It seems around this time every year we start receiving calls about falling leaves. Some callers are concerned about the trees health, others are wondering the best way to dispose of leaves and some people are just curious about how it all happens. So this is the time of the year to once again explain briefly how this process works.

I should record some of the calls I receive. I had one citizen saying they were over fertilizing their trees to try to allow them to be strong enough to hold their leaves all winter. Another woman thought her Bradford pear lost leaves last year but not the year before, and wondered what might happen this year. Unfortunately there is nothing anyone can do about nature’s changes anytime in the year. Mother Nature’s power is much greater than any human response, so let’s all sit back and enjoy the change in scenery over the next few months.

Q: What explains leaves falling?

A: Nature has an amazing way of always replenishing its resources. Often, when nature takes something away, it comes back better.

In order for these new sights to occur we have to lose the old piece. Soon millions of leaves will be stretched across our city. So what causes this spectacle?

The changing of the leaves is a natural chemical process that is common in many aspects of the plant kingdom. Although many factors such as temperature and the photoperiod affect this change, it is not the sole cause. In fact, most leaves fall long before the first frost or daylight savings.

The leaves are relied on heavily during the spring and summer to provide food for growing throughout the year. Each leaf has millions of microscopic cells that produce small green bodies called chlorophyll. Chlorophyll is what gives trees the green color during these growing months. The tree works as a factory using all its parts, including roots for water and bark for protection, to help make all this happen.

Around this time of the year as the environment begins changing, the tree begins to slow down, and the work of the leaves begins to end. At this point, like a bear going into hibernation for the winter, the tree starts to store up for the winter ahead. The chlorophyll remaining in the leaf is broken down and stored in the tree’s roots for use during the winter and in the spring when it needs energy for new growth.

What remains is a leaf that is losing its green color. The leaf body now consists of cell cavities that have a watery substance where you can see oil globules and small yellow refractive bodies, thus giving a yellow appearance. Sometimes there is more sugar in the leaf than can readily be transferred back to the tree. Then the chemical combination with other substances produces many color shades, from the brilliant red of the dogwood to the red-browns of the oaks. In the cone-bearing trees that do not lose their foliage in the fall, the green coloring takes on a slightly brownish tinge that gives way to a lighter color in spring.

David Carter is the director of the Adams County Extension Service. He can be reached at 601-445-8201.