The following article was written by Jason Prigge, the Development Director at the Woodland Dunes Nature Center.
The color green is never simply green. In nature, it is a vast family of colors, cool and blue in the shadows, warm and yellow beneath the sun and muted by distance. The summer landscape in our area may appear overwhelmingly green at first glance, but careful observation reveals olive, emerald, sage, chartreuse, turquoise, and nearly black-green. Nature mixes color with greater subtlety than anything squeezed from a tube.
The science of green begins with chlorophyll, the pigment used in photosynthesis. Chlorophyll absorbs primarily red and blue wavelengths of sunlight while reflecting green wavelengths back toward our eyes. Plants use the energy to combine carbon dioxide from the air with water drawn through their roots to manufacture sugars. Oxygen is released as a byproduct. The green landscape surrounding us is evidence of sunlight being transformed into life.
Throughout spring and summer, chlorophyll is continually produced and replaced. Its strong green color dominates the leaves, concealing other pigments that are already present. As autumn approaches the Lake Michigan shoreline, trees gradually stop producing chlorophyll, and the existing pigment begins to break down.
When the green retreats, pigments called carotenoids are revealed. These create the yellows and golds of birch, aspen, hickory, and many maples. Carotenoids were in the leaves throughout the growing season, helping collect light and protect leaf tissue, but they were hidden beneath the stronger chlorophyll.
Red and purple colors have a different origin. Pigments called anthocyanins are produced in some leaves and during the autumn, especially when bright, sunny days are followed by cool nights that stay above freezing. During this time, sugars are trapped in the leaves as the tree begins sealing them from its circulatory system. Those sugars, combined with sunlight, encourage anthocyanin production. This is why certain maples blaze crimson while sumac turns scarlet and burgundy.
The Lakeshore has its own autumnal rhythm. Lake Michigan acts as a great thermal reservoir, warming and cooling more slowly than the land. This influence can moderate temperatures near the shoreline, sometimes delaying the progression of fall color compared with places inland. Moisture, rainfall, soil conditions, tree species, and the pattern of sunny days and cool nights all affect the brilliance and timing of the display.
Eventually, a layer of cells forms where each leaf joins its stem. This abscission layer cuts off the flow of water and nutrients until wind and gravity release the leaf. What appears to us as a glorious transformation is also an act of conservation. The tree is actually protecting itself from winter’s cold and lack of available water.
For a painter, autumn is not merely the replacement of green with red and gold. It is the revelation of colors that green had been holding quietly all summer. The landscape becomes a lesson in light, chemistry, change, and letting go. Green builds the season; autumn reveals what was hidden inside it.
