AUTUMN LEAVES

There is an old Indian legend that says every fall heavenly hunters kill and cook a great bear. Blood drips from the sky on the leaves of the earth. Then bear fat spatters from the cooking pot onto leaves, spotting the blood-red leaves with gold.

And there's also the tale of Jack Frost flitting from tree to tree with his paint brush and palette, to give us our fall colors.

Fun stories to tell.  Actually, it is three color  pigments in combination - xanthophyllo, carotene, and anthocyanin - hiding behind the green of chlorophyll that give the leaves their autumn finery.

Variables come into play here, causing the brilliant reds, oranges, and yellows.  I seems that the brightest colors come following a warm, dry summer. dry conditions encourage the production of anthocyanin.  drought conditions will not bring the same results.

A warm dry summer has to be followed by temperature extremes in autumn. Leaves store more sugars during warm days and the sugars remain in place if the nights are cool. Sugar is a color-enhancing ingredient. So, the warmer the days and cooler the nights - short of freezing, - produces the grandest effects.

Moisture is also important. Just like the story of the three bears: too much moisture can ruin the leaf colors; too little moisture causes the trees to drop the leaves early; but just the right amount of moisture adds sparkle and brightness of color to the leaves. 

So if the summer has been warm and dry, good rains come early in the fall and then clears, the chances are excellent for natures fall art show.

Genetics also determines the range of shades within a color. for example, in aspens you can see the shades of yellow from orangish-yellow to canary yellow, and all the yellows in between.

Maybe this has been too much information. But, to me, the factors determining our fall colors are interesting.  It just adds to the beauty and mystery of our seasons.