ARBORETUM NEWS (NATURALISTSNOTES)

Halfway to Spring

SUNDAY, FEBRUARY 2, 2014

Don’t say we didn’t warn you! “It may not feel much like spring yet,” said the tour description. And indeed it didn’t – but we had a lovely wintry day for our tour, with a temperature in the high teens, bright sunshine, and calm air. Add to that fluffy white snow and a bit of exercise in good company, and what more could one ask?

The “halfway” reference is because Feb 1st marks precisely the midpoint between the December solstice and the March equinox. Notice that I used the month-names for those phenomena, not the adjectives “winter” and “spring”. Kindly remember that on the southern half of our planet, the seasons are precisely opposite ours. They are approaching autumn there, not spring. Let’s not be “northern-centric”.

Ancient calendars divided the year into four parts based on the solstices and the equinoxes, then bisected those quarters to define “cross-quarter days” – the first days of our modern months of February, May, August, and November. Vestiges of those old festivals remain as Groundhog Day, May Day, and Halloween/Day of the Dead.

Thus we’ve broken winter’s back and are now just past the halfway point to spring! Keep that thought in mind when the inevitable cold winds blow.

I had decided I wanted to visit the Jackson Oak, the grand old oak snag which stands at the western edge of the Curtis Prairie. Though no longer a living tree, it is particularly majestic in winter, with each horizontal branch wearing a mantle of snow. The Jackson Oak has been an icon of the Arboretum since the institution’s earliest days.

En route, we stopped at the “magic spot” in the McCaffrey Savanna where it is obvious that the surrounding bur oak trees line up precisely with one another. These are the Fencerow Oaks, enduring evidence of a lot-line between adjoining farms; look to your right and left from the main trail near marker B-1, and you will see.

I pointed out the rare wafer ash tree along that same firelane. Right now this small tree is demonstrating its name better than at any other time of year: trunk and branches are bare, but the thin, flat seed pods persist. Communion, anyone? We also noted many still-identifiable dried prairie/savanna plants: Canada goldenrod, giant hyssop, indigo, bush clover, coneflower, beebalm, and the various tall grasses. Each retains its unique shape and color.

And speaking of shape … presently we arrived at the Jackson Oak. A lovely example of an open-grown white oak, it features horizontal branching and a wide, rounded crown. Several apparent descendants surround it.

People often ask how long this tree, leafless now since sometime in the early 2000s, lived. When last measured in life—by the Dane County Tree Board in 2001 as part of its Oak Project—the Jackson’s circumference was 11 feet, 7 inches. A rough calculation based on that number yields an age of 222 years.

Can you stand a little more math? 2001 minus 222 equals 1779. So if we allow ourselves a small “plus or minus” factor, this particular tree stem – for oaks can resprout any number of times after damage from grazing or fire – got its start right about when Thomas Jefferson and friends were putting their pens to the American Declaration of Independence.

The Jackson Oak already has great dignity, in my mind. Making the historical connection only enhances it.

We continued our tour with a short loop into Noe Woods, where fresh snow cover enhanced every tree. I could not resist quoting James Russell Lowell: Every pine and fir and hemlock/Wore ermine too dear for an earl/And the poorest twig on the elm-tree/Was ridged inch deep with pearl.

Most of the prints we saw in the woods were obviously deer or turkey trails. There was one possible skunk track, appearing to show the “belly drag” typically left when this creature waddles through deep snow.

Turning away from the Beltline highway noise and emerging from the woods, we found ourselves back on the prairie. We took interior (narrow) trails as much as possible to avoid traffic jams with skiers. Along the way we were treated to the sight of meadow vole tunnels and tracks. If you peer closely at such a tunnel entrance, you may discern that the ice crystals surrounding the opening are subtly larger than those of the surrounding snow. This is because the warmth of the vole’s body and breath has a momentary melting effect; the crystals re-freeze in a slightly different form.

All in all a most pleasant hour and a half. On my tours I always hope to live up to the words of the late UW soil scientist Francis Hole: By sense of touch the feet assess/The nature of the wilderness/Of earth beneath. Yet human speech/Cannot express what feet can teach.

May our feet continue to teach us, at the Arboretum and elsewhere.

Kathy Miner, 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.