Itchy eyes, runny nose and scratchy throat may have told you that this is a banner year for tree pollen. White Pines (Pinus strobus) get much of the credit. They bear both male and female cones on the same tree (monoecious), as do most conifers. The familiar female (seed) cones are between four and eight inches long, woody and dark brown. The male (pollen) cones are much smaller (1/2”), papery and light in color. They are borne in clusters and have tightly overlapping scales that open up when the pollen is mature, releasing massive amounts of pollen into the air which is distributed by the wind. (To see this phenomenon, go to https://www.smithsonianmag.com/smart-news/watch-pine-tree-unleashes-huge-fluffy-pollen-cloud-180969048/.) Pollen can remain airborne for up to 11 hours, and can travel up to 1,800 miles in a short amount of time. Once the pollen is dispersed, the male cones fall off the tree and disintegrate quite quickly.
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