ARBORETUM NEWS (NATURALISTSNOTES)

Woodlands Hike

SUNDAY, OCTOBER 13, 2013

Finally, the fruits of another Wisconsin Autumn are nearly upon us. Our Friends of the Arboretum-funded hike began under blue skies with a nip to the air in the shade. The multitude of colors expressed in our Southern Wisconsin forests are a sight to see and an experience fondly kindled until the next autumn. The Arboretum’s stock is primed, but not yet fully flavored.

What makes for the spectacular dendrologic show anyhow? University of Wisconsin – Extensions published a short piece of literature on the science behind the phenomenon roughly ten years ago. Currently, most of our leaves are only showing the early signs of the fall spectacle. Carotenoids are ever-present in leaves, but only become visible to our eyes once the autumnal process has begun. Until now, the green coloration of the chloroplasts masked the yellow of the carotenoids. At this time, the tree has begun to dismember its leave’s chloroplasts in a complex and organized manner. The tree is reclaiming other things as well. Along with the chloroplasts, proteins and nutrients and their respective pieces are being redistributed among the tree’s stems and roots. This way, the plant need not miss its leaves as much by the time it has come to discard them. Additionally, anthocyanins have begun to be synthesized by the tree and are adding colors of red, orange, burgundy and purple to the mix of yellow. As the tree is reclaiming materials that were invested into the leaf, it needs to use anthocyanins to provide protection from the continuing bombardment of rays from the sun. Interestingly, many of the outer leaves to our trees have significantly changed whereas the inner ones, which are a bit more shaded, are still in full green. This is because conditions are still right for them to be eating light and creating usable energy for the tree. Also, intense light is not as big of a concern for these leaves, and so production of anthocyanins will be less or nearly non-existent.

In any case, we numbered near thirty individuals on this hike with Friends members and first-timers alike. Our hike began along the southern edge of Longenecker Gardens. I pointed out the metal markers found on each of the specimen displayed in the Gardens, and we took stock of the small collection of locusts. We also noted the protection being granted the younger individuals through use of plastic tubing along the first couple of feet of trunk. This way, the tree’s young, less developed and therefore susceptible to damage from cottontails and otherwise, bark receives better odds as the seasons tick by. At the southeast corner we ducked into Gallistel Woods to enjoy the maple, basswood, cherry and hickory trees found there. It is a season of change in the forest, and not only the trees are making a concerted effort to prepare for the winter months. Squirrels and birds could be seen and heard collecting food during the stretch of fine weather.

Just prior to crossing Arboretum Drive and entering Wingra Woods, we discussed the inherent differences between maple and oak forests. Maples tend to get the jump on other trees in the spring. Their leaves come early and horizontal – both aspects are important. By “leafing out” before much of the understory, and by holding their leaves in such a way to collect and therefore block as much sun as possible, maple forests tend to be a bit more gentle on those wishing to hike openly through the woods. Oaks, on the other hand, take a bit longer to get their leaves and once they do, they will hold them at greater angles to the sky. In this way, the oaks permit greater growth on the forest floor and offer the hiker less.

After crossing the road, we took straight for the south shore of Lake Wingra and headed west toward the Big Spring. Once we arrived, I took the opportunity to speak about the merits of such a place and such a spring for the local flora and fauna. Then I pulled out a copy of the Sand County Almanac to read an October passage, “Too Early.” It was well received and one individual approached me to get the name of the book. Afterwards, we took a couple of minutes to quietly observe and listen to the life and sounds around us. I asked for people to share their experience and two different hikers told of the sounds of the spring and the sight of the warblers fly-catching above the open water.

At this point we had a mere ten minutes to hike up to the top of Wingra Woods, across the road and back to the visitor center through Longenecker Garden. In the interest of time I took only one break, and that was to observe the turkeys as they muddled around a conifer in the Garden. After reaching the visitor center, I bid adieu to a number of our participants yet offered to read a poem by Elsie Brady entitled “Leaves” to the folks that had the time and interest…

How silently they tumble down

And come to rest upon the ground

To lay a carpet, rich and rare,

Beneath the trees without a care,

Content to sleep, their work well done,

Colors gleaming in the sun.

At other times, they wildly fly,

Until they nearly reach the sky.

Twisting, turning through the air

Till all the trees stand stark and bare.

Exhausted, drop to earth below

To wait, like children, for the snow.

Respectfully Submitted by Arboretum Naturalist – David Laufenberg

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.