October 15

Saturday was a good day at Forest Hill for a hike with my dog, Remi.  The early morning weather was mostly cloudy, drizzly with a temperature of 45 degrees and a stiff wind out of the northwest. I descended the hill to Mallard Marsh where I once again saw a Great Blue Heron take off from the cattails. Soon it will fly south to spend the winter in wetlands and coastal waters of either southern United States or Central America. I walked through Bobolink Meadow, entered North Woods and followed the trail west to the large footbridge. I stepped down into the lowest point of the dried up vernal pond, observed the high water marks on the surrounding trees and estimated that the maximum depth of the water last spring was around 3 feet. I exited North Woods and continued around Succession Field where I was surprised to see some very tiny, pale blue blossoms mixing in with the grass on the trail. I stooped down, pick one and observed it carefully to see it was Thyme-leaved Speedwell. Looking up at the trees, I was disappointed that most of the colorful leaves had fallen. Leaves contain three main pigments: carotene, anthocyanin, and the photosynthetic pigment, chlorophyll, which captures the sun’s energy to make food for plants. As the most abundant pigment, chlorophyll is what gives leaves their green color. Reduced sunlight and colder temperatures in the fall causes chlorophyll to disintegrate rapidly, letting carotene show through as the yellow in maple, aspen and birch leaves. Anthocyanin, meanwhile, provides the oranges and reds of maples, sumacs and oaks. Next, I entered South Woods and hiked past Swanson Swamp where I noticed a heavy layer of leaves on the forest floor. A chemical in these leaves, called Auxin controls a special band of cells at the base of each leaf stem called the abscission layer. During the growing season, Auxin prevents this layer from fully developing.  In fall, however, cooler and shorter days trigger an end to Auxin production, allowing the abscission layer to grow, releasing the leaf from the branch so it falls to the ground. Although the yellow and red pigments in the leaves last for a few days once on the ground, they soon disintegrate. All that remains are these leaves brown, russet, tan and gold leaves colored by another leaf pigment called tannin. Next, I exited South Woods and continued on to Artist Overlook. Continuing along the south trail, I turned at Frog Fen toward Brady Cemetery. I passed the cemetery and observed that several Chicory plants still had their lovely sky blue blossoms. I entered Native Grassland and followed the trail along the edge of Grebe Pond. A large patch of lime green duckweed outlined the pond’s border along the north shore. I passed the barn and arrived back at the Classroom Building. Finally, I got in the van and took off for home.

How innocent were these Trees, that in 


Mist-green May, blown by a prospering breeze, 


Stood garlanded and gay; 


Who now in sundown glow


Of serious color clad confront me with their show


As though resigned and sad,


Trees, who unwhispering stand umber, bronze, gold; 


Pavilioning the land for one grown tired and old;


Elm, chestnut, aspen and pine, I am merged in you, 


Who tell once more in tones of time, 


Your foliaged farewell.

Siegfried Sassoon,