Nature Notebook
As we ease into autumn, the temperatures are dropping, days are getting shorter and nature prepares for winter. Soon we will see the leaves change colors on the trees and fall to the ground.
The preparations are most easily observed in our deciduous trees, the ones that lose their leaves each year. What the trees are preparing for is a drought, when groundwater will be unavailable for the roots to absorb because it is frozen. The trees drop leaves which waste the precious water by letting it escape with oxygen during photosynthesis.
The dwindling amount of sunlight is also responsible for the color change in leaves. Chlorophyll, the green part of leaves, needs sunlight to be produced. Less light means less chlorophyll. Less chlorophyll means the other leaf colors, which have been there all along, are visible.
