ARBORETUM NEWS (NATURALISTSNOTES)

A Sample of Dane County in 1834

SUNDAY, AUGUST 19, 2012

My goal for Sunday’s visitors was to do some “learning by walking”. In the course of reviewing for the tour I’d stumbled on the following delightful passage, written by the late UW soil scientist Francis D. 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.

Francis Hole proudly appended the initials “T.N.S.” to his name. They stand for “Temporarily Not Soil” – which we all are, if we are honest about it. The soil upon which we stand incorporates all formerly-living organisms, along with many currently-living ones plus rock particles, air, and water.

Why did we choose 1834 in our tour name? Three reasons occur to me: one, it represents 100 years before the dedication and public opening of the Arboretum; two, it was before large-scale settlement and farming had occurred in our area; and three, we have data from federal land surveys done in the 1830s designed to determine the then-Wisconsin Territory’s value as future agricultural land. Thus the year comprises one accessible snapshot of the land in a natural state.

Frankly, if you’d been here in 1834, very little of the present Arboretum acreage would have looked the way it does today. I can speak with certainty of only two elements: the remnant (East Curtis) prairie, and the Jackson Oak.

Our remnant prairie – the eastern portion of the Curtis – was never plowed (though part of it was mowed, and most of it was likely grazed). There is every expectation that it was a prairie patch in 1834.

And the Jackson Oak, which stands at the far western limit of the prairie, has been estimated to have lived about 230 years before dying in the late 1990s. Which is to say it was a seedling around the time America’s founding fathers were signing a little document we call the Declaration of Independence (using ink made from oak galls, I might add, but that is another story for another time). So the tree was likely in its sixth decade of life, and of adult size, in our chosen “sample” year.

Two features … at opposite ends of our flagship prairie restoration. Not practicable to visit both in one tour. But life is compromise. I went with the old white oak, reasoning that this route offered the greater variety in natural ecosystems.

A map created in 1949 by Robert Ellarson, based on the aforementioned 1830s land surveys, shows the primary habitat type in Dane County pre-settlement to have been oak “opening”, or savanna as we would now term it. The other major players were open marsh and upland prairie; small areas of maple forest, low prairie, oak woods, and “swamp conifers” were also present.

On that map, which I showed and passed around as we began our tour, the effects of glaciation on our landscape are readily apparent. Although the same types of habitat existed across Dane County, the glaciated area shows a much finer “grain”, with smaller and more intricately patterned areas of each type of ecosystem.

As we set out to learn-by-feet about our native ecosystems, the “prairie requirement” was easy to satisfy, since the restored tallgrass prairie named for UW botanist John T. Curtis lies immediately south of the Visitor Center. The prairie is still in its midsummer “yellow phase”, with Canada goldenrod and the Four Silphiums (rosinweed, prairie dock, compass plant, and cupplant) dominating the picture.

A few pinkish or purple notes can be detected: blooming thistles, biennial gaura, and coneflower. The coneflower in the western part of the Curtis – at least what is currently evident – is Echinacea purpurea, purple coneflower, not E. pallida or pale purple coneflower. The latter species is thought to be the one that is actually native here. Oops.

Along our prairie trail, we found a large patch of bracken fern. While not toxic to the touch, this plant is poisonous when ingested by people and livestock. We also noted two different dogwoods: gray (Cornus racemosa), with its distinctive red berry stems and white berries, and silky (C. amomum), whose berries start out white but are now turning blue.

Another interesting plant which is currently as showy as it will get (which is not saying much) is round-headed bush clover, Lespedeza capitata. A magnifying glass will help you appreciate its tiny, tightly-bunched blooms.

We also passed through the McCaffrey Savanna restoration, where tall old bur oaks hold court over grasses and flowering species. In the savanna we noted the fuzzy heads of old, spent Joe-Pye-weed, as well as pale Indian plantain, bottlebrush grass, giant hyssop, and a considerable bramble of black raspberries.

Wafer ash (Ptelea trifoliata) is very visible in the savanna right now. This is a small tree with fruits that immediately explain its common name. They are pale green, flat, and wafer-thin, with a single seed enclosed in the center of each. It is not related to other trees called “ash”; rather, it’s in the rue family. Seldom seen in Wisconsin, it’s listed as a species of special concern.

We did make it out as far as the Jackson Oak, noting its apparent progeny nearby. In fact, the young trees are just now producing fresh green acorns, so the cycle continues. Just beyond the Jackson Oak stands a witch hazel tree. This odd organism flowers in November! If you search it carefully now, at the ends of twigs, you may find a small green growth that looks a bit like a miniature pineapple. It’s the home of a particular species of aphid, which alternates its cycles between witch hazel and birch trees.

Time did not permit us to take a loop into Noe Woods – an oak forest that grew up after settlement and fire suppression, and served as farmer Seth Bartlett’s woodlot. Retracing our steps back to the Visitor Center, we noted the approach of darkening skies. Within 10 minutes of the tour’s end, rain had begun to fall. Can’t ask for better timing than that!

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.