Seeds on Snow

By Carl Strang

 

There is a magnificent paper birch near the entrance of Mayslake Hall which has managed to evade the bronze birch borers long enough to become robust and beautiful.

 

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Yesterday I noticed that the birch had dropped seeds onto the snow.

 

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For a moment I was a little surprised that there were any seeds left. A couple weeks ago that tree was filled with goldfinches, juncos and pine siskins pigging out on seeds they were digging out of the tree’s cones. Obviously they missed some, for the snow was covered with yellow-brown seeds and shed cone scales.

 

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After taking some photos, I thought about the timing. Now, with leaves dropped from deciduous trees, the little winged seeds have their best chance of being carried away on the wind. Furthermore, if there happens to be snow on the ground, the wind can further push the seeds, increasing the area over which they are spread. This might improve the possibility that some will find suitable places to grow.

 

That thought brought out a memory, of a presentation decades ago at an Ecological Society meeting. Someone had studied Queen Anne’s lace and found that its seeds are contained within the closed umbrella of its flower/fruit support struts.

 

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The struts remain closed when the air’s humidity is high, but open as humidity drops, so that seeds are released in the dry air of winter when there is a good chance the ground will be snow-covered, allowing the seeds to be wind dispersed over a smooth surface.

 

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Later during my lunchtime walk I found some Queen Anne’s lace, and sure enough, though some were closed, others had opened and begun to drop their seeds onto the snow.

 

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