Sunday, September 20, 2009

First frost and will the color be good this year?

The picture to the left has nothing to do with frost, it is a fire pit project I finished. I built the benches out of left over hemlock from the earlier dam project.
Its official last night was the first frost of the season. It got down to 31 just enough to leave a little glaze on the ground this morning. I thought I would see if there is anything that might predict the fall color and the following is what I found.
During the spring and summer the leaves have served as factories where most of the foods necessary for the tree's growth are manufactured. This food-making process takes place in the leaf in numerous cells containing chlorophyll, which gives the leaf its green color. This extraordinary chemical absorbs from sunlight the energy that is used in transforming carbon dioxide and water to carbohydrates, such as sugars and starch.

Along with the green pigment are yellow to orange pigments, carotenes and xanthophyll pigments which, for example, give the orange color to a carrot. Most of the year these colors are masked by great amounts of green coloring.

Chlorophyll Breaks Down

But in the fall, because of changes in the length of daylight and changes in temperature, the leaves stop their food-making process. The chlorophyll breaks down, the green color disappears, and the yellow to orange colors become visible and give the leaves part of their fall splendor.

At the same time, other chemical changes may occur, which form additional colors through the development of red anthocyanin pigments. Some mixtures give rise to the reddish and purplish fall colors of trees such as dogwoods and sumacs, while others give the sugar maple its brilliant orange.

The autumn foliage of some trees shows only yellow colors. Others, like many oaks, display mostly browns. All these colors are due to the mixing of varying amounts of the chlorophyll residue and other pigments in the leaf during the fall season.

Weather Affects Color Intensity Temperature, light, and water supply have an influence on the degree and the duration of fall color. Low temperatures above freezing will favor anthocyanin formation, producing bright reds in maples. However, early frost will weaken the brilliant red color. Rainy and/or overcast days tend to increase the intensity of fall colors. The best time to enjoy the autumn color would be on a clear, dry and cool (not freezing) day.

Our experience has been that the rain tends to knock the leaves off a little faster so for long lasting color we need little rain or wind during the color period. The frost we had last night was probably not heavy enough to affect the tree color and we often get frost in the middle of September. So we will see how true this information stays as we progress into the fall color season. Our best color usually lands in the second to third week of October about a month from now. Mountain girl, Paula, logging out.

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