UAF Cooperative Extension Service

For the first time in weeks, the heavy yellow blanket over the Tanana Valley has officially lifted. Spruce has finally broken its long, stubborn "high" streak, tumbling down into the moderate zone. With all other tree and plant species resting safely at low levels, today is easily the clearest, most comfortable day so far this June!

Today’s Official Counts (June 16, 2026):

Spruce (Picea): 43 (Moderate) – THE STREAK IS BROKEN! Down significantly from yesterday's 144, spruce has dropped to its lowest level in weeks.

Birch (Betula): 6 (Low) – Barely a blip on the radar as the species wraps up its season.

Alder (Alnus): 2 (Low)

Juniper (Juniperus): 1 (Low)

Chokecherry / Bird Cherry (Prunus): 1 (Low)

Sedge (Cyperaceae): 2 (Low)

Mold* Spores: 456 (Low) – Following the trend, mold concentrations took a step back today, remaining well clear of any public health concern threshold.
*Pollen counts are certified by the National Allergy Bureau; Mold counts are independently analyzed and provided for general informational and educational purposes only.

Behind the Lens: Wide Open Spaces
After days of navigating slides packed to the brim with giant, winged spruce gliders, sticky fruit-tree clusters, and tangles of cottonwood seed fluff, today’s microscope slide was beautifully quiet.

Take a look at the photo from this morning's slide of a lone spruce grain floating in a vast sea of empty glass with absolutely no other pollen in sight! Finding an isolated grain like this with nothing else crowding the frame is a rare treat after weeks of heavy pollen blankets.

While the grass and summer weeds are still waiting in the wings to make their true midsummer push, enjoy this spectacular, low-pollen reprieve!

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

The Georgeson Botanical Garden did a chokecherry replacement demonstration and shared what they learned just in time for Invasive Species Week!

Happy Monday! Susan Harry is back at the microscope at the Arctic Health Research Building to kick off a new week of tracking.

Today’s Official Counts (June 15, 2026):
Spruce: 144 (High)
Alder: 21 (Moderate)
Birch: 19 (Moderate) – Both species are experiencing a minor mid-June bump.
Juniper: 7 (Low)
Chokecherry / Bird Cherry: 2 (Low)
Grass: 3 (Low)
Sedge: 1 (Low)
Dandelion: 3 (Low)

Mold* Spores: 1,052 (Low)
*Pollen counts are certified by the National Allergy Bureau; Mold counts are independently analyzed and provided for general informational and educational purposes only.

Behind the Lens:
Today we have three fantastic photos that show exactly what it’s like to navigate a slide during mid-June in Interior Alaska:

(Photo 1): Remember our talk last week about the white cottony fluff in the air? This image shows exactly what cottonwood seed fluff looks like under the microscope, and it is a total lab hazard! These massive, tangled fibers weave across the slide, trapping pollen grains underneath and creating giant blockages that make counting the actual microscopic pollen a tricky game of hide-and-seek.

(Photo 2) This frame captures a massive, winged spruce grain floating right next to a small, smooth grass grain. If you look closely at the grass grain, today’s lighting perfectly illuminates its definitive pore—the single little circular opening surrounded by a doughnut-like ring (annulus) that acts as the hallmark identification feature for the entire grass family. What is that little pore for? That distinctive doughnut-shaped ring is called a germ pore. Because a pollen grain's outer shell is one of the toughest, most indestructible structures in nature, it needs a designated "weak spot." When the grass grain lands on a flower, it uses this pore as an exit hatch to grow a microscopic tube down into the plant for fertilization. It also acts as a tiny valve, helping the grain regulate moisture and expand or contract safely while floating through the dry Fairbanks air.

(Photo 3) On Friday, we caught just one lone dandelion grain, but today we hit the jackpot with a tight clump of 8 dandelion grains stuck together! Because dandelions are insect-pollinated, finding a cluster like this means a heavy, sticky bundle was likely shaken off right near our sampler. Look at those beautiful, spiked outer walls interlocking with each other.

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

This week is Alaska Invasive Species Awareness week, which highlights the work it takes to manage invasive species in Alaska, like European green crab, chokecherry trees, elodea, pike (south of the Alaska Range) and orange hawkweed.

A growing number of invasive species are entering Alaska through multiple pathways. Early detection and rapid response are critical tools for preventing the spread of invasive species in Alaska and helping mitigate their negative impacts.

The Alaska Invasive Species Partnership works hard to manage invasive species in Alaska. Follow them to learn more about invasive species and how you can help prevent the spread.

The Fairbanks atmosphere is keeping us on our toes this week! After dipping briefly following Tuesday's cool rain, spruce has climbed right back up into heavy-hitting territory today.

Today’s Official Counts (June 12, 2026):

• Spruce: 265 (High) – Stepping back up as warm, breezy conditions help the remaining male cones disperse their heavy yellow payload.
• Juniper: 26 (Moderate) – Climbing steadily into the moderate zone! Keep an eye on this if you are sensitive to evergreens.
• Birch: 16 (Moderate) – Nudging slightly up into the lower boundary of the moderate category, though nothing like the massive peaks of May.
•Alder: 9 (Low)
• Chokecherry / Bird Cherry: 5 (Low)
• Sedge: 1 (Low)
• Grass: 1 (Low) – FIRST OF THE SEASON! Marking the true boundary line of mid-June.

Mold* Spores: 999 (Low) – Sitting just a hair shy of the 1,000 mark, remaining steady and low.
*Pollen counts are certified by the National Allergy Bureau; Mold counts are independently analyzed and provided for general informational and educational purposes only.

Behind the Lens: A rare dandelion, our first grass, and an evergreen duo
Today’s three microscope snapshots showcase the amazing diversity drifting through the Interior Alaska air right now.

(Photo 1): We caught exactly one lone dandelion grain on the entire slide today. Because dandelions are insect-pollinated, their pollen rarely hitches a ride on the wind to land in our air sampler. Finding this one grain is not of clinical significance for allergies, but it is an absolute stunner to look at — featuring a beautifully intricate, jagged and spiky outer wall (exine) that helps it stick to visiting bees.

(Photo 2): Say hello to the grain that will define the next month of monitoring! Grass pollen is stenopalynous, meaning grains across the entire family look almost identical. Under the lens, it appears as a smooth, perfectly round-to-ovoid sphere characterized by a singular, circular pore surrounded by a distinct doughnut-like ring called an annulus.

Have a great weekend!
Susan Harry, certified pollen counter

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

(Photo 3): This frame gives you a perfect sense of scale in our boreal forest. You can see a massive, winged Spruce grain floating right next to a small, spherical Juniper grain. It really highlights the difference between a heavyweight "glider" and a lightweight "beach ball" evergreen design!

The tree pollen battle continues, but there is a major shift in the air today, Fairbanks. While spruce has eased down slightly from yesterday's spike, it is still commanding the airspace in the high zone. But the big news today is under the lens: we are officially adding juniper to our tracker after catching some classic grains this morning.

Today’s official counts (June 11, 2026):
• Spruce (Picea): 170 (High) – Dropping slightly from yesterday's 210, but still dominating the atmospheric canopy.
• Birch (Betula): 9 (Low) – Beautifully quiet and holding steady at trace baselines.
• Juniper (Juniperus): 8 (Low) – NEW SEASON ENTRY! We tracked a small wave of these tiny evergreen grains drifting into the valley today.
• Alder (Alnus): 5 (Low)
• Chokecherry / Bird Cherry (Prunus): 3 (Low)
• Sedge (Cyperaceae) : 2 (Low)

Mold* Spores: 1,110 (Low) – Officially crossing into four digits! The humid, warm soils are encouraging fungal development, though 1,110 remains securely in the low national allergy category.

*Pollen counts are certified by the National Allergy Bureau; mold counts are independently analyzed and provided for general informational and educational purposes only.

Behind the Lens: A Sticky Prunus Jam & Spotting the New Juniperus
Today’s two microscope captures tell a fantastic story about how differently plants distribute their pollen:

(Photo 1): Look at this massive, tightly packed clump of chokecherry/bird cherry (Prunus) grains! This image perfectly demonstrates their heavy, highly sticky nature. Because these trees rely on insects rather than wind to cross-pollinate, their grains are coated in a thick, oily fluid designed to stick to bumblebee legs. Every now and then, a whole cluster gets yanked off a blossom by a breeze right outside our Arctic Health window and hits our sampler all at once!

(Photo 2): This frame highlights our two newly logged juniper grains. Compared to the massive, winged spruce shapes, Juniperus grains are quite small (around 20–30 micrometers) and spherical. They feature a thin outer shell (exine) and a distinctive, slightly dimpled, starburst-like internal cellular collapse when stained, making them look like tiny, wrinkled beach balls.

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

The garden is looking beautiful!

Just when we thought the yellow dust storm was clearing out... it bounced right back! Yesterday’s cool temps and scattered showers gave our sinuses a brief window of relief, but today the thermometer crept back up, the breezes returned, and spruce went right back on a tear. It jumped from yesterday's 92 straight back up into the high zone at 210.

Today's Official Counts (June 10, 2026):

Spruce (Picea): 210 (high) - A big rebound from yesterday's 92. The "spruce yo-yo" is in full effect as remaining cones release their final waves.

Birch (Betula): 9 (low) - Continuing its wonderful downward trend! The spring birch season may be officially in our rearview mirror.

Alder (Alnus): 4 (low)

Chokecherry/bird cherry (Prunus): 2 (low)

Sedge (Cyperaceae): 1 (low) - All remaining quiet at low baselines.

Mold* spores: 552 (low) - Nudging upward slightly from yesterday, enjoying the lingering ground moisture.

*Pollen counts are certified by the National Allergy Bureau; Mold counts are independently analyzed and provided for general informational and educational purposes only.

Under the Lens: Why is Spruce Pollen Shaped Like Mickey Mouse?
I know you've seen a lot of spruce on the page lately, but today’s clear slide gave me a perfect opportunity to talk about why these grains look the way they do under the lens.

Spruce pollen is famously recognizable because it looks like it has a pair of giant cartoon ears attached to a central body called saccacae (air bladders).

These bladders are hollow and filled with air. They act exactly like microscopic balloons or water wings. Because spruce trees don't rely on colorful petals or sweet nectar to attract insects, they have to rely entirely on the wind to travel miles across the Tanana Valley.

These tiny air-filled sacs make the massive grain incredibly aerodynamic, allowing a slight Interior Alaska breeze to carry it for miles. It’s also the reason they float so beautifully to the top of our liquid slide stains!

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

Here are the results of Susan Harry's pollen count late Tuesday afternoon:

"Thanks to the rain, our spring tree counts have plummeted across the board. Spruce is the only tree hanging onto the "high" zone, but its numbers are a mere fraction of what we saw late last week."

Today’s Official Counts -June 9, 2026:

Spruce: 92 (High) – A massive drop from yesterday's 275! While it technically sits just inside the "high" threshold, the yellow dust blanket is finally easing up.

Birch: 13 (Low) – Down into the low zone!

Alder: 4 (Low) – Dropping to trace levels.

Chokecherry / Bird Cherry: 1 (Low) – Tapering off as the petals begin to drop.

Mold* Spores: 422 (Low) – Though the overall count dipped slightly along with the pollen, the visual variety of fungal spores on the slides Tuesday was absolutely incredible.
*Pollen counts are certified by the National Allergy Bureau; Mold counts are independently analyzed and provided for general informational and educational purposes only.

Behind the Lens: The Mysterious Micro-Fungi of Fairbanks

Because our slides aren't completely crowded with giant spruce grains, I was able to isolate and photograph two distinct, unstained mold spores floating alongside our usual counts.

(Photo 1): Look at this massive, dark brown, multi-segmented spore! It looks like a long, compartmentalized seed pod or a tiny caterpillar. This is an excellent example of a complex, multicellular macro-spore (resembling genera like Alternaria or Curvularia) that typically thrives on decaying outdoor plant matter and wet soil after rain. To its upper left, you can also spot a much smaller, two-celled brown spore for scale.

The "Mickey Mouse" Guard (Photo 2): In this frame, a classic, deep-pink spruce grain is surrounded by a handful of smooth, transparent-brown, two-celled oblong spores. It looks like a giant winged spaceship flanked by a fleet of tiny micro-scouts!

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

Monday's slides bring a mix of shifting seasons: some spring trees are finally winding down, summer species are stepping up, and we caught a beautiful, rare garden favorite under the lens!

Official Counts (June 8, 2026):
• Spruce (Picea): 275 (High) – Down slightly from Friday's record peak, but still firmly in the high zone. The yellow dust storm continues.

• Birch (Betula): 40 (Moderate) – BIG RELIEF! Birch has finally dropped out of the High category for the first time in a week, giving our lungs a much-needed break.

• Alder (Alnus): 40 (Moderate) – Holding perfectly steady at a manageable baseline.

• Chokecherry / Bird Cherry (Prunus): 9 (Low) – Still hanging around as late blooms finish up

• Lilac (Syringa): 1 (Low) – RARE FIND! Look at the photos to see this gorgeous newcomer.

• Sedge (Cyperaceae): 5 (Moderate) – Climbing steadily into the Moderate zone as our local wetlands and lawns mature.

• Mold* Spores: 972 (Low) – Creeping upward as the summer soils warm up, though still technically in the "Low" threshold nationally.
*Pollen counts are certified by the National Allergy Bureau; Mold counts are independently analyzed and provided for general informational and educational purposes only.

From certified pollen counter Susan Harry:
"Today I have two distinct microscope photos to share with you:

(Photo 1): Capturing a lilac grain (Syringa) on the sampler is incredibly rare! Because lilacs are heavily insect-pollinated, their pollen is thick, heavy, and sticky—meant to travel via bumblebee, not the breeze. Catching even one grain means the lilac bushes are officially bursting open! It is a medium-sized grain, typically spheroidal to prolate (slightly oblong) in shape, with a heavily textured, net-like outer shell called a reticulate exine. This detailed mesh pattern helps aerobiologists distinguish it from other pollen types.

(Photo 2): This frame shows a classic early-June cocktail of spruce, birch and alder. But we want to draw your eye to the sedge grain highlighted in this shot. Sedge pollen looks like a distinct, elongated, pear- or golf-tee-shaped grain with faint, delicate indentations. Unlike wind-heavy trees, sedges mark the true transition into summer ground vegetation season.

MythBusting:
You have likely noticed a massive amount of white, cottony "fluff" drifting through the Fairbanks air. A very common misconception is that this fluff is the culprit behind your allergy symptoms.

Here is the scientific reality: Our official poplar count has officially wound down to zero. The microscopic, allergy-triggering pollen from Poplar and Aspen trees was released weeks ago. What you are seeing in the air right now are the tree seeds, equipped with tiny cotton parachutes to aid in dispersal.

Because these fuzzy seeds are massive compared to microscopic pollen, they are far too large to pe*****te deep into your respiratory system and trigger an allergic reaction.