The Kindergarten fall color hikes have been a huge success. Each child, a crayon clutched in chubby little hand, searched Crossroads at Big Creek trying to match his or her color to a fall color in nature. The children found vivid reds, oranges, and yellows. On Saturday, October 19, at 9:00, pink will be added to the list of fall colors as Crossroads joins with Ministry Door County Health Center to celebrate Breast Cancer Awareness Month with a special hike.
Leaves have color because they contain chemicals called pigments. During spring and summer, chlorophyll is so intensely green, it masks all the other pigments. But when the days start getting short, the plants stop producing chlorophyll. Then the yellow pigments, which were in the leaf all along, become visible.
Throughout the summer, tree leaves are full of sugars, gums, and tannins. As we ease into autumn, when the chorophyll stops functioning, the sugars andalso the minerals in most trees migrate from the leaves into the roots for winter storage.
Maple trees are different. During the growing season, the roots of maple trees absorb nutrients from the deep in the ground. These minerals go into the leaves, but are not reabsorbed. So while maples store some food in their roots (think maple sap and syrup), sugars and minerals remain in maple leaves in autumn. Even when they fall, maple leaves still contains magnesium, calcium, and potassium and consequently, they fertilize the soil.
But while it is still in the tree, maple leaves manufacture the greatest concentration of sugars if they are in direct sunlight. And in the leaves, sugars react to form the anthocyanins….the pigments which cause leaves to turn red in maples and oaks, and to a lesser degree, in other tree species.
This means that when maple leaves are in direct sunshine… especially if we have a lot of sunny days in the fall, maples will turn red. Actually, because we had a great deal of sun in September, even other tree species on the edges of the forests or growing in the open are showing crimsons and oranges. The leaves on the shady side of the tree and the trees in the deep forest generally are yellow, except for those at the very top of the canopy where sunlight can reach them.