Thursday, 29 October 2015

Autumn Colour, Science and Art - all in one day!

The autumn colours are amazing at the moment and so I snatched a few hours at the weekend to enjoy the beauty of it all before the wind blows all the leaves away. I do like autumn but in the past it has always been a bit of a sad time of year for me as it signifies the end of summer and the onset of those long winter nights. However, over recent years I have started to embrace Autumn and really think about the science behind it and appreciate how amazing nature really is and of course to enjoy the beauty of it.

Autumn colours near Thirlmere
Without sounding too arty, autumn is also a time of reflection. It is a time of slowing down after the summer. The summer is so busy both in the human world and the natural world. Everything is busy growing, feeding, reproducing...insects, birds and mammals are all flying and running around making the most of the summer months. The trees have been making the most of the sunshine and using its energy to produce sugars for food, by the process of photosynthesis. Chlorophyll is an important chemical in the photosynthetic process and is involved in the process of turning carbon dioxide and water into sugars. It is this chemical, chlorophyll that makes the leaves green.
Autumn colour near Elterwater
Reflective colours at Thirlmere

Due to the vast array of tones of red, orange, green and yellow, autumn really reveals the vast diversity of tree and plant species that there are. The colours make it easier to demonstrate just how diverse the natural world is. It also makes me stop and think about what is actually happening here. As the days get shorter and there is less sunlight, trees conserve their energy by ceasing photosynthesis and the chlorophyll in their leaves begins to break down. As the green chlorophyll is breaking down, this means that the other pigments found in leaves such as carotenoids and anthocyanins are now more apparent and visible. There are also red and brown pigments which are now visible through other chemical changes that are taking place within the leaves. If the carotenoids are also broken down then brown colours are revealed such as in the oak leaves we find in autumn.

An array of autumn colour
When I was out exploring the autumn colours, I headed into the woods to get a closer look at the variety of colours and leaves. Beech trees are amazing with a variety of red, oranges and browns and they produce big piles of leaves that you just want to run and jump in! This displays the important process behind autumn, and so the reason behind the chemical breakdown of chlorophyll and that is senescence. Senescence is the process where the nutrients are taken back by the tree from its leaves and absorbed into other areas. As the leaves are no longer needed through winter (as there is not enough sunlight for photosynthesis) they are a drain on resources. So after the chemicals have broken down and the nutrients have been removed the leaves are released from the tree and so we find them in great big piles to play in!

Autumn Leaves
Beech leaves
Beautiful colours
And its not only the just large flat leaves are shed in autumn, some needles are also shed too! Larch trees are one of the coniferous trees that are actually deciduous. The needles are the leaves of larch trees and they turn yellow before falling from the tree.

Beech and larch trees
And so after hours of fun and being totally absorbed by so many different colours and leaf shapes, I gathered some up to have a little bit of a closer look at them. What started as a home scientific study turned into a bit of leaf art!

Autumn leaf art!

But then of course I got my science head back on and split all my leaves up and really started to look at the various colours and shapes and to think about how the various trees had evolved to produce these differences. Every tree species has leaves with their own special 'design' specifics for both survival, growth and to out-compete each other. So much to consider than just a beautiful bunch of leaves!

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