OneTree Alaska

Wondering why your eyes are itching?

Today, Susan Harry is zooming out to show you the variety of what’s currently in the Fairbanks air.

She said, "At this lower magnification, you can see the whole 'neighborhood' on the sampling rod. The massive spruce grains are easy to spot, but look closer and you'll see the 118 birch grains that are currently keeping our count in the HIGH zone.

"We do our official scientific counting at 400x (4 times closer than this!) to make sure we don't miss a single grain."

The pollen count as of May 28, 2026:
• After dipping to 92 yesterday, birch has ticked back up to 118. It is refusing to let go of its "high" status as we move toward the end of May.
• Spruce dropped slightly to 64, while alder rose to 46. This "moderate" mix of the two species is what's currently contributing to the hazy air and itchy eyes across town.

Birch - 115 - high
Alder - 46 - moderate
Spruce - 64 - moderate
Willow - 1 - low
Poplar/aspen - 1 - low

Susan Harry’s Pollen Counts are provided by One Tree Alaska, with help from UAF Cooperative Extension. For updates, visit https://www.uaf.edu/ces/healthy-individuals/pollen-count/index.php

A really interesting explanation of why certified pollen counter Susan Harry stains the pollen in her slides.

Ever wonder why the pollen grains in Susan Harry's microscope photos look like glowing gems?

Susan writes, "In this single frame, you can see both unstained and stained Betula (birch) grains. Without the stain, the grains look like pale, translucent ghosts — nearly impossible to distinguish from air bubbles or mineral dust at a glance. By staining the outer shell with Calberla's solution (containing basic fuchsin), we can see the tiny pores and structures that tell us exactly which tree a grain came from.

"The reason the stain works so well is that it binds specifically to the exine, the outer shell of the pollen grain. This shell is one of the toughest organic polymers known to science, allowing pollen to stay preserved for thousands of years in the soil — or just long enough for us to catch and count it outside the Arctic Health Research Building. Notice how the three pores (the little circles at the corners) become sharply defined, allowing us to confidently count them even in a crowded sample."

Pollen count, updated Wednesday, May 27, 2026
• For the first time in nearly two weeks, birch has dropped into the double digits (92). While still "high" by medical standards, the density on the slides is visibly thinning.
• Spruce has jumped from 15 to 81 today. We are officially entering the "yellow dust" era of Fairbanks spring. At this rate, spruce may overtake birch as the most numerous grain by Thursday or Friday.
• Alder has dropped to 28, continuing its slow decline as the trees transition from flowering to leafing out.

Birch - 92 - high
Spruce - 81 - moderate
Alder - 28 - moderate
Poplar/cottonwood/aspen - 3 - low
Willow - 1 - low

For updates, visit https://www.uaf.edu/ces/healthy-individuals/pollen-count/index.php

Susan Harry’s Pollen Counts are provided by One Tree Alaska, with help from UAF Cooperative Extension.

Achoo!

Fairbanks is in the middle of what Susan Harry calls the "birch plateau."

"While we haven't seen another massive jump in numbers, the air remains heavily saturated with Betula (birch) pollen. Meanwhile, the early-season dominance of poplar seems to be winding down significantly," Harry said on Monday, May 18. "The total volume of pollen in the air is still very high, but the "flavor" of the air has changed. We have moved from a birch/poplar mix to a landscape almost entirely defined by birch and alder."

You can see all of the pink-stained birch pollen grains on the slide.

Here are Monday's pollen count totals:

"While we haven't seen another massive jump in numbers, the air remains heavily saturated with Betula (birch) pollen. Meanwhile, the early-season dominance of poplar seems to be winding down significantly," Harry said on Monday, May 18. "The total volume of pollen in the air is still very high, but the 'flavor' of the air has changed. We have moved from a birch/poplar mix to a landscape almost entirely defined by birch and alder."
Poplar/cottonwood/aspen - 12 - low
Alder - 72 - moderate
Willow - 12 - low
Tamarack - 5 - low

Susan Harry’s Pollen Counts are provided by One Tree Alaska, with help from UAF Cooperative Extension. You can view the updates at https://www.uaf.edu/ces/healthy-individuals/pollen-count/index.php

While poplar pollen levels remain high, birch pollen exploded Friday, May 15, nearly quadrupling its count from Thursday and completely dominating the slides. Certified pollen counter Susan Harry titled the microscopic slide from Friday's count "The Birch Takeover." She said in previous days, she had to hunt for specific grains; on Friday the Betula (birch) grains were so densely packed they were overlapping in some areas. It is a wall-to-wall carpet of tri-pored pollen.

Here are the counts for Friday.
Birch - 931 - high

Poplar/cottonwood/aspen - 113 - high

Alder - 40 - moderate

Willow - 7 - low

Tamarack - 2 - low

Sedge - 2 - low

Susan Harry’s Pollen Counts are provided by One Tree Alaska, with help from UAF Cooperative Extension.

Populus pollen out to play!

While our other botanical friends are keeping things low-key pollen-wise, the Populus genus has officially moved from its "seasonal premiere" to a "blockbuster release."

Today's pollen numbers are:
Willow: 3
Alder: 5
Poplar and Aspen: 113

This photo from today's sample shows pink-stained Populus pollen.

See daily updates on our website: https://www.uaf.edu/ces/healthy-individuals/pollen-count/index.php

Get your tissues ready, today marks the official start of the pollen season with a pollen count of 7 for Alder from the Rotorod sampler newly installed on UAF's Arctic Health Research building

This photo shows two distinct, stained-pink Alder grains (lower left and upper right) surrounded by environmental particulate matter.

As of today, the Rotorod pollen collector is officially installed and operational on the roof of the Arctic Health Research Building!

The new unit sits just feet from where the late Jim Anderson conducted his foundational pollen sampling.

Susan Harry, our pollen counter, says, "This is a profound full-circle moment; Jim brought me to this very roof in 1999 to train me in the art and science of pollen counting. Today, with my office located in this same building, looking up at that collector feels like a true homecoming."

From the vantage point on the AHRB roof, we are once again keeping a close eye on Chena Ridge for the first signs of green-up. Combining those visual phenological cues with the data from the Rotorod allows us to continue the high-standard monitoring Jim pioneered decades ago.

Stay tuned for the first pollen counts of the season!

Good news for all! Whether you're tapping on a sunny south-facing slope or in a shaded valley bottom, it's time for all tappers to get their drills out!

Sap flow officially started on Friday in especially warm spots, like heat islands (UAF lower campus, for example, where there is a lot of asphalt). And since then, sap has been flowing in trees at all aspects and elevations.