The intricacy of nature and how everything works together never ceases to amaze me. Even in the grimmest of mother nature’s ways, some kind of beauty can often be found. One of my favourite kinds of beauty to be found in nature is the changing colours of the autumn leaves, as I’m sure many of you would agree. How the fairly uniform green of the leaves can change to an array of colours on the same tree fascinates me, as does the variety of so many different autumnal colours between trees! But how and why do leaves actually change colour?
How and why do leaves change colour?
I’m sure I learnt this in biology, but I did have to have a little refresher to remind myself. I love going for a walk to admire the autumn leaves and all their colours as I briefly discussed yesterday. My favourite place to go so far has definitely been glorious Sheffield Park in Sussex. While it’s a 90 minute drive from us, it’s well worth it. I try to go for at least one leaf admiring walk every autumn. However, I don’t remember the last time that I looked at them and actually thought about the science behind the process!
Why leaves are green in summer
To understand why leaves change colour in the autumn, you need to understand why they’re green to begin with. What makes them green is a chemical called chlorophyll. The chlorophyll captures sunlight and transforms it into food for the tree, giving it the energy to grow. This process is called photosynthesis.
What happens to leaves in autumn
Autumn brings shorter and colder days, resulting in less sunlight for trees to photosynthesise with. Trees begin to break down the chlorophyll to get the nutrients out, safely storing them in their roots for the winter. When the chlorophyll is broken down, you see colours that you wouldn’t usually see because of the chlorophyll making them green. The autumn colours you see depend on the type of tree, as well as how the weather has been.
How is losing their leaves good for trees?
According to Helen Keating at the Woodland Trust, there are 2 benefits to trees shedding their leaves in autumn:
- Instead of withering out and dying, trees can preserve the moisture in their branches and trunks. Plus, without its leaves, a tree is in a dormant state where it doesn’t need to use as much energy to stay alive.
- Strong winds can move through branches more easily, making them more tolerable to winter storms.
I have a long history of hugging trees (check out the picture of me below from 2007!) The more I learn about them the more I love them.
