The muted Fall colors of 2018
A couple of weeks ago, when I was going upstate from the city, looking at the scenery along the highway, it suddenly came to me: something was different. The usually breathtaking Fall colors were not there. I saw Fall colors, but they were different. I saw yellow, which was a bit washed out, and no reds whatsoever, just a rusty brown. The brown reminded me of an old iron pipe, and most important, there was no brilliancy to any of the colors, although the sun was shining.
This observation peaked my interest and I did some research. I found that even the papers had picked up on the “muted fall colors”. They gave as an explanation- ‘the wet summer’, and left it at that, without digging a little deeper. Did the trees really react only to a lot of rain and turned the trees rusty and watered down? It did not explain why the reds are missing. And was the rain the only factor? Here is what I found out.
This observation peaked my interest and I did some research. I found that even the papers had picked up on the “muted fall colors”. They gave as an explanation- ‘the wet summer’, and left it at that, without digging a little deeper. Did the trees really react only to a lot of rain and turned the trees rusty and watered down? It did not explain why the reds are missing. And was the rain the only factor? Here is what I found out.
For much of the northeastern United States, the rolling arrival of the brilliantly colored Fall leaves are an event that most everyone looks forward to enjoying. Indeed, ‘leaf peepers’- as they are affectionately called in much of the region, come from all over the country and even abroad. They come to photograph and hike in the spectacularly painted hardwood forests. People from the large urban centers like NYC, Boston and Philadelphia, make day and weekend trips into the countryside for a refreshing break from the urban grayness, spending hundreds of millions of tourist dollars in the local economies. For us locals, it is a yearly respite we happily await.
However, this year, it has been widely reported, that the colors were very muted throughout the region. Our first thought was how disappointing! But it was just a wasted day or weekend for us locals. What about the tourists though, who travel great distances and use up valuable vacation time, to make that perhaps once in a lifetime trip? Could they have planned around what would be a disappointing trip ahead of time? What conditions might predict a lackluster Fall show?
However, this year, it has been widely reported, that the colors were very muted throughout the region. Our first thought was how disappointing! But it was just a wasted day or weekend for us locals. What about the tourists though, who travel great distances and use up valuable vacation time, to make that perhaps once in a lifetime trip? Could they have planned around what would be a disappointing trip ahead of time? What conditions might predict a lackluster Fall show?
The color of the maple leaves is muted. To understand what goes into creating the colorful tableau each year, one has to understand light, plant leaf chemistry and weather. So what happened in 2018, to mute the Fall colors, enough to create news stories throughout the region? Should this be examined? So let’s try.
How can we predict a
disappointing color foliage this year?
For plants, light is food! They use it to turn water and carbon dioxide into sugars. For this they have a blue-green pigment called phytochrome, which regulates various developmental processes. It signals growth mechanisms in the Spring, and tells the plants when to flower and set seeds in the Fall, as the nights get progressively longer.
How can we predict a
disappointing color foliage this year?
For plants, light is food! They use it to turn water and carbon dioxide into sugars. For this they have a blue-green pigment called phytochrome, which regulates various developmental processes. It signals growth mechanisms in the Spring, and tells the plants when to flower and set seeds in the Fall, as the nights get progressively longer.
Plant vision is much more complex than human vision, when it comes to perceiving light frequencies. Around WWII, botanists discovered that they could prevent plant flowering by quickly turning on and then off, the lights in a greenhouse in the middle of the night. This was the result of a terrible mistake by a flower grower’s disastrous loss of an entire market crop of chrysanthemums, when a worker checked on something in the greenhouses late one night by turning on the lights briefly. They realized that what the plant was measuring was the continuous period of darkness, not the length of the day. But this was true only for a few seconds of red light; blue or green lights had no effect. The plants were distinguishing colors, needing red to measure the night and blue light to bend towards the sun. By altering the frequencies of the light in the greenhouses or their periodicities (daytime or nighttime), they could alter the growth of the plants. Using this technique, they could delay flower harvests until just before Mother’s Day, to yield maximum profits!
Light, as it comes from the sun at given times of the year, and how the various frequencies of its light are filtered over a period of time by weather conditions, will be a factor in predicting the vibrancy of colors in the Fall! So, of the three factors mentioned above (light, leaf physiology and weather), light sets the ground.
Leaf physiology is driven by how the many pigments (e.g- carotenoids for yellows and oranges, and anthocyanin for reds) contained in each leaf, react to the different color frequencies in sunlight. All of these are present in the green leaf that you see in the summer, but they are masked by the chlorophyll. Nevertheless, they are all still there, driving the many different mechanical processes of the plant. So it makes sense, that over the Spring and Summer, how much and what light frequencies are being absorbed, will affect the health and mechanical workings of the plant. And this will be due to the prevailing weather, before Fall even begins, with its own weather and solar effects.
Leaf physiology is driven by how the many pigments (e.g- carotenoids for yellows and oranges, and anthocyanin for reds) contained in each leaf, react to the different color frequencies in sunlight. All of these are present in the green leaf that you see in the summer, but they are masked by the chlorophyll. Nevertheless, they are all still there, driving the many different mechanical processes of the plant. So it makes sense, that over the Spring and Summer, how much and what light frequencies are being absorbed, will affect the health and mechanical workings of the plant. And this will be due to the prevailing weather, before Fall even begins, with its own weather and solar effects.
Surprisingly, to most people, extended wet weather can be very stressful on trees! Their feeder roots in the top six inches or so of soil, need to absorb oxygen and other nutrients. If the ground is saturated by water for extended periods of time, the drowning roots produce harmful gases and can’t absorb nutrients, so the tree becomes stressed. Built up ethylene gas may cause premature yellowing. Proliferating anaerobic bacteria in the soil will prevent the tree from taking up minerals like iron and sulphur, and fungi will begin to feed on the roots themselves. So excessive rainfall in an area over a period of a season or more, leads to stressed or dying trees, with compromised leaf physiologies.
Long overcast weeks will affect the light frequencies the forests are getting as well. So the various life sustaining machineries of the plant, provided by the leaf pigments, will be altered.
Long overcast weeks will affect the light frequencies the forests are getting as well. So the various life sustaining machineries of the plant, provided by the leaf pigments, will be altered.
Following the possible foliage predictors of the Spring and Summer, Fall will start the annual show in motion, with its own conditions. As we said earlier, all of the color pigments are present in the Summer leaf, but they are masked by chlorophyll. It is the unyielding annual clockwork of our earth’s orbit around our sun, that shortens the lengths of days going into the Fall. It is this inexorable waning of light, that signals plants to shut down chlorophyll (food) production and begin the preparation for Winter. As the pigment decomposes, the others come to the fore. Their relative abundance, has been set already by the ambient conditions of the Spring and Summer that year. Maybe they had wet feet for so long, that they started to decompose earlier, or not enough of the right light frequencies for full production. Most people think it is triggered by the first frost. It is not. It is the length of the day. The specific arrival time of the colors, is influenced by all of the above.
So what about this year- 2018?
Well, the entire region had record setting rainfalls and prolonged wet spells and cloud cover. Indeed, the southern U.S. received record floods. Record monthly rainfalls were common throughout the eastern part of the country. The late Summer was unseasonably mild, as was September and October as well. Understanding the science behind the Fall colors, then seems to confirm that people’s disappointment in the colors this year, was justified.
What about next year?
So how should we try to predict the Fall show? Well watch the weather in the region in which you are interested, starting in the Spring and monitor it through the Summer. High rainfalls and mild temperatures will be discouraging omens. If the outlook is for a mild, wet September and October, then perhaps your plans should change.
It is a little like baking a cake. You need the correct ingredients to start with in the Spring when you are making the dough.. Then you add to them in the Summer, with heat and the right amount of moisture. In the Fall, the ‘baking’ is completed with a warm base and cooling air. In the end, you have a tasty and colorful cake! (Or not if you didn’t follow the recipe!).
So how should we try to predict the Fall show? Well watch the weather in the region in which you are interested, starting in the Spring and monitor it through the Summer. High rainfalls and mild temperatures will be discouraging omens. If the outlook is for a mild, wet September and October, then perhaps your plans should change.
It is a little like baking a cake. You need the correct ingredients to start with in the Spring when you are making the dough.. Then you add to them in the Summer, with heat and the right amount of moisture. In the Fall, the ‘baking’ is completed with a warm base and cooling air. In the end, you have a tasty and colorful cake! (Or not if you didn’t follow the recipe!).
FALL COLOR RECIPE
For the best Fall colors, look for average or at least seasonable temperatures, and sufficient - but not excessive, rainfall, leading into the Fall. in the area you are visiting. Sunny and mild afternoons, with cold nights as the season begins in the area, are the recipe for the most vibrant colors.
For the best Fall colors, look for average or at least seasonable temperatures, and sufficient - but not excessive, rainfall, leading into the Fall. in the area you are visiting. Sunny and mild afternoons, with cold nights as the season begins in the area, are the recipe for the most vibrant colors.
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