ARBORETUM NEWS (NATURALISTSNOTES)

Solstice – Friday, June 21st, 2013

FRIDAY, JUNE 21, 2013

As our group of about three dozen headed out into Longenecker Gardens to be begin the hike, we noticed that against our highest of hopes it seemed unlikely that we would later be able to catch sight of a solstice sunset. The clouds were thick, and although they tumbled about, they were likely to still be around following our visit to Icke Boardwalk and Teal Pond. In any case, following a few formalities (a thank-you to the Friends of the Arboretum and a couple of quick marketing questions to try and ascertain where our advertisements are finding their target), I welcomed the group on our annual tour to celebrate the day of the summer solstice or, colloquially, Midsummer day. I say the day of the summer solstice, because the solstice is an actual moment in time – it is not an entire day. It is a seasonal step in our globe’s perpetual dance with the sun. At the moment of the solstice, Earth’s maximum axial tilt is realized. Due to our planet’s axis being approximately 23.4 degrees off of the plane of ecliptic (the plane upon which the earth revolves around the sun), we experience seasonality. If earth’s axis was perfectly aligned with our plane of ecliptic, each day would bring the same amount of sunlight at each latitude. As we revolved around the sun, day length would not change. Fortunately, this is not the case and the moment at which we turned the corner and headed back toward the depths of winter was this past Friday, June 21st at 5:04pm (nearly 3 full hours before our tour began). There is a delay in our seasons relative to the amount of energy the earth is receiving because, similar to large bodies of water, it takes time for the energy to be absorbed and affect the seasons. I mention this only because sometimes people wonder why our warmest and coldest of days are not usually around the solstices but rather in August and February.

I would like to offer a brief note on an observation I have made as a young naturalist and educator. Generally speaking, I have noticed that adults can be content to sit back and cruise along on tours and subjects whereas children continue to create, discover, prod and poke (particularly in such a dynamic environment as the Arboretum). Therefore, I was encouraged by the fact that our group had a healthy proportion of young and old. Young ones often act as the catalyst for rich, inclusive conversations that draw in the larger group. When left to explore they will discover all sorts of imaginative trails of thought. When I see children getting ready for a hike, I smile because I know that there will be teachable opportunities around every bend. Many times, adults will be pulled or sometimes dragged into the story and most often this makes for a more colorful experience. But enough on that – back to the tour!

Ancient cultures and peoples around the globe began celebrating the astronomical event prior to written language. The significance of such a truth cannot be over-emphasized or pondered. The solstices have been described as the “hinges” of our seasons and I like this particular analogy. As soon as we reach the top or bottom of solar energy, we immediately begin the long journey in the other direction.

We did, in fact make it out to Icke Boardwalk. Upon our arrival, the songs of two territorial male Swamp Sparrows (Melospiza georgiana) could be observed and the group took time to identify the song and its importance given the time of year and the limited amount of habitat surrounding the boardwalk. We also spoke briefly about the high number of Horsetail or Equisetum present. I spoke about the vestigial, black leaves that only a careful observer would notice and until a couple weeks ago I had only wondered about. It is an ancient plant, a living fossil, for it is the sole remaining genus of its class, Equisetopsida.

While enjoying the calm of the gazebo, Kristin Lamers, the other naturalist on this tour, offered a fitting story (of Wisconsin Native American origin) that described how mosquitoes came into being and why they ended up as such a nuisance. I say fitting, because, although calm, the gazebo help a number of mosquitoes that night. Fortunately for us, our flying mammalian brethren came out and began to snag the insects from the dusk air. I have seen numbers as high as 600 hundred mosquitoes taken each hour by a bat! The dragonflies were eating their fair share that night as well.

From Icke, we hiked to Teal Pond. Prior to diving onto the short path that leads to the pond, I took a moment with the group to get everyone on the same page so that we could try and remain as silent observers for the first couple of minutes. In this way, we might be able to sneak up on, without startling, any wildlife. Unfortunately, our efforts bore little fruit. We did see an American Woodcock skitter and madly flap across the night sky, as well as hear a number of tree frogs in the trees near the water, but our quiet approach did not earn us these. Our patience and continued observance of subtler movements and sounds won us those experiences. It was an impressive showing by a lot of people, a number of whom with fewer years than the number of digits on my two hands.

The rain from earlier in the day returned and so began our trip back to the visitor center. It was a comfortable hike with many folks interested in both the solstice and the wonders of the Arboretum. Both Kristin and I fielded a number of intriguing questions – most of which began as a poke or prod from young minds just embarking on their journey to discover the world around them.

David Laufenberg, UW 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.