ARBORETUM NEWS (NATURALISTSNOTES)

End of Winter

SUNDAY, MARCH 23, 2014

Although the vernal equinox, an occurrence symbolizing rebirth and fertility, happened just three days ago, today’s temperature hovered just above 30 degrees Fahrenheit and the ground remains frozen in most areas. In the naturalist’s notes at this time in 2012, spring ephemerals were already in bloom. Not nearly the case this year. However, as I did my pre-tour scouting, I noticed that the earliest blooming plant of the Arboretum is holding to the schedule. The skunk cabbage patch in Wingra Woods is very active; the splotchy purplish-green, hooded orbs congregate at the wet woods edge and hold back the snow cover with their steamy stench. Unfortunately, the paths leading down through the woods were solid ice and since no one brought skates to the tour today, we decided to forego that route this time around.
We used the opportunity to explore Longenecker Gardens, taking time to inspect buds on trees and evidence of animal movement. We stopped at the magnolia trees

magnolia buds

first, and appropriately so as they are among the first flowering plants, evolving millions of years ago. The large buds are distinctive in their fuzzy, insulating covering. The highly anticipated, showy flowers are very simple in structure and have a tough texture to withstand the clumsy foraging of beetles that carry pollen between magnolia flowers. The more discerning and adaptive pollinators, such as bees, moths, and butterflies, did not appear until 20 million years later. As it was, the magnolias had to withstand the chewing mouthparts and weight of beetles in order to move their pollen around, resulting in the development of large, leathery petals and well-concealed seeds in aggregate pods.
We stopped at the larch trees to see if they exhibited signs of spring, notably the formation of needles. The larch or tamarack (Larix) tree is more common in northern boreal climates and is actually a deciduous conifer, meaning it loses its needles or leaves in autumn. In more extreme cold climates, this strategy may pay off in water conservation and the reduction of damage to branches from heavy snows.
I had hoped the vernal witch hazels (Hamamelis) would come through for us with a little color, but only one plant was getting close to opening its delicately explosive buds. Along with the native autumnal witch hazel, these light-hearted, vivid flowers are always a fun sight to behold in either season.
Bird sightings reported this week at the Arboretum include sandhill cranes, tufted titmouse, northern shrike, woodcock, cedar waxwing, eastern meadowlark, and several species of warblers and song sparrows. The sandhill cranes made note of their presence several times during the tour, making the rounds in the sky above us, revealing that the song of spring can carry a prehistoric tune.

A note on spring soil—that ‘earthy’, spring scent that we often notice shortly after a spring rain is actually emitted by a soil bacteria known as Mycobacterium vaccae. It is a soil-residing actinomycete that releases spores as the soil dries following a warm rainfall. These Mycobacterium are not only harmless, but recent studies suggest they may also trigger the release of serotonin, a naturally occurring transmitter in our bodies that is known to elevate mood and relieve stress and anxiety. This type of research is increasingly popular in the fields of microbiology, oncology and horticultural therapy. Yet another reason for us to get outdoors and take in the fresh air!
A line in a poem by Anne Barbara Ridler refers to the spring equinox as “the pause between asleep and awake”. I think this is an apt expression for this year’s end of winter tour. There are years when the spring season has swept in boldly and loudly. In contrast, this year the transition happening in the landscape is subtle and sleepy, but it is coming…soon. The smell of the soil tells me so.

Amy Jo Dusick

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.