Tuesday, October 25, 2016

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Mirna Santana

The Joy of Nature: Fall Colors

In the splendor and beauty of this Autumn or Fall season we experience awe. This is the season that perhaps best shows us the delicate threads of life, the temporality of things. This beauty would last but a few days or at most a few weeks. Then it is gone, and the trees will be bare and yet in that nudity, they are ready to confront the harsh winter.  We may experience this beauty just as it is or we can do so with the curiosity of a child or the inquiring mind of a scientist. Why do the colors change?

Some of my most special moments of contemplating nature happens when we experience nature as it is.  It is the experience of being alive and being just another living creature within the environment. For example, It was a magic moment when I experienced the splendor of this tree in its pick colors and let that experience travel within my body, integrating it into my whole being. The experience of togetherness with nature happens just before the decision of placing my bag on the ground and proceeding to take the picture. Because the first moment was pure contemplation and in the second the rational mind was involved. Yet, as I love taking snap shoots of all things nature, I also experience the joy of an ordinary daily activity. As a trained scientist, there is also that wonder and inquiring about nature and what we observe. Do we really know what the changing trees are doing?

As it happens, the tree is doing a lot through this changing process. The changes are also the result of physiological responses to changes in environmental conditions. The tree receives the signals of the upcoming winter (cold days with some warm ones, less light, cloud covers) and starts to get ready for it. Many processes are involved in the changing colors. Some are physiological responses that scientists understand such as relocation of nitrogen and nutrients before the leaf falls and the protective value of anthocyanin, red pigments from chlorophyll inhibition. Less light and colder temperatures let the trees know that they can stop producing chlorophyll, the green pigments and the more efficient among plant pigments. But the tree needs to be alive when the chlorophyll is not working for the tree. Other pigments take the job of continuing the processes such as carotenoids (orange, yellowish colors to stand out. Eco-physiological responses to weather (less light, cold days) and cloud cover bring about anthocyanins (red pigment) to the game. Others potential evolutionary or coevolutionary processes that may signal herbivores to get off the plant or residents to move on, because the leaves are going to fall are not well studied and thus not well understood. When I first so the hypothesis I thought all things mushrooms (I am biased towards them.) There is a link between the mushrooms above and those below the trees, because the leaves of all trees eventually fall.  A suit of ecological hypotheses including the defense mechanism activation to avoid predation by signaling danger (red) and other hypothesis have been proposed. Other theoretical works suggest physical/environmental factors such as soil moisture, temperature, tree position and status (dominant tree vs seedling), amount of light available and so on, play stronger roles in the outcome of the colors.  However, funding for studies that do not involve molecular or genetics are low these days so many field scientists take data on leaf phenology (changes) and correlated patterns to available environmental data (e.g. precipitation) through time. Yet many of us, would not seek answer to these questions and mostly watch the colors as tourist do.

Speaking of tourism, the Autumn brings about a lot of tourism and economic incentive to several states and countries. The colors are more intense in the USA and Canada than they tend to be in Europe. Seasonal variations influence the outcome of the colors . But if you are going to any place famous for the Autumn colors, you do not need to concern about what causes the changes. The leaf trackers (e.g., Department of Natural Resources) or the tourist agencies, webpages and brochures could tell you when and where the colors are picking. They will tell you what the best locations are for you to take your trip to observe the Autumn in its magnificence. If you do, you and the trees would be somehow 'conspiring' to bring more wealth to those regions. Of course, the trees never get pay for providing aesthetic value or moments of awe. For those who enjoy the changing trees on their yards, the raking of leaves may be another time for peaceful relaxation or rage. Cities in which the conditions allow for these scenes of changing colors wisely invest on planting attractive deciduous trees. The trees naturally respond to the conditions and make their residents and visitors glad. Because we already know that nature has a positive impact on the wellbeing of people, and the wealth of cities, I say, lets stop here and lets get out to enjoy the Autumn colors while they last.

Copyrights © Mirna Santana
Biologist and Freelance writer
Published by Mirna Santana blog on Environment, October 2016.