ARBORETUM NEWS (NATURALISTSNOTES)

Snow

SUNDAY, DECEMBER 29, 2013

A local news channel started off with us for Sunday’s tour – with a local interest story about why in the world people would go out into the cold to hike around on a dreary January afternoon…but a huge crowd of people seemed to think it was a good idea!

I didn’t check the thermometer as we set out but I’m pretty sure that the temperature dropped a good number of degrees (F) during our tour and it was 16 F when we returned.

Sunday’s tour theme was SNOW. You’ve likely heard of the biosphere, the atmosphere, the hydrosphere, and the geosphere. Snow is part of the cryosphere—the components of Earth’s surface where water is frozen. (Of course the different “spheres” all interact with one another….)

Snow is, of course, crystals of ice. A crystal, from the chemical perspective, is a solid that has an ordered three-dimensional structure. The familiar and infinitely variable snowflake is six-sided, because of the crystal structure (molecular pattern) of frozen water.

snowflake by Chuck Henrikson

The exact conditions under which a snowflake forms influence the exact shape, but it will be, in general, six-sided.

As we hiked, we listened to the sound of the crunching snow. The group expressed experience with the fact that the sound of crunching snow changes, and correlates with temperature. As you step on snow, the snowflakes rub against one another. The colder the temperature, the greater the friction, producing the squeaky crunching. At least that’s how the National Snow & Ice Data Center explains it.

In Curtis prairie, we found coyote scat that looked quite fresh (last night?). Coyote scat is characteristically twisty, and typically contains at least some hair (from consumed animals). It commonly contains berry remains, too—and this one had what looked like some sad-looking winter-leftover berries. Just around the bend, we saw the coyote’s meal remains – rabbit fur aplenty. And more scat at the dinner site—is that typical?

We spotted a blue jay, some turkeys, and a junco. It was otherwise quiet (and we were a big group so birds and other animals were likely quite aware of our presence).

Junco

The topic of snow fleas came up – and I promised I would find out what they ate. It appears that they eat a variety of things, including decaying plant matter and microscopic organisms.

We talked quite a bit about snow on the tour but I’ll refer you to the National Snow & Ice Data Center (http://nsidc.org/)if you want to learn more. It’s fascinating!

And for the last guided tour of 2013, join us on Tuesday, December 31, 6:30 pm – 8 pm. Although the temperature may be quite low, the tour is still planned to go out. (Otherwise, join us for the first tour of 2014 on Sunday, January 4, 1 – 2:30 pm!)

Sara Christopherson, Arboretum Naturalist

Located between Lake Wingra and the West Beltline Highway at 1207 Seminole Highway, the University of Wisconsin-Madison Arboretum features the restored prairies, forests and wetlands of pre-settlement Wisconsin. This 1,260-acre arboretum also houses flowering trees, shrubs and a world-famous lilac collection. Educational tours for groups and the general public, science and nature-based classes for all ages and abilities, and a wide variety of volunteer opportunities for groups, families and individuals are available.