We had really high pollen abundance in Galena this spring. In our area we are definitely having a "mast year" (large cone crop) in white-spruce this year. As a result we also have a large number of White-winged Crossbills who have come here to eat the seeds. I have attached a couple of articles I have found interesting (available in the documents section of this post). Here is some text from Matt Bowzer's Kenai article in the Refuge Notebook that sums up the weather patterns thought to make mast years happen. The article explains more about why this is advantageous to the white spruce population on a larger scale.
"It turns out that year-to-year climate variation synchronizes cone production cycles in white spruce, at least in part. We see the largest cone crops following optimal conditions: a cool growing season two years before a cone crop, allowing trees to grow and build reserves; a hot spring in the year preceding a cone crop, stimulating trees to initiate cone development; and cool growing conditions the year of a cone crop, enabling maximum development of the cones. The trees’ reserves are exhausted during a masting event, resulting in very few cones the following year. The cycle repeats every two to six years."
Another benefit for white spruce to have large cone crops following warm summer seasons in the previous year has to do with wildfire. Unlike black spruce which is able to keep its seeds safe during a burn event and reseed locally, white spruce depends on seeds coming in from outside of the burn to reseed an area. If spruce produce numerous seeds following a year when wildfire may have been likely, those seeds are available to blow on the wind into the burn and establish.
Comments from LEO Editors:
Over the summer, LEO received several observations of unusually high levels of pollen in Saint Mary's, Chuathbaluk, Anchorage, Nome, Stebbins, Golovin, and Koyuk.
This temperature pattern can be applied to this mast even in Koyuk! According to temperature records from the Koyuk Airport, temperatures in 2017 and 2018 were cooler, warmer in 2019 and slightly cooler in 2020 than the spike in 2019. This follows the perfect recipe for this mast event. Chyna Williams