, and we will try to answer them as we're going along. Any questions we don't get to in the chat, I will, save and bring them up during the Q&A at the end. This presentation and webinar is being recorded, and I will send out an email later today with the recording, which will be on our website.

And... One new thing we're doing with our ACCAP webinars, if you attend these frequently, at the end, you're going to be prompted for a brief Two... three-question survey. If you're using Zoom in the browser. If you could hit leave meeting rather than just closing your browser tab, this will allow you to be prompted for the survey, and we really appreciate you taking a few moments to answer the survey questions. Like I said, there's only 3 really short questions, and this is really helpful for us. Okay, so with that, we'll go ahead and get started.

My name is Ed Plumb, and I am the Weather and Flood Hazard Specialist here at ACCAP. And it is my pleasure to introduce today's speakers. First off, we have Rick Thoman. Rick is the Alaska Climate Specialist here at ACCAP, and has many years of experience producing reliable Alaska climate information and graphics describing Alaska's changing environment. His work spans the bridge between climate modeling, Alaska communities, and the media. Susan Harry is the Laboratory and Safety Coordinator for the Department of Veterinary Medicine here at UAF, with over 30 years of experience in the medical laboratory field. Since 2000, she has led pollen counting efforts in Fairbanks. Providing valuable data for the community and researchers studying changes in the environment and climate. She continues this work through One Tree Alaska and UAF's Institute of Agricultural and Natural Resources and Extension. And our final speaker, will be Jane Dawe.

Jane is... sorry, Jan Dawe. Jan is a research assistant professor of the Natural Resource Education and Community Engagement at UAF. She directs the One Tree Alaska and STEM Plus Art, otherwise known as STEAM Studio, engaging learners in boreal forest education, citizen science, and forest products. Her work focuses on plant timing and seasonal change, including using the green up forecast to better understand events like birch sap flow and the pollen season. Well, thanks for joining us today, and I will hand it over to the speakers. I think we're starting here with Rick.

Richard Thoman:
All right, great. Thanks, Ed, and, thanks everyone for joining. So, as Ed said, we've got, three of us are gonna, gonna talk today, so, let's jump right in so we have the most amount of time that we can here, so let's see if I can make the technology work today.

Hopefully you can see the title slide. Yep.

Edward Plumb:
Yes, see the slide, right?

Richard Thoman:
Alright, so... My part is, is, mostly, kind of the backstory of, this, this whole idea of, a green-up forecast, and, from that work that started, almost 30 years ago now, as Ed said, it's branched off, and added other parts of the spring, happenings in the, in the boreal forest. So, like, things like sap flow, and things like, the pollen release that come right after green-up. So, and then, Susan and Jan will go into more detail on some of those aspects. So. here's... here's just what my part of Iowa wanted to talk about, just to set out kind of our, our, what we mean by green up, and Fairbanks' unique observational record of that, phenomena. And then the backstory of some of the history on how to... how we've gone about trying to understand, how to predict when this, is gonna happen. So, what is greenup? So, 40 years ago, Jim Anderson, here at UAF defined interior Alaska Greenup as birch and aspen leaves open just enough to produce a faint but distinct flush through the forest canopy.

So, there's a couple of important elements here. One, we're looking at the landscape scale when we talk about green up for this purpose, not an individual tree, but rather across some larger area. And then the other thing is, it needs to be distinct. It's not like, oh, look, there's a little teeny green right there. We want it to be, reasonably obvious to, you know, to an attentive, person looking at it. So, during the spring, a lot of stuff happens, in the boreal ecosystem. So, birch and aspen biology, of course. change long before the snow melts, as the sun's coming back, things start to happen in the trees. Even, you know, moose change their diet, transitioning from a winter to summer diet in the course of the spring. 

Of course, a favorite activity for many folks, In mainland Alaska, birch sap tapping, that is... needs to be carefully timed and is done before green-up. And there's even a weather and climate aspect to Greenup. As soon as those leaves pop out, we are getting that evaporotranspiration of water through the leaves into the atmosphere, and that, by itself. All other things being equal, that means that relative humidities are going to be somewhat higher in the afternoons than right before green-up. And that helps to fuel some of those early season, particularly May, showers that will pop up. Often, there's not enough moisture for the rain to reach the ground, but a lot of that moisture for those showers being provided By that moisture being moved from the ground into the atmosphere through the leaves. So... what's happening, weather-wise before green-up happens? Well, solar heating is increasing, of course. Not only are the days longer, but the sun is higher in the sky each day in the spring, so we're getting more of that solar radiation.

In general, of course, we have warming air temperatures. Of course, as soon as it gets above freezing, the snowpack does not immediately melt. The snowpack has to get up to freezing. Before a substantial amount of that is going to melt and run off. And then eventually, of course, the ground will thaw, and we'll get water from snowmelt infiltrating into the ground. Now, in the forest, one of the first signs of coming spring will be the development of snow wells. Around the base of trees, and that is important, because that will be, the ground there will start to warm, earliest, compared to, say, flat areas without trees that are still solidly snow-covered. For birch and aspen trees, those winter buds swell, they change color and elongate, and then... the sap starts to flow. And again, all of this is happening, prior to green-up.

So, I mentioned Fairbanks' unique, green-up record. Jim Anderson and Bob Elsner, a long time ago, the Institute of Arctic Biology started systematically noting the date of green-up of Chena Ridge as seen from, from, UAF Westridge, and they started that, systematically doing that in the mid-1970s. And then, the late, great, Ted Fathauer, meteorologist in charge of the National Weather Service Fairbanks Forecast Office for nearly 20 years, he started, independently recording green updates in the mid-1980s. And then, when the Weather Service moved to what's now the Akasofu Building on West Ridge, Weather Service kind of became the keeper of those green updates Happily, the Weather Service has a spectacular view of Westridge, a whole bank of south-facing windows, and so... and so, able to continue, that... the observations that, Jim and Bob started, more than 50 years ago now. And this... this is the view, this is where we're looking at for... for Greenup, this picture taken from... from the, the parking lot right in front of the Akasofu building, and, looking towards, West Ridge there. Or, I'm sorry, looking towards Chena Ridge from The trough yet, there, here on West Ridge UAF. So here is what the time series of those green-up dates look like since 1974. Each green dot is the date of green-up, that year, and the black line is just the 7-year moving average there centered. And, you can see there is a notable, variability, almost looks like it's cyclical. But overall, there is not, at this point, any statistically significant long-term trend. Last year, Greenup was on May 10th, but you can see there, it's been as early as April 26, 2016, and a couple times, 2013 and 1992, it was May 25th or later. So, the date of Greenup varies, just in the last 50-odd years, by more than a month, but a pretty decent clustering there. Somewhere between the 5th and 15th is most of the dates. So... Can we estimate green-up data from climate data?

So, 38 years ago, Ted and I looked into this. This followed a bunch of really early green-ups in the mid-1990s, and we had this bright idea to see, well, could we use simple climate data To, predict, when greenup occurred. And at the time. our focus was really... we wanted to be able to backcast green up. We wanted to be able to estimate green up from places where we didn't have observations, but we did have some kind of climate data. So it was really that retrospective view that was driving our work in 1998 that we presented at an Arctic Science Conference here at UAF. So... Almost 20 years later. Jan, urged me, Jan Dahl urged me, to take a fresh look at, at this idea, with the eye of, could we use this more systematically to, forecast green up ahead of time?

By 1999... 2017, of course, we had, 20 years additional, green updates, and, some new ways to... to process that data, and so, So we had a big push there in the 2000 teens, that continue today to refine our ability to forecast green up. Now, right off the bat, there's a bunch of, there's a bunch of, experiential considerations, that we wanted to take into account. First of all. A few above-freezing days in the middle of winter has absolutely no effect on when spring green-up is gonna be. We also, just from experience, know that Greenup, usually starts first on south, southeast-facing, hill... lower hillsides, spreads quickly down across the valley floor, but more slowly uphill. And there is a significant correlation as well with aspects. So even at similar elevations, north side, northwest sides of hills will green up much later than the same elevation on the other side of the hill. This suggests to us that high temperatures are more important than the average daily temperature because temperature inversions at night are still common. Through the, early and mid-spring. Now, we... we think that, or we... this was really not so much a experiential consideration as, a hypothesis that we didn't really fully test, but spring is historically a dry season in interior Alaska, and there is far more water in the snowpack from accumulating for 6 months. than, spring precipitation. So, the idea was that with snowmelt, there's, at least as far as the trees go, there's lots of moisture available right around the time of greenup, so we didn't need to take into account, spring precipitation.

So, here's what we did. We... we tested out various combinations of when do we start accumulating a... some kind of metric to predict green-up, whether in hindcast fashion or forward. What thresholds to use, what weightings? In 2017, one of the additions that we made were solar considerations. And so, how do we, how do we determine which is best? Well, that's the, the, the formula that has the lowest variation of the typical value at Greenup, relative to the absolute value. So, the winter that we're still using, we start accumulating the index of high temperatures above freezing on March 1st, and we add in two, weighting factors. One is accounting for... basically, it's a date weight, so the later in the season it gets, an equivalent temperature gets a little bit higher boost. That kind of implicitly accounts for that increasing daylight and the increasing elevation of the sun during the day, so that total solar heating.

And then another experiential weighting factor is, just from observations. Especially late April, early May, when you get temperatures really warm, up in the 60s or low 70s, that really seems to boost things along, so we added basically a slight nonlinear increase to give those really warm temperatures a little bit more of a boost. And the little graphic here, plots our, our cumulative green-up index here. It actually plots every year, and the last, the highest and lowest, or I'm sorry, the earliest and latest green-ups, as well as, last year in orange and this year in black, shows where our index is This year, we're running pretty behind the curve, but not at the lowest. 2013 and 2002. We're lower than we're at at this point, and As we'll see here in a moment, things are about to take off. So, how would we go about predicting a future, you know, to use this in a forecast mode? Well, before the season starts, we've got, of course, our old friend Climatology. Might be able to tweak those with, with any forecast from the Climate Prediction Center, and we can look at correlations with larger-scale climate drivers, like El Nino or La Nina. Now, once we get into the season like we are now, we really need high temperature forecasts.

That's what our index is based on. So, we have, we have the weather service forecast, we have weather model forecasts out. 7 to 14 days, depending on what you're looking at. And then, then we have, again, our climatology, but with, able to tweak that. with, Climate Prediction Center outlooks. Now, throughout this whole process, in the in-season forecasts, and even pre-season, we really need to do this in a probabilistic sense, because there's uncertainty in all temperature forecasts, and there is a myriad of climate and biological factors that are not being explicitly accounted for. So, a single deterministic forecast, a one date, one number. Just is not, the best way to go, given all the uncertainty and all these elements. So, here's the, here's, okay, it's, it's, February, and, what, how's Greenup gonna be?

Well, a significant guide here is the state of El Nino, or La Nina. Turns out there's actually a, a reasonable forecast skill here. So what I've done here is I've taken all the green-ups dates and then plotted the the Relative Oceanic Nino Index, that's the index that we use to track El Nino La Nina. And, And see how these have played out, and then the column there on the right-hand side, I've just counted the dots for you. So, when we have La Nina, as we do now, that's the dashed black line for the January through March of value. Somewhere on that black line, we will plot the 2026 green-up date. When we have La Nina, the majority of green-ups have been later Then the, than the 51-year average During El Nino, not quite as dramatic, about half of them have been, early, but you'll notice that, 1992 there, the second latest green-up, was, was a, actually a strong El Nino, late winter, January, February, March. So, we have this... we have this as a possibility. So, even back in February, we might have anticipated a late green-up, just based on the state of...

that we were in with La Nina in the equatorial Pacific. Now, I've mentioned several times the Climate Prediction Center outlooks, and here... This is just a graphic illustrating the panoply of products that the CPC provides. The 6-10 and 8 to 14 day, outlooks there are provided every single day. There's also a week 3-4 outlook provided once a week on Fridays, and then the monthly outlook. Which is released, once a month. There, and so these are all from a couple days ago, and you can see, you can see how these look. So we could use these Potentially to tweak, tweak the forecast of high temperatures, because we need those daily high temperatures, to make our scheme work. Oops, wrong way. Alright, so...

accounting for uncertainty. One of the... one of the... one of the tools in the Forecaster Toolbox is, day-to-day persistence. If today is colder than normal, a reasonable forecast is tomorrow will be colder than normal. Temperatures don't vary, randomly, say, around normal. There's persistence. And this is just an example of about 18 different models here. Each is a model, and the dots are the high temperature forecast, and you can see that there's, there is consistency Within the same colors there. So that, kind of that purple line that's lower than most of them, that's a model that has a relatively, chilly forecast for the end of, April for Fairbanks, whereas you can see, the teal and the green ones have some very warm temperatures that persist over multiple days.

We also need to, constrain our long-range forecasts. to be climatologically reasonable. It can't be 90 degrees in Fairbanks in late April, and so we need to make sure our forecasts don't include things that, aren't gonna happen. And we need to do this a lot. So, currently we do more than 3,000, temperature simulations for every day of the forecast. Now, that was just the, kind of, the day-to-day, uncertainty. We also have the individual day uncertainty, this graphic here on the left-hand side. plots the high temperature forecast from the European model, and there are 51 black dots for each day. That's 51 separate models. high temperature forecast for those days is marked there.

And obviously, there is a massive range, starting... typically starting, 4 to 6 days out, the spread in the models increases dramatically. And if you look down there on, say, May 3rd, so the individual models have high temperatures ranging anywhere from the lower 40s to the upper 60s. By May 5th, it's even more extreme. One model has a high temperature barely above freezing, and another model here has a high in the upper 60s. So we need to account for that variability. These are all physically modeled. from physical models, so in that sense, they're physically plausible, but we need to really account for that increasing uncertainty as we go out in the forecast. Period. We have much higher confidence in the high temperature tomorrow than we do a week today, and that's normally higher than we have for two weeks from today.

There's also model bias. And particularly in interior Alaska in the spring, there is a strong bias for, forecasts to be too cold with high temperatures. And interestingly, for years, the worst bias is actually on the Today forecast. the models often significantly and consistently under-forecast the high temperature. So we need to account for that bias in our forecast scheme. Otherwise, we're going to be systematically wrong. In this case, for interior Alaska, it's often, the forecasts are too low. So, using our index here, here is the plot of showing when greenup occurred, using our index scheme here. And you can see, there's... there's a fair bit of spread, but 80% of the green-ups over the last 51 years have occurred inside those dashed lines there, so that's what we're going to... that's what we're going to call our green-up zone. When our index gets up to there, we've got a pretty good chance of having a green-up occur. So, we put all this together. We do this first 11 days, weather models accounting for the spread and systematic error, and then from day 12 on out to the end of May. At this point, we're mostly using, climate... climatology, but tweaked. When that's possible by the CPC outlook, so we just saw This week, the CPC outlooks beyond day 12 are mostly favoring above normal, so we tweak that climatology a little bit, and as I mentioned, we run thousands of simulations to account for all of these different factors. And here's what we get. Here is, as of this morning, our green-up forecast. Right now, we've got a 57% chance that this is going to occur in the 5 days, May 12th to 16th.

It's... the color bar there shows lesser chances on either side, but it's still possible. And occasionally, you know, a 10% chance, does happen. We saw that a few years ago, where the model, it was much later than the model had, but it was still in the window where there was some chance. So, this is the result of putting all these ingredients together. So, just to recap, this... this year, so this was the first year in Fairbanks that it didn't get above freezing in March since 1918. That actually doesn't have a big effect on our green-up index. Typically, only about 5% of the index occurs in March, so the fact there was zero is not a big deal that's easy to make up, depending on the weather in April. And early May.

April's been an interesting month in the interior. Many places, high temperatures are way below normal, but nighttime lows are actually close to normal. But since we are using the high temperatures. Not the average... daily averages, that, that's in part accounts why our index is so low at the moment. As of... as of this morning, this model suggests that SAT flow initiation is going to start in favored locations, soon. If not this weekend, then early next week. Again, big variability in when the sap starts to flow. Green up, as I showed before, likely in that, in that May 12th to 16th window.

That would be later than last year, but earlier than both, 2022 and 2023. So, just in summary, we've got this, this really, this unique, as far as I know, multi-decade record of green-up dates for Alaska, and we can estimate Greenup reasonably skillfully with the simple data, and then the things that we've added on in recent years, predicting sap flow. And as well as green up, if we have reasonable high temperature forecasts, we can actually have a... produce a skillful forecast well in advance. So that's what I've got for you, and... Susan is up next!

Susan Harry:
Okay.

All right, thanks, Rick. So Rick just talked to us about Greenup. And while we watch the canopy fill in, my work looks at actually what's in the air during that window, the invisible season of pollen. So, next. So, we're gonna cover a little bit about pollen identification. It has to do with the time of year, and then the physical features to differentiate the different pollen types. We're going to go into that. So, next. So, the timing of the different pollen. This graph kind of shows alder and willow are early birds, late April.

People will often sneeze before green up, so they may think they have a cold, but they also could be allergic to alder or willow. After that, birch explodes mid-May. This is our big one. It's our most intense allergen. In 2020, we had the world record-breaking year where Fairbanks hit just over 7,000 grains per cubic meter. That's approximately 4.5 times the national very high threshold of 1,500. So that was a... that was a big year, and I think a lot of people felt that. Green up milestone, you can see, occurs mid-May. Birch pollen peaks right as the hills turn green.

And then the cottonwood Aspen, Start about around the time birch is peaking, followed by spruce. Spruce is the visible dust that appears on your vehicles, in the puddles. This is also when birch is tending to decrease, so if you see the dust, know that birch is most likely subsiding, so that's a good thing for anybody who's allergic to that. Tree... pollen season is fast and intense. Our long winters tend to lead to kind of a light switch effect. Trees will release all at once, rather than trickling, whereas the grass and weeds, they come a little bit later, they linger a little longer into the season, as you can see. So, we can go to the next slide. Okay, so we'll cover the big five tree pollen of the interior.

The first two that show up are alder, alder and willow. Alder is considered a moderate allergen. It is usually the first one to show up. It has 5 pores around the perimeter, as you can see in that top picture, which will become important in a little bit later in the season. Willow, we've got several species around the interior. They have 3 deep furrows, as you can see in the graphic on the second picture. So we can go to the next. So, we have birch, Birch is dubbed the ragweed of the North. It's considered a moderate allergen, but we also have them as the biggest contributor to our pollen count because of the large population around the Fairbanks area. It has 3 pores around the perimeter.

which... since it overlaps with Alder, is very important for me when I'm differentiating between the two, because they're similar in size. So... We can move to the next slide. We're going to take a little closer look at birch. It usually starts about 2 days prior to bud burst. That's the top, both the top pictures, the left and right. You can see in the top picture of the pollen, the little darker grain, that is one birch, and then the other four that are clustered close together, those are poplar, cottonwood, and aspen. And then... Once the first grains are observed, we see pollen counts roughly triple every 24 hours until they reach their peak saturation by the third day, which is the bottom picture.

There's a picture of the leaves have Burst through, and then the pollen, you can see how much more birch... that's all birch in the bottom picture. So we can go to the next slide. So... This is a little bit closer look at the... In 2016, we saw a massive year that came close to the world record set by Denmark, a little over 4,000 pollen grains they had. We thought that was our limit until 2020. That year, we didn't just break the record, we shattered it with a count of over 7,000 grains per cubic meter of air. To put that in perspective, imagine a box of air, just about 3 feet wide. about the size of a standard desk.

Inside that small space, you're gonna put, you're looking at 7,000 individual grains or particles. The sheer volume of pollen was so thick that you can see in the picture it actually prevented some of the grains from taking up the stain. There's some just unstained green circles. Those were actually birch, but it was too thick to grab the stain. So we can go to the next. Okay, and then these are the Cottonwood Poplar Aspen.

They're all from the same genus, they're considered moderate allergens, and because the grain looks very similar, it makes them very hard to differentiate, so they're just lumped in one category. And one common misconception is when you see the fluff in the air, that that's the pollen, but that's actually after they pollinated, and that's the seed release. So we can go to the next. And, spruce is one of the last tree pollens to show. It's a large grain which can obscure other types of pollen. You can kind of see that on the picture there, that... how large a spruce grain is versus the birch that's the tiny one down below it. Spruce have two air bladders on each end, which makes it kind of resemble Mickey Mouse. That's when Jim Anderson was Teaching me how to count pollen, that's how he... dubbed it, was Mickey Mouse, so I've stuck with that.

These bladders allow them to be carried great distances, because they are so large by the wind. And it tends to arrive, like I said, as the birch is winding down, you can sometimes see it billowing from the trees if we have a windy day. It's rarely allergenic, but they pollinate profusely, so that's what we'll see. Okay, so we can move to the next.

So this is a quick slide, just showing the, increasing in size the different pollen grains that we see primarily with the trees here in Fairbanks. So we can move to the next. So, to count the rod, we'll go into how we collect the sample. We use a rotor rod sampler. It uses small silicone grease clear rods that spin at a high speed to capture whatever's floating by at the time, and it cycles 1 minute for every 10 for 24 hours. And after that 24-hour period, I collect the rods, I stain them with a special pink dye, it's caliberless solution. So the pollen pops, and I can see the details to help differentiate. And then I spend, on a light day, it could be 20 minutes to count all the pollen. On a heavier day, it could be 60 to 90 minutes per rod, to count every grain under the microscope. And then that's considered the raw count.

Then... That raw count is entered into a mathematical formula to calculate and estimate how many grains are in a cubic meter of air, which is then reported to the public via the co-op extension or the National Allergy Bureau. And keep in mind, given the 24-hour collection period, the number that is reported is actually represents the number of grains over the previous 24 hours. So we can go to the next. The calculated number is also categorized into the level of intensity using the National Allergy Bureau standard chart. The chart values were calculated using data from all NAB-certified counting stations across the United States. The higher the count, the greater the chance people that are suffering from allergies will experience symptoms. When they are outdoors or exposed to outdoor air, each person's sensitivity is uniquely theirs, so levels that bother one person may not bother another, even though they're allergic to the same thing. It's just how your own individual body reacts. So we can go to the next slide.

So, here are some symptoms of seasonal allergies. Itchy nose, sneezing, stuffy nose, runny nose, teary eyes, dark circles, So, they usually correspond with the pollen count, so if you're suspicious you may have allergies, keep track of the counts and your symptoms to see if there's a pattern. And if you see that, then it's a good time to go see your healthcare provider to get diagnosed for sure. So we go to the next. Okay, some birch and alder sufferers Also, allergy sufferers also develop oral allergy syndrome.

It involves such foods as pitted fruits, apples, cherries, peaches, as well as vegetables like carrots, celery, peas. It's caused by the body's immune system mistakenly identifying proteins. In these foods, as similar to pollen, leading to an allergic reaction primarily in the mouth and throat. The allergy is usually limited to the raw form. Once the food is cooked, symptoms typically disappear, not always, but this, remember, this only applies to oral allergy. If someone has a true food allergy, like a severe peanut or shell food, cooking will not make it safe. So, we can move to the next slide. So, how can we navigate the invisible season if you have allergies? Pollen is highest midday during the warmest time. If possible, avoid outdoor chores during that time, and keep the windows closed.

If you have to go outside to do, you know, take care of your yard, or go for a walk, early mornings or late evenings are better. Keep in mind that your pets can also bring the pollen in on their coat and on their paws. So they may have to have a bath more often. Try to keep create a nice, safe space or clean space for yourself, utilizing an air purifier with a HEPA filter in your home. Bedside is great, because you'll be sleeping there. As soon as you come in, you want to change your clothes, take a shower, Just to get the pollen off of you so you're not spreading it through your house. Wash your bedding frequently, especially, like, the sheets and the pillowcases. Remember to stay hydrated. Their, healthcare provider can provide, help you figure out your specific allergies in a treatment plan that best works for you. Of course, there's over-the-counter, such as antihistamines, nasal sprays, nasal wrenches, eye drops.

There's also some research being done on drinking birch sap, as well as oral birch pollen immunotherapy with apples that looks promising, so that would be something that would be nice. So we can move to the next. So where can you get the pollen count? you can... the local was best for most up-to-date and accurate information. We have that... ours will be posted with UAF Cooperative Extension and the National Allergy Bureau. There is some pollen forecasting that are on the national sites. That are predicted based on the previous year's counts and current weather conditions. They're still working on it.

It's a 70-53% accuracy at this time. Alaska is particularly challenging due to our subarctic climate and variabilities, so again, just, trying to find the local pollen count. And it's done in real time, so that's probably the best place to get that information. So we go to the next. There's a couple other things that can affect the pollen counts year to year. Masting and specific weather conditions are major drivers of the fluctuating pollen counts. Here we have weather conditions and how they affect the pollen counts. The best thing for allergy sufferers is a nice, gentle rain to provide a break. It, doesn't make it go away permanently, but it does help lower it for a little bit and makes things a little more tolerable. So we can move to the next.

Masting, there's masting years where the trees coordinate to produce massive amounts of seeds every few years. Since seeds start as pollen, the big mass years equals our higher pollen count years. Which is more intense for the allergy sufferer. Mass year consumes the tree's energy reserves, often leading to one to two years of lower reproduction and potentially lower pollen levels. while the tree replenishes its energy, and that's considered the bust year. So a bust year, lower counts, and relief for those people with allergies. So we can move to our next. So, to understand the scale of what we deal with here in Fairbanks, we have to look at the historical data. This graph is showing the single highest count each... for each year since, 2000, when I started to begin counting.

Since 2010, the volatility has increased, as you can see. We had 4 years in the last 15, 2010, 2020, 2022, and 2023 that reached or exceeded the 4,000 mark. With the warming trend, the baseline is shifting. By 2030, a light pollen year will probably feel heavier than a heavy year did, say, back in the early 2000s, making it a tougher environment for allergy sufferers. So we can move to the next. So, in the bigger picture, in 2019, a study also supports the previous graph, and international research team looked at 17 locations across 3 continents, including Fairbanks. Fairbanks not only had one of the biggest changes in the pollen alone, meaning it was heavier, but also an increased length of season. So, you can... move to the next. So, the shift over 25 years, we're seeing a little bit earlier springs, and more importantly, more intense pollen storms.

When we have a late cold spring followed by a sudden heat wave, the trees release everything at once, so I'm not sure how... This spring will go, but we will see. And then the next slide. So here's some additional links. The first two are... mostly deal with the lower 48, but there's some good, it's a good reference, and just some things that you could look at if you have allergies, or, and how... where does the pollen count come from, and understanding it a little bit better. And then we can move to the last slide. So, to wrap up, I want to leave you with this comic, that hopefully will not be our reality this spring. We've talked about the trees, what they're sending out into the air, but all that pollen and leaf growth requires massive amount of internal energy to understand the tree's power, this... how they power the cycle from the roots up. I'm going to hand it off to Jan to talk about the liquid gold of the interior sap production, and how you can get involved.

Jan Dawe:
Thank you, Susan. That was great, and a great reminder of what lies ahead. Okay, so, next slide, please.

This table represents 27 years of community source data, and I should say right here that one tree's role, and my role in this, is to bring humans in the environment into consideration of Fairbanks Spring Phenology. So. We've been doing this work looking at sapflow since 1999, and... This represents to us the biotic response, the response of birch trees to whatever the climate and the weather that year is bringing to us. You'll see some gaps in In this table, they're labeled either no data or insufficient data because we only had one tapper reporting. And I'm presenting this warts and all table to you because this is real-world citizen science, and that is what One tree does in bringing people to this work is, we do as many different presentations of interesting questions that could take a citizen science aspect to them, and every year, members, participants in the Fairbanks Birch Sap Cooperative, which has run from Oh. 4... K-12 classrooms in the beginning, up to about 70 tappers who collect SAP and either send their daily SAP data to us, or, as we'll be doing again this year for the first time since 2020, there will be people bringing their sap to us at the One Tree Alaska STEAM Studio in the Lola Tilly Commons building. We'll be producing the syrup from that sap, and then the people who bring it in will receive a 20% share from what their SAP contributed. So, Again, I just wanted to say that we're showing this warts and all table.

It's a short timeline compared to that which, which Rick and climate scientists traditionally use, but it's beginning to be a bit respectable, and this is an open call to anyone in the audience. If you have or know anyone who has tapping records for these missing years. 2004 or 5, 2010, 14, 15, please, we would love to have them, so please get in touch with me, and my contact information is on the, introductory slide. Next, please. This is the live data file that Rick and I begin updating daily, starting March 1st, the first day of spring, and please take a look at that, at the... at the... the link that's given at your convenience. The first snapshot that's cut and pasted in underneath the link Shows you the header names. And I just wanted to mention that what we... what we collate in this live data is a combination of information provided every morning by... by NOAA through their online portal, NOW data, then derived values that we calculate just for daily degree days and accumulated heat sum every day, and that one tree manages based on the NOAA data, and then the best, in blue, a sample of Rick's green-up forecast, which he usually does for, I believe, please correct me, 10 to 12 days out. And so, that's... what we're... that is, in a way, Susan, that's the liquid gold, because all of the work that One Tree does is, done as actionable science that's... we're... we are the land-grant unit at the university, and we are providing information that that producers, so sap producers and pollen, people who suffer from pollen allergies, that they can use. And so that's why we do all of this work. And Rick's work is instrumental, essential to our being able to predict A few days to a week out when people should set their taps, because You don't want to set your taps in trees to start pulling sap until what you think is going to be 5 days or less before sap flow begins, because otherwise the tree just creates a callus, it heals up that wound, the tap hole that you put into the tree, so we try to be very careful with that.

And so, all new information is added here on a daily basis. So, in addition to to, Rick's data, the next information that will come on will be the SAP flow initiation, or SAPUP, as Rick coined it a few years back, which is really catching on. And then. Soon after that, we'll have more information from tappers in the area around the state when their sap flow begins, so we're trying to track that. And then next, Susan will begin placing her daily pollen data in additional counts not shown On the screen here, but as soon as pollen flow begins. Next, please. So, the previous slide showed The spreadsheet, that's our go-to spot for all things in the current season, but that is just a snippet from the 53-year record of greenup. index that was created by Ted Fathauer and Rick Thoman, and that Rick has maintained steadily since 1974. Next, please. Oh, I guess, Rick, maybe you could go back just for a second.

Kind of the only reason I put this in was so that you could see at the very bottom of this slide that every year from 1974 onwards is in here, and by that I mean that all of the data for that day that's presented by NOAA is in this master file, and that's what we can draw on to begin to do individual day and periods, decades, whatever length of time. It's a goldmine for beginning to look at things in a statistical way. Next, please. Just want to show this data visualization is display... is, From that master file, and it's... displayed in the One Tree Steam Studio in the Lolla Tilly Commons, and the 1974-1998 temperature graph shown on this particular screen are ones that only have green up that's marked by small green dots on them, but since 1999, Susan and I have been adding the sap flow initiation and peak birch pollen data to each of the climate stripes or phonology calendars, which are based on Accumulated degree days and the corresponding calendar dates, so that visitors who come can look and use what they're comfortable with in tracking. And people do come, and they do start thinking about, oh, I remember that. that spike in heat in 1991, and I know where I was that day, and our hope is that we begin to have people recording their information in journals that... yearbooks, we'll call them, that we have in the Lola Tilly Commons, because first and last, this is a community collaboration. Next, please.

So, as I've said, One Tree's role in this collaborative effort has been to add community in to the mix of factors and what we're looking at that have to do with spring phonology. We do this in as many ways as we can think of, and we see what sticks, what ways resonate with the community. This slide shows one of those ways. We have in our... in our... our spot in the Little Utility Commons, in the loading dock room, a... a door. And we track degree day increase, accumulated heat sum increase, and date. Every day. from March 1st through May 31st, every year, since... well, I guess on this store, it's been since 2000. And as we've been doing that, we've also been looking, tracking snow cover. And pollen flow. And as we were doing that, we began to notice that snow cover, it looked to us that There was a trend that we could see in when sap flow would begin, and it had to do with when snow cover began to decrease by at least 1 to 2 inches per day. So... That was a clue. Next, please. the first thing we did, because I should say that when we had our 2026, sap season kickoff on April 13th. We began talking about what a late year this is, and so we began to look at how we could perhaps begin to look at this question. It would look like a gold mine, a way that we could begin to look at this question of how does snow snow depth and snow melt, begin to look at how that relates to sat flow initiation.

So, this slide shows you the 2026 season so far in weeks, from Sunday each week to Saturday. It shows it by degree days and date. And you can see not a whole lot of melting going on until, what, week 6, and then not so much in week 7. So it's been a really consistent... year, and we decided that with the help of the Birch Syrup Cooperative and K-12 classrooms that are working with us. and university students, including the ESL students, we would begin to look at this question of what's going on with the snow? So, people are out there now, while we're talking. The first classes are going to be looking at, I believe, Wood River this afternoon, taking measurements both 10 feet back from their candidate tree that they're going to tap when sap flow begins, and they've already chosen that tree, and then going up to the tree, looking at the characteristics of its snow. well, and tracking that, both its depth and width, as it increases. Next, please.

So there are 16, we'll call them labs. their classrooms and also individual tappers and households who are taking part in this... really, it's a... it's just a first glimpse, and we're going to learn more from this year's pilot inquiry than anything about the data. We're going to learn more about what we left out, what we need to consider. But we are, yesterday, Susan and Rick and I met, and I was saying, we need a catchier title than the one we're using. And we came up with 2026, the epic battle of the sun versus the snow. It's a tug of war. And the question, of course, for everyone is, when will sap flow begin? Next, please.

So, to test this, because we now have this great 53-year record, and also a 21-year record of SAP flow. I chose 4 snapshots, 4 days from the 53-year record that seemed like they were had a lot to say about the changing, dynamics of the Fairbanks Spring phonology. And so, you can see the links to each one of those, and you can... if you download the, recording that Ed Plum will... will supply, you can go and link to these Sheets and see those years. Next, please. The reasons that we chose these four days as critical bookmarks is, vernal equinox March 20th. There's, I believe Rick says only 10% of the the heat sum to get to greenup occurs on average in March, and so the vernal equinox on March 20th or 21st, represents the baseline. And then April 1st. Is really what you can kind of set your...

Your phonology clock to in recent memory is when things really begin to heat up. April 13th, I chose just because we were having our sap up, I'm sorry, our SAP season kickoff event that day, and it turns out that that is, in fact, a really significant day. And it's a day, when you analyze it, through the 53-year record, that that the... snow really begins to act more like a snow break if there's significant snow left behind. And we'll talk more about that in a second, in the next slide. And then finally. just because we all love Earth Day, and that was yesterday, Earth Day happens to be the mean day for sap flow to begin in our 21-year history, and it is indicative of what's going on in terms of climate, which is Spring is getting squeezed. Squeeze down more and more. Next slide, please. So, as the season progresses, when we do the statistical tests, the math shows us that the snow doesn't just stay on the ground, it actually becomes more influential in dictating the forest timeline.

And so, by the time we get down to Earth Day, April 22nd, we're seeing 24% direct correlation Between snow depth and heat sum. Which is a massive signal when it comes to a complex ecosystem. So there's a lot more to study, and we really welcome all of you snow and atmospheric scientists and soil scientists and ecologists And people who are just plain interested to come and help us think through this more, because Everything we do at one tree, which includes trying to do high-quality citizen science that can lead in to, more bounded research. We really need everybody's eyes and help in thinking this through and how to do it carefully. Next, please. Okay, I'm seeing that the time is up, so I'm just gonna say, if you get...

I'm gonna just rush past these. To say that if you look at this slide, it will show you, More information about what the statistics show. Next slide. And now, this is something... My favorite thing that Rick does often in his monthly outlooks is that he always has, and the answer is... this is the closest I can get to it. So, what is the answer to the 2026 epic battle of the sun versus the snow? And the next slide is going to be a spoiler alert, warning us all. Next slide, please. The answer is, the snow may win the battle from day to day.

But the sun... always wins the war. So, in that tug of war, That we're having. Sap flow is the next to happen, and if you'd like to join One Tree and the Fairbanks Birch SAP Cooperative, please get in touch. And... I'd like to acknowledge, and this acknowledgement's is not done. This last slide, please, if you'll look at that, Rick, thank you. I want to thank ACCAP for hosting this annual Greenup webinar, which is a highlight of the year. for... for...

for me personally and professionally. And Rick Thoman, Susan Harry, and Ed Plum, who has been such a magnificent slide wrangler, and that's where this slide stops, but that's not where the acknowledgements end. I want to thank all of the One Tree staff for the efforts they put into helping this presentation, which that staff is Shawn Johnson, Jesse Lobato, Wade Harry, Summer Home. And also, all of the tappers and participants in the Birch SAP Cooperative. Without you, none of this is possible. So thank you. That's it.

Edward Plumb:
Thank you, Jan, and thank you, Susan and Rick, and... We appreciate that, and doing this annually, and it's exciting to see when we're expecting to see green-up and the sap running. We are a few minutes after the hour, so I know people are dropping off. I think for questions, I'm just gonna get the... anyone that wants to stay over, and then this is recorded as well, there was a couple that came in the chat that I'll ask, and then, we'll close it out after those two questions. But the first one, Rick, this one was for you. The green-up data reminded me of the 2012-2013 winter, which was cold, and in Denali National Park, April was colder than ordinary years, according to the rangers. Then the 2013 summer was hot and dry in the interior. Could it be a similar summer this year? I also heard that it is changing to El Nino. What would be the effect? of it on the summer forecast, can you expect next spring's sap flow from previous year's condition? A lot of questions there, Rick.

Richard Thoman:
So, yes, so 2013, very cold spring across, across the interior. including Denali Park, which I should say, where there is also a reasonably lengthy, green-up record, right there around park headquarters. That's very valuable, too. Yes, we had a... we had a La Nina over the winter, and, Climate Prediction Center is expecting a fairly rapid transition to El Nino, during the... during the early summer here, and for most of the world does not have a big effect. El Nino doesn't have a big effect in summer, but here in Alaska, over virtually all of the state, that does increase the chances that the June through August average temperatures will be above normal over just, say, random chance. So, that is a little boost. That doesn't mean it'll happen. There have been cool summers. During El Nino, but it's, it is a thumb on the scale to favor significantly above normal temperatures for the summer as a whole. And I would guess I would leave it to Jan. Do the current year, warm season conditions tell us anything about greenup or sap flow next year?

Edward Plumb:
You're muted, Jan.

Jan Dawe:
Okay, that is a great question, and...

There is the beginning of what really looks like a trend that when we do have El Nino years. SAP flow begins earlier, and there's a steadier, A steadier climb in... In daily degree days, it accumulated heat So, I think that we'll likely be seeing an earlier start to the sap season next year, and we're really interested in a lot that has to do with sap quality. For this year, though, I just want to go back to this year, because it looks from... from Rick's forecast that it's going to warm up into the 50s and stay there, and climb towards the 60s quickly. It's going to be a short, intense. Maybe a 10- or 12-day sap season, and the sap, because it's going to be so warm, will get buddy, will begin to be yeasty, so taking care of your sap buckets is going to be really important, too. To wipe them out with a damp cloth if you live in a waterless cabin, or actually rinse them out every day or two at in a spigot, and then rehang them on the tree. So, sap cleanliness is going to be a big deal because of the heat. That's going to be present throughout this short sap season.

Edward Plumb:
Great. Thanks. Good advice, Chan. Especially, for people that live in a water... in a dry cabin, too.

Jan Dawe:
Right.

Edward Plumb:
When they can just use the damp cloth. Well, I will ask this one last question, and then we'll... we'll finish it off for today. Somebody had a question. We live up on Chena Ridge. And up here, it seems like everything takes longer to bloom than in the valley. Why does this happen?

Richard Thoman:
So, I'll take, I'll take that, So, up on Chena Ridge, of course, higher elevation, this time of year. Daily high temperatures are gonna be, on average, lower than in the valley floor, so it takes longer to get that accumulated heat at elevation than it does on the valley floor.

Edward Plumb:
Okay, well, thanks, Rick, and thanks again, Susan and Jan. Appreciate you joining again this year for the annual green up. outlook for the Fairbanks area, and At that, everybody have a great afternoon, and we'll see you again next year for the same webinar with new information.

Jan Dawe:
Thanks, everyone!

Richard Thoman:
Everyone.